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1.
Proc Natl Acad Sci U S A ; 121(1): e2303423120, 2024 Jan 02.
Artículo en Inglés | MEDLINE | ID: mdl-38150501

RESUMEN

The ability to efficiently control charge and spin in the cuprate high-temperature superconductors is crucial for fundamental research and underpins technological development. Here, we explore the tunability of magnetism, superconductivity, and crystal structure in the stripe phase of the cuprate La[Formula: see text]Ba[Formula: see text]CuO[Formula: see text], with [Formula: see text] = 0.115 and 0.135, by employing temperature-dependent (down to 400 mK) muon-spin rotation and AC susceptibility, as well as X-ray scattering experiments under compressive uniaxial stress in the CuO[Formula: see text] plane. A sixfold increase of the three-dimensional (3D) superconducting critical temperature [Formula: see text] and a full recovery of the 3D phase coherence is observed in both samples with the application of extremely low uniaxial stress of [Formula: see text]0.1 GPa. This finding demonstrates the removal of the well-known 1/8-anomaly of cuprates by uniaxial stress. On the other hand, the spin-stripe order temperature as well as the magnetic fraction at 400 mK show only a modest decrease under stress. Moreover, the onset temperatures of 3D superconductivity and spin-stripe order are very similar in the large stress regime. However, strain produces an inhomogeneous suppression of the spin-stripe order at elevated temperatures. Namely, a substantial decrease of the magnetic volume fraction and a full suppression of the low-temperature tetragonal structure is found under stress, which is a necessary condition for the development of the 3D superconducting phase with optimal [Formula: see text]. Our results evidence a remarkable cooperation between the long-range static spin-stripe order and the underlying crystalline order with the three-dimensional fully coherent superconductivity. Overall, these results suggest that the stripe- and the SC order may have a common physical mechanism.

2.
Nature ; 571(7766): 541-545, 2019 07.
Artículo en Inglés | MEDLINE | ID: mdl-31341304

RESUMEN

Although the possibility of spatial variations in the superfluid of unconventional, strongly correlated superconductors has been suggested1-7, it is not known whether such inhomogeneities-if they exist-are driven by disorder, strong scattering or other factors. Here we use atomic-resolution Josephson scanning tunnelling microscopy to reveal a strongly inhomogeneous superfluid in the iron-based superconductor FeTe0.55Se0.45. By simultaneously measuring the topographic and electronic properties of the superconductor, we find that this inhomogeneity in the superfluid is not caused by structural disorder or strong inter-pocket scattering and is not correlated with variations in the energy required to break electron pairs. Instead, we see a clear spatial correlation between the superfluid density and the quasiparticle strength (the height of the coherence peak) on a local scale. This result places iron-based superconductors on equal footing with copper oxide superconductors, where a similar relation has been observed on the macroscopic scale. Our results establish the existence of strongly inhomogeneous superfluids in unconventional superconductors, excluding chemical disorder and inter-band scattering as the causes of the inhomogeneity, and shed light on the relation between quasiparticle character and superfluid density. When repeated at different temperatures, our technique could further help to elucidate what local and global mechanisms limit the critical temperature in unconventional superconductors.

3.
Nature ; 575(7781): 156-163, 2019 11.
Artículo en Inglés | MEDLINE | ID: mdl-31666697

RESUMEN

Although copper oxide high-temperature superconductors constitute a complex and diverse material family, they all share a layered lattice structure. This curious fact prompts the question of whether high-temperature superconductivity can exist in an isolated monolayer of copper oxide, and if so, whether the two-dimensional superconductivity and various related phenomena differ from those of their three-dimensional counterparts. The answers may provide insights into the role of dimensionality in high-temperature superconductivity. Here we develop a fabrication process that obtains intrinsic monolayer crystals of the high-temperature superconductor Bi2Sr2CaCu2O8+δ (Bi-2212; here, a monolayer refers to a half unit cell that contains two CuO2 planes). The highest superconducting transition temperature of the monolayer is as high as that of optimally doped bulk. The lack of dimensionality effect on the transition temperature defies expectations from the Mermin-Wagner theorem, in contrast to the much-reduced transition temperature in conventional two-dimensional superconductors such as NbSe2. The properties of monolayer Bi-2212 become extremely tunable; our survey of superconductivity, the pseudogap, charge order and the Mott state at various doping concentrations reveals that the phases are indistinguishable from those in the bulk. Monolayer Bi-2212 therefore displays all the fundamental physics of high-temperature superconductivity. Our results establish monolayer copper oxides as a platform for studying high-temperature superconductivity and other strongly correlated phenomena in two dimensions.

4.
Proc Natl Acad Sci U S A ; 119(39): e2211670119, 2022 Sep 27.
Artículo en Inglés | MEDLINE | ID: mdl-36126100

RESUMEN

The interplay between charge order and superconductivity remains one of the central themes of research in quantum materials. In the case of cuprates, the coupling between striped charge fluctuations and local electromagnetic fields is especially important, as it affects transport properties, coherence, and dimensionality of superconducting correlations. Here, we study the emission of coherent terahertz radiation in single-layer cuprates of the La2-xBaxCuO4 family, for which this effect is expected to be forbidden by symmetry. We find that emission vanishes for compounds in which the stripes are quasi-static but is activated when c-axis inversion symmetry is broken by incommensurate or fluctuating charge stripes, such as in La1.905Ba0.095CuO4 and in La1.845Ba0.155CuO4. In this case, terahertz radiation is emitted by surface Josephson plasmons, which are generally dark modes, but couple to free space electromagnetic radiation because of the stripe modulation.

5.
Artículo en Zh | MEDLINE | ID: mdl-37006143

RESUMEN

Objective: To investigate the level of psychosocial factors in workplace and their health effects among workers in a natural gas field. Methods: A prospective and open cohort of natural gas field workers was established to study the level of workplace psychosocial factors and their health effects, with a follow-up every 5 years. In October 2018, a cluster sampling method was used to conduct a baseline survey of 1737 workers in a natural gas field, including a questionnaire survey on demographic characteristics, workplace psychosocial factors and mental health outcomes, physiological indicators such as height and weight, and biochemical indicators such as blood routine, urine routine, liver function and kidney function. The baseline data of the workers were statistically described and analyzed. The psychosocial factors and mental health outcomes were divided into high and low groups according to the mean score, and the physiological and biochemical indicators were divided into normal and abnormal groups according to the reference range of normal values. Results: The age of 1737 natural gas field workers was (41.8±8.0) years old, and the length of service was (21.0±9.7) years. There were 1470 male workers (84.6%). There were 773 (44.5%) high school (technical secondary school) and 827 (47.6%) college (junior college) graduates, 1490 (85.8%) married (including remarriage after divorce), 641 (36.9%) smokers and 835 (48.1%) drinkers. Among the psychosocial factors, the detection rates of high levels of resilience, self-efficacy, colleague support and positive emotion were all higher than 50%. Among the mental health outcomes evaluation indexes, the detection rates of high levels of sleep disorder, job satisfaction and daily stress were 41.82% (716/1712), 57.25% (960/1677) and 45.87% (794/1731), respectively. The detection rate of depressive symptoms was 22.77% (383/1682). The abnormal rates of body mass index (BMI), triglyceride and low density lipoprotein were 46.74% (810/1733), 36.50% (634/1737) and 27.98% (486/1737), respectively. The abnormal rates of systolic blood pressure, diastolic blood pressure, uric acid, total cholesterol and blood glucose were 21.64% (375/1733), 21.41% (371/1733), 20.67% (359/1737), 20.55% (357/1737) and 19.17% (333/1737), respectively. The prevalence rates of hypertension and diabetes were 11.23% (195/1737) and 3.45% (60/1737), respectively. Conclusion: The detection rates of high level psychosocial factors in natural gas field workers are high, and their effects on physical and mental health remain to be verified. The establishment of a cohort study of the levels and health effects of psychosocial factors provides an important resource for confirming the causal relationship between workplace psychosocial factors and health.


Asunto(s)
Gas Natural , Yacimiento de Petróleo y Gas , Humanos , Masculino , Adulto , Persona de Mediana Edad , Estudios de Cohortes , Estudios Prospectivos , Lugar de Trabajo/psicología , Encuestas y Cuestionarios
6.
Nat Mater ; 20(3): 329-334, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33462464

RESUMEN

Dissipationless currents from topologically protected states are promising for disorder-tolerant electronics and quantum computation. Here, we photogenerate giant anisotropic terahertz nonlinear currents with vanishing scattering, driven by laser-induced coherent phonons of broken inversion symmetry in a centrosymmetric Dirac material ZrTe5. Our work suggests that this phononic terahertz symmetry switching leads to formation of Weyl points, whose chirality manifests in a transverse, helicity-dependent current, orthogonal to the dynamical inversion symmetry breaking axis, via circular photogalvanic effect. The temperature-dependent topological photocurrent exhibits several distinct features: Berry curvature dominance, particle-hole reversal near conical points and chirality protection that is responsible for an exceptional ballistic transport length of ~10 µm. These results, together with first-principles modelling, indicate two pairs of Weyl points dynamically created by B1u phonons of broken inversion symmetry. Such phononic terahertz control breaks ground for coherent manipulation of Weyl nodes and robust quantum transport without application of static electric or magnetic fields.

7.
Proc Natl Acad Sci U S A ; 116(40): 19875-19879, 2019 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-31527271

RESUMEN

Quantum materials are amenable to nonequilibrium manipulation with light, enabling modification and control of macroscopic properties. Light-based augmentation of superconductivity is particularly intriguing. Copper-oxide superconductors exhibit complex interplay between spin order, charge order, and superconductivity, offering the prospect of enhanced coherence by altering the balance between competing orders. We utilize terahertz time-domain spectroscopy to monitor the c-axis Josephson plasma resonance (JPR) in La2-xBaxCuO4 (x = 0.115) as a direct probe of superconductivity dynamics following excitation with near-infrared pulses. Starting from the superconducting state, c-axis polarized excitation with a fluence of 100 µJ/cm2 results in an increase of the far-infrared spectral weight by more than an order of magnitude as evidenced by a blueshift of the JPR, interpreted as resulting from nonthermal collapse of the charge order. The photoinduced signal persists well beyond our measurement window of 300 ps and exhibits signatures of spatial inhomogeneity. The electrodynamic response of this metastable state is consistent with enhanced superconducting fluctuations. Our results reveal that La2-xBaxCuO4 is highly sensitive to nonequilibrium excitation over a wide fluence range, providing an unambiguous example of photoinduced modification of order-parameter competition.

8.
Proc Natl Acad Sci U S A ; 116(22): 10691-10697, 2019 May 28.
Artículo en Inglés | MEDLINE | ID: mdl-31085657

RESUMEN

With the discovery of charge-density waves (CDWs) in most members of the cuprate high-temperature superconductors, the interplay between superconductivity and CDWs has become a key point in the debate on the origin of high-temperature superconductivity. Some experiments in cuprates point toward a CDW state competing with superconductivity, but others raise the possibility of a CDW-superconductivity intertwined order or more elusive pair-density waves (PDWs). Here, we have used proton irradiation to induce disorder in crystals of [Formula: see text] and observed a striking 50% increase of [Formula: see text], accompanied by a suppression of the CDWs. This is in sharp contrast with the behavior expected of a d-wave superconductor, for which both magnetic and nonmagnetic defects should suppress [Formula: see text] Our results thus make an unambiguous case for the strong detrimental effect of the CDW on bulk superconductivity in [Formula: see text] Using tunnel diode oscillator (TDO) measurements, we find indications for potential dynamic layer decoupling in a PDW phase. Our results establish irradiation-induced disorder as a particularly relevant tuning parameter for the many families of superconductors with coexisting density waves, which we demonstrate on superconductors such as the dichalcogenides and [Formula: see text].

9.
Zhonghua Yu Fang Yi Xue Za Zhi ; 56(8): 1087-1094, 2022 Aug 06.
Artículo en Zh | MEDLINE | ID: mdl-35922236

RESUMEN

Objective: To explore the relationship between DNA methylation and occupational noise-induced hearing loss. Methods: A case-control study was conducted. People with hearing loss induced by occupational noise were recruited as the case group and those with normal hearing but still exposed to occupational noise were recruited as the control group. A total of 60 participants were included, of which 30 participants were in the case group and 30 in the control group. The methylation level was detected by 850k genome-wide DNA methylation chip technology. The significance of differential methylated position (DMP) was tested by R-packet 'Champ'. The differential methylated region (DMR) was analyzed by using Champ's Bumphunter algorithm. Cluster profiler was used to analyze the gene list for GO and KEGG pathway enrichment. Results: There was significant difference between two groups in binaural high-frequency average hearing threshold (P<0.05), but there was no significant difference in age, smoking, drinking, hypertension, physical exercise and cumulative noise exposure. The results of DMP and DMR analysis showed that 713875 sites were detected in the case group and the control group, and 439 methylation sites with significant difference, accounting for 0.06%; 650 regions were detected, and 72 methylation regions with significant differences, accounting for 11.08%. Compared with the control group, the results of GO enrichment analysis showed that the case group had statistically significant differences in four pathways: axogenesis of projection neurons in the central nervous system, neuronal development in the central nervous system, axogenesis of neurons in the central nervous system and neuronal differentiation in the central nervous system. KEGG enrichment analysis showed that there were significant differences in sphingolipid metabolism, aldosterone synthesis and secretion, primary bile acid biosynthesis pathway between the case group and the control group. Conclusion: The occurrence of occupational noise-induced hearing loss may be related to the regulation of gene expression related to axogenesis of projection neurons in the central nervous system, development of neurons in the central nervous system, axogenesis of neurons in the central nervous system, differentiation of neurons in the central nervous system, sphingolipid metabolism, aldosterone synthesis and secretion, primary bile acid biosynthesis and gene methylation related to metabolism.


Asunto(s)
Pérdida Auditiva Provocada por Ruido , Ruido en el Ambiente de Trabajo , Enfermedades Profesionales , Exposición Profesional , Aldosterona , Ácidos y Sales Biliares , Estudios de Casos y Controles , Metilación de ADN , Pérdida Auditiva Provocada por Ruido/epidemiología , Pérdida Auditiva Provocada por Ruido/genética , Humanos , Ruido en el Ambiente de Trabajo/efectos adversos , Esfingolípidos
10.
Proc Natl Acad Sci U S A ; 115(21): 5392-5396, 2018 05 22.
Artículo en Inglés | MEDLINE | ID: mdl-29735712

RESUMEN

A central mystery in high-temperature superconductivity is the origin of the so-called strange metal (i.e., the anomalous conductor from which superconductivity emerges at low temperature). Measuring the dynamic charge response of the copper oxides, [Formula: see text], would directly reveal the collective properties of the strange metal, but it has never been possible to measure this quantity with millielectronvolt resolution. Here, we present a measurement of [Formula: see text] for a cuprate, optimally doped Bi2.1Sr1.9CaCu2O8+x (Tc = 91 K), using momentum-resolved inelastic electron scattering. In the medium energy range 0.1-2 eV relevant to the strange metal, the spectra are dominated by a featureless, temperature- and momentum-independent continuum persisting to the electronvolt energy scale. This continuum displays a simple power-law form, exhibiting q2 behavior at low energy and q2/ω2 behavior at high energy. Measurements of an overdoped crystal (Tc = 50 K) showed the emergence of a gap-like feature at low temperature, indicating deviation from power law form outside the strange-metal regime. Our study suggests the strange metal exhibits a new type of charge dynamics in which excitations are local to such a degree that space and time axes are decoupled.

11.
Zhonghua Zhong Liu Za Zhi ; 43(8): 821-826, 2021 Aug 23.
Artículo en Zh | MEDLINE | ID: mdl-34407585

RESUMEN

Objective: To analyze the expression pattern, mechanism and clinical significance of melanoma-associated antigen-C2 (MAGE-C2) in tumor-free breast specimens, breast benign disease specimens and breast cancer specimens. Methods: Reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry were used to investigate the expressions of MAGE-C2 in 60 tumor-free breast specimens, 60 breast benign disease specimens and 60 breast cancer specimens. The correlation of MAGE-C2 expression with clinicopathological parameters and prognosis of breast cancer patients were analyzed. The expression of MAGE-C2 was also detected by RT-PCR in breast cancer cell MCF-7 and MDA-MB-231 treated with DNA methylase inhibitor 5-aza-2'-deoxycytidine (5-aza-CdR) and histone deacetylase inhibitor trichostatin A (TSA). Results: The positive expression rates of MAGE-C2 mRNA and protein were 61.7% (37/60) and 58.3% (35/60) in breast cancer specimens, respectively, while negative expressed in breast and begin disease specimens. MAGE-C2 protein expression was associated with tumor grade, histological type and blood vessel invasion of breast cancer patients (P<0.05). The incidence of recurrence-free survival of patients with positive MAGE-C2 expression were lower than that of patients with negative MAGE-C2 expression (P<0.05). Multivariate Cox regression analysis showed that the clinical stage (P<0.01), lymph node metastasis (P<0.05) and MAGE-C2 expression (P<0.05) were the independent prognostic factors of breast cancer patients. The MAGE-C2 mRNA was not observed in the control and TSA treated breast cancer cells while upregulated in the 5-aza-CdR treated cells. Besides, 5-aza-CdR combined with TSA further enhanced MAGE-C2 mRNA level in breast cancer cells (P<0.05). Conclusions: MAGE-C2 is one of the tumor-specific antigen and its expression is related with the poor prognosis of breast cancer patients. DNA methylation and histone acetylation may be an important regulation mechanism of MAGE-C2 gene expression.


Asunto(s)
Neoplasias de la Mama , Melanoma , Azacitidina/farmacología , Neoplasias de la Mama/genética , Decitabina/farmacología , Femenino , Inhibidores de Histona Desacetilasas/farmacología , Humanos
12.
Artículo en Zh | MEDLINE | ID: mdl-34488263

RESUMEN

Objective: To explore the occurrence level of depressive symptoms and it's influencing factors among gas field workers. Methods: In October 2018, a cross-sectional study was conducted in 1726 gas field workers from a gas field by using cluster sampling method. Questionaire was used to evaluate the individual factors, depressive symptoms, occupational stress factors and stress regulatory factors. The correlation between depressive symptoms and occupational stress was analyzed. Multivariate logistic regression was used to analyze the influencing factors of depressive symptoms. Results: The depressive symptoms score of gas field workers was 12.00 (7.00, 19.00) point. Correlation analysis revealed that depressive symptoms score was positively related to sleep disorders (r=0.598) , effort (r=0.186) , daily tension (r=0.478) , negative affectivity (r=0.565) , social support (r=0.446) and monotony of work (r=0.484) (P<0.01) . And it was negatively related to reward (r=-0.386) , work stability (r=-0.294) , promotion opportunities (r=-0.258) , positive affectivity (r= -0.310) , self-efficacy (r=-0.312) , contral strategy (r=-0.268) , support strategy (r=-0.209) and job satisfaction (r=-0.398) (P<0.01) . Multivariate logistic regression analysis revealed that sleep disorder, high negative affectivity, low support from colleagues, low support from family, high monotony of work and high daily tension were the risk factors for depressive symptoms of gas field worker (OR=3.423, 95%CI: 2.644-4.397; OR=2.847, 95%CI: 2.200-3.683; OR=1.646, 95%CI: 1.215-2.116; OR=1.496, 95%CI: 1.164-1.923; OR=1.578, 95%CI: 1.227-2.303; OR=1.903, 95%CI: 1.480-2.440; P<0.01) . High work stability, high self-efficacy and high job satisfaction were protective factors for depressive symptoms of gas field workers (OR=0.752, 95%CI: 0.591-0.958; OR=0.590, 95%CI: 0.465-0.749; OR=0.718, 95%CI: 0.516-0.999; P<0.05) . Conclusion: Occupational stress factors have a great influence on the depressive symptoms of gas field workers. Increased work stability, self-efficacy and job satisfaction could reduce the risk of depressive symptoms.


Asunto(s)
Depresión , Estrés Laboral , Estudios Transversales , Depresión/epidemiología , Humanos , Satisfacción en el Trabajo , Estrés Laboral/epidemiología , Yacimiento de Petróleo y Gas , Estrés Psicológico , Encuestas y Cuestionarios
13.
Phys Rev Lett ; 124(20): 207005, 2020 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-32501068

RESUMEN

The discovery of charge-density-wave-related effects in the resonant inelastic x-ray scattering spectra of cuprates holds the tantalizing promise of clarifying the interactions that stabilize the electronic order. Here, we report a comprehensive resonant inelastic x-ray scattering study of La_{2-x}Sr_{x}CuO_{4} finding that charge-density wave effects persist up to a remarkably high doping level of x=0.21 before disappearing at x=0.25. The inelastic excitation spectra remain essentially unchanged with doping despite crossing a topological transition in the Fermi surface. This indicates that the spectra contain little or no direct coupling to electronic excitations near the Fermi surface, rather they are dominated by the resonant cross section for phonons and charge-density-wave-induced phonon softening. We interpret our results in terms of a charge-density wave that is generated by strong correlations and a phonon response that is driven by the charge-density-wave-induced modification of the lattice.

14.
Proc Natl Acad Sci U S A ; 114(5): 816-821, 2017 01 31.
Artículo en Inglés | MEDLINE | ID: mdl-28096330

RESUMEN

Three-dimensional topological insulators (3D TIs) represent states of quantum matters in which surface states are protected by time-reversal symmetry and an inversion occurs between bulk conduction and valence bands. However, the bulk-band inversion, which is intimately tied to the topologically nontrivial nature of 3D Tis, has rarely been investigated by experiments. Besides, 3D massive Dirac fermions with nearly linear band dispersions were seldom observed in TIs. Recently, a van der Waals crystal, ZrTe5, was theoretically predicted to be a TI. Here, we report an infrared transmission study of a high-mobility [∼33,000 cm2/(V ⋅ s)] multilayer ZrTe5 flake at magnetic fields (B) up to 35 T. Our observation of a linear relationship between the zero-magnetic-field optical absorption and the photon energy, a bandgap of ∼10 meV and a [Formula: see text] dependence of the Landau level (LL) transition energies at low magnetic fields demonstrates 3D massive Dirac fermions with nearly linear band dispersions in this system. More importantly, the reemergence of the intra-LL transitions at magnetic fields higher than 17 T reveals the energy cross between the two zeroth LLs, which reflects the inversion between the bulk conduction and valence bands. Our results not only provide spectroscopic evidence for the TI state in ZrTe5 but also open up a new avenue for fundamental studies of Dirac fermions in van der Waals materials.

15.
Proc Natl Acad Sci U S A ; 114(47): 12430-12435, 2017 11 21.
Artículo en Inglés | MEDLINE | ID: mdl-29114049

RESUMEN

Although all superconducting cuprates display charge-ordering tendencies, their low-temperature properties are distinct, impeding efforts to understand the phenomena within a single conceptual framework. While some systems exhibit stripes of charge and spin, with a locked periodicity, others host charge density waves (CDWs) without any obviously related spin order. Here we use resonant inelastic X-ray scattering to follow the evolution of charge correlations in the canonical stripe-ordered cuprate La1.875Ba0.125CuO4 across its ordering transition. We find that high-temperature charge correlations are unlocked from the wavevector of the spin correlations, signaling analogies to CDW phases in various other cuprates. This indicates that stripe order at low temperatures is stabilized by the coupling of otherwise independent charge and spin density waves, with important implications for the relation between charge and spin correlations in the cuprates.

16.
Nano Lett ; 19(2): 1112-1117, 2019 02 13.
Artículo en Inglés | MEDLINE | ID: mdl-30698977

RESUMEN

In pursuit of the elusive mechanism of high- T C superconductors (HTSC), spectroscopic imaging scanning tunneling microscopy (SI-STM) is an indispensable tool for surveying local properties of HTSC. Since a conventional STM utilizes metal tips, which allow the examination of only quasiparticles and not superconducting (SC) pairs, Josephson tunneling using STM has been demonstrated by many authors in the past. An atomically resolved scanning Josephson tunneling microscopy (SJTM), however, was realized only recently on Bi2Sr2CaCu2O8+ x (Bi-2212) below 50 mK and on the Pb(110) surface at 20 mK. Here we report the atomically resolved SJTM on Bi2Sr2CaCu2O8+ x at 4.2 K using Bi-2212 tips created in situ. The I- V characteristics show clear zero bias conductance peaks following Ambegaokar-Baratoff (AB) theory. A gap map was produced for the first time using an atomically resolved Josephson critical current map I C( r) and AB theory. Surprisingly, we found that this new gap map is anticorrelated to the gap map produced by a conventional method relying on the coherence peaks. Quasiparticle resonance due to a single isolated zinc atom impurity was also observed by SJTM, indicating that atomically resolved SJTM was achieved at 4.2 K. Our result provides a starting point for realizing SJTM at even higher temperatures, rendering possible investigation of the existence of SC pairs in HTSC above the T C.

17.
Nano Lett ; 19(8): 4890-4896, 2019 Aug 14.
Artículo en Inglés | MEDLINE | ID: mdl-31268723

RESUMEN

Combining topology and superconductivity provides a powerful tool for investigating fundamental physics as well as a route to fault-tolerant quantum computing. There is mounting evidence that the Fe-based superconductor FeTe0.55Se0.45 (FTS) may also be topologically nontrivial. Should the superconducting order be s±, then FTS could be a higher order topological superconductor with helical hinge zero modes (HHZMs). To test the presence of these modes, we have fabricated normal-metal/superconductor junctions on different surfaces via 2D atomic crystal heterostructures. As expected, junctions in contact with the hinge reveal a sharp zero bias anomaly that is absent when tunneling purely into the c-axis. Additionally, the shape and suppression with temperature are consistent with highly coherent modes along the hinge and are incongruous with other origins of zero bias anomalies. Additional measurements with soft-point contacts in bulk samples with various Fe interstitial contents demonstrate the intrinsic nature of the observed mode. Thus, we provide evidence that FTS is indeed a higher order topological superconductor.

18.
Zhonghua Yu Fang Yi Xue Za Zhi ; 54(11): 1202-1206, 2020 Nov 06.
Artículo en Zh | MEDLINE | ID: mdl-33147917

RESUMEN

Objective: To explore the correlation of job monotony and social support on daily hassle. Methods: A convenient sampling survey of demographics characteristics, job monotony, social support and daily hassle was conducted on 1 466 natural gas field workers by questionnaire in October; 2018. Multivariate logistic regression model was used to analyze the correlation of job monotony and social support on daily hassle. Results: The age of 1 466 subjects was (44.47±8.0) years and the length of service was (20.46±5.77) years. There were 258(17.6%), 173(11.8%), 799(54.5%), 120(8.2%) and 116(7.9%) subjects from production and marketing department, processing plant, branch, maintenance department and emergency center respectively. There were 374(25.5%) and 1 092(74.5%) subjects with high and low level of job monotony, and 398(27.1%), 648(44.2%) and 420(28.6%) subjects with high, middle and low level of social support. There were 464(31.7%) and 1 002(68.3%) subjects with high and low daily tension respectively. Compared with the low level of job monotony, the high level of job monotony had a higher risk of daily hassle(OR=4.83,P<0.001), and compared with the high level of social support, the middle and low level of social support had a higher risk of daily hassle(OR=1.25, 2.24,P<0.05). Conclusion: Job monotony and social support were associated with daily hassle.


Asunto(s)
Gas Natural , Estrés Psicológico , Estudios Transversales , Humanos , Satisfacción en el Trabajo , Apoyo Social , Encuestas y Cuestionarios
19.
Zhonghua Yu Fang Yi Xue Za Zhi ; 54(11): 1213-1219, 2020 Nov 06.
Artículo en Zh | MEDLINE | ID: mdl-33147919

RESUMEN

Objective: To explore the interaction between shift work and psychological capital on abnormal glucose and lipid metabolism. Methods: A convenient sampling survey of demographics characteristics, shift work and psychological capital was conducted on 1 415 natural gas field workers by questionnaire in October 2018,and their physiological and biochemical indexes were measured according to standard norms. Multivariate logistic regression model was used to analyze the interaction between shift work and psychological capital on abnormal glucose and lipid metabolism. Results: For 1 415 subjectsthe prevalence of abnormal blood glucose was 21.2%, the prevalence of diabetes was 8.3%.The prevalence of abnormal total cholesterol was 40.4%, the prevalence of hypercholesterolemia was 11.3%.The prevalence of abnormal triglyceride was 41.6%, the prevalence of hypertriglyceridemia was 24.7%.The detection rate of Low-density Lipoprotein was 17.3%, the detection rate of Low-density Lipoprotein was 4.0%, and the detection rate of high-density Lipoprotein was 1.3%. Multiple logistic regression model analysis showed that shift work, the low level of self-efficacy and the low level of optimism was positively associated with abnormal blood glucose, respectively (P<0.05). Shift work was positively associated with abnormal triglyceride (P<0.05). However, there was no interaction between shift work, low self-efficacy, low hope, low resilience, and low optimism on abnormal glucose and lipid metabolism. Conclusion: Shift work was a risk factor of abnormal blood glucose and triglyceride, self-efficacy and optimism were protective factors of abnormal blood glucose. There was no multiplicative interaction between shift work and psychological capital on abnormal glucose and lipid metabolism in the study population.


Asunto(s)
Hipertrigliceridemia , Horario de Trabajo por Turnos , Glucemia , Glucosa , Humanos , Metabolismo de los Lípidos , Gas Natural
20.
Artículo en Zh | MEDLINE | ID: mdl-32306678

RESUMEN

Objective: Through the investigation of the injured persons in explosion accidents, the impact of wearing the ear protectors device (anti-noise earplugs) on the auditory organs and hearing loss of the injured person was understood, which could provide reference for the clinical diagnosis, treatment and prevention of the explosive hearing impairment. Methods: A retrospective survey was conducted on 39 directly injured persons who were injured in 23 explosion accidents involving a steel plant from 1990 to 2016 as the explosive hearing loss, taking the time of the patient's injury and 3-6 months after the injury as the time of investigation and evidence collection, and according to whether to wear the ear protectors device for group comparison and statistical analysis. Results: There was no significant difference between the two groups in hearing loss, tinnitus, earache, headache, some patients with dizziness and craniocerebral injury, regardless of whether the injured person wore anti-noise earplugs or not (P=0.444-1) , the shock (coma) patients in the non-protected group were more common (34.8%, 8/23) , and the difference was statistically significant (P=0.012) ; Although auricle injury was detected in both groups and there was no significant difference between the two groups (P=1) , but the external ear canal injury, tympanic membrane perforation were more common in the non-protected group, and there was no external ear canal and tympanic membrane perforation in the wearing earplug group, and the difference between the two groups was significant (P=0.000) . After 3-6 months, the rehabilitation of auditory system and other symptoms in patients showed that the hearing loss, tinnitus, earache, headache, dizziness and other symptoms all disappeared in patients wearing earplugs, while the above symptoms in the non-protected group were improved but more persisted, and the difference between the two groups was statistically significant (P=0.000-0.012) , and there was no significant difference in rehabilitation conditions such as craniocerebral injury between the two groups (P=1) ; There were patients with unhealed auricle injury in both groups in 3-6 months after the injury, and there was no significant difference between the two groups (P=1) , however, in the non-protected group, 69.57% (16/23) of the patients with external auditory canal injury were still unhealed and none of the patients with tympanic membrane perforation recovered, and the difference between the two groups was obvious (P=0.000~0.001) ; Pure tone air conduction examination showed that the hearing of the earplugs wearers was well recovered at the time of the explosion, while irreversible hearing impairment was common in the non-protective group, the difference was statistically significant (P=0.000) . Conclusion: Ear protector plays an important role in protecting the auditory organs and hearing of workers in explosion accident, and it is an effective protective measure to prevent and reduce the damage of external ear canal, perforation of tympanic membrane and explosive hearing loss caused by explosion accidents.


Asunto(s)
Accidentes de Trabajo , Explosiones , Pérdida Auditiva Provocada por Ruido , Metalurgia , Dispositivos de Protección de los Oídos , Pérdida Auditiva Provocada por Ruido/prevención & control , Humanos , Estudios Retrospectivos , Acero
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