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1.
Nature ; 628(8007): 313-319, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38570689

RESUMEN

Transition metal tellurides (TMTs) have been ideal materials for exploring exotic properties in condensed-matter physics, chemistry and materials science1-3. Although TMT nanosheets have been produced by top-down exfoliation, their scale is below the gram level and requires a long processing time, restricting their effective application from laboratory to market4-8. We report the fast and scalable synthesis of a wide variety of MTe2 (M = Nb, Mo, W, Ta, Ti) nanosheets by the solid lithiation of bulk MTe2 within 10 min and their subsequent hydrolysis within seconds. Using NbTe2 as a representative, we produced more than a hundred grams (108 g) of NbTe2 nanosheets with 3.2 nm mean thickness, 6.2 µm mean lateral size and a high yield (>80%). Several interesting quantum phenomena, such as quantum oscillations and giant magnetoresistance, were observed that are generally restricted to highly crystalline MTe2 nanosheets. The TMT nanosheets also perform well as electrocatalysts for lithium-oxygen batteries and electrodes for microsupercapacitors (MSCs). Moreover, this synthesis method is efficient for preparing alloyed telluride, selenide and sulfide nanosheets. Our work opens new opportunities for the universal and scalable synthesis of TMT nanosheets for exploring new quantum phenomena, potential applications and commercialization.

2.
Small ; : e2401384, 2024 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-38940385

RESUMEN

Understanding the reconstruction mechanism to rationally design cost-effective electrocatalysts for oxygen evolution reaction (OER) is still challenging. Herein, a defect-rich NiMoO4 precatalyst is used to explore its OER activity and reconstruction mechanism. In situ generated oxygen vacancies, distorted lattices, and edge dislocations expedite the deep reconstruction of NiMoO4 to form polycrystalline Ni (oxy)hydroxides for alkaline oxygen evolution. It only needs ≈230 and ≈285 mV to reach 10 and 100 mA cm-2, respectively. The reconstruction boosted by the redox of Ni is confirmed experimentally by sectionalized cyclic voltammetry activations at different specified potential ranges combined with ex situ characterization techniques. Subsequently, the reconstruction route is presented based on the acid-base electronic theory. Accordingly, the dominant contribution of the adsorbate evolution mechanism to reconstruction during oxygen evolution is revealed. This work develops a novel route to synthesize defect-rich materials and provides new tactics to investigate the reconstruction.

3.
Glob Chang Biol ; 30(1): e17141, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38273520

RESUMEN

Droughts have been implicated as the main driver behind recent vegetation die-off and are projected to drive greater mortality under future climate change. Understanding the coupling relationship between vegetation and drought has been of great global interest. Currently, the coupling relationship between vegetation and drought is mainly evaluated by correlation coefficients or regression slopes. However, the optimal drought timescale of vegetation response to drought, as a key indicator reflecting vegetation sensitivity to drought, has largely been ignored. Here, we apply the optimal drought timescale identification method to examine the change in coupling between vegetation and drought over the past three decades (1982-2015) with long-term satellite-derived Normalized Difference Vegetation Index and Standardized Precipitation-Evapotranspiration Index data. We find substantial increasing response of vegetation to drought timescales globally, and the correlation coefficient between vegetation and drought under optimal drought timescale overall declines between 1982 and 2015. This decrease in vegetation-drought coupling is mainly observed in regions with water deficit, although its initial correlation is relatively high. However, vegetation in water-surplus regions, with low coupling in earlier stages, is prone to show an increasing trend. The observed changes may be driven by the increasing trend of atmospheric CO2 . Our findings highlight more pressing drought risk in water-surplus regions than in water-deficit regions, which advances our understanding of the long-term vegetation-drought relationship and provides essential insights for mapping future vegetation sensitivity to drought under changing climate conditions.


Asunto(s)
Cambio Climático , Sequías , Agua , Ecosistema , China
4.
Angew Chem Int Ed Engl ; 63(3): e202316903, 2024 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-37997556

RESUMEN

Proton exchange membrane water electrolysis is a highly promising hydrogen production technique for sustainable energy supply, however, achieving a highly active and durable catalyst for acidic water oxidation still remains a formidable challenge. Herein, we propose a local microenvironment regulation strategy for precisely tuning In-RuO2 /graphene (In-RuO2 /G) catalyst with intrinsic electrochemical activity and stability to boost acidic water oxidation. The In-RuO2 /G displays robust acid oxygen evolution reaction performance with a mass activity of 671 A gcat -1 at 1.5 V, an overpotential of 187 mV at 10 mA cm-2 , and long-lasting stability of 350 h at 100 mA cm-2 , which arises from the asymmetric Ru-O-In local structure interactions. Further, it is unraveled theoretically that the asymmetric Ru-O-In structure breaks the thermodynamic activity limit of the traditional adsorption evolution mechanism which significantly weakens the formation energy barrier of OOH*, thus inducing a new rate-determining step of OH* absorption. Therefore, this strategy showcases the immense potential for constructing high-performance acidic catalysts for water electrolyzers.

5.
Neurosurg Rev ; 46(1): 311, 2023 Nov 23.
Artículo en Inglés | MEDLINE | ID: mdl-37993665

RESUMEN

PURPOSE: This study aimed to identify prognostic factors associated with survival in patients with high-grade glioma (HGG) after leptomeningeal spread (LMS) and to clarify the behavior and treatment response. METHODS: This retrospective study included 114 patients with HGGs diagnosed with LMS from August 1, 2014, to July 30, 2021, at our institution. Clinical, radiological, pathological, and outcome data were collected. Univariable and multivariable Cox regression were used for overall survival (OS) and post-LMS survival (PLS) analysis. RESULTS: The median OS was 17.0 months and the median PLS was 6.0 months. Gross total resection (GTR) after LMS diagnosis and pathology grade III were statistically significantly associated with longer OS in all patients. GTR after LMS diagnosis and nodular LMS were independent favorable prognostic factors on PLS. Non-adjuvant therapy after LMS diagnosis was associated with shorter OS and PLS. In glioblastoma (GBM) subgroup analysis, GTR after LMS diagnosis and secondary LMS were independent favorable prognostic factors on OS. Karnofsky Performance Status (KPS) of ≥80 at LMS diagnosis, chemotherapy after LMS and intrathecal methotrexate (MTX) treatment were statistically significantly associated with longer PLS. MRI type II was a predictor of shorter PLS. CONCLUSION: The treatment of patients with glioma after LMS diagnosis is very challenging and limited. Safe GTR of tumor and subsequent adjuvant therapy after LMS remains a powerful weapon to improve survival for HGG patients with LMS. Chemotherapy and Intrathecal MTX treatment are feasible treatments after LMS. The extent of tumor dissemination may affect the survival after LMS.


Asunto(s)
Neoplasias Encefálicas , Glioblastoma , Glioma , Humanos , Estudios Retrospectivos , Neoplasias Encefálicas/cirugía , Neoplasias Encefálicas/tratamiento farmacológico , Glioma/cirugía , Terapia Combinada
6.
Neurosurg Rev ; 47(1): 17, 2023 Dec 19.
Artículo en Inglés | MEDLINE | ID: mdl-38112846

RESUMEN

Primary central nervous system lymphoma (PCNSL) is a rare and highly aggressive type of extranodal non-Hodgkin lymphoma (NHL), and the prognosis is poor. Currently, the most used prognostic models are the Memorial Sloan-Kettering Cancer Center (MSKCC) and International Extranodal Lymphoma Study Group (IELSG) scores; however, their predictive effects are changing with increasing incidence and changing treatment regimens. A growing body of evidence has demonstrated that inflammatory and nutritional markers are factors that can determine tumor prognosis. Therefore, the aim of this study was to identify and validate novel prognostic factors for PCNSL. Clinical information was collected from 223 patients with PCNSL. Patients younger than 18 years of age were excluded. Progression-free survival (PFS) and overall survival (OS) were used as endpoints, and receiver operating characteristic (ROC) curve analyses were conducted to determine the cutoff values for the inflammatory indicators. Correlations between variables and PFS or OS were assessed using univariate and multivariate analyses, and positive indicators were selected for survival analysis. A prognostic nutritional index (PNI) < 49.38 was associated with worse PFS (p = 0.003), and outcomes significantly differed between patients with a PNI ≥ 49.38 and < 49.38 (p < 0.001). Age < 60 years (p < 0.001) and C-reactive protein (CRP) levels < 3.14 (p = 0.001) were associated with better OS. In elderly patients (≥ 60 years), a lactate dehydrogenase-to-lymphocyte ratio (LLR) < 95.69 (p = 0.021) was associated with better OS, and the outcome significantly differed between patients with an LLR ≥ 95.69 and LLR < 95.69 (p = 0.015). The PNI and CRP levels are prognostic factors for PCNSL, and CRP was the first time shown to be a prognosis factor of PCNSL. In elderly patients with PCNSL, the LLR can predict prognosis.


Asunto(s)
Linfoma , Evaluación Nutricional , Humanos , Anciano , Persona de Mediana Edad , Pronóstico , Proteína C-Reactiva , Linfocitos , Linfoma/diagnóstico , Sistema Nervioso Central , Lactato Deshidrogenasas , Estudios Retrospectivos
7.
J Environ Manage ; 330: 117115, 2023 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-36587549

RESUMEN

Natural capital is a constraint on sustainable development goals. There are multiple methods available for natural capital accounting, many of which are inconsistent with each other in accounting items. Another common defect is an inability to represent both physical and monetary quantities. To address these issues, we integrated the ecological footprint and ecosystem service methods by introducing ecosystem service equivalence factors that facilitate the formulation of a standardized and flexible natural capital accounting framework. Adopting the provinces along the Silk Road Economic Belt (SREB) in China as the target research area, this study calculated and analyzed the spatiotemporal evolution of natural capital utilization and ecological pressure from 2000 to 2020. The results revealed that the supply of natural capital in China's SREB cannot meet consumer demands, resulting in the expansion of the ecological deficits. From 2000 to 2020, the physical and monetary quantities of ecological footprint per capita in the SREB increased by 2.51 and 3.66 times and the ecological carrying capacity per capita decreased by 6.81% in physical terms, gradually increasing by 59.93% in monetary terms. The physical and monetary quantities of ecological deficit per capita continued expanding negatively, at rates of -0.133 nha/cap/yr and -299.837 CNY/cap/yr, respectively. Integrating the physical and monetary dimensions, the sustainability of natural capital in China's SREB was weakening, and the ecological pressure was increasing step by step, from the low-relatively low (L-RL) class to the relatively high-relatively high (RH-RH) class. Ningxia, Chongqing, Shaanxi, Guangxi and Xinjiang were the provinces facing the greatest ecological challenges along the SREB in China, while Qinghai faced the least ecological pressure. These findings provide a reference for the scientific utilization and management of natural capital in provinces along the SREB in China. Additionally, the proposed framework enriches the interactive research achievements of ecological footprint and ecosystem service theories, in ways that not only compensate for the lack of monetary quantity in the ecological footprint, but also have the potential to serve the compilation of China's government-mandated Natural Resource Balance Sheet.


Asunto(s)
Conservación de los Recursos Naturales , Ecosistema , China , Desarrollo Sostenible , Gobierno , Desarrollo Económico
8.
Angew Chem Int Ed Engl ; 62(6): e202214372, 2023 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-36480194

RESUMEN

Metallic Na is a promising metal anode for large-scale energy storage. Nevertheless, unstable solid electrolyte interphase (SEI) and uncontrollable Na dendrite growth lead to disastrous short circuit and poor cycle life. Through phase field and ab initio molecular dynamics simulation, we first predict that the sodium bromide (NaBr) with the lowest Na ion diffusion energy barrier among sodium halogen compounds (NaX, X=F, Cl, Br, I) is the ideal SEI composition to induce the spherical Na deposition for suppressing dendrite growth. Then, 1,2-dibromobenzene (1,2-DBB) additive is introduced into the common fluoroethylene carbonate-based carbonate electrolyte (the corresponding SEI has high mechanical stability) to construct a desirable NaBr-rich stable SEI layer. When the Na||Na3 V2 (PO4 )3 cell utilizes the electrolyte with 1,2-DBB additive, an extraordinary capacity retention of 94 % is achieved after 2000 cycles at a high rate of 10 C. This study provides a design philosophy for dendrite-free Na metal anode and can be expanded to other metal anodes.

9.
Small ; 18(29): e2200678, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-35754164

RESUMEN

The prosperity of smart portable microdevices urgently requires an advanced integrated microsystem equipped with cost-effective safe microbatteries and ultra-stable sensitive sensors. However, the practical application of smart microdevices is limited by complex active materials with single function. Here, the two-dimensional (2D) mesoporous nanosheets of polyaniline decorated on graphene with large specific surface area of 141 m2  g-1 , ample active sites, comparable conductivity, and ordered mesopores of 18 nm for a new-type co-planar integrated microsystem of zinc ion microbattery and gas sensor are developed. These unique triple-function mesoporous nanosheets are well proved for dendrite-free zinc anode with long cyclability (>500 h) and small overpotential (48 mV), a high performance cathode of zinc ion microbattery with outstanding volumetric capacity of 78 mAh cm-3 outperforming their counterparts reported, and a highly sensitive gas sensor with a resistance response (ΔR/R0 %) of 118% for 20 ppm NH3 . Moreover, the co-planar battery-sensor integrated microsystem exhibits superior mechanical stability and smart integration. Therefore, this work will open many opportunities to develop multifunctional 2D mesoporous materials for high performance smart integrated microsystems.

10.
Small ; 18(5): e2104506, 2022 02.
Artículo en Inglés | MEDLINE | ID: mdl-34837671

RESUMEN

Pursuing high areal energy density and developing scalable fabrication strategies of micro-batteries are the key for the progressive printed microelectronics. Herein, the scalable fabrication of multi-layer printable lithium ion micro-batteries (LIMBs) with ultrahigh areal energy density and exceptional flexibility is reported, based on highly conductive and mechanically stable inks by fully incorporating the polyurethane binders in dibasic esters with high-conducting additives of graphene and carbon nanotubes into active materials to construct a cross-linked conductive network. Benefiting from relatively higher electrical conductivity (≈7000 mS cm-1 ) and stably connected network of microelectrodes, the as-fabricated LIMBs by multi-layer printing display robust areal capacity of 398 µAh cm-2 , and remarkable areal energy density of 695 µWh cm-2 , which are much higher than most LIMBs reported. Further, the printed LIMBs show notable capacity retention of 88% after 3000 cycles, and outstanding flexibility without any structure degradation under various torsion states and folding angles. Importantly, a wearable smart bracelet, composed of a serially connected LIMBs pack, a temperature sensor, and a light-emitting diode, is realized for the automatic detection of body temperature. Therefore, this strategy of fabricating highly conductive and mechanically stable printable ink will open a new avenue for developing high-performance printable LIMBs for smart microelectronics.


Asunto(s)
Nanotubos de Carbono , Dispositivos Electrónicos Vestibles , Electrónica , Tinta , Litio/química , Nanotubos de Carbono/química
11.
Reprod Domest Anim ; 57(10): 1165-1175, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-35713115

RESUMEN

Donkeys are indispensable livestock in China because they have transport function and medicinal value. With the popularization of artificial insemination on donkeys, semen cryopreservation technology has gradually become a research hotspot. Seminal plasma is a necessary medium for transporting sperm and provides energy and nutrition for sperm. Seminal plasma metabolites play an important role in the process of sperm freezing, and also have an important impact on sperm motility and fertilization rate after freezing and thawing. In this study, liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis was used to compare the metabolic characteristics of seminal plasma of high freezability (HF) and low freezability (LF) male donkeys. We identified 672 metabolites from donkey seminal plasma, of which 33 metabolites were significantly different between the two groups. Metabolites were identified and categorized according to their major chemical classes, including homogeneous non-metal compounds, nucleosides, nucleotides, and analogues, organosulphur compounds, phenylpropanoids and polyketide, organoheterocyclic compounds, organic oxygen compounds, benzenoids, organic acids and derivatives, lipids and lipid-like molecules, organooxygen compounds, alkaloids and derivatives, organic nitrogen compounds. The results showed that the contents of phosphatidylcholine, piceatannol and enkephalin in donkey semen of HF group were significantly higher than those of LF group (p < .05), while the contents of taurocholic and lysophosphatidic acid were significantly lower than those of LF group (p < .05). The different metabolites were mainly related to sperm biological pathway response and oxidative stress. These metabolites may be considered as candidate biomarkers for different fertility in jacks.


Asunto(s)
Policétidos , Preservación de Semen , Animales , Biomarcadores/análisis , Cromatografía Liquida/veterinaria , Criopreservación/métodos , Criopreservación/veterinaria , Encefalinas/análisis , Equidae , Lisofosfolípidos/análisis , Masculino , Compuestos de Nitrógeno/análisis , Nucleótidos/análisis , Fosfatidilcolinas/análisis , Policétidos/análisis , Semen/fisiología , Preservación de Semen/métodos , Preservación de Semen/veterinaria , Motilidad Espermática , Espermatozoides/fisiología , Espectrometría de Masas en Tándem/veterinaria
12.
BMC Plant Biol ; 21(1): 535, 2021 Nov 13.
Artículo en Inglés | MEDLINE | ID: mdl-34773988

RESUMEN

BACKGROUNDS: Populus and Salix belong to Salicaceae and are used as models to investigate woody plant physiology. The variation of karyotype and nuclear DNA content can partly reflect the evolutionary history of the whole genome, and can provide critical information for understanding, predicting, and potentially ameliorating the woody plant traits. Therefore, it is essential to study the chromosome number (CN) and genome size in detail to provide information for revealing the evolutionary process of Salicaceae. RESULTS: In this study, we report the somatic CNs of seventeen species from eight genera in Salicaceae. Of these, CNs for twelve species and for five genera are reported for the first time. Among the three subfamilies of Salicaceae, the available data indicate CN in Samydoideae is n = 21, 22, 42. The only two genera, Dianyuea and Scyphostegia, in Scyphostegioideae respectively have n = 9 and 18. In Salicoideae, Populus, Salix and five genera closely related to them (Bennettiodendron, Idesia, Carrierea, Poliothyrsis, Itoa) are based on relatively high CNs from n = 19, 20, 21, 22 to n = 95 in Salix. However, the other genera of Salicoideae are mainly based on relatively low CNs of n = 9, 10, 11. The genome sizes of 35 taxa belonging to 14 genera of Salicaceae were estimated. Of these, the genome sizes of 12 genera and all taxa except Populus euphratica are first reported. Except for Dianyuea, Idesia and Bennettiodendron, all examined species have relatively small genome sizes of less than 1 pg, although polyploidization exists. CONCLUSIONS: The variation of CN and genome size across Salicaceae indicates frequent ploidy changes and a widespread sharing of the salicoid whole genome duplication (WGD) by the relatives of Populus and Salix. The shrinkage of genome size after WGD indicates massive loss of genomic components. The phylogenetic asymmetry in clade of Populus, Salix, and their close relatives suggests that there is a lag-time for the subsequent radiations after the salicoid WGD event. Our results provide useful data for studying the evolutionary events of Salicaceae.


Asunto(s)
Populus/metabolismo , Salicaceae/metabolismo , Salix/metabolismo , Duplicación de Gen/genética , Duplicación de Gen/fisiología , Genoma de Planta/genética , Filogenia , Populus/genética , Salicaceae/genética , Salix/genética , Secuenciación Completa del Genoma
13.
Brain Behav Immun ; 98: 110-121, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34403737

RESUMEN

Parkinson's disease (PD) is a chronic neurodegenerative disease. Recently, neuroinflammation driven by CD4+ T cells has been involved in PD pathophysiology. Human and murine lymphocytes express all the five subtypes of dopamine receptors (DRs), DRD1 to DRD5. However, roles of DRs particularly DRD2 expressed on CD4+ T cells in PD remain elucidated. Global Drd1- or Drd2-knockout (Drd1-/- or Drd2-/-) mice or CD4+ T cell-specific Drd2-knockout (Drd2fl/fl/CD4Cre) mice were intraperitoneally injected with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) to induce PD with the different mutants. On the 7th day following MPTP injection, mice were assessed for dopaminergic neurodegeneration, locomotor impairments, microglial activation, as well as CD4+ T-cell differentiation and function. Furthermore, in vitro CD4+ T cells were exposed to DRD2 agonist and antagonist and then differentiation and function of the cells were determined. MPTP induced dopaminergic neuronal loss in the nigrostriatal system, motor coordinative and behavioral impairments, microglial activation, and CD4+ T-cell polarization to pro-inflammatory T-helper (Th)1 and Th17 phenotypes. Importantly, either Drd2-/- or Drd2fl/fl/CD4Cre mice manifested more severe dopaminergic neurodegeneration, motor deficits, microglial activation, and CD4+ T-cell bias towards Th1 and Th17 phenotypes in response to MPTP, but Drd1-/- did not further alter MPTP intoxication. DRD2 agonist sumanirole inhibited shift of CD4+ T cells obtained from MPTP-intoxicated mice to Th1 and Th17 phenotypes and DRD2 antagonist L-741,626 reversed sumanirole effects. These findings suggest that DRD2 expressed on CD4+ T cells is protective against neuroinflammation and neurodegeneration in PD. Thus, developing a therapeutic strategy of stimulating DRD2 may be promising for mitigation of PD.


Asunto(s)
Enfermedades Neurodegenerativas , Enfermedad de Parkinson , 1-Metil-4-fenil-1,2,3,6-Tetrahidropiridina , Animales , Modelos Animales de Enfermedad , Neuronas Dopaminérgicas , Ratones , Ratones Endogámicos C57BL , Enfermedades Neuroinflamatorias , Receptores de Dopamina D2 , Receptores de Dopamina D5 , Células Th17
14.
Angew Chem Int Ed Engl ; 60(51): 26747-26754, 2021 Dec 13.
Artículo en Inglés | MEDLINE | ID: mdl-34665490

RESUMEN

Modulation of A-site defects is crucial to the redox reactions on ABO3 perovskites for both clean air application and electrochemical energy storage. Herein we report a scalable one-pot strategy for in situ regulation of La vacancies (VLa ) in LaMnO3.15 by simply introducing urea in the traditional citrate process, and further reveal the fundamental relationship between VLa creation and surface lattice oxygen (Olatt ) activation. The underlying mechanism is shortened Mn-O bonds, decreased orbital ordering, promoted MnO6 bending vibration and weakened Jahn-Teller distortion, ultimately realizing enhanced Mn-3d and O-2p orbital hybridization. The LaMnO3.15 with optimized VLa exhibits order of magnitude increase in toluene oxidation and ca. 0.05 V versus RHE (reversible hydrogen electrode) increase of half-wave potential in oxygen reduction reaction (ORR). The reported strategy can benefit the development of novel defect-meditated perovskites in both heterocatalysis and electrocatalysis.

15.
Inorg Chem ; 59(2): 1218-1226, 2020 Jan 21.
Artículo en Inglés | MEDLINE | ID: mdl-31891266

RESUMEN

A nanostructural catalyst with long-term durability under harsh conditions is very important for an outstanding catalytic performance. Herein, a new ultrastable PtCo/Co3O4-SiO2 nanocatalyst was explored to improve the catalytic performance of carbon monoxide (CO) oxidation by virtue of the surface active lattice oxygen derived from strong metal-support interactions. Such a structure can overcome the issues of Co3O4-SiO2 inactivation by water vapor and the Pt inferior activity at low temperature. Further, Co3O4-SiO2 nanosheets endow superior structure stability under high temperatures of up to 800 °C, which gives long-term catalytic cyclability of PtCo/Co3O4-SiO2 nanocomposites for CO oxidation. Moreover, the large specific surface areas (294 m2 g-1) of the nanosheet structure can expose abundant surface active lattice oxygen, which significantly enhanced the catalytic activity of CO oxidation at 50 °C over 30 days without apparent aggregation of PtCo nanoparticles after 20 cycles from 50 to 400 °C. It can be expected to be a promising candidate as an ultrastable efficient catalyst.

16.
Angew Chem Int Ed Engl ; 59(29): 12147-12153, 2020 Jul 13.
Artículo en Inglés | MEDLINE | ID: mdl-32237031

RESUMEN

Guiding the lithium ion (Li-ion) transport for homogeneous, dispersive distribution is crucial for dendrite-free Li anodes with high current density and long-term cyclability, but remains challenging for the unavailable well-designed nanostructures. Herein, we propose a two-dimensional (2D) heterostructure composed of defective graphene oxide (GO) clipped on mesoporous polypyrrole (mPPy) as a dual-functional Li-ion redistributor to regulate the stepwise Li-ion distribution and Li deposition for extremely stable, dendrite-free Li anodes. Owing to the synergy between the Li-ion transport nanochannels of mPPy and the Li-ion nanosieves of defective GO, the 2D mPPy-GO heterostructure achieves ultralong cycling stability (1000 cycles), even tests at 0 and 50 °C, and an ultralow overpotential of 70 mV at a high current density of 10.0 mA cm-2 , outperforming most reported Li anodes. Furthermore, mPPy-GO-Li/LiCoO2 full batteries demonstrate remarkably enhanced performance with a capacity retention of >90 % after 450 cycles. Therefore, this work opens many opportunities for creating 2D heterostructures for high-energy-density Li metal batteries.

17.
Small ; 15(50): e1904248, 2019 12.
Artículo en Inglés | MEDLINE | ID: mdl-31724823

RESUMEN

Switchable structured adhesion on rough surfaces is highly desired for a wide range of applications. Combing the advantages of gecko seta and creeper root, a switchable fibrillar adhesive composed of polyurethane (PU) as the backing layer and graphene/shape memory polymer (GSMP) as the pillar array is developed. The photothermal effect of graphene (under UV irradiation) changes GSMP micropillars into the viscoelastic state, allowing easy and intimate contact on surfaces with a wide range of roughness. By controlling the phase state of GSMP via UV irradiation during detachment, the GSMP micropillar array can be switched between the robust-adhesion state (UV off) and low-adhesion state (UV on). The state of GSMP micropillars determines the adhesion force capacity and the stress distribution at the detaching interface, and therefore the adhesion performance. The PU-GSMP adhesive achieves large adhesion strength (278 kPa), high switching ratio (29), and fast switching (10 s) at the same time. The results suggest a design principle for bioinspired structured adhesives, especially for reversible adhesion on surfaces with a wide range of roughness.

18.
Environ Sci Technol ; 53(1): 224-233, 2019 01 02.
Artículo en Inglés | MEDLINE | ID: mdl-30511575

RESUMEN

Integrated Assessment Models based on Computable General Equilibrium (IAM/CGE) and dynamic Material Flow Analysis (dynamic MFA) are two most widely used prospective model families to assess large-scale and long-term socioeconomic metabolism (SEM) and inform sustainable SEM transition. The latter approach could complement the former by a more explicit understanding of service provision, in-use stocks, and material cycles in a mass balanced framework. In this paper, we demonstrated this by integrating the dynamic MFA and CGE model approaches for the Chinese building sector from 2012 to 2030. Our results revealed the impacts of building stock dynamics on sectoral and economy-wide CO2 emissions: lower service saturation levels and later saturation time of building stock development could free up investment on buildings and accumulatively save up to 25.4 Gt in embodied CO2 emissions of the building construction sector, representing a 2.7-fold of 2012 countrywide CO2 emissions. However, the save-ups are partly compensated by an increase of embodied CO2 emissions in the other sectors due to economy-wide rebound effect (ca. 18.8 Gt or about 74%). The integrated model we developed could help ensure both mass and monetary balances, explore rebound effects in prospective modeling, and thus better understand the economy-wide consequences of infrastructure development.


Asunto(s)
Entorno Construido , Dióxido de Carbono , China , Modelos Teóricos , Estudios Prospectivos
19.
Angew Chem Int Ed Engl ; 58(30): 10173-10178, 2019 Jul 22.
Artículo en Inglés | MEDLINE | ID: mdl-31140216

RESUMEN

Free-standing 2D porous nanomaterials have attracted considerable interest as ideal candidates of 2D film electrodes for planar energy storage devices. Nevertheless, the construction of well-defined mesopore arrays parallel to the lateral surface, which facilitate fast in-plane ionic diffusion, is a challenge. Now, a universal interface self-assembly strategy is used for patterning 2D porous polymers, for example, polypyrrole, polyaniline, and polydopamine, with cylindrical mesopores on graphene nanosheets. The resultant 2D sandwich-structured nanohybrids are employed as the interdigital microelectrodes for the assembly of planar micro-supercapacitors (MSCs), which deliver outstanding volumetric capacitance of 102 F cm-3 and energy density of 2.3 mWh cm-3 , outperforming most reported MSCs. The MSCs display remarkable flexibility and superior integration for boosting output voltage and capacitance.

20.
J Am Chem Soc ; 140(26): 8198-8205, 2018 07 05.
Artículo en Inglés | MEDLINE | ID: mdl-29893575

RESUMEN

Scalable production of high-quality heteroatom-modified graphene is critical for microscale supercapacitors but remains a great challenge. Herein, we demonstrate a scalable, single-step electrochemical exfoliation of graphite into highly solution-processable fluorine-modified graphene (FG), achieved in an aqueous fluorine-containing neutral electrolyte, for flexible and high-energy-density ionogel-based microsupercapacitors (FG-MSCs). The electrochemically exfoliated FG nanosheets are characterized by atomic thinness, large lateral size (up to 12 µm), a high yield of >70% with ≤3 layers, and a fluorine doping of 3 at%, allowing for large-scale production of FG-MSCs. Our ionogel-based FG-MSCs deliver high energy density of 56 mWh cm-3, by far outperforming the most reported MSCs. Furthermore, the all-solid-state microdevices offer exceptional cyclability with ∼93% after 5000 cycles, robust mechanical flexibility with 100% of capacitance retention bended at 180°, and outstanding serial and parallel integration without the requirement of metal-based interconnects for high-voltage and high-capacitance output. Therefore, these FG-MSCs represent remarkable potential for electronics.

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