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1.
Sci Total Environ ; : 151944, 2021 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-34838919

RESUMO

Water table decline is one of the most serious environmental problems in the peatland in the Qinghai-Tibetan Plateau. However, the effect of water table decline on the structure of aboveground arthropod communities is still not clear. We investigated changes in the abundance of different arthropod groups, and estimated the abundance, height, and biomass of the plant community in a soil water table reduction experiment to reveal the effect of water table decline on the arthropod community structure. The effect of water level decline on herbivorous arthropods varied according to the feeding habits. Specifically, water table decline treatment decreased the abundance of grass-preferring herbivores but increased the abundance of forb-preferring herbivores. However, the density of predators (e.g., spiders) did not change significantly. The variations in arthropod communities were correlated with the increase in forbs and leaf nitrogen content in the water table decline treatments. Our experiment demonstrated that the effect of water table decline on plant communities cascades upwardly to alter the arthropod community. Such trophic interactions should be considered in studies aimed at predicting shifts in the arthropods communities in a changing climate.

2.
ACS Nano ; 2021 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-34549941

RESUMO

Two-dimensional (2D) borophene has attracted tremendous interest due to its fascinating properties, which have potential applications in catalysts, energy storage devices, and high-speed transistors. In the past few years, borophene was theoretically predicted as an ideal electrode material for lithium-sulfur (Li-S) batteries because of its low-density, metallic conductivity, high Li-ion surface mobility, and strong interface bonding energy to polysulfide. But until now, borophene-based Li-S batteries have not yet been achieved in experiments due to the absence of a large-scale synthetic method of freestanding borophene nanostructures with a high enough structural stability, conductivity, and uniformity. Herein, we developed a low-temperature liquid exfoliation (LTLE) method to synthesize freestanding few-layer ß12-borophene single-crystalline sheets with a P6¯m2 symmetry in tens of milligrams. The as-synthesized 2D sheets were used as the polysulfide immobilizers and electrocatalysts of Li-S batteries. The resulting borophene-based Li-S battery delivered an extralarge areal capacity of 5.2 mAh cm-2 at a high sulfur loading of 7.8 mg cm-2, an excellent rate performance of 8 C (@721 mAh g-1), and an ultralow capacity fading rate of 0.039% in 1000 cycles, outperforming commercial Li-ion batteries and many other 2D material-based Li-S batteries. Based on the density functional theory model, the excellent electrochemical performances of the borophene-based Li-S batteries should originate from the enormous enhancement of ß12-borophene sheets for both the surface migration of the Li-ions and the adsorption energy of Li2Sn clusters. Our results thus demonstrate a great potential for scalable production of freestanding ß12-borophene single-crystalline sheets in future high-performance Li-S batteries.

3.
J Phys Chem Lett ; 12(35): 8598-8604, 2021 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-34468154

RESUMO

Charge and electronic energy transfer form the basis of many natural and artificial energy transduction systems. The energy landscapes that drive these transfer processes are often constructed from enthalpy changes. In contrast, the entropic effect, although occasionally invoked to explain some excited-state dynamics, has rarely been used to actively control charge/energy flow. Here we derive a generic formula describing how entropy can quantitatively gate the thermally activated delayed emission lifetime in semiconductor nanocrystal-molecular triplet acceptor complexes and experimentally verify the model using highly emissive, quantum-confined CsPbBr3 nanocrystals surface-functionalized with multiple phenanthrene triplet acceptors. Triplet energy transfer from photoexcited CsPbBr3 nanocrystals to phenanthrene is followed by thermally activated repopulation of nanocrystal excitons, leading to delayed nanocrystal emission. The lifetime of delayed emission increases with the phenanthrene/nanocrystal ratio, due to lowering of the free energy of the acceptor state by entropic gain. This study points toward a direction of using entropy to artificially design donor-acceptor light-emitting materials with predetermined excited-state lifetimes.

4.
Int J Clin Pract ; : e14738, 2021 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-34399017

RESUMO

PURPOSE: Atrial fibrillation (AF) is one of the most common persistent arrhythmia, and its complications include cerebral embolism, arterial embolism and heart failure. Some studies have found that elevated Homocysteine (HCY) levels is a new risk factor for AF. Currently, there is no meta-analysis to explore whether the HCY levels is related to AF. Therefore, a meta-analysis was conducted to evaluate the relationship between the HCY levels and AF, in order to draw the attention of clinicians to the HCY levels. METHODS: A meta-analysis was performed in the study to evaluated the association between the HCY levels and AF. In order to identify eligible original articles, The EMBASE, PubMed, and web of science were systematically searched until November 2020. All data were analyzed with Review Manager 5.3. The meta-analysis results were evaluated depending on standardized mean differences (SMD) with 95% confidence intervals (CI). Moreover, the subgroup analysis and sensitivity analysis were also analyzed. RESULTS: The HCY levels was significantly associated with AF (WMD = 0.81, 95% CI: 0.58 to 1.03; P < .00001). In the analysis, there was a medium degree of heterogeneity (I2 = 73%). Subgroup analysis showed that female < 60, BMI≥25, BMI <25, age ≥60 and publication year ≥2010 were identified as possible sources of heterogeneity. Sensitivity analysis showed that the main results remained unchanged after omitting any single study or converting the random effects model (REM) to fixed effects model (FEM). CONCLUSIONS: The meta-analysis showed that there is a significant correlation between the HCY levels and AF, and the role of HCY in AF patients should not be ignored in clinical.

5.
Signal Transduct Target Ther ; 6(1): 300, 2021 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-34381015

RESUMO

Elderly people and patients with comorbidities are at higher risk of COVID-19 infection, resulting in severe complications and high mortality. However, the underlying mechanisms are unclear. In this study, we investigate whether miRNAs in serum exosomes can exert antiviral functions and affect the response to COVID-19 in the elderly and people with diabetes. First, we identified four miRNAs (miR-7-5p, miR-24-3p, miR-145-5p and miR-223-3p) through high-throughput sequencing and quantitative real-time PCR analysis, that are remarkably decreased in the elderly and diabetic groups. We further demonstrated that these miRNAs, either in the exosome or in the free form, can directly inhibit S protein expression and SARS-CoV-2 replication. Serum exosomes from young people can inhibit SARS-CoV-2 replication and S protein expression, while the inhibitory effect is markedly decreased in the elderly and diabetic patients. Moreover, three out of the four circulating miRNAs are significantly increased in the serum of healthy volunteers after 8-weeks' continuous physical exercise. Serum exosomes isolated from these volunteers also showed stronger inhibitory effects on S protein expression and SARS-CoV-2 replication. Our study demonstrates for the first time that circulating exosomal miRNAs can directly inhibit SARS-CoV-2 replication and may provide a possible explanation for the difference in response to COVID-19 between young people and the elderly or people with comorbidities.


Assuntos
COVID-19/genética , Diabetes Mellitus/genética , MicroRNAs/genética , Glicoproteína da Espícula de Coronavírus/genética , Adulto , Fatores Etários , Idoso , COVID-19/sangue , COVID-19/patologia , COVID-19/virologia , China , MicroRNA Circulante/sangue , MicroRNA Circulante/genética , Estudos de Coortes , Diabetes Mellitus/sangue , Diabetes Mellitus/patologia , Diabetes Mellitus/virologia , Exercício Físico , Exossomos/genética , Exossomos/metabolismo , Exossomos/virologia , Feminino , Regulação da Expressão Gênica , Células HEK293 , Interações Hospedeiro-Patógeno/genética , Humanos , Masculino , MicroRNAs/sangue , Pessoa de Meia-Idade , SARS-CoV-2/genética , SARS-CoV-2/crescimento & desenvolvimento , SARS-CoV-2/metabolismo , Glicoproteína da Espícula de Coronavírus/sangue , Replicação Viral
6.
Appl Opt ; 60(18): 5465-5470, 2021 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-34263787

RESUMO

Gaseous Raman lasers cover a range of wavelengths but lack wavelength tunability. Here, a 1cm-1 linewidth 532 nm laser was used as a pump laser, and with a narrow-linewidth seed laser injection, a narrow-linewidth first Stokes (S1) Raman laser was achieved. By tuning the wavelength of the seed laser, a tuning range of S1 up to 1cm-1 was obtained. The wavelengths of the first anti-Stokes and second Stokes lasers could also be tuned. A theoretical model was developed, and spectral profiles of Raman lasers from experiments and simulations agreed well; further simulation predicted that the linewidth of S1 could be compressed to as narrow as 0.01cm-1 under optimal conditions. A universal method of fine-tunable Raman lasers is presented that can be utilized in several important applications.

7.
Sci Total Environ ; 761: 143211, 2021 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-33172642

RESUMO

Soil respiration is one of the largest carbon (C) sources in terrestrial ecosystems and is sensitive to soil nutrient variation. Although nitrogen (N) availability affects soil respiration, other nutrients, such as phosphorous (P), which play pivotal roles in plant growth and microbial activity, may also affect soil respiration. In addition, N and P have been widely reported to interactively affect plant growth; however, their interactive effects on soil respiration have rarely been studied. Therefore, we conducted a short-term, two-factor experiment (from 2013 to 2015) to determine whether N and P addition can interactively affect soil respiration in a northern Chinese steppe. Nitrogen addition elevated soil respiration by 9.5%, whereas P addition did not affect soil respiration in the studied steppe across all treatments. However, neither N nor P addition significantly affected soil respiration alone in the experiment. Furthermore, N and P interactively affected soil respiration. Nitrogen addition did not affect soil respiration in the ambient P plots, but significantly elevated soil respiration (by 17.7%) in P addition plots across the three growing seasons. The effects of N addition on soil respiration were primarily correlated with the responses of vegetation cover and litter biomass to N addition in the experiment. Our results demonstrate that P addition augments the effects of N addition on soil respiration. Soil nutrient contents should be incorporated into predictive models for terrestrial C cycle response to N addition.

8.
Phytopathology ; 110(11): 1781-1790, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32567977

RESUMO

The ascomycete fungus Pyrenophora tritici-repentis is the causal agent of tan spot of wheat. The disease can occur on both common wheat (Triticum aestivum) and durum wheat (T. turgidum ssp. durum) and has potential to cause significant yield and quality losses. The fungal pathogen is known to produce necrotrophic effectors (NEs) that act as important virulence factors. Based on the NE production and virulence on a set of four differentials, P. tritici-repentis isolates have been classified into eight races. Race 4 produces no known NEs and is avirulent on the differentials. From a fungal collection in North Dakota, we identified several isolates that were classified as race 4. These isolates caused no or little disease on all common wheat lines including the differentials; however, they were virulent on some durum cultivars and tetraploid wheat accessions. Using two segregating tetraploid wheat populations and quantitative trait locus mapping, we identified several genomic regions significantly associated with disease caused by two of these isolates, some of which have not been previously reported. This is the first report that race 4 is virulent on tetraploid wheat, likely utilizing unidentified NEs. Our findings further highlight the insufficiency of the current race classification system for P. tritici-repentis.


Assuntos
Ascomicetos , Triticum , Ascomicetos/genética , Humanos , North Dakota , Doenças das Plantas , Tetraploidia , Triticum/genética
9.
ACS Appl Mater Interfaces ; 12(8): 10050-10057, 2020 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-31957437

RESUMO

We describe herein a flexible and tunable random laser made from a flexible poly(dimethylsiloxane) substrate. The substrate is prepared by casting via soft lithography from a lotus leaf to produce a micropapilla surface structure similar to that of a lotus leaf. The micropapilla provides efficient multiple scattering for the photons generated in the gain medium, and random lasing emerges because photons undergo closed-loop paths by scattering from three equilaterally arranged micropapillae. Given the diverse distribution of microscale features on the soft substrate, the random laser spectrum can be tuned by as much as 26.0 nm by changing the pump position. Furthermore, the random laser can be easily tuned by about 14 nm by flexing it, which modifies the micropapilla density and thereby changes the reabsorption strength of the laser dye. The photostability of the random laser is ensured by sealing the gain medium (i.e., dye solution) in a closed system. The results provide a promising method to realize a variety of laser-based applications such as optical biosensors on chips, microscale structural alteration detectors, flexible wearable devices, and multicolor (even white) random lasers.

10.
J Phys Chem Lett ; 10(10): 2357-2362, 2019 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-31006244

RESUMO

Metal-halide perovskites are promising optical gain materials because of their excellent photophysical properties. Recently, large perovskite single crystals with phase purity, less defects, and over millimeter dimensions have been successfully synthesized. However, the optical gain effect from these large-size single crystals has not yet been realized. Herein, we for the first time report efficient two-photon pumped amplified spontaneous emission (ASE) from millimeter-sized CsPbBr3 single crystals (SCs) with a low threshold of 0.65 mJ cm-2 and an optical gain of 38 cm-1. Furthermore, the CsPbBr3 SCs also exhibit ultrastable ASE under continuous laser irradiation for more than 40 h (corresponds to 1.5 × 108 laser shots) at ambient condition. This work suggests the potential application of large-size perovskite single crystals in practical nonlinear optical devices.

11.
Angew Chem Int Ed Engl ; 58(8): 2278-2283, 2019 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-30576043

RESUMO

A series of lead-free double perovskite nanocrystals (NCs) Cs2 AgSb1-y Biy X6 (X: Br, Cl; 0≤y≤1) is synthesized. In particular, the Cs2 AgSbBr6 NCs is a new double perovskite material that has not been reported for the bulk form. Mixed Ag-Sb/Bi NCs exhibit enhanced stability in colloidal solution compared to Ag-Bi or Ag-Sb NCs. Femtosecond transient absorption studies indicate the presence of two prominent fast trapping processes in the charge-carrier relaxation. The two fast trapping processes are dominated by intrinsic self-trapping (ca. 1-2 ps) arising from giant exciton-phonon coupling and surface-defect trapping (ca. 50-100 ps). Slow hot-carrier relaxation is observed at high pump fluence, and the possible mechanisms for the slow hot-carrier relaxation are also discussed.

12.
Appl Opt ; 57(29): 8757-8765, 2018 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-30461955

RESUMO

A new method to improve the resolution of a slightly non-parallel solid etalon is proposed. The method is aimed to reduce the spectrum broadening caused by non-parallel surfaces; it contains a theoretical formula for adjusting image distances, and an algorithm for processing the corresponding fringe patterns. Theoretical consideration, computer simulation, experimental results, and application demonstration are given. The fringe patterns captured by a CCD showed good agreement with the computer simulation, and the resolution of a λ/10-wavefront-error etalon was improved from 3.1 GHz to 0.51 GHz. In comparison with other methods, this new method is convenient and economical.

13.
Pathogens ; 7(3)2018 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-30213041

RESUMO

The fungus Pyrenophora tritici-repentis (Ptr) causes tan spot of wheat crops, which is an important disease worldwide. Based on the production of the three known necrotrophic effectors (NEs), the fungal isolates are classified into eight races with race 4 producing no known NEs. From a laboratory cross between 86⁻124 (race 2 carrying the ToxA gene for the production of Ptr ToxA) and DW5 (race 5 carrying the ToxB gene for the production of Ptr ToxB), we have obtained some Ptr isolates lacking both the ToxA and ToxB genes, which, by definition, should be classified as race 4. In this work, we characterized virulence of two of these isolates called B16 and B17 by inoculating them onto various common wheat (Triticum aestivum L.) and durum (T. turgidum L.) genotypes. It was found that the two isolates still caused disease on some genotypes of both common and durum wheat. Disease evaluations were also conducted in recombinant inbred line populations derived from two hard red winter wheat cultivars: Harry and Wesley. QTL mapping in this population revealed that three genomic regions were significantly associated with disease, which are different from the three known NE sensitivity loci. This result further indicates the existence of other NE-host sensitivity gene interactions in the wheat tan spot disease system.

14.
Appl Opt ; 57(16): 4595-4600, 2018 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-29877368

RESUMO

In this work, the anisotropy of nonlinear absorption in a crystal Q-switch was considered when we established coupled rate equations of a passively Q-switched laser. A [100]-cut Cr4+:YAG crystal, with initial transmission T0=40%, was used as the Q-switch to evaluate the theoretical model, and the results of the simulation were in good accordance with the experiment. In order to control timing jitter of the passively Q-switched laser, an actively Q-switched Nd:YAG laser was applied to directly bleach the [100]-cut Cr4+:YAG crystal. The timing jitter was more than 1 µs without bleaching light. While there was a bleaching light, the time lag between the laser pulse and the bleaching light was less than 100 ns, which meant the timing jitter decreased. The pulse width of the passively Q-switched laser was found to decrease from 45 to 35 ns due to the existing of bleaching light. As the peak power of bleaching light was increased, the laser pulse energy increased from 18.2 to 24.6 mJ, which meant a 35% increment in the pulse energy. The increase in pulse energy can be explained by the increase of α coefficient, and the results of simulation agreed well with the experiment.

15.
J Phys Chem A ; 122(24): 5361-5369, 2018 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-29807430

RESUMO

The kinetic processes for the Xe (6p[1/2]0) atoms in Kr, Ar, Ne, and He buffer gases were studied. We found that Kr, Ar, and Ne atoms can be used to switch the amplified spontaneous emission (ASE) channel from 3408 nm (6p[1/2]0-6s'[1/2]1) to 3680 nm (5d[1/2]1-6p[1/2]1), while Xe and He atoms do not show such a phenomenon. This ASE channel switch is mainly ascribed to the fast transfer of 6p[1/2]0 → 5d[1/2]1. On the basis of the rate equations for two-state coupling (energy-transfer processes between the two states are very rapid), the reason why the ASE channel switch effect normally coincides with a double exponential decay of the spontaneous emission at 828 nm (6p[1/2]0-6s[3/2]1) is explained. The actual situations in Xe, Ar, Ne, and He follow this rule. However, the strictly single exponential decay of the spontaneous emission at 828 nm and strong ASE channel switch effect simultaneously emerge in Kr. This indicates that the transfer of 6p[1/2]0 → 5d[1/2]1 in Kr does not occur via two-state coupling, but via two steps of near-resonance collision through the 5s[3/2]2 (Kr) state as the intermediate state (6p[1/2]0 → 5s[3/2]2 (Kr) → 5d[1/2]1). In addition, we found Xe (6p[1/2]0) atoms strongly tend to reach the 6p[3/2]2, 6p[3/2]1, and 6p[5/2]2 states through the 5s[3/2]2 (Kr) state as the intermediate state in Kr. The 5s[3/2]2 (Kr) state plays a very important role in the energy-transfer kinetics for the Xe (6p[1/2]0) atoms. Kr is probably an excellent buffer gas for laser systems based on Xe.

16.
Appl Opt ; 57(10): 2577-2583, 2018 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-29714243

RESUMO

The sum-frequency generation (SFG) in potassium dihydrogen phosphate (KDP) powder with µm-grade particle size is successfully demonstrated under various experimental conditions. Two focused beams of 870 nm and 1369 nm are used for SFG excitation. SFG is observed under different excitation energies. The SFG intensity shows isotropy with different observation azimuths. The intersection angle between two excitation beams is not limited by conventional phase-matching conditions, and it owns the flexibility of a very large allowed range, e.g., it can be 0°âˆ¼100° in this work. The polarization combination of excitation beams is not limited either. Thanks to the non-toxicity, low price, and low SFG threshold properties of KDP material and the optical flexibility, this powder SFG technology is a versatile method and is expected to be applied to various situations of optical alignment, e.g., surface SFG, four-wave mixing, coherent anti-Stokes Raman spectroscopy, multi-color laser excitation, etc. The effect of potential powder SFG-assisted optical alignments is also discussed. Extension of this method to multi-beams, tight focusing beams, and plasmonic polariton devices is proposed.

17.
J Phys Chem A ; 121(18): 3430-3436, 2017 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-28441478

RESUMO

In optically pumped laser systems, rare gas lasers (RGLs) are a field of great interest for researchers. Gas laser regimes with metastable Ne, Ar, and Kr atoms have been investigated, while studies of RGLs based on metastable Xe are sparse. In this work, when a strong excitation laser (2.92 mJ/pulse, 7.44 × 105 W/cm2) was applied to excite Xe atoms from the ground state to the 6p[1/2]0 state, an interesting phenomenon emerged: An intense fluorescence of 980 nm (6p[1/2]1-6s[3/2]2) was produced. However, when the energy of excitation laser was decreased to 0.50 mJ/pulse (1.27 × 105 W/cm2), the fluorescence of 980 nm became very weak. Besides, lifetime and decay rate constant of the 6p[1/2]0 state under the condition of E = 2.92 mJ are significantly different from either those measured by other groups or those of E = 0.50 mJ. These phenomena indicate that the high energy of excitation laser should trigger some new kinetic mechanisms. Further works identified that the new kinetic mechanism is the MIR ASE of 3408 nm (6p[1/2]0-6s'[1/2]1). The mechanisms are proposed as follows. Substantial 6p[1/2]0 atoms are produced by laser excitation. Then, the ASE of 3408 nm (6p[1/2]0-6s'[1/2]1) is quickly produced to populate substantial 6s'[1/2]1 atoms. The 6s'[1/2]1 atoms can readily arrive at the 6p[1/2]1 states through collision by virtue of the small energy difference (84 cm-1) and high collision rate constant of the transition from the 6s'[1/2]1 state to the 6p[1/2]1 state. As a result, the intense fluorescence of 980 nm is generated.

18.
PLoS One ; 11(10): e0164815, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27755575

RESUMO

The wheat powdery mildew resistance gene Pm40, which is located on chromosomal arm 7BS, is effective against nearly all prevalent races of Blumeria graminis f. sp tritici (Bgt) in China and is carried by the common wheat germplasm PI 672538. A set of the F1, F2 and F2:3 populations from the cross of the resistant PI 672538 with the susceptible line L1034 were used to conduct genetic analysis of powdery mildew resistance and construct a high-density linkage map of the Pm40 gene. We constructed a high-density linkage genetic map with a total length of 6.18 cM and average spacing between markers of 0.48 cM.Pm40 is flanked by Xwmc335 and BF291338 at genetic distances of 0.58 cM and 0.26 cM, respectively, in deletion bin C-7BS-1-0.27. Comparative genomic analysis based on EST-STS markers established a high level of collinearity of the Pm40 genomic region with a 1.09-Mbp genomic region on Brachypodium chromosome 3, a 1.16-Mbp genomic region on rice chromosome 8, and a 1.62-Mbp genomic region on sorghum chromosome 7. We further anchored the Pm40 target intervals to the wheat genome sequence. A putative linear index of 85 wheat contigs containing 97 genes on 7BS was constructed. In total, 9 genes could be considered as candidates for the resistances to powdery mildew in the target genomic regions, which encoded proteins that were involved in the plant defense and response to pathogen attack. These results will facilitate the development of new markers for map-based cloning and marker-assisted selection of Pm40 in wheat breeding programs.


Assuntos
Cromossomos de Plantas/genética , Resistência à Doença/genética , Proteínas de Plantas/genética , Triticum/genética , Brachypodium/genética , Mapeamento Cromossômico , Cromossomos de Plantas/metabolismo , Hibridização Genômica Comparativa , Etiquetas de Sequências Expressas , Ligação Genética , Genótipo , Repetições de Microssatélites/genética , Oryza/genética , Doenças das Plantas/genética , Sorghum/genética
19.
Opt Express ; 24(13): 15012-20, 2016 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-27410652

RESUMO

A direct-liquid-cooled side-pumped Nd:YAG multi-disk QCW laser resonator is presented, in which the oscillating laser propagates through multiple thin disks and cooling flow layers in Brewster angle. Twenty Nd:YAG thin disks side-pumped by LD arrays are directly cooled by flowing deuteroxide at the end surfaces. A laser output with the highest pulse energy of 17.04 J is obtained at the pulse width of 250 µs and repetition rate of 25 Hz, corresponding to an optical-optical efficiency of 34.1% and a slope efficiency of 44.5%. The maximum average output power of 7.48 kW is achieved at the repetition rate of 500 Hz. Due to thermal effects, the corresponding optical-optical efficiency decreases to 30%. Under the 12.5 kW pumping condition while not oscillating, the wavefront of a He-Ne probe passing through the gain module is as low as 0.256 µm (RMS) with the defocus and tetrafoil subtracted.

20.
Opt Lett ; 41(14): 3335-8, 2016 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-27420529

RESUMO

We have observed unusual blue-shifted radiations in water pumped by a strong 532-nm nanosecond laser. Properties including divergence, polarizations, and pulse shapes of the unusual radiations are measured and compared with those of the regular stimulated Raman scattering (SRS) in water. The unusual radiations are attributed to the parametric anti-Stokes SRS that occurs on the interface of water and ionization plasma (or gas) formed in the laser-induced breakdown of water.

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