Low-frequency conductivity of low wear high-entropy alloys.

High-entropy alloys (HEAs) provide new research avenues for alloy combinations in the periodic table, opening numerous possibilities in novel-alloy applications. However, their electrical characteristics have been relatively underexplored. The challenge in establishing an HEA electrical conductivity model lies in the changes in electronic characteristics caused by lattice distortion and complexity of nanostructures. Here we show a low-frequency electrical conductivity model for the Nb-Mo-Ta-W HEA system. The cocktail effect is found to explain trends in electrical-conductivity changes in HEAs, while the magnitude of the reduction is understood by the calculated plasma frequency, free electron density, and measured relaxation time by terahertz spectroscopy. As a result, the refractory HEA Nb15Mo35Ta15W35 thin film exhibits both high hardness and excellent conductivity. This combination of Nb15Mo35Ta15W35 makes it suitable for applications in atomic force microscopy probe coating, significantly improving their wear resistance and atomic-scale image resolution.

Analysis of influencing factors of multi-site work-related musculoskeletal disorders in surgeons / 中国职业医学

@# Objective - - To analyze the prevalence and influencing factors of multi site work related musculoskeletal disorders （ ） Methods WMSDs in surgeons. A total of 102 surgeons from four hospitals were selected as study subjects by convenient sampling method. The Chinese version of Musculoskeletal Disorders Questionnaire was used to investigate the prevalence of ， Results WMSDs in the past one year the related individuals and occupational factors. The total prevalence of WMSDs among （ ）， （ ） （ ） surgeons was 54.9%. The top three sites were neck 48.0% lower back 35.3% and shoulder 32.4% . The prevalence of （ vs ，P ） WMSDs in multiple sites was higher than that in a single site 43.1% 11.8% <0.01 . Multivariate logistic regression ， ， analysis showed that surgeons who smoked were tired at work and had a bent back had a higher risk of developing WMSDs ［ （ - ）， （ - ）， （ - ）， P ］ odds ratios and 95% confidence intervals were 3.66 1.41 9.46 8.33 2.15 32.20 and 18.74 2.14 166.77 all <0.01 Conclusion - after excluding the influence of confounding factors. The prevalence rate of multi site WMSDs among surgeons is ， high and the influencing factors include bad living habits and occupational factors such as working load and working posture.

A new stilbene dimer from Vitis amurensis.

One new stilbene dimer named amurensin O (1), together with one known resveratrol trimer melapinol B (2), was isolated from Vitis amurensis, and their structures were identified on the basis of spectral analysis, especially 2D NMR spectral analysis.

[Discussion of the characteristic indexs in using three-dimensional fluorescence method to identify different crude oils].

The present paper investigates the influence of solvent purity on the test of three-dimensional fluorescence spectra, determines the process of its pre-purification, and studies the influence of the concentrations on the three-dimensional fluorescence characteristic indexes such as the characteristic peaks position, fluorescence intensity (F), and ratio (R) of fluorescence intensity when the phenomena of fluorescence quenching won't appear. The result shows that the concentration affects the value F and value R largely but its effect on the relative peak intensity (R(s)) is relatively small. Different crude oils has different value R(s). According to those characteristics, this paper presents that the value R(s) can be used as a new characteristic index for identification of crude oil. This conclusion was confirmed by testing many crude oils stably and reliably from different areas with their concentrations at 5 mg x L(-1). This method can be applied to identify most crude oils preliminary and further accurate analysis can be carried out together with other index.

Oxidation of catechin and rutin by pentaammineruthenium(III) complexes.

The reaction of catechin and rutin with Ru(NH(3))(5)L(3+) (L = N-methylpyrazinium (pzCH(3)(+)), pyrazine (pz), and isonicotinamide (isn)) complexes underwent a two-electron oxidation on the catechol ring (B ring) with the formation of quinone products. The kinetics of the oxidation, carried out at [H(+)] = 0.01-1.0 M and pH = 4.0-7.6, suggested that the reaction process involves the rate determining one-electron oxidation of the flavonoids in the form of H(2)X (k(0)), HX(-) (k(1)), and X(2-) (k(2)) by Ru(NH(3))(5)L(3+) complexes to form the corresponding semiquinone radicals, followed by the rapid scavenge of the radicals by the Ru(III) complexes. The specific rate constants (k(0), k(1), and k(2)) were measured and the results together with the application of the Marcus theory were used to estimate the self-exchange parameters for the one-electron couples of the flavonoids, H(2)X/H(2)X(+*), HX(-)/HX(*), and X(2-)/X(-*).

An isorhapontigenin tetramer and a novel stilbene dimer from Gnetum hainanense.

The first isorhapontigenin tetramer, gnetuhainin R (1) and a novel dimeric stilbene, gnetuhainin S (2) were isolated from the lianas of Gnetum hainanense. Their structures were elucidated on the basis of spectroscopic and chemical evidence, especially 2D NMR analysis. The structure of 2 was further supported by X-ray crystallographic analysis. The anti-inflammatory activity of 1 has been tested, and it showed potent activity of histamine receptor antagonism.