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Determination of the Amplification Factor for 2-Hydroxy-ethylperoxy Radicals in PERCA

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Chinese Chemical Letters 2006年第7期17卷 957-960页

作者： Bin QI yan MA xiao Qian LI xiao yan TANG School of Chemistry and Material Sciences Shaanxi Normal University Xian 710062 College of Environmental Sciences Peking University Beijing 100871

A new method is proposed to determine the amplification factor for 2-hydroxy ethylperoxy radicals （HOC2H4O2·） in chemical amplifier. The radical source comes from the reaction of excess ethene with HO· radicals generated in the photolysis of water vapor at the wave length of 185 nm in air in a flow tube. This produces a radical source which contains equal amount of HO2·and HOC2H4O2·. The amplification factor is derived from the slopes of the lines between produced NO2 in chemical amplifier and total initial radical concentrations measured for the source of HO2· and that of the same amount of HO2· and HOC2H4O2· respectively. The amplification factor of HOC2H4O2· was similar to that of HO2·, indicating that HOC2H4O2· can be measured with the same sensitivity as HO2· by chemical amplifier.

关键词： 2-Hydroxy ethylperoxy radical amplification factor chemical amplification.

High-throughput screening of single-atom catalysts confined in monolayer black phosphorus for efficient nitrogen reduction reaction

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Nano Research 2024年第4期17卷 2360-2367页

作者： xiao-yan Li Manyi Duan Pengfei Ou Department of Electrical and Computer Engineering University of TorontoTorontoOntario M5S 1A4Canada School of Physics and Electronic Engineering Sichuan Normal UniversityChengdu 610101China Department of Chemistry Northwestern UniversityEvanstonIL 60208USA

The discovery of metal-nitrogen centers as the active sites for electrolysis has aroused significant interest in utilizing single-atom catalysts for nitrogen reduction reaction(NRR).Properly designed nanostructured catalysts that strongly interact with nitrogen molecules(N_(2))can promote adsorption and activation,thereby resulting in efficient catalysts with high stability,activity,and *** this study,using density functional theory calculations,we selected monolayer black phosphorus(BP)as the substrate and screened a series of single-atom transition metals confined in tri-coordinated and tetra-coordinated active centers(without and with N dopants)to electro-catalyze *** a result,we have identified two promising candidates(Hf_(1)-N_(1)P_(2)-1 and Tc_(1)-N_(4)),which exhibit not only low overpotentials of 0.56 and 0.49 V but also high thermodynamic and electrochemical stability,as well as good selectivity towards NRR over the competing hydrogen evolution *** also demonstrate the ability of Hf_(1)-N_(1)P_(2)-1 and Tc_(1)-N_(4) to activate and hydrogenate N_(2) by donating electrons and regulating charge *** study not only predicts new BP-based promising catalysts but also provides guidance for the rational design of high-performance NRR electrocatalysts under ambient conditions.

关键词： N_(2) electroreduction reaction single-atom catalysts black phosphorus density functional theory high-throughput calculations

Metallothionein Induction by Cd(II) and Zn(II)

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Chinese Chemical Letters 2006年第2期17卷 269-272页

作者： xiao yan ZHANG Xin GAO yan LI xiao Dong FAN Northwestern Polytechnical University Xi＇an 710072 School of Chemical Engineering Northwest University Xi＇an 710069 The Hospital Lab New York University

The induction of MT（metallothionein） by Cd（Ⅱ） and Zn（Ⅱ） in renal proximal tubule cells （LLC-PKI） and the effects of simultaneous administration of Cd（Ⅱ） and Zn（Ⅱ） on MT induction were discussed. The two metals administered together are able to induce MT to almost 40/ag MT/mg protein. The additive production of MT may be due to two different effects by Cd（Ⅱ） and Zn（Ⅱ） on the activation of MT transcription. The experiments of simultaneous administration of Cd（Ⅱ） and Zn（Ⅱ） to the renal proximal tubule cells demonstrated the interaction of these metals, MT induction and proximal tubule toxicity.

关键词： Metal metallothionein induction toxicity.

Microstructural evolution and mechanical properties of Ni-45Ti-5Al-2Nb-1Mo alloy subjected to different heat treatments

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Rare Metals 2023年第8期42卷 2774-2780页

作者： xiao-Yun Song yan Li Fei Zhang State Key Laboratory of Nonferrous Metals and Processes GRIMAT Engineering Institute Co.LtdBeijing 101407China School of Materials Science and Engineering Beihang UniversityBeijing 100191China

The effects of solution and aging heat treatment on microstructural evolution and room temperature tensile properties for as-forged Ni-45Ti-5Al-2Nb-1Mo alloy were investigated through scanning electron microscopy(SEM),transmission electron microscopy(TEM)and tensile *** results show that the microstructure of solution-treated alloy comprises NiTi matrix,Ti_(2)Ni and(Nb,Ti)ss *** aging treatment at 700℃for 6 and100 h,the distribution of Ti_(2)Ni and(Nb,Ti)ss precipitates increases in *** new type of precipitate is observed in the specimen aged at 700℃.After aging at800℃for 100 h,numerous nanosized Ni_(2)TiAl phases are precipitated within the *** and aging treatments improve the tensile properties at room *** strength and ductility are improved after solution treatment at 1100℃plus aging treatment at 800℃for 6 h or 700℃for 100 *** aging time prolonging to 100 h at 800℃,the precipitation of fine Ni2TiAl particles leads to the improvement in tensile strength and deterioration of elongation.

关键词： NiTi-Al-based alloy Intermetallics Microstructure Mechanical properties Heat treatment

Shaped charge penetration into high-and ultrahigh-strength Steel-Fiber reactive powder concrete targets

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Defence Technology（防务技术） 2020年第1期16卷 217-224页

作者： Qiang-qiang xiao Zheng-xiang Huang Xudong zu Xin Jia Qi-feng Zhu Wei Cai School of Mechanical Engineering Nanjing University of Science and TechnologyXiaolingwei 200Nanjing210094China China South Industries Group Corporation Chongqing400039China

Experiments on shaped charge penetration into high and ultrahigh strength steel-fiber reactive powder concrete(RPC) targets were performed in this *** show that the variation of penetration depth and crater diameter with concrete strength is different from that of shaped charge penetration into normal strength concrete(NSC).The crater diameter of RPC is smaller than that of NSC penetrated by the shaped *** jet particles are strongly disturbed and hardly reach the crater bottom because they pass through the narrow channel formed by jet penetration into the *** effects of radial drift velocity and gap effects of jet particles for a shaped charge penetration into RFC target are ***,a theoretical model is presented to describe the penetration of shaped charge into RPC *** the concrete strength increases,the penetration resistance increases and the entrance crater diameter *** the drift velocity and narrow crater channel,the low-velocity jet particles can hardly reach the crater bottom to increase the penetration ***,the narrow channel has a stronger interference to the jet particles with increasing concrete strength;hence,the gap effects must be *** drift velocity and gap effects,which are the same as penetration resistance,also have significant effects during the process of shaped charge penetration into ultrahigh-strength concrete,The crater profiles are calculated through a theoretical model,and the results are in good agreement with the experiments.

关键词： Shaped charge Reactive powder concrete target Penetration Radial drift velocity Gap effects

A lightweight global awareness deep network model for flame and smoke detection

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Optoelectronics Letters 2023年第10期19卷 614-622页

作者： xiao Bowei yan Chunman School of Physics and Electronic Engineering Northwest Normal UniversityLanzhou730070China

Aiming at the trouble of low detection accuracy and the problem of large model size,this paper proposes a lightweight flame-and-smoke detection model depending on global awareness of *** proposed method replaces the Conv+BatchNorm+SiLU(CBS)module of original you only look once version 5(YOLOv5)in the backbone with DSConv+BatchNorm+SiLU(DBS),and the C3 module with GC3,and thus constructs a lightweight backbone ***,involution(InvC3)module is proposed to enhance the global modeling ability and compress the model size,and a module using adaptive receptive fields,named FConv,is proposed to enhance the model’s perception capacity for foreground complex flame-and-smoke information in feature *** results show that the proposed model increases the mean average precision of all categories at 0.5 IOU(mAP@0.5)to 70.8%,the mAP@0.5:0.95 to 39.7%,reduces the number of parameters to 3.57M and the amount of calculation to 7.4 giga floating-point operations per second(GFLOPs)under the premise of ensuring the detection *** has been verified that the model can achieve high-precision real-time detection of flame and smoke.

关键词： smoke backbone replace

Rayleigh-Enhanced Nondegenerate Four-Wave Mixing

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Chinese Physics Letters 1996年第9期13卷 672-674页

作者： YU zu-he MI Xin JIANG Qian Ll xiao-feng FU Pan-ming Laboratory of Optical Physics Institute of PhysicsChinese Academy of SciencesBeijing 100080

We report a Rayleigh-enhanced nondegenerate four-wave mixing(NFWM)in carbon *** the Rayleigh-enhanced NFWM spectrum a relaxation time of as short as 220fs was deduced.

关键词： Rayleigh relaxation disulfide

Hugoniot equation of state of olivine and its geodynamic implications

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Science China Earth Sciences 2016年第3期59卷 619-625页

作者： HUANG xiao Ge YUAN Xian Hao CHEN zu An LIU Fu Sheng BAI Wu Ming Key Laboratory of Earth and Planetary Physics Institute of Geology and Geophysics Chinese Academy of Sciences Institute of High Temperature and High Pressure Physics Key Laboratory of Advanced Technologies of Materials Ministry of Education of China Southwest Jiaotong University

Large olivine samples were hot-pressed synthesized for shock wave experiments. The shock wave experiments were carried out at pressure range between 11 and 42 GPa. Shock data on olivine sample yielded a linear relationship between shock wave velocity D and particle velocity u described by D=3.56(?0.13)+2.57(?0.12)u. The shock temperature is determined by an energy relationship which is approximately 790°C at pressure 28 GPa. Due to low temperature and short experimental duration, we suggest that no phase change occurred in our sample below 30 GPa and olivine persisted well beyond its equilibrium boundary in metastable phase. The densities of metastable olivine are in agreement with the results of static compression. At the depth shallower than 410 km, the densities of metastable olivine are higher than those of the PREM model, facilitating cold slab to sink into the mantle transition zone. However, in entire mantle transition zone, the shock densities are lower than those of the PREM model, hampering cold slab to flow across the "660 km" phase boundary.

关键词： Hugonite density Shock temperature Olivine Mantle transition zone

Epigallocatechin gallate content change of the fresh tea leaf homogenates extracted by different methods in extraction and preservation

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Journal of Forestry Research 2006年第4期17卷 329-331页

作者： yanG Lei GAO yan-hua zu Yuan-gang LIU xiao-na WANG Lei zu Shu-chong Plant Medicine Project Research Center Northeast Forestry University Harbin 150040 P. R. China

The fresh leaves of China green tea, Camellia sinensis, were collected from Fuyang, Zhejiang Province, China, in April. The tea polyphenols was extracted by four different methods （homogenized with distilled water at room temperature, homogenized with 0.3% citric acid （w/v） at room temperature, 5- min boiling and homogenized with distilled water at room temperature, homogenized with 85℃ distilled water）, and after preserving at room temperature, the change of the Epigallocatechin gallate （EGCG） contents of the extracts was investigated. Results indicated that the EGCG content of homogenate extracted with 85℃ distilled water was the highest before the extract was preserved, followed by that of the extract homogenized with 0.3% citric acid at room temperature. During preservation, EGCG content changed obviously. The EGCG contents of homogenates extracted with distilled water at room temperature and 85℃ distilled water declined quickly and separately reduced to 21.52% and 54.6% of their initial contents after preservation for 12 h. The EGCG contents extracted by 0.3% citric acid （w/v） solvent at room temperature and 5- min boiling/homogenized with distilled water at room temperature declined relatively slowly ,and separately reduced to 76.9% and 85.16% of their initial contents after preservation for 12 h. It was also found that the citric acid can prevent the degradation of EGCG and the extract solution color is light green

关键词： Epigallocatechin gallate (EGCG) Homogenate extraction Content change