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Tungsten nanoparticle-strengthened copper composite prepared by a sol–gel method and in-situ reaction

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International Journal of Minerals,Metallurgy and Materials 2019年第11期26卷 1477-1483页

作者： tian-xing Lu Cun-guang Chen Zhi-meng Guo Pei Li Ming-xing Guo Institute for Advanced Materials and Technology University of Science and Technology BeijingBeijing 100083China State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China

Tungsten nanoparticle-strengthened Cu composites were prepared from nanopowder synthesized by a sol–gel method and in-situ hydrogen *** tungsten particles in the Cu matrix were well-dispersed with an average size of approximately 100–200 *** addition of nanosized W particles remarkably improves the mechanical properties,while the electrical conductivity did not substantially *** Cu–W composite with 6 wt%W has the most comprehensive properties with an ultimate strength of 310 MPa,yield strength of 238 MPa,hardness of HV 108 and electrical conductivity of 90%*** enhanced mechanical property and only a small loss of electrical conductivity demonstrate the potential of this new strategy to prepare W nanoparticle-strengthened Cu composites.

关键词： copper composites second phase strengthening tungsten sol–gel method

Study on Wave Characteristics from the South Atlantic Ocean to the Gulf of Guinea Based on Short-Term Numerical Simulation in Winter Season

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China Ocean Engineering 2023年第2期37卷 312-322页

作者： XU Fu-min ZHENG Jin-hai YA Han-zheng xing tian Key Laboratory of Ministry of Education for Coastal Disaster and Protection Hohai UniversityNanjing 210098China College of Harbor Coastal and Offshore EngineeringHohai UniversityNanjing 210098China

Waves play a major role in the ocean phenomena in the Gulf of Guinea(GoG). In order to reveal the spatial-temporal distribution characteristics and the propagation mechanism of waves from the South Atlantic Ocean to the GoG, 4typical points located in mid-latitude of South Atlantic(14°30′W, 30°0′S), south of the GoG(10°30′W, 15°0′S), offshore of the GoG(0°0′, 0°0′) and near shore of the GoG(6°4′58.8″W, 4°3′36″S) are selected, and waves from Atlantic Ocean to GoG are simulated by using a two-layer-nesting wave numerical model SWAN(Simulating Waves Nearshore). The results show that the hybrid waves(waves hereafter) and the swells have strong relationship with local wind in Roaring Forties and at mid-latitude of South Atlantic Ocean, while there is no obvious correlation between waves and local winds in the GoG. Swells are generated in the South Atlantic Ocean and propagate into the GoG. 2D wave spectra at the four selected typical points are simulated. The spectral pattern and wave component structure indicate that the wave system in GoG is dominated by the S-SW swells generated from Roaring Forties and mid-latitude of South Atlantic, whether it is at maximum(2.2-2.8 m), medium(1.8-2.2 m) or minimum(1.2 m) significant wave height in the GoG during simulation period.

关键词： Gulf of Guinea wave characteristics 2D wave spectra swell roaring forties

Experimental investigation of the cyclic degradation of the one-way shape memory effect of NiTi alloys

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International Journal of Minerals,Metallurgy and Materials 2019年第12期26卷 1539-1550页

作者： tian-xing Zhao Guo-zheng Kang Chao Yu Qian-hua Kan Institute of Applied Mechanics State Key Laboratory of Traction PowerSouthwest Jiaotong UniversityChengdu 610031China Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province School of Mechanics and EngineeringSouthwest Jiaotong UniversityChengdu 610031China

Based on stress-and strain-controlled cyclic tension-unloading-heat-cooling tests,cyclic degradation of the one-way shape memory effect(OWSME)of NiTi shape memory alloys(SMAs)was *** was seen,in thermo-mechanical coupled cyclic tests,that residual strain after each cycle accumulated,but the martensite reorientation stress and dissipation energy-per-cycle decreased as the number of cycles ***,the cyclic degradation of OWSME was aggravated by increasing the stress/strain *** addition,the stress-strain response of NiTi SMAs was further investigated by performing simultaneous thermo-mechanical coupled cyclic tests with various phase-angle differences between the mechanical and thermal cyclic *** can be concluded that such cyclic response depends significantly on prescribed phase-angle *** experimental results are helpful for both the development of constitutive models and engineering applications of NiTi SMAs.

关键词： NiTi shape memory alloys one-way shape memory effect cyclic degradation thermo-mechanical coupling martensite orientation

The trend of mechanizing road header for coal mine entry

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Journal of Coal Science & Engineering(China) 2010年第1期16卷 99-103页

作者： HUI xing-tian School of Architecture and Civil Engineering Xi＇an University of Science and Technology Xi＇an 710054 China

In discussing coal mine entry construction with rock bolt technology, examinedthe craft and machinery problems as well as the conditions in which to use each kind ofmachine and *** exposed the intrinsic flaws of the widely used road *** problemis that it was designed according to early timbering support state but is not suitable forrock bolt *** way to improve the function of existing road headers is notthrough parallel operations but using the SUDM (Shield Union Driving Machine), which isa new machine that improves *** article proposed a few solutions in designto solve this problem.

关键词： coalmine gateway mine entry construction road header mechanization suggestion

Safety Evaluation of Diacylglycerol Microemulsion in Rats/Mice

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Agricultural Sciences in China 2011年第7期10卷 1117-1124页

作者： HUANG Tao CHEN Ying SHOU tian-xing YANG Jing LI Duo Department of Food Science and Nutrition Zhejiang University Hangzhou 310029 P.R.China Centre of Nutrition and Food Safety of Asia Pacific Clinical Nutrition Society Hangzhou 310029 P.R.China

The objective of the present study was to evaluate potential adverse effects of diacylglycerol microemulsion （DAGM） in rats/mice. Acute safety evaluation was carried out by giving intragastrically with 20 mL 25% DAG kg-1 body weight of DAGM or water with two groups of mice. Chronic safety evaluation with 40 male and 40 female Sprague-Dawley rats was carried out by setting a control group and 3 different dose groups （n=10 male＋10 female） administered with DAGM with 6.7, 10 and 20 mL kg-1 body weight per day. Relevant parameters of liver and kidney function and biochemistry were determined by standard methods at end point. Acute toxicity study revealed the maximum tolerated dose （MTD） of DAGM was 20 mL kg-1 body weight in mice. No death was observed at the dose of 20 mL kg-1 body weight per day. Chronic safety evaluation did not show significant changes on hematological, histopathologic, clinical, and biochemical tests when administered at levels of 6.7, 10 and 20 mL kg-1 body weight per day to rats for 30 d. No significant body weight changes were observed in different dosages in both male and female rats. Our results suggested that acute and chronic adverse effects were not observed in histology and clinical parameters in both mice and rats. The results suggested that DAGM is safe at the experimental levels.

关键词： safety evaluation diacylglycerol microemulsion acute safety chronic safety

Comparison of forage yield,silage fermentative quality,anthocyanin stability,antioxidant activity,and in vitro rumen fermentation of anthocyanin-rich purple corn(Zea mays L.) stover and sticky corn stover

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Journal of Integrative Agriculture 2018年第9期17卷 2082-2095页

作者： tian xing-zhou Pramote Paengkoum Siwaporn Paengkoum Sorasak Thongpea BAN Chao School of Animal Production Technology Institute of Agricultural Technology Suranaree University of Technology Program in Agriculture Faculty of Science and Technology Nakhon Ratchasima Rajabhat University

The objective of this study was to observe the forage yield, silage fermentative quality, anthocyanin stability, and antioxidant activity during the storage period and in vitro rumen fermentation of anthocyanin-rich purple corn （Zea mays L.） stover （PS） and sticky corn stover （SS）. Forage yield of corn stover was weighed and ensiled with two treatments：（1） hybrid sticky waxy corn stover （control）, and （2） hybrid purple waxy corn stover （treatment）. Samples were stored in mini-silos for periods of 0, 7, 14, 21,42, 63, 84, and 105 d. The results showed that PS had significantly higher （P〈0.05） yields of dry matter （DM）, organic matter （OM）, gross energy （GE）, crude protein （CP）, neutral detergent fiber （NDF）, acid detergent fiber （ADF）, and total anthocyanins than that of the SS. Anthocyanin-rich purple corn stover silage （PSS） showed higher （P〈0.05） levels of DM and CP relative to the sticky corn stover silage （SSS）. Although anthocyanin-rich PSS displayed a lower （P〈0.05） level of pelargonidin-3-glucoside （P3G）, it had higher （P〈0.05） levels of peonidin （Peo） and pelargonidin （Pel） compared to the control. Delphinidin （Del） and malvidin （Mal） were not detected in SSS during the ensilage period; in PSS, Del was no longer detected after 7 d of ensilage. Specifically, total anthocyanins in anthocyanin-rich PSS decreased rapidly （P〈0.05） prior to 7 d of ensilage, and then remained at relatively stable （P〉0.05） constants. Compared to the anthocyanin-rich PSS, SSS displayed significantly higher （P〈0.05） pH value and ammonia nitrogen （NH3-N） content. Propionic acid （PA） at 0 d and butyric acid （BA） during the entire study period were not detected, whereas anthocyanin-rich PSS showed a higher （P〈0.05） level of lactic acid （LA） than that of the SSS. Compared with the SSS extract, anthocyanin-rich PSS extract showed a higher （P〈0.05） level of 2,2-diphenyl-1-picryihydrazyl （DPPH） scavenging activity and displayed a lower （P〈0.05） half maximal inhibitory concentration （IC50） v

关键词： anthocyanin-rich purple corn stover silage anthocyanin stability silage fermentative quality antioxidant activity rumen fermentation

Degradation induces changes in the soil C:N:P stoichiometry of alpine steppe on the Tibetan Plateau

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Journal of Mountain Science 2019年第10期16卷 2348-2360页

作者： ZHANG Zhen-chao HOU Ge LIU Miao WEI tian-xing SUN Jian School of Soil and Water Conservation Beijing Forestry UniversityBeijing100083China Synthesis Research Centre of Chinese Ecosystem Research Network Key Laboratory of Ecosystem NetworkObservation and ModellingInstitute of Geographic Sciences and Natural Resources ResearchChinese Academy ofSciencesBeijing100101China State Key Laboratory of Urban and Regional Ecology Research Center for Eco–environmental SciencesChineseAcademy of SciencesBeijing100085China Department of Ecology Evolutionand Natural ResourcesSchool of Environmental and Biological SciencesRutgersUniversityNew BrunswickNew Jersey08901USA

Due to the Tibetan Plateau’s unique high altitude and low temperature climate conditions,the region’s alpine steppe ecosystem is highly fragile and is suffering from severe degradation under the stress of increasing population,overgrazing,and climate *** soil stoichiometry,a crucial part of ecological stoichiometry,provides a fundamental approach for understanding ecosystem processes by examining the relative proportions and balance of the three *** the impact of degradation on the soil stoichiometry is vital for conservation and management in the alpine steppe on the Tibetan *** study aims to examine the response of soil stoichiometry to degradation and explore the underlying biotic and abiotic mechanisms in the alpine *** conducted a field survey in a sequent degraded alpine steppe with seven levels inNorthern *** plant species,aboveground biomass,and physical and chemical soil properties such as the moisture content,temperature,pH,compactness,total carbon(C),total nitrogen(N),and total phosphorus(P)were measured and *** results showed that the contents of soil C/N,C/P,and N/P consistently decreased along intensifying degradation *** regression analysis and a structural equation model(SEM),we found that the C/N,C/P,and N/P ratios were positively affected by the soil compactness,soil moisture content and species richness of graminoids but negatively affected by soil pH and the proportion of aboveground biomass of *** soil temperature had a negative effect on the C/N ratio but showed positive effect on the C/P and N/P *** current study shows that degradation-induced changes in abiotic and biotic conditions such as soil warming and drying,which accelerated the soil organic carbon mineralization,as well as the increase in the proportion of forbs,whichwere difficult to decompose and input less organic carbon into soil,resulted in the decreases in soil C/N,C/P,and N/P contents to a great ex

关键词： Tibetan Plateau Alpine steppe Degradation Soil stoichiometry C/N C/P N/P

Incommensurate Antiferromagnetism in the Extended t-J Model

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Communications in Theoretical Physics 2002年第5期38卷 617-620页

作者： LIANG Ying MA tian-xing FENG Shi-Ping CHEN Wei-Yeu Department of Physics and Key Laboratory of Beam Technology and Material Modification Beijing Normal University Beijing 100875 China National Laboratory of Superconductivity Academia Sinica Beijing 100080 China Department of Physics and Key Laboratory of Beam Technology and Material Modification Beijing Normal University Beijing 100875 China National Laboratory of Superconductivity Academia Sinica Beijing 100080 China Department of Physics and Key Laboratory of Beam Technology and Material Modification Beijing Normal University Beijing 100875 China National Laboratory of Superconductivity Academia Sinica Beijing 100080 China Department of Physics Tamkang University Tamsui 25137 Taiwan

The effect of the extra second neighbor hopping t' on the incommensurate spin correlation in the t-J modelin the underdoped regime is studied within the fermion-spin theory. It is shown that although the extra second neighborhopping t' is systematically accompanied with the increasing of the weight of the incommensurate peaks in the dynamicalspin structure factor, for the physical reasonable small value of t' the qualitative behavior of the incommensurate spincorrelation in the t-t'-J model is the same as in the case of t-J model.

关键词： incommensurate antiferromagnetism, t-J model, fermion-spin theory

Curcumin induces apoptosis through the mitochondria-mediated apoptotic pathway in HT-29 cells

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2009年第2期10卷 93-102页

作者： Jin-bo WANG Li-li QI Shui-di ZHENG tian-xing WU Department of Chemistry College of Science Zhejiang University Hangzhou 310027 China Ningbo Institute of Technology Zhejiang University Ningbo 315100 China

Objective： To investigate the effects of curcumin on release of cytochrome c and expressions of Bcl-2, Bax, Bad, Bcl-xL, caspase-3, poly ADP-ribose polymerase （PARP）, and survivin of HT-29 cells. Methods： HT-29 cells were treated with curcumin （0-80 μmol/L） for 24 h. The release of cytochrome c from the mitochondria and the apoptosis-related proteins Bax, Bcl-2, Bcl-xL, Bad, caspase-3, PARP, and survivin were determined by Western blot analysis and their mRNA expressions by reverse transcriptase-polymerase chain reaction （RT-PCR）. Results： Curcumin significantly induced the growth inhibition and apoptosis of HT-29 cells. A decrease in expressions of Bcl-2, Bcl-xL and survivin was observed after exposure to 10-80 μmol/L curcumin, while the levels of Bax and Bad increased in the curcumin-treated cells. Curcumin also induced the release of cyto- chrome c, the activation ofcaspase-3, and the cleavage of PARP in a dose-dependent manner. Conclusion： These data suggest that curcumin induced the HT-29 cell apoptosis possibly via the mitoehondria-mediated pathway.

关键词： Curcumin Apoptosis Mitochondrial pathway HT-29 cells