检索结果-南通市图书馆

High energy window for probing dark matter with cosmic-ray antideuterium and antihelium

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

chinese Physics c 2021年第6期45卷 188-201页

作者： Yu-c.en Ding nan Li chun-c.eng Wei Yu-Feng Zhou cAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China University of chinese Academy of Sc.ences Beijing 100049China School of Fundamental Physics and Mathematical Sc.ences Hangzhou Institute for Advanced StudyUCASand International Centre for Theoretical Physics Asia-PacificBeijing/HangzhouChina Key Laboratory of Particle Acceleration Physics and Technology Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China

cosmic-ray(cR)anti-nuclei are often considered important observables for indirect dark matter(DM)detection at low kinetic.energies,below GeV per *** the primary cR fluxes drop quickly towards high energies,the secondary anti-nuclei in cR are expected to be significantly suppressed in high energy regions(≥10 GeV per nucleon).If DM particles are heavy,the annihilation productions of DM can be highly boosted,and thus the fluxes of anti-nuclei produced by DM annihilation may exceed the secondary background at high energies,which opens a high energy window for indirect DM *** investigate the possibility of detecting heavy DM particles which annihilate into high energy *** use the Monte carlo generators PYTHIA,EPOS-LHc and DPMJET and the coalescence model to simulate the production of anti-nuclei,and constrain the DM annihilation cross-sections by using the AMS-02 and HAWc antiproton data and the HESS galactic center-ray *** find that the conclusion depends on the choice of DM density *** the“cored”type profile with a DM particle mass≥10 TeV,the contributions from DM annihilation can exceed the secondary background in high energy regions,which opens the high energy window,while for the“cuspy”type profile,the excess disappears.

关键词： dark matter coalescence model antideuterium antihelium

Heat transfer in high density electronics packaging

在线全文

学校读者我要写书评

暂无评论

Journal of central South University of Technology 2001年第4期8卷 278-282页

作者： ZHOU Jie min 1, YANG ying 1, DenG Sheng xiang 1, yi Zheng ming 1, WANG Xi tao 2, c.en Liu 2, Johan Liu 2 (1.Department of Applied Physics and Heat engineering, central South University, changsha 410083, china 2.Department of Production en Department of Applied Physics and Heat engineering Central South University Changsha China Department of Production engineering Chalmers University of Technology Göteborg Sweden

In order to get an insight into the thermal characteristic and to evaluate the thermal reliability of the "System in Packaging"(SIP), a new solution of electronics packaging, a heat transfer model of SIP was developed to predict the heat dissipation capacity and to investigate the effect of different factors on the tempe rature distribution in the electronics. The affecting parameters under consideration include the thermophysical properties of the substrates, the coeffic.ent of convection heat transfer, the thickness of the chip, and the density of power dissipation. ALGOR, a kind of finite element analysis software,was used to do the model simulation. Based on the simulation and analysis of the heat conduction and convection resistance, criteria for the thermal design were established and possible measurement for enhancing power dissipation was provided. The results show that the heat transfer model provides a new and effective way to the thermal design and thermal analysis of SIP and to the mechanical analysis for the further investigation of SIP.

关键词： electronics packaging thermal reliability heat transfer

Fluorine,chlorine,and gallium co-doped zinc oxide transparent conductive films fabricated using the sol-gel spin method

在线全文

学校读者我要写书评

暂无评论

Journal of Materiomics 2023年第4期9卷 745-753页

作者： Liwei che Jianmin Song Jinzheng Yang Xiaoyang c.en Junjie Li nan Zhang Shaopeng Yang Yanfeng Wang college of Sc.ences Hebei North UniversityPhotovoltaic Conductive Film Engineering Research Center of Hebei ProvinceZhangjiakou075000China college of Sc.ences Hebei Agriculture UniversityBaoding071001China Department of Intelligence Reconnaissance Special Police Academy of the Chinese People's Armed Police ForceBeijing102211China Province-Ministry co-construction collaborative Innovation center of Photovoltaic Technology of Hebei Province Hebei UniversityBaoding071002China

Transparent conductive films(TcFs)are crucial components of solar *** this study,F,cl,and Ga codoped ZnO(FcGZO)TcFs were deposited onto a glass substrate using the sol-gel spin-coating method and rapid thermal *** effects of F-doping content on the structural,morphological,electrical,and optical properties of FcGZO films were examined by XRD,TEM,FE-SEM,PL spectroscopy,XPS,Hall effects testing,and UVevisenIR *** prepared ZnO films exhibited a hexagonal wurtzite structure and preferentially grew along the c axis perpendicular to the *** in the doping concentration of F changed the interplanar crystal spacing and O vacancies in the *** a doping ratio of 2%(in mole),the F,cl,and Ga co-doped ZnO film exhibited the best photoelectric performance,with a carrier concentration of 2.62×10^(20)cm^(-3),mobility of 14.56 cm^(2)/(V·s),and resistivity of 1.64×10^(-3)*** average transmittance(AT)in the 380-1600 nm region nearly 90%with air as the reference,and the optical band gap was 3.52 eV.

关键词： ZnO transparent conductive films Sol-gel spin coating Electrical property Optical property

Light Fraction carbon and Water-Stable Aggregates in Black Soils

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Pedosphere 2007年第1期17卷 97-100页

作者： SHI yi c.en Xin SHen Shan-Min Key Laboratory of Terrestrial Ecological Process Institute of Applied Ecology Chinese Academy of Sciences Shenyang 110016 （China）

The distribution of light fraction carbon （LF-c） in the various size classes of aggregates and its relationship to water- stable aggregates as well as the influence of cultivation on the organic components in virgin and cultivated black soils were studied by wet sieving and density separation methods. The total organic carbon （TOc） and LF-c were significantly higher （P≤ 0.05） in the virgin soils than in the cultivated soils. The LF-c in aggregates of different size classes varied from 0.9 to 2.5 g kg^-1 in the cultivated soils and from 2.5 to 7.1 g kg^-1 in the virgin soils, whereas the ratio of LF-c to TOc varied from 1.9% to 7.3% and from 5.0% to 12.2%, respectively. After being incubated under constant temperature and controlled humidity for three months, the contribution of LF-c to TOc sharply decreased to an amount （1.7%4.5%） close to the level in soils that had been cultivated for 20 to 25 years （1.3%-8.8%）. As a result, the larger water-stable macro-aggregates （especially 〉 1 mm） decreased sharply, indicating that the LF-c pool in virgin soils declined quickly after cultivation, which reduced the water stability of soil aggregates.

关键词： black soil light fraction carbon water-stable aggregates

南酸枣多糖的体外抗氧化、降血糖与降血脂作用

在线全文

学校读者我要写书评

暂无评论

食品研究与开发 2024年第3期45卷 59-66页

作者：李景恩董金娇谢美珍隋文吴南生江西农业大学食品科学与工程学院江西南昌330045 江西农业大学南酸枣研究所江西南昌330045

以南酸枣多糖体积分数40%乙醇沉淀组分cAP-40为研究对象,初步评价其体外抗氧化、降血糖与降血脂作用。分别利用高效液相凝胶渗透色谱及高效液相离子色谱测定cAP-40的分子量与单糖组成,同时测定其对DPPH·和ABTS+·的清除率,α-葡萄糖苷... 详细信息

以南酸枣多糖体积分数40%乙醇沉淀组分cAP-40为研究对象,初步评价其体外抗氧化、降血糖与降血脂作用。分别利用高效液相凝胶渗透色谱及高效液相离子色谱测定cAP-40的分子量与单糖组成,同时测定其对DPPH·和ABTS+·的清除率,α-葡萄糖苷酶和α-淀粉酶的抑制率,甘氨胆酸钠和牛磺胆酸钠的结合率以及胰脂肪酶的抑制率。结果表明,cAP-40的洗脱曲线为单一对称峰,分子量约156206 Da,单糖主要由葡萄糖、半乳糖醛酸、半乳糖、阿拉伯糖、鼠李糖组成,摩尔百分比分别为40.8%、40.7%、9.3%、5.1%、2.0%。cAP-40浓度为1 mg/mL时,对DPPH·和ABTS^(+)·的清除率分别为(88.85±0.49)%和(87.13±1.63)%。浓度为16 mg/mL时,cAP-40对α-葡萄糖苷酶的抑制率为(71.28±2.34)%;在8 mg/mL处,对α-淀粉酶的抑制率为(72.29±4.85)%。此外,浓度为20 mg/mL时,cAP-40对胰脂肪酶的抑制率为(26.34±1.41)%;在5 mg/mL处,对甘氨胆酸钠和牛磺胆酸钠的结合率分别达到(31.87±4.53)%和(38.98±0.60)%。综上所述,南酸枣多糖cAP-40具有一定的体外抗氧化、降血糖与降血脂作用,为开发天然降糖、降脂功能食品提供理论依据,也为南酸枣资源的综合开发利用提供新的思路。

关键词：南酸枣多糖抗氧化降血糖降血脂

膨胀剂掺量对机制砂UHPc工作性和自收缩性能的影响

在线全文

学校读者我要写书评

暂无评论

混凝土与水泥制品 2024年第7期 29-32,37页

作者：任蒙恩宁利恒康海何晓丹元成方河南汇创实业有限公司河南郑州450003 郑州大学河南郑州450001

针对不同膨胀剂掺量下机制砂超高性能混凝土(UHPc)的工作性及自收缩性能进行了试验研究。结果表明:随着膨胀剂掺量的增加,机制砂UHPc的流动性和凝结时间均呈先增后减的趋势,当膨胀剂掺量为10%时,二者皆达到峰值,扩展度为445 mm,初凝时... 详细信息

针对不同膨胀剂掺量下机制砂超高性能混凝土(UHPc)的工作性及自收缩性能进行了试验研究。结果表明:随着膨胀剂掺量的增加,机制砂UHPc的流动性和凝结时间均呈先增后减的趋势,当膨胀剂掺量为10%时,二者皆达到峰值,扩展度为445 mm,初凝时间和终凝时间分别为44.4 h和50.2 h;机制砂UHPc的早期自收缩随着膨胀剂掺量的增加整体呈先减少后增加的趋势,当膨胀剂掺量为10%时,能够起到较好的收缩补偿作用。

关键词：机制砂超高性能混凝土膨胀剂工作性自收缩性能凝结时间

Influence of Glycerol content on Properties of Wheat Gluten/Hydroxyethyl cellulose Biocomposites

在线全文

学校读者我要写书评

暂无评论

chemical Research in chinese Universities 2008年第5期24卷 644-647页

作者： SONG yi-hu ZHenG Qiang LIU c.eng Department of Polymer Sc.ence and engineering Key Laboratory of Macromolecular Synthesis and Functionalization of Ministry of Education Zhejiang University Hangzhou 310027 P. R. China

environmentally friendly biocomposites were prepared by blending wheat gluten（WG）as a matrix, hydroxyethyl cellulose（HEc）as a filler,and glycerol as a plasticizer,followed by thermo-molding of the mixture at 120°c for crosslinking the *** absorption,tensile properties,dynamic mechanical analysis,and dynamic rheology were evaluated in relation to the glycerol *** strength and modulus drop dramatically with increasing glycerol content,which is accompanied by significant depression in the glass transition temperature and improvement in the extensibility of the biocomposites.

关键词： Wheat gluten Hydroxyethyl cellulose Biocomposite

Effect of Precipitation on Intergranular corrosion Resistance of 430 Ferritic Stainless Steel

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2015年第11期22卷 1062-1068页

作者： Xun-zeng HUANG Dan WANG yi-tao YANG School of Materials Sc.ence and engineering Shanghai University

With Nb-Ti-stabilized 430 ferritic stainless steel（NTS430FSS） and SUS 430 ferritic stainless steel（SUS430FSS） as experimental materials, the influence of precipitation on intergranular corrosion resistance was investigated. A series of aging treatment were carried out. The free-exposure corrosion test and double loop electrochemical potentiokinetic reactivation（DL-EPR） test with a scan rate of 1.67 m V/s at 26 °c were applied to evaluate the intergranular corrosion（IGc） resistance. Metallographic observation, scanning electron microscope（SEM）, transmission electron microscope（TEM） with energy dispersive spectroscopy（EDS） and X-ray diffraction（XRD） analysis were conducted. The results show that IGc occurred in SUS430 FSS aged above 700 °c, while it occurred in NTS430 FSS as the temperature was improved to 1 050 °c. The critical degree of sensitization Ir/Ia reaches 0.305 in SUS430 FSS, which is higher than that of NTS430 FSS, i.e. 0.010, aged at 950 °c for 2 h. The TEM, EDS and XRD results show that a large amount of cr23c6 precipitates with size of 60 nm×22 nm are located at the SUS430 FSS grain boundaries as chains. With the addition of Nb and Ti and reduction of c, the amount of precipitates reduces significantly in NTS430 FSS. A majority of cr23c6 were replaced by Ti c and Nb c. Only a small amount of spherical Ti c（R=186 nm） and square Ti N（312 nm×192 nm） with Nb and cr adsorbed are left along grain boundaries. Due to the dual stabilization of Nb and Ti, the precipitation of cr23c6 is restrained, the chromium depleted region is avoided and accordingly the resistance to the intergranular corrosion is improved.

关键词： 430 ferritic stainless steel intergranular corrosion double-loop electrochemical potentiokinetic reactivation carbonitride extraction precipitation

Hydrogen production by steam reforming of acetic acid and bio-oil using Ni/γ-Al2O3 catalysts

在线全文

学校读者我要写书评

暂无评论

International Journal of Agricultural and Biological engineering 2015年第6期8卷 69-76页

作者： Li Yanmei Fu Peng yi Weiming Bai Xueyuan School of Agricultural and Food engineering Shandong University of TechnologyZiboShandong 255049China Shandong Research center of engineering and Technology for clean energy ZiboShandong 255049China

Hydrogen production from steam reforming of bio-oil and acetic acid using Ni/γ-Al2O3 catalyst was studied in a laboratory-scale fixed bed *** study selected different Ni loadings(16.8%and 30.5%)in Ni/γ-Al2O3 catalysts and reaction temperatures(500°c,600°c and 700°c)as variables to optimize the hydrogen yield and selectivity of gases *** were carried out in an isothermal *** catalysts were prepared on wet impregnation of aγ-Al2O3 which supported with two different Ni *** principal gases generated were H2,cO,cO2 and *** results from steam reforming of acetic acid showed that the yield and selectivity of hydrogen using the catalyst with 30.5%Ni were significantly higher than that with 16.8%*** results showed that the most favorable temperature for hydrogen production was 600°c,and the steam reforming of bio-oil using Ni/γ-Al2O3 catalyst with 30.5%Ni showed that the yields and selectivity of H2 and cO2 increased with the temperature increasing while cH4 and cO selectivity *** results showed that the most favorable temperature for hydrogen production from bio-oil using 30.5%Ni/γ-Al2O3 was 600°c,at which hydrogen yield was at its maximum of 65%.

关键词： hydrogen bio-oil Ni/γ-Al2O3 catalyst steam reforming acetic acid