期刊文献+
共找到4,394篇文章
< 1 2 220 >
每页显示 20 50 100
Solar Driven 15.7% Hydrogen Conversion by Harmony of Light Harvesting,Electron Transporting Bridge,and S-Defection in a Self-Assembled Microscale CuS/rGO/CP Photoanode
1
作者 Sujeong Kim Boseok Seo +6 位作者 Hyerim Park Younghwan Im Jeong Yeon Do Byung Sub Kwak Namgyu Son Minkyu Kim Misook Kang 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2024年第3期190-201,共12页
CuS is an encouraging photoelectrode candidate that meets the essential requirements for efficient solar-to-hydrogen production,but it has not been thoroughly studied.A CuS light absorber layer is grown by the self-as... CuS is an encouraging photoelectrode candidate that meets the essential requirements for efficient solar-to-hydrogen production,but it has not been thoroughly studied.A CuS light absorber layer is grown by the self-assembly of copper and sulfur precursors on a carbon paper(CP)electrode.Simultaneously,rGO is introduced as a buffer layer to control the optical and electrical properties of the absorber.The well-ordered microstructural arrangement suppresses the recombination loss of electrons and holes owing to enhanced charge-carrier generation,separation,and transport.The potential reaching 10 mA cm^(-2)in 1.0 M KOH solution is significantly lowered to 0.87 V,and the photocurrent density at 1.23 V is 94.7 mA cm^(-2).The computational result reveals that the potential-determining step is sensitive to O^(*)stability;the lower stability of O^(*)in the thin layer of CuS/rGO decreases the free-energy gap between the initial and final states of the potential-determining step,resulting in a lowering of the onset potential.The faradaic efficiency for the photoelectrochemical oxygen evolution reaction in the optimized 2CuS/1rGO/CP photoanode is 98.60%,and the applied bias photon-to-current and the solar-to-hydrogen efficiencies are 11.2%and 15.7%,respectively,and its ultra-high performance is maintained for 250 h.These record-breaking achievement indices may be a trigger for establishing a green hydrogen economy. 展开更多
关键词 15.7%-solar to hydrogen density functional theory lower photopotential p-CuS/rGO/cp photoanode photoelectrochemical oxygen evolution
下载PDF
Resonance Raman Spectra of Purified PS Ⅱ Core Antenna Complexes CP43 and CP47 被引量:2
2
作者 单际修 杨昆云 +7 位作者 冯丽洁 李良璧 匡廷云 王居硕 赵南明 刘玉龙 朱恪 杨国桢 《Acta Botanica Sinica》 CSCD 1999年第3期280-284,共5页
PSⅡ core antenna complexes, CP43 and CP47, were purified from spinach (Spinacia oleracea L.) by DEAE Fractogel TSK 650S anion exchange chromatography. Their normal temperature (298 K) resonance Raman spectra were... PSⅡ core antenna complexes, CP43 and CP47, were purified from spinach (Spinacia oleracea L.) by DEAE Fractogel TSK 650S anion exchange chromatography. Their normal temperature (298 K) resonance Raman spectra were measured. The results suggest that all β carotenoids bound to CP43 and CP47 are in all trans configuration and likely in twisted conformations. 展开更多
关键词 PSⅡ Core antenna complexes cp43 cp47 Resonance Raman spectrum β carotene
下载PDF
Construction of Plant Virus Expression Vector pClYVV/CP/W and Expression of GFP
3
作者 王振东 王晓华 +5 位作者 孟鹏 秦会权 郑新伟 刘芳普 薛立江 张敏 《Agricultural Science & Technology》 CAS 2009年第5期38-41,48,共5页
[ Objective] The study was to report the construction of plant virus expression vector pCIYVV/CP/W and the expression of green fluorescent protein(GFP) with pCIYVV/CP/W, and to develop effective plat virus vector fo... [ Objective] The study was to report the construction of plant virus expression vector pCIYVV/CP/W and the expression of green fluorescent protein(GFP) with pCIYVV/CP/W, and to develop effective plat virus vector for plant bioreactor to produce useful protein. [ Method] A section of multiple cloning sites among NIb/CP genes in pCIYVV genome and deoxyribonucleotide polylinker of cleavage recognition sequence containing viral protease Nla were cloned with infectivity full-length cDNA of clover yellow vein virus (CIYVV), and pCIYVV/CP/W vector was constructed, GFP gene was inserted into pCIyVV/CP/W to construct the pCIYVV/CP/W/GFP vector. The transcription situation of recombinant virus clone was detected by RT-PCR, and targeted gene products expressed by recombinant virus clone were detected with western blot (WB). [Result] The broad bean seedling inoculated with pCIYVV/CP/W/GFP expressed the same symptom as wild type CIYVV, morbidity was of 100%, the result showed that recombinant virus clone pCIYVV/CP/W/GFP didn't suppress, insertion of foreign gene didn't destroy the open reading frame of pCIYVV/CP/W. Foreign gene can keep living in F, progeny virus genorne steadily, recombinant virus clone pCIYVV/CP/W/GFP could steadily express GFP in progeny virus at least.[ Conclusion] The useful plant virus vector was provided for useful protein expressing. 展开更多
关键词 Plant virus expression vector pCIYVV/cp/W pCIYVV/cp/W/GFP CONSTRUCTION EXPRESSION
下载PDF
Kinetic Fluorescence Spectral Analysis of Core Antennas CP43 and CP47 of Photosystem Ⅱ with Ultrafast Time-resolved Technology
4
作者 贺俊芳 王水才 +3 位作者 张舒 贺锋涛 单际修 匡廷云 《Acta Botanica Sinica》 CSCD 2001年第7期704-708,共5页
Ultrafast time_resolved fluorescence experiments have been performed with core antennas CP43 and CP47 of PS Ⅱ. Their dynamic fluorescence spectra were obtained with excitation wavelength 514.5 nm. For CP43, the emiss... Ultrafast time_resolved fluorescence experiments have been performed with core antennas CP43 and CP47 of PS Ⅱ. Their dynamic fluorescence spectra were obtained with excitation wavelength 514.5 nm. For CP43, the emission spectrum was found to be from 640 to 780 nm with a peak at ~680 nm and the lifetime of fluorescence was 3.54 ns. For CP47, the emission spectrum was from 630 to 775 nm with a peak at ~691 nm and the fluorescence lifetime was 3.22 ns. The fluorescence emission efficiencies of Chl a in CP43 and CP47 were calculated to be approximately 38.3% and 40.6%, respectively. The energy transfer from β_Car to Chl a in CP43 and CP47 was discussed. The rates of energy transfer from β_Car to Chl a were measured to be about 9.6×10 11 s -1 and 1.3×10 12 s -1 and energy transfer efficiencies 47.5% and 66.5% respectively. The edge_edge distances between β_Car and Chl a in CP43 and CP47 were estimated to be ~0.110 nm and ~0.085 nm respectively. 展开更多
关键词 core antenna cp43 cp47 β-Car Chl a energy transfer PS
下载PDF
空中交通CPS结构特性及韧性评估 被引量:1
5
作者 王兴隆 魏奕雯 贺敏 《北京航空航天大学学报》 EI CAS CSCD 北大核心 2024年第4期1187-1196,共10页
针对空中交通体系结构复杂、耦合性强、脆弱性高的特点,为缓解因受扰导致的级联失效现象,对其结构韧性进行研究。建立了空中交通信息物理系统(CPS)模型,提出同层度与层间度、同层介数与层间介数等指标,分析级联失效过程;提出空中交通CP... 针对空中交通体系结构复杂、耦合性强、脆弱性高的特点,为缓解因受扰导致的级联失效现象,对其结构韧性进行研究。建立了空中交通信息物理系统(CPS)模型,提出同层度与层间度、同层介数与层间介数等指标,分析级联失效过程;提出空中交通CPS韧性的概念,并采用定量评估方法对受损能力和恢复能力进行度量;对比不同扰动-恢复策略下的空中交通CPS表现,制定最佳恢复策略,提高受扰时的韧性。以华东地区空中交通CPS为例进行分析,结果表明:空中交通CPS网络度分布服从幂率分布,介数服从指数分布;在基于介数度值扰动下,采用介数恢复策略可以有效提高受扰时空中交通CPS的韧性。 展开更多
关键词 信息物理系统 级联失效 扇区网络 航路网络 空中交通cpS韧性
下载PDF
Roundup Ready大豆中Lectin、CaMV 35S、NOS和CP4 EPSPS基因的提取与RT-PCR定性范围研究
6
作者 王飞 陈伟莉 +3 位作者 付宝莲 王硕 徐艳辉 许传彬 《检验检疫科学》 2009年第1期14-17,共4页
[目的]研究Roundup Ready大豆的Lectin、CaMV35S、NOS和CP4EPSPS等被检测基因的RT-PCR定性范围。[方法]用CTAB法提取DNA,对Lectin、CaMV35S、NOS和CP4EPSPS等被检测基因的检测条件进行了优化,确定了被检测基因在相同RT-PCR条件下的定性... [目的]研究Roundup Ready大豆的Lectin、CaMV35S、NOS和CP4EPSPS等被检测基因的RT-PCR定性范围。[方法]用CTAB法提取DNA,对Lectin、CaMV35S、NOS和CP4EPSPS等被检测基因的检测条件进行了优化,确定了被检测基因在相同RT-PCR条件下的定性范围。[结果]研究发现,不同被检测基因在相同RT-PCR条件下的浓度检出范围不同。Lectin为0.05~792mg/L,CaMV35S为0.25~792mg/L,NOS为0.25~396mg/L,CP4EPSPS为0.05~1980mg/L;共同的方法检出限LOD为5ng,体系浓度范围为0.25~396mg/L。[结论]确定了Roundup Ready大豆被检测基因的定性范围和检出限,可应用于大豆中相关基因的检测。 展开更多
关键词 大豆 LECTIN CaMV 35S NOS cp4 EPSPS RT-PCR
下载PDF
3种平差基准下高速铁路CPⅢ平面控制网的精度分析
7
作者 宋占峰 余世峰 +1 位作者 李荣之 李军 《铁道学报》 EI CAS CSCD 北大核心 2024年第10期107-113,共7页
针对工程实际CPⅢ网复测中以CPⅡ进行约束平差出现大量CPⅢ点坐标超限的情况,提出合理的CPⅢ网平差方法,设计总长为4020 m的标准网和加密网两种CPⅢ平面网。建立重心、一点一长方向和一点一短方向3种平差基准,分别计算各基准下两种网形6... 针对工程实际CPⅢ网复测中以CPⅡ进行约束平差出现大量CPⅢ点坐标超限的情况,提出合理的CPⅢ网平差方法,设计总长为4020 m的标准网和加密网两种CPⅢ平面网。建立重心、一点一长方向和一点一短方向3种平差基准,分别计算各基准下两种网形600 m间距CPⅢ点间的相对中误差,并与CPⅡ点相对中误差8 mm的规范规定进行比较。研究结果表明:两种网形在3种基准下,测距精度对点位相对精度影响均非常小,方向精度是影响点位相对精度的主要因素。在重心、一点一长方向(CPⅠ的间距)基准下,两种网形600 m间距CPⅢ点间的相对中误差均显著小于8 mm,高于CPⅡ的相对精度。 展开更多
关键词 高速铁路 cpⅢ平面网 平差基准 精度 相对中误差
下载PDF
国有企业对接CPTPP规则的六点建议
8
作者 王婧 《国企管理》 2024年第5期26-26,共1页
《全面与进步跨太平洋伙伴关系协定》(简称CPTPP)作为当前具有世界影响力、引领未来的国际经贸规则代表,对国有企业设有专门的规制章节,这也是CPTPP的一大特色。然而,目前我国国有企业在对接CPTPP规则时,还存在法律体系尚不健全,企业的... 《全面与进步跨太平洋伙伴关系协定》(简称CPTPP)作为当前具有世界影响力、引领未来的国际经贸规则代表,对国有企业设有专门的规制章节,这也是CPTPP的一大特色。然而,目前我国国有企业在对接CPTPP规则时,还存在法律体系尚不健全,企业的股权结构。 展开更多
关键词 跨太平洋伙伴关系协定 国际经贸规则 国有企业 股权结构 世界影响力 cp 引领未来
下载PDF
温度变化对CPⅢ平面测量结果的影响
9
作者 李杰 《测绘标准化》 2024年第3期58-64,共7页
目前我国高速铁路建设里程已达3万余公里,在全球首屈一指。在高铁建设过程中,轨道控制网(CPⅢ)测量是一项必不可少的工作。某高铁CPⅢ建网测量过程中,相同点位搭接时两次测量结果坐标较差较大,不满足规范搭接要求,需进行外业补测。本文... 目前我国高速铁路建设里程已达3万余公里,在全球首屈一指。在高铁建设过程中,轨道控制网(CPⅢ)测量是一项必不可少的工作。某高铁CPⅢ建网测量过程中,相同点位搭接时两次测量结果坐标较差较大,不满足规范搭接要求,需进行外业补测。本文对搭接不成功处的数据进行了分析,认为两次测量温差较大可能是导致搭接不成功的原因之一,温度变化会对CPⅢ测量结果产生影响。同时,梁体宽度确定时引入混凝土膨胀系数计算得到的梁体宽度变化值与实测值互差较小,均未超过0.7 mm,验证了本文的观点。根据气温变化调整补测时间后,数据成果满足规范要求。最后通过定量分析得出,若将梁体宽度变化阈值设置为±2 mm,梁体宽度为9.25 m时,两次测量温差不应超过-21.6℃~21.6℃;梁体宽度为12.20 m时,两次测量温差不应超过-16.4℃~16.4℃。 展开更多
关键词 cpⅢ测量 温差 混凝土膨胀系数 梁体宽度
下载PDF
CP+TBL教学在住院医师规范化培训中的效果探究
10
作者 张清华 徐长生 《中文科技期刊数据库(全文版)教育科学》 2024年第7期0056-0059,共4页
分析临床路径(CP)+以团队为基础学习(TBL)教学在住院医师规范化培训中效果。方法 纳入2022年8月—2023年7月在新疆医科大学第二附属医院妇科轮转的41名住院医师为分析样本,将其划分成观察组(21名)与对比组(20名)。对比组予以传统教学法... 分析临床路径(CP)+以团队为基础学习(TBL)教学在住院医师规范化培训中效果。方法 纳入2022年8月—2023年7月在新疆医科大学第二附属医院妇科轮转的41名住院医师为分析样本,将其划分成观察组(21名)与对比组(20名)。对比组予以传统教学法,观察组在对比组基础上予以CP+TBL教学法。对比两组综合测评成绩、学习倦怠及综合能力。结果 观察组综合测评成绩与综合能力高于对比组,学习倦怠低于对比组(P<0.05)。结论 CP+TBL教学法能提高妇科住院医师综合测评成绩,降低其学习倦怠,优化其综合能力。 展开更多
关键词 cp教学法 TBL教学法 住院医师 规范化培训 综合能力
下载PDF
抗差Helmert分量估计在地铁CPⅢ控制网平差中的应用
11
作者 朱武松 《城市勘测》 2024年第2期133-136,共4页
为使CPⅢ控制网数据定权合理、提高平差成果精度,并具有抗粗差特性,论文提出采用结合Huber的Helmert抗差分量估计定权方法对CPⅢ控制网中的水平角、竖直角和斜距三类观测值进行合理定权平差,以福州市轨道交通4号线工程西门站至东街口站... 为使CPⅢ控制网数据定权合理、提高平差成果精度,并具有抗粗差特性,论文提出采用结合Huber的Helmert抗差分量估计定权方法对CPⅢ控制网中的水平角、竖直角和斜距三类观测值进行合理定权平差,以福州市轨道交通4号线工程西门站至东街口站区间右线CPⅢ控制网测量项目为例,验证了该方法的定权合理性和可靠性,并可获得点位偏差小、精度可靠且有抗粗差能力的平差成果。 展开更多
关键词 cpⅢ控制网 定权 抗差Helmert方差分量估计 平差
下载PDF
Effect of Al2O3np on the Properties and Microstructure of B4Cp/Al Composites 被引量:4
12
作者 LIU Tingting PANG Xiaoxuan +2 位作者 XIAN Yajiang LUO Hao ZHANG Pengcheng 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2020年第3期514-519,共6页
Aluminum-matrix boron carbide (B4Cp/Al) is a kind of neutron absorbing material widely used in nuclear spent fuel storage. In order to improve the tensile property of B4Cp/Al composites, a new type of nano-Al2O3 parti... Aluminum-matrix boron carbide (B4Cp/Al) is a kind of neutron absorbing material widely used in nuclear spent fuel storage. In order to improve the tensile property of B4Cp/Al composites, a new type of nano-Al2O3 particle (Al2O3np) reinforced B4Cp/Al + Al2O3np composites were prepared by powder metallurgy method. The Monte Carlo particle transport program (MCNP) was used to determine the influence of Al2O3np on the thermal neutron absorptivity of composites. The universal material testing machine and scanning electron microscope (SEM) were used to study the mechanical properties, microstructure and fracture morphology of B4Cp/Al composites. The results indicated that the neutron absorption properties of B4Cp/Al composites were not affected by the addition of nano-Al2O3 particles in the range of 1 wt%-15 wt%. The addition of Al2O3np can obviously reduce the grain size of B4Cp/Al matrix metals thus improve the tensile strength of the composites. The addition threshold of Al2O3np is about 2.5 wt%. Both B4Cp and Al2O3np change the fracture characteristics of the composites from toughness to brittleness, and the latter is more important. 展开更多
关键词 B4cp/Al composites nano-Al2O3 particles PROPERTIES MICROSTRUCTURE
下载PDF
CP-25 inhibits the functions of activated human B cells through regulating BAFF-TRAF2-NF-κB and TNF-alpha-TRAF2-NF-κB signaling 被引量:1
13
作者 Ling-ling ZHANG Feng ZHANG +12 位作者 Jin-ling SHU Ying LI Yu-jing WU Xian-zheng ZHANG Le HAN Xiao-yu TANG Chen WANG Yu TAI Qing-tong WANG Jing-yu CHEN Yan CHANG Hua-xun WU Wei WEI 《中国药理学与毒理学杂志》 CAS CSCD 北大核心 2017年第10期982-983,共2页
OBJECTIVE This study was to investigate the effects of CP-25 on the functions of activated human B cells through regulating BAFF and TNF-alpha signaling.METHODS B cells from peripheral blood mononuclear cells(PBMCs) o... OBJECTIVE This study was to investigate the effects of CP-25 on the functions of activated human B cells through regulating BAFF and TNF-alpha signaling.METHODS B cells from peripheral blood mononuclear cells(PBMCs) of normal human were isolated using magnetic cell separation(MACS) by a positive selection.B cells(107 cells·mL^(-1)) were stimulated by BAFF(100 ng·mL^(-1))or TNF-alpha(100 ng·mL^(-1)) for two hours,and then were treated with CP-25(10-5 mol·L^(-1)) or Rituximab(5 μg·mL^(-1)) or Etanercept(10 μg·mL^(-1)).B cell proliferation was detected by CCK-8.B cell subsets and BAFF receptors(BAFFR,BCMA and TACI) were analyzed by flow cytometry.The expression of TNFR1 and TNFR2 on B cells was analyzed by flow cytometry.The expression of MKK3,MKK6,P-p38,P-p65,TRAF2 and p100/52 was analyzed by Western blotting.RESULTS CP-25 inhibited B cells proliferation stimulated by BAFF or TNF-alpha.CP-25,Rituximab and Etanercept reduced the percentage and numbers of CD19^+B cells,CD19^+CD20^+B cells,CD19^+CD27^+B cells and CD19^+CD20^+CD27^+B cells induced by BAFF or TNF-alpha.CP-25 down-regulated the high expression of BAFFR,BCMA and TACI stimulated by BAFF or TNF-alpha.CP-25,Rituximab and Etanercept down-regulated significantly the expression of TNFR1 and TNFR2 on B cell stimulated by BAFF or TNF-alpha.CP-25,Rituximab and Etanercept down-regulated the expression of MKK3,P-p38,P-p65,TRAF2 and p52 in B cells stimulated by BAFF and the expression of TRAF2 and P-p65 in B cells stimulated by TNF-alpha.CONCLUSION CP-25 regulated moderately activated B cells function by by regulating the classical and alternative NF-κB signaling pathway mediated by BAFF and TNF-alpha-TRAF2-NF-κB signaling pathway.This study suggests that CP-25 may be a promising anti-inflammatory immune and soft regulation drug. 展开更多
关键词 BAFF TNF alpha signaling pathway cp 25 ETANERCEPT RITUXIMAB
下载PDF
Energy absorption characteristics of novel high-strength and hightoughness steels used for rock support 被引量:1
14
作者 Ding Wang Manchao He +3 位作者 Liangjiu Jia Xiaoming Sun Min Xia Xuchun Wang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第6期1441-1456,共16页
Nowadays,the development of novel metallic materials for rock support have attracted research interests since they can significantly improve the deformation and energy absorption capacities of rock bolts.Although prev... Nowadays,the development of novel metallic materials for rock support have attracted research interests since they can significantly improve the deformation and energy absorption capacities of rock bolts.Although previous studies proved the importance and mechanical advantages of utilizing high-strength and high-toughness(HSHT)steels in rock support,there is no systematic analysis to reveal the essential energy absorption parameter and the guidelines for further development of metallic rock support materials.This paper analyzes the energy absorption characteristics of novel HSHT steels(negative Poisson’s ratio(NPR)and twinning-induced plasticity(TWIP)steels)in comparison with conventional rock support materials.A physically based crystal plasticity(CP)model was set up and calibrated to study the effect of strain hardening rate(SHR).Meanwhile,the roles of underlying physical mechanisms,i.e.the dislocation density and twin volume fraction,were studied.The results show that the improvement of energy absorption density(EAD)is essential for further development of rock support materials,besides the increase of energy absorption rate(EAR)for previous development of conventional rock support materials.The increase of EAD requires increases of both strength and deformation capacity of materials.For HSHT steels,the decrease of SHR has a positive effect on the improvement of EAD.In addition,the increase of EAD is followed by the increase of twin volume fraction and the decrease of plastic Poisson’s ratio which can promote deformation plasticity of materials.Meanwhile,the increase of EAR is correlated with the accumulation of dislocation density,which can increase the strength of materials.This paper provides the theoretical basis and guidelines for developing rock support materials in deep underground engineering and other related fields. 展开更多
关键词 Rock support Steel Energy absorption Strain hardening rate(SHR) Crystal plasticity(cp)
下载PDF
Science Letters:A novel reduction of diketones with i-RMgBr catalyzed by Cp2TiCl2 and deoxygenation of sulfoxides by Cp2TiCl2/Al system 被引量:1
15
作者 张永敏 林茂钦 俞永平 《Journal of Zhejiang University Science》 CSCD 2004年第10期1175-1179,共5页
α-diketones and β-diketones react with Grignard reagents in the presence of a catalytic amount of Cp2TiCl2 to yield a-ketols and corresponding ketones respectively. Sulfoxides can be deoxygenated by Cp2TiCl2/Al syst... α-diketones and β-diketones react with Grignard reagents in the presence of a catalytic amount of Cp2TiCl2 to yield a-ketols and corresponding ketones respectively. Sulfoxides can be deoxygenated by Cp2TiCl2/Al system. The possible mechanisms are also discussed. 展开更多
关键词 Grignard reagent cp2TiCl2-catalyzed α-diketone β-diketone REDUCTION
下载PDF
Alternating Double Trinucleate[Yb_3(μ_3-OH)_2O]_2 Chain Bridged byμ_3-OH Mode in a 3D Yb^(3+)-CP and Its Near Infrared Luminescent Properties 被引量:3
16
作者 王潇 王浩 +5 位作者 侯向阳 吕磊 曹佳 陈小莉 王记江 付峰 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2016年第10期1615-1621,共7页
A new 3D coordination polymer,namely,[Yb_3(μ_3-OH)_3(μ_2-OH)(DDLA)_(2.5)(BIPY)](1,H_2DDLA = 2,2-dipyridyl-4,4-dicarboxylic acid,BIPY = 2,2?-bipyridine),has been synthesized via solvothermal method. The ... A new 3D coordination polymer,namely,[Yb_3(μ_3-OH)_3(μ_2-OH)(DDLA)_(2.5)(BIPY)](1,H_2DDLA = 2,2-dipyridyl-4,4-dicarboxylic acid,BIPY = 2,2?-bipyridine),has been synthesized via solvothermal method. The complex crystallizes in triclinic,space group P1 with a = 7.7339(4),b = 15.6699(8),c = 17.2221(9) ?,α = 68.8630(10),β = 88.1890(10),γ = 88.1740(10)°,V = 1945.27(17) ?~3,Z = 2,D_c = 2.296 g·cm^3,μ(MoKα) = 1.075 mm^(-1),F(000) = 1268,S = 1.068,R = 0.0263 and wR = 1.067 for 5176 observed reflections with I 〉 2σ(I). Compound 1 contains a unique alternating double trinucleate {[Yb_3(μ_3-OH)_2OH]_2}_n chain,in which Yb^(3+) is bridged through μ_3-OH and μ_2-OH two coordination modes. The alternating double trinucleate chains are further extended into a 3D structure through DDLA^(2-) ligands by different coordination modes. The photoluminescence spectra show 1 is highly sensitized by the characteristic emission of Yb^(3+) in the NIR region. 展开更多
关键词 3D Yb3+ cp unique alternating Yb3+ chain NIR luminescent properties
下载PDF
Practical synthesis allenyl and homopropargyl alcohol through Cp_2TiCl_2 -Mg with propargyl alcohol derivatives 被引量:1
17
《厦门大学学报(自然科学版)》 CAS CSCD 北大核心 1999年第S1期291-291,共1页
Reaction of Cp2TiCl2-Mg synthetic equivalent of practical Ti(II) reagent with propargyl alcohol derivatives affords allenyl titanium compounds in good yields.thus, providing an efficient and practical methods for synt... Reaction of Cp2TiCl2-Mg synthetic equivalent of practical Ti(II) reagent with propargyl alcohol derivatives affords allenyl titanium compounds in good yields.thus, providing an efficient and practical methods for synthesis of both allenyl and homopropargyl alcohols by the successive treatment with aldehydes and ketones. 展开更多
关键词 Mg with propargyl alcohol derivatives Practical synthesis allenyl and homopropargyl alcohol through cp2TiCl2
下载PDF
基于CP基因的中国云南省烟草TMV群体遗传多样性分析
18
作者 赵正婷 盖晓彤 +4 位作者 张俊蕾 夏振远 刘弟 姜宁 刘雅婷 《植物保护》 CAS CSCD 北大核心 2024年第4期48-60,共13页
为探明云南烟草上烟草花叶病毒(tobacco mosaic virus,TMV)的群体遗传多样性特征,本研究使用TMV外壳蛋白(coat protein,CP)基因的特异性引物对采自云南各烟区的疑似烟草花叶病样品进行检测,通过克隆测序获得138个TMV CP基因序列,对其进... 为探明云南烟草上烟草花叶病毒(tobacco mosaic virus,TMV)的群体遗传多样性特征,本研究使用TMV外壳蛋白(coat protein,CP)基因的特异性引物对采自云南各烟区的疑似烟草花叶病样品进行检测,通过克隆测序获得138个TMV CP基因序列,对其进行了一致性比对,及系统发育、错配分布、遗传变异、群体多样性等分析。变异分析显示,138条CP基因序列共有变异位点数122个,占总位点数的25.42%,变异类型只有核苷酸替换,核酸多样性为0.018,单倍型多样性为0.970;一致性比对结果显示,138条序列的核苷酸和氨基酸序列一致性均为96%~100%;重组分析未检测到重组信号;对来自云南烟草,NCBI上其他地区烟草及云南地区其他寄主的TMV分离物的CP基因进行系统发育分析,结果显示,所有TMV分离物在进化上可分为4个组,本试验获得的分离物分布在1、2、3组,其中只有来源昭通地区的分离物倾向于聚成簇,表明云南烟草TMV分离物的适应性进化受地理适应性所驱动,与寄主适应性基本无关;错配分布分析显示,云南烟草TMV群体呈多峰分布,表明该群体近期未经历群体扩张事件;群体间遗传分化分析结果表明,除昭通和曲靖烟草TMV群体与其他TMV群体之间很容易发生遗传漂变促使群体发生遗传分化外,其余大部分TMV群体之间的基因流都可以抵制遗传漂变。本研究首次报道了云南各烟区TMV分离物群体遗传变异情况,研究结果可为TMV的抗病育种和制定更为有效的防治策略提供重要参考。 展开更多
关键词 烟草 云南 烟草花叶病毒 cp基因 遗传多样性
下载PDF
喷丸强化对预变形CP800复相钢疲劳性能的影响
19
作者 崔浩诚 王荃 +3 位作者 陈卓 周俊 戚天武 汪宏斌 《上海大学学报(自然科学版)》 CAS CSCD 北大核心 2024年第2期278-288,共11页
喷丸强化可以提高CP800复相钢的抗疲劳性能.采用低(0.15 mmA)、中(0.3 mmA)、高(0.5 mmA)3种喷丸强度对5%预拉伸变形后的CP800复相钢进行表面喷丸处理,研究了喷丸后材料的表面形貌和表面残余应力,并通过拉压疲劳试验分析了疲劳断口.研... 喷丸强化可以提高CP800复相钢的抗疲劳性能.采用低(0.15 mmA)、中(0.3 mmA)、高(0.5 mmA)3种喷丸强度对5%预拉伸变形后的CP800复相钢进行表面喷丸处理,研究了喷丸后材料的表面形貌和表面残余应力,并通过拉压疲劳试验分析了疲劳断口.研究发现:2 mm板厚的CP800复相钢更适合采用低喷丸强度,疲劳寿命约为未喷丸试样的3倍;疲劳寿命的提升归因于表层发生塑性变形、位错密度提高,且残余压应力可抑制裂纹萌生;喷丸后材料表面粗糙度增大;喷丸强度过高易造成表面缺陷增多,尤其在高喷丸强度下,试样表面会出现分层损伤现象,对疲劳性能有不利影响. 展开更多
关键词 喷丸强化 cp800复相钢 抗疲劳性能 残余压应力
下载PDF
基于GNSS的五塔连续斜拉桥主梁上CPⅢ平面网快速测量方法试验研究及应用
20
作者 李鲲鹏 李麒麟 +2 位作者 杨雪峰 孙洪斌 渠述锋 《测绘通报》 CSCD 北大核心 2024年第7期83-87,共5页
大跨度桥梁的长大连续梁会随着温度的变化,产生较大的纵向和竖向位移,导致连续梁桥上CPⅢ点坐标存在多值性,设站精度无法满足高铁对轨道板测量相关精度要求。本文提出了一种基于GNSS静态测量的连续梁上CPⅢ点平面坐标快速测量新方法,并... 大跨度桥梁的长大连续梁会随着温度的变化,产生较大的纵向和竖向位移,导致连续梁桥上CPⅢ点坐标存在多值性,设站精度无法满足高铁对轨道板测量相关精度要求。本文提出了一种基于GNSS静态测量的连续梁上CPⅢ点平面坐标快速测量新方法,并依托郑济高铁长清黄河特大桥,设计了实际测量试验,并对新方法的可行性进行了验证。试验结果表明,这种基于GNSS的CPⅢ点平面坐标快速测量方法,在观测时长为30 min的情况下就能达到大跨度桥梁上底座板、轨道板等施工对CPⅢ平面网相关测量精度的要求。 展开更多
关键词 GNSS静态相对定位 大跨斜拉桥 长大连续梁 cpⅢ平面网 快速测量方法
下载PDF
上一页 1 2 220 下一页 到第
使用帮助 返回顶部