检索结果-南通市图书馆

Synthesis of chiral phosphine derivatives through a copper（I）-catalyzed desymmetric SNAr reaction

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China Chemistry 2025年

作者： Shuai zhang Pei-Zhi Liu Yan-bo Li Qi zhang Jun-Zhao Xiao Yi-Fan Wang Tian-Yu Wei Jia-Wei Jiang Ye Wang Qian Peng Liang Yin Key Laboratory of Fluorine and Nitrogen Chemistry and Advanced Materials Shanghai Institute of Organic Chemistry University of Chinese Academy of Sciences Chinese Academy of Sciences State Key Laboratory of Elemento-Organic Chemistry and Tianjin Key Laboratory of Biosensing and Molecular Recognition College of Chemistry Frontiers Science Center for New Organic Matter Nankai University Haihe Laboratory of Sustainable Chemical Transformations

Axially chiral phosphines are a class of extremely important ligands in asymmetric catalysis. Herein, an unprecedented copper（I）-catalyzed asymmetric SNAr reaction with HP（S）R2is uncovered, which delivers a series of axially chiral phosphine derivatives in high yields with excellent enantioselectivity. Furthermore, the diastereoselective reaction with the kinetic resolution of racemic HP（S）ArR proceeds smoothly, providing the products with moderate diastereoselectivity and excellent enantioselectivity. Control experiments indicate that HP（S）Ph2is much more active than HPPh2and HP（O）Ph2as the pronucleophile in the present reaction. It is found that the SNAr reaction （the first SNAr） proceeds in a desymmetric manner, providing the desired chiral products while a continued SNAr reaction （the second SNAr） slightly occurs in a kinetic resolution manner in the present catalytic system, which enhances the ee of the desired chiral products. DFTcalculations support a concerted reaction pathway rather than a step-wise mechanism. Finally, axially chiral olefin-phosphines produced by the present method work as suitable ligands in Pdcatalyzed asymmetric allylic substitution with C-, N-, and O-nucleophiles and Rh-catalyzed asymmetric addition of arylboronic acid to benzil.

关键词：

Sensitivity improvement by Vernier effect in microwave photonic filter based on F-P fiber ring

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Optoelectronics Letters 2025年

作者： LIN Rui zhang Ailing CHANG Pengxiang PAN Honggang WANG Minghe WANG bo Engineering Research Center of Optoelectronic Devices & Communication Technology， Ministry of Education， Tianjin Key Laboratory of Film Electronic and Communication Devices， School of Electrical and Electronic Engineering， Tianjin University of Technology

A high sensitivity fiber optic temperature sensor based on Vernier effect in microwave photonic filter based on two paralleled F-P (Fabry-Perot) fiber ring is proposed and experimentally verified. Sensitivity is improved through the Vernier effect， which is caused by two parallel F-P fiber rings with approximate lengths. Temperature interrogation is achieved by monitoring the notch frequency of the superimposed frequency response curve. The temperature sensitivity of -484.514kHz/℃ is achieved in experiment， which is 57 times of the sensor without Vernier effect. The improved sensitivity and simple structure make it have wide potential applications in temperature monitoring of power systems.

关键词：

Cs阳离子掺杂对CH_(3)NH_(3)PbI_(3)钙钛矿电子性质的影响研究

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

原子与分子物理学报 2025年第6期42卷 174-182页

作者：张平丽吉林师范大学物理学院四平136000

有机-无机杂化钙钛矿太阳能电池被报道具有极高的功率转换效率,是下一代太阳能电池材料有希望的候选者,但其化学性质极不稳定,在高温高湿条件下易分解.本研究采用无机Cs阳离子取代CH_(3)NH_(3)PbI_(3)结构中的CH_(3)NH_(3)有机阳离子,... 详细信息

有机-无机杂化钙钛矿太阳能电池被报道具有极高的功率转换效率,是下一代太阳能电池材料有希望的候选者,但其化学性质极不稳定,在高温高湿条件下易分解.本研究采用无机Cs阳离子取代CH_(3)NH_(3)PbI_(3)结构中的CH_(3)NH_(3)有机阳离子,利用第一性原理密度泛函理论,计算了未掺杂CH_(3)NH_(3)PbI_(3)钙钛矿和Cs阳离子掺杂钙钛矿的电子性质.结果表明,适当比例的Cs阳离子掺杂能够增强Pb-I的相互作用力,且Cs阳离子掺杂并未改变钙钛矿直接半导体的属性.Cs阳离子与Pb-I框架之间强的共价相互作用,导致Cs阳离子掺杂钙钛矿具有更加稳定的晶体结构.这项工作阐明了Cs阳离子掺杂钙钛矿材料高稳定性的潜在机理,可以为将来设计高效稳定的钙钛矿光伏材料提供一定的理论依据.

关键词：钙钛矿 Cs阳离子掺杂能带结构态密度

维普期刊数据库博看期刊

A versatile synthetic strategy towards rare earth based metal-organic frameworks

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2025年

作者： Quan Shi Yun-Hao Xu Ming-Hui Chen Peng Zhao Wen-bo Deng Ji Xiong Kai Guo Ya-Qing Feng Bao zhang School of Chemical Engineering and Technology Tianjin University Tianjin Collaborative Innovation Center of Chemical Science and Engineering Guangdong Laboratory Chemistry & Fine Chemical Industry Jieyang Center

Rare earth metal-organic frameworks (RE-MOFs) have drawn wide attention owing to diverse network structures and various application ***,due to the unpredictable formation of the nodes,it is still challenging to design novel RE-MOFs.A novel versatile strategy was developed employing a RE-acetate complex (RE2(CH3COO)6·4H2O) as a precursor to construct RE-MOFs.2D RE-MOFs (RE-DBP) and 3D RE-MOFs (RE-TCPP) could be obtained by using dicarboxylic porphyrin ligands H2DBP and tetracarboxylic porphyrin ligands H2TCPP,*** RE-MOFs were further synthesized to verify the universality of the *** crystalline RE-MOFs could also be prepared at room temperature via the developed strategy,which could significantly promote large-scale preparation and practical application of *** proof of the concept,the performance of porphyrin-based RE-MOFs was investigated in the photocatalytic cycloaddition of CO2with *** the RE-DBP(Co) MOFs,Tb-DBP(Co) exhibited the best photocatalytic performance,which was also greater than that of the corresponding 3D MOF Tb-TCPP(Co) due to the optimal 2D structure and thus the accelerated photogenerated charge separation and transfer *** work not only provides a novel versatile strategy to design and develop RE-MOFs,but also proposes a promising approach for the potential bulk production of RE-MOFs at room temperature.

关键词：

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

基于可变制造环境的成本—公差模型的研究

太原重型机械学院学报 2001年第3期22卷 204-207页

作者：王伯平张平宽孔令德太原重型机械学院太原030024

对成本—公差关系建模是产品精度优化设计中重要的基础问题。本文应用模糊数学原理建立一种新的成本—公差模型 ,它既紧密联系实际加工工艺过程 ,又可按制造环境的变化进行方便地调整。

关键词：可变制造环境公差成本模型优化设计机械设计

单宁酸改性互穿网络水凝胶促进断裂跟腱术后的组织重塑

在线全文

学校读者我要写书评

暂无评论

中国组织工程研究 2025年第4期29卷 721-729页

作者：张博张振江东北京大学第三医院运动医学科北京市100191

背景:跟腱断裂术后的再生与重塑是临床治疗的难点,组织工程水凝胶材料为促进跟腱修复提供了可能。目的:探究单宁酸改性互穿网络水凝胶对大鼠断裂跟腱组织再生与重塑的作用。方法:①通过蓝光照射及CaSO4溶液浸泡交联制备单宁酸改性互穿... 详细信息

背景:跟腱断裂术后的再生与重塑是临床治疗的难点,组织工程水凝胶材料为促进跟腱修复提供了可能。目的:探究单宁酸改性互穿网络水凝胶对大鼠断裂跟腱组织再生与重塑的作用。方法:①通过蓝光照射及CaSO4溶液浸泡交联制备单宁酸改性互穿网络水凝胶,表征水凝胶的微观形貌、力学性能、黏附性能、体外释药性能与生物相容性。②取30只SD大鼠,采用随机数字表法分为假手术组、手术组与水凝胶组,每组10只,后2组建立右后肢跟腱断裂模型,手术组采用改良Kessler法将断裂跟腱重新缝合,水凝胶组采用相同术式缝合断裂跟腱后将单宁酸改性互穿网络水凝胶贴片完全缠绕包裹于断端接合处。术后4周,对断裂跟腱进行影像学检查、组织学评价、生物力学测试及炎症因子水平检测。结果与结论:①扫描电镜下可见单宁酸改性互穿网络水凝胶呈多孔微观结构,孔径为3-10μm,并且水凝胶具备良好的体外释药性能、黏附强度与拉伸强度;CCK-8检测与活/死染色显示,该水凝胶对大鼠骨髓间充质干细胞增殖活性无明显影响,具备良好的生物相容性。②MRI成像显示,与手术组比较,水凝胶组大鼠跟腱呈均一低信号,跟腱前后径厚度减小,与周围组织分界更为明确,表现更接近假手术组。苏木精-伊红与Masson染色显示,手术组大鼠跟腱纤维排列松散混乱,细胞密度增加且排布杂乱,伴有明显炎性细胞浸润,部分区域出现腱内骨化;水凝胶组大鼠跟腱纤维排列有序,细胞密度降低且排布规整,炎性细胞浸润明显减少。手术组大鼠跟腱的拉伸强度低于假手术组(P<0.05),水凝胶组大鼠跟腱的拉伸强度高于手术组(P<0.05)。与假手术组比较,手术组大鼠跟腱中白细胞介素1β、白细胞介素6及肿瘤坏死因子α质量浓度及mRNA表达升高(P<0.05);与手术组比较,水凝胶组3种炎症因子水平及mRNA表达降低。③结果表明,单宁酸改性互穿网络水凝胶可显著抑制局部炎症反应、促进断裂跟腱组织重塑。

关键词：单宁酸水凝胶互穿网络跟腱断裂组织重塑组织再生

Possible Effect of 30K Proteins in Embryonic Development of Silkworm bombyx mori

在线全文

学校读者我要写书评

暂无评论

Acta Biochimica et Biophysica Sinica 2005年第5期37卷 355-361页

作者： bo-Xiong ZHONG~1 Jian-Ke LI~(1.2) Jian-Rong LIN~3 Jian-She LIANG~4 Song-Kun SU~1 Hai-Sheng XU~1 Hai-Yan YAN~1 ping-bo zhang~5 Hiroshi FUJII~5 1 Laboratory of Molecular Biology of Silkworm and Honeybee, Department of Bioresource Science, College of Animal Science,Zhejiang University, Hangzhau 310029, China 2 Institute of Apicultural Research, Chinese Academy of Agricultural Science, Beijing 100093, China 3 Department of Sericulture, South China Agricultural University.Guangzhou 510642, China 4 Biochemistry Co. Ltd. of Zhejiang University, Hangzhou 310029. China 5 Faculty of Agriculture,Kyushu University, Fukuoka 812-81. Japan Laboratory of Molecular Biology of Silkworm and Honeybee Department of Bioresource Science College of Animal Science Zhejiang UniversityHangzhou 310029 China Institute of Agicultural Research Chinese Academy of Agricultural ScienceBeijing 100093 China Department of Sericulture South China Agricultural UniversityGuangzhou 510642 China Biochemistry Co. Ltd. of Zhejiang UniversityHangzhou 310029 China Faculty of Agriculture Kyushu UniversityFukuoka 812-81 Japan

The silkworm bombyx mori possesses a 30K protein family of 3×10～4 Da,the biologicalfunctions of which have not been fully *** relationship between the 30K protein family and theembryonic development of temperature sensitive sex-linked mutant strain of silkworm was investigated bytwo dimensional polyacrylamide gel electrophoresis(2D-PAGE)and Matrix assisted laser desorption ionization-time of flight mass spectrometry(MALDI-TOF MS).The results show that protein spots 1-5 of the 30Kprotein family,mainly existing in normal strain,are possibly related to embryonic *** earlyconsumption of a 30K protein named 6G1-30K-1 and the accumulation of 30K proteins named 6G1-30K-3and 6G1-30K-4 are likely caused by the destruction of physiological balance in normal embryonic development,which may lead to lower hatchability of the temperature sensitive *** results suggest that reasonablemetabolism of 30K proteins is a prerequisite for the embryo's normal development.

关键词： silkworm bombyx mori 30K protein embryonic development 2D-PAGE MALDI-TOF MS

Mechanism of oxygen releasing of copper ferrite in the formation of the corresponding oxygen-deficient compound

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China Chemistry 2009年第1期52卷 101-108页

作者： zhang ping YU bo zhang Lei Institute of Nuclear and New Energy Technology Tsinghua UniversityBeijing 102201China

Copper ferrite is a promising material for hydrogen production through thermochemical water splitting. In this work, the cation distribution of copper ferrite and the corresponding oxygen-deficient compound of spinel structure was analyzed based on the crystal structural chemistry theory. The mechanism of oxygen releasing of CuO, Fe2O3, CuFe2O4 and metal (M=Ni, Mn or Zn) doped copper ferrite in the process of temperature rising was investigated by differential thermal analysis-thermogravimetry (DTA-TG). By combining the theoretical analysis with experimental results, the mechanism of oxygen releasing of copper ferrite is proposed, which is different from that of other ferrites. For copper ferrite, the oxygen releasing caused by Cu(II)→Cu(I) plays a predominant role, while for other ferrites, the oxygen releasing resulting from Fe(III)·Fe(II) is dominant.

关键词： copper ferrite oxygen deficient compound crystal structural chemistry theory DTA-TG oxygen releasing mechanism

在线全文

学校读者我要写书评

暂无评论

环太湖假日体育圈发展路径研究

南京体育学院学报（社会科学版） 2017年第2期31卷 93-98页

作者：王波韩顺平张建民王凯温阳朱晓军南京邮电大学管理学院江苏南京210003 南京大学国家文化产业研究中心江苏南京210093 南京大学商学院江苏南京210093 南京体育学院江苏南京210014 江苏省体育竞赛管理中心江苏南京210029

环太湖区域是我国经济最为发达的地区之一,体育事业在全国也处于领先地位。本文对环太湖区域体育产业、群众体育、竞技体育、社会影响四个方面进行了基础梳理,分析了环太湖假日体育圈发展迫切需要解决的问题,并提出了构建环太湖假日体... 详细信息

环太湖区域是我国经济最为发达的地区之一,体育事业在全国也处于领先地位。本文对环太湖区域体育产业、群众体育、竞技体育、社会影响四个方面进行了基础梳理,分析了环太湖假日体育圈发展迫切需要解决的问题,并提出了构建环太湖假日体育圈的发展路径,为其长效发展提供了可行的战略。

关键词：环太湖假日体育圈体育产业体育现状社会影响发展路径