检索结果-南通市图书馆

基于步履式顶推技术的钢箱梁桥施工风险评价与质量控制分析

在线全文

学校读者我要写书评

暂无评论

工程建设与设计 2024年第3期 257-259页

作者：刘学冬王凤武中咨公路养护检测技术有限公司北京100089

结合某桥梁工程,对基于步履式顶推技术的钢箱梁桥施工风险评价进行介绍,并从杆件拼接、临时结构、顶推过程、落梁精度4方面提出基于步履式顶推技术的钢箱梁桥施工质量控制措施。结果表明:步履式顶推技术不仅可以提高桥梁的施工质量,还... 详细信息

结合某桥梁工程,对基于步履式顶推技术的钢箱梁桥施工风险评价进行介绍,并从杆件拼接、临时结构、顶推过程、落梁精度4方面提出基于步履式顶推技术的钢箱梁桥施工质量控制措施。结果表明:步履式顶推技术不仅可以提高桥梁的施工质量,还能准确地进行顶推作业。

关键词：钢箱梁桥顶推技术风险评价

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

无损检测技术在桥梁桩基检测中的运用分析

工程建设与设计 2024年第2期 161-163页

作者：王凤武刘学冬中咨公路养护检测技术有限公司北京100089

针对桥梁桩基施工质量检测问题,对常用的桥梁桩基无损检测技术进行介绍,包括低应变检测技术、高应变检测技术、声波透射检测技术、钻芯检测技术、红外成像检测技术等,以解决桥梁桩基施工质量检测问题,实现桥梁桩基施工的安全高效发展,... 详细信息

针对桥梁桩基施工质量检测问题,对常用的桥梁桩基无损检测技术进行介绍,包括低应变检测技术、高应变检测技术、声波透射检测技术、钻芯检测技术、红外成像检测技术等,以解决桥梁桩基施工质量检测问题,实现桥梁桩基施工的安全高效发展,切实保证桥梁施工建设项目顺利进行。

关键词：无损检测桩基检测桥梁桩基

维普期刊数据库博看期刊

丙胺盐酸盐辅助结合气淬法制备高效宽带隙钙钛矿太阳电池

在线全文

学校读者我要写书评

暂无评论

物理学报 2024年第15期73卷 243-253页

作者：杨静韩晓静刘冬雪石标王鹏阳许盛之赵颖张晓丹中国长江三峡集团有限公司科学技术研究院北京101199 南开大学光电子薄膜器件与技术研究所天津300350 天津市光电子薄膜器件与技术重点实验室天津300350 薄膜光电子技术教育部工程研究中心天津300350 化学科学与工程协同创新中心天津300072 南开大学可再生能源转换与储存中心天津300072

宽带隙钙钛矿与晶硅电池结合制备叠层太阳电池,其效率可以超越单结太阳电池的理论极限.然而,宽带隙钙钛矿薄膜结晶速率快,导致薄膜结晶质量差且具有大量缺陷,严重降低电池的光电转换性能.本文采用温和的气淬法制备宽带隙钙钛矿薄膜,并... 详细信息

宽带隙钙钛矿与晶硅电池结合制备叠层太阳电池,其效率可以超越单结太阳电池的理论极限.然而,宽带隙钙钛矿薄膜结晶速率快,导致薄膜结晶质量差且具有大量缺陷,严重降低电池的光电转换性能.本文采用温和的气淬法制备宽带隙钙钛矿薄膜,并引入丙胺盐酸盐作为添加剂改善钙钛矿薄膜的结晶质量.丙胺阳离子与钙钛矿组分相互作用生成了二维钙钛矿相,钙钛矿以二维相作为生长模板降低了α相钙钛矿的形成能,同时辅助钙钛矿均匀成核和择优取向生长,增大了晶粒尺寸.使用该策略制备的带隙为1.68 eV的钙钛矿太阳电池实现了21.48%的光电转换效率.此外,制备的8 cm×8 cm的宽带隙钙钛矿薄膜具有良好的均匀性.本工作为高效、大面积钙钛矿基的光伏器件的制备工艺提供了新的策略.

关键词：宽带隙钙钛矿气淬法丙胺盐酸盐结晶

腹腔镜配合苍附导痰汤加减治疗多囊卵巢综合征临床观察

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

湖北中医药大学学报 2024年第3期26卷 95-98页

作者：刘冬雪胡丽娜武汉市第三医院光谷院区湖北武汉430070

目的观察腹腔镜配合苍附导痰汤加减治疗多囊卵巢综合征(PCOS)疗效。方法将我院72例PCOS患者随机为治疗组与对照组各36例。对照组采用腹腔镜治疗,治疗组采用腹腔镜联合苍附导痰汤加减治疗。比较两组综合疗效,评价中医证候积分,测定雌二醇... 详细信息

目的观察腹腔镜配合苍附导痰汤加减治疗多囊卵巢综合征(PCOS)疗效。方法将我院72例PCOS患者随机为治疗组与对照组各36例。对照组采用腹腔镜治疗,治疗组采用腹腔镜联合苍附导痰汤加减治疗。比较两组综合疗效,评价中医证候积分,测定雌二醇(E_(2))、睾酮(T)、黄体生成素(LH)、黄体生成素/卵巢生成素(LH/FSH)、胰岛素抵抗指数(HOMA-IR)、甘油三酯(TG)、总胆固醇(TC)水平,对比术后6个月两组妊娠率。结果治疗后,治疗组总有效率显著高于对照组(P<0.05);两组中医证候积分、T、LH、LH/FSH、HOMA-IR、TG、TC水平均显著低于治疗前,治疗组中医证候积分、T、LH、LH/FSH、HOMA-IR、TG、TC水平均显著低于对照组(P<0.05);两组E_(2)水平显著高于治疗前;治疗组E_(2)水平显著高于对照组。术后6个月治疗组妊娠率显著高于对照组(P<0.05)。结论腹腔镜配合苍附导痰汤加减显著提高治疗PCOS临床疗效,降糖,降脂,提高妊娠率。

关键词：多囊卵巢综合征腹腔镜苍附导痰汤加减疗效妊娠

An unprecedented synthesis of axially chiral biaryls by rearrangement and aromatization of carbocations with central-to-axial conversion of chirality

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2024年第9期67卷 2998-3003页

作者： Qi liu xue-dong Li Liang Cheng Li liu Beijing National Laboratory for Molecular Sciences(BNLMS) CAS Key Laboratory of Molecular Recognition and FunctionCAS Research/Education Center for Excellence in Molecular SciencesInstitute of ChemistryChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

The central-to-axial chirality conversion represents a fascinating class of chemical processes consisting of the destruction of stereogenic centers and the simultaneous installation of axial chiral elements,which provides efficient methods for the preparation of axially chiral ***,developing catalytic asymmetric approaches for constructing these central chirality precursors and the efficient central-to-axial chirality conversion remains a challenge due to the requirement of aromatization or elimination *** this work,we have developed an unprecedented enantioselective intramolecular FriedelCrafts alkylation with unactivated-ketone carbonyls from which a chiral tertiary alcohol was generated with high efficiency and excellent *** addition,the central-to-axial chirality conversion strategy has been successfully applied to the synthesis of enantioenriched biaryls via a less-explored carbocation-initiated rearrangement and aromatization under the promotion of Lewis *** methodology provided a straightforward and sustainable access to a broad range of biaryl-2-carboxylic acid and in excellent yields(up to 92%)and excellent central-to-axial chirality conversion(up to 99%conversion percentage).This work could be a great model for developing new methods for synthesizing axially chiral biaryls and a general protocol for the rearrangement and aromatization of carbocations for further functionalization.

关键词： br?nsted acid catalysis desymmetrization phosphoric acid axially chiral biaryls central-to-axial conversion

Ds-echinoside A,a new triterpene glycoside derived from sea cucumber,exhibits antimetastatic activity via the inhibition of NF-κB-dependent MMP-9 and VEGF expressions

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2011年第7期12卷 534-544页

作者： Qin ZHAO Zhi-dong liu Yong xue Jing-feng WANG Hui LI Qing-juan TANG Yu-ming WANG Ping dong Chang-hu xue College of Food Science and Engineering Ocean University of China Qingdao 266003 China

Ds-echinoside A (DSEA),a non-sulfated triterpene glycoside,was isolated from the sea cucumber Pearsonothuria *** vitro and in vivo investigations were conducted on the effects of DSEA on tumor cell adhesion,migration,invasion,and *** this study,we found that DSEA inhibited the proliferation of human hepatocellular liver carcinoma cells Hep G2,with a half-maximal inhibitory concentration (IC50) of 2.65 μmol/L,and suppressed Hep G2 cell adhesion,migration,and invasion in a dose-dependent *** also reduced tube formation of human endothelial cells ECV-304 on matrigel in vitro and attenuated neovascularization in the chick embryo chorioallantoic membrane (CAM) assay in *** analysis revealed that DSEA significantly decreased the expression of matrix metalloproteinase-9 (MMP-9),which plays an important role in the degradation of basement membrane in tumor metastasis and *** also increased the protein expression level of tissue inhibitor of metalloproteinase-1 (TIMP-1),an important regulator of MMP-9 *** the results of Western blotting,the expressions of nuclear factor-kappa B (NF-κB) and vascular endothelial growth factor (VEGF) were found to be remarkably reduced by *** findings suggest that DSEA exhibits a significant antimetastatic activity through the specific inhibition of NF-κB-dependent MMP-9 and VEGF expressions.

关键词： Triterpene glycoside Ds-echinoside A (DSEA) Metastasis Angiogenesis Nuclear factor-κB (NF-κB) Matrix metalloproteinase-9 (MMP-9) Vascular endothelial growth factor (VEGF)

在线全文

学校读者我要写书评

暂无评论

副舟骨与扁平足影像学相关性研究进展

中国骨与关节杂志 2024年第8期13卷 643-647页

作者：刘冬雪赵锦翠刘松竹倪东贺修超于洋北华大学附属医院放射科吉林省132001 北华大学附属医院骨科吉林省132001 吉林中西医结合医院放射科吉林省132012

足踝部存在诸多籽骨、副骨,其中副舟骨(accessory navicular bone,AN)为足踝部最常见的副骨之一,临床上认为AN的出现是引起扁平足的一个重要因素,针对AN引起扁平足提出来诸多手术方案,但对于AN是否引起扁平足的机制尚无统一定论,近年来... 详细信息

足踝部存在诸多籽骨、副骨,其中副舟骨(accessory navicular bone,AN)为足踝部最常见的副骨之一,临床上认为AN的出现是引起扁平足的一个重要因素,针对AN引起扁平足提出来诸多手术方案,但对于AN是否引起扁平足的机制尚无统一定论,近年来从影像学方面对其相关性的研究层出不穷,但结论不一,笔者针对AN与扁平足相关性影像学方面的进展进行综述,并对其相关性力学方面的研究进行总结分析。

关键词： X线磁共振成像扁平足副舟骨综述

Simulation of an aircraft thermal management system based on vapor cycle response surface model

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2024年第6期37卷 64-77页

作者： Haodong liu Hongsheng JIANG Sujun dong Longxian xue Yongji liu Jianjun WU School of Aeronautic Science and Engineering Beihang UniversityBeijing 100191China Chengdu Aircraft Design and Research Institute Aviation Industry Corporation of ChinaChengdu 610091China

The modern aircraft Thermal Management System(TMS)faces significant challenges due to increasing thermal loads and limited heat dissipation *** optimize TMS during the conceptual design stage,the development of a modeling and simulation tool is *** this study,a TMS simulation model library was created using MATLAB/*** simplify the complexity of the Vapor Cycle System(VCS)model,a Response Surface Model(RSM)was constructed using the Monte Carlo method and validated through simulation *** the F-22 fighter TMS as an example,a thermal dynamic simulation model was constructed to analyze the variation of thermal response parameters in key subsystems and elucidate their coupling ***,the impact of total fuel flow and ram air flow on the TMS was *** findings demonstrate the existence of an optimal total fuel flow that achieves a balance between maximizing fuel heat sink utilization and minimizing bleed air *** adaptive distribution of fuel and ram air flow was found to enhance aircraft thermal management *** study contributes to improving modeling efficiency and enhancing the understanding of the thermal dynamic characteristics of TMS,thereby facilitating further optimization in aircraft TMS design.

关键词： Thermal management sys-tem Vaporcycle Response surface model Dynamic simulation MonteCarlo

A New Manganese(Ⅱ) Coordination Compound Constructed by 1,10-Phenanthroline Derivative and Chlorine Anions: Synthesis, Crystal Structure and Theoretical Calculation

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2019年第5期38卷 819-824,671页

作者： WANG Xiu-Yan GAO Wen-Yu ZHOU Xiao-Hang liu dong-xue HU Bo KONG Zhi-Guo Key Laboratory of Preparation and Applications of Environmental Friendly Materials Jilin Normal University Siping 136000 China Key Laboratory of Functional Materials Physics and Chemistry of the Ministry of Education Jilin Normal University Siping 136000 China Department of Chemistry Jilin Normal University Siping 136000 China

The new manganese（Ⅱ） coordination compound, [Mn（Cl）2（L）2]（1, L = 11-fluorodipyrido[3,2-a:2?,3?-c]phenazine）, has been achieved under hydrothermal conditions. The structure of compound 1 was determined by single-crystal X-ray diffraction. 1 crystallizes in monoclinic system, space group C2/c with a = 8.419（2）, b = 12.286（2）, c = 28.451（6） ?, β = 95.889（3）°, V =2927.5（10） ?3, Z = 4, C36 H16 MnF2 Cl2 N8, Mr = 724.41, Dc = 1.644 g/cm3, F（000） = 1460, μ（Mo Ka）= 0.691 mm-1, R = 0.0445 and wR = 0.0982. Adjacent compounds are stacked by one type of π-πinteraction among L ligands to generate a 1D supramolecular chain. Further, the 1D supramolecular chains are stacked by another type of π-π interaction among L ligands to give a 2D supramolecular layer. Moreover, the C-F···π interactions between the carbon atom of the L ligand and the pyrazine ring of the adjacent L ligand further stabilize the supramolecular layer of 1. In addition, natural bond orbital（NBO） analysis has been calculated by the B3LYP/LANL2DZ method, which shows obvious covalent interaction between the coordinated atoms and Mn（Ⅱ） ion.

关键词： crystal structure coordination compound 11-fluoro-dipyrido[3,2-a:2',3'-c]phenazine manganese(Ⅱ) theoretical calculation