检索结果-南通市图书馆

Asian Herpetological Research 2020年第4期11卷 312-319页

作者： yue qi Li DING Yangyang ZHAO Chenkai NIU Xiaoning WANG Wei ZHAO Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution School of Life SciencesLanzhou UniversityLanzhou 730000China

Speciation has never been directly observed in nature because it is a lengthy *** rare,ring species are an optimal natural example of speciation and can be identified through the assessment of the geographical conditions of their potential *** forsythii is endemic to the Tarim Basin,which compnses the Taklamakan Desert and surrounded by mountains on three *** study aimed to determine whether *** had a ring-species-like divergence pattern through the characterization of the genetic features of 17 populations covering the major distribution of this *** distribution modelling revealed that *** had a continuous circular distribution around the Tarim *** flow was observed in most adjacent populations except for two terminal populations of the ring,which exhibit the highest *** distance and geographic distance were significantly correlated,indicating that the observed differentiation resulted from genetic variation gradually accumulating during population *** our results do not definitively indicate that *** is a ring species,our results indicate a ring-shaped diversification This phenomenon elucidates the potential mechanism underlying speciation in the presence of gene flow,providing insight into this evolutionary process.

关键词： continuous variation gene flow Phrynocephalus forsythii ring species Tarim Basin

基于三点弯曲试验的混凝土叠合梁跨中挠度研究

在线全文

学校读者我要写书评

暂无评论

建筑技术 2024年第13期55卷 1634-1636页

作者：胡运郭瑞高振博苏悦琦北京市建设工程质量第三检测所有限责任公司北京100037 北京市市政工程研究院北京100037

预制装配式结构采用工厂预制与现场安装相结合的方式,可降低环境污染,减少资源浪费,其中装配式混凝土结构常采用叠合梁、叠合板,叠合结构整体性和抗震性能好。选取某构件厂成品叠合梁(YKL2a-XS-1)进行了三点弯曲试验,获得叠合梁荷载挠... 详细信息

预制装配式结构采用工厂预制与现场安装相结合的方式,可降低环境污染,减少资源浪费,其中装配式混凝土结构常采用叠合梁、叠合板,叠合结构整体性和抗震性能好。选取某构件厂成品叠合梁(YKL2a-XS-1)进行了三点弯曲试验,获得叠合梁荷载挠度曲线,分析叠合梁跨中挠度与荷载的关系;依据梁跨中挠度计算公式,计算叠合梁跨中挠度。叠合梁加载变形特点与适筋梁受弯性能相似,加载期间,叠合面无滑移,预制再生混凝土与后浇普通混凝土整体性较好;随着荷载增加,叠合梁的挠度增加,跨中挠度实测值增加幅度最大,跨中挠度未超过设计限值,叠合梁满足工程实际中构件的延性要求;依据梁跨中挠度计算公式得到的跨中挠度理论值高于真实值。

关键词：混凝土叠合梁跨中挠度变形理论预测

在线全文

学校读者我要写书评

暂无评论

基于优化算法的天然气脱硫单元能耗优化

现代化工 2024年第S01期44卷 332-337页

作者：尹晓云李佳亿文明岳添漆游香杨董栖君黄征宇李杨中国石油西南油气田分公司安全环保与技术监督研究院四川成都610041 页岩气评价与开采四川省重点实验室四川成都610041 国家管网集团西南管道有限责任公司贵州省管网有限公司四川成都610000 中石油遂宁天然气净化有限公司四川遂宁610500 中国石油西南油气田川中油气矿四川遂宁629000

针对天然气净化厂脱硫单元能耗较高的问题,对天然气净化厂脱硫单元能耗优化方法进行研究。基于ASPEN HYSYS软件,建立天然气净化厂脱硫单元数值模拟模型,利用现场数据验证模型的准确性。通过单因素分析确定了胺液循环量、贫胺液进料温度... 详细信息

针对天然气净化厂脱硫单元能耗较高的问题,对天然气净化厂脱硫单元能耗优化方法进行研究。基于ASPEN HYSYS软件,建立天然气净化厂脱硫单元数值模拟模型,利用现场数据验证模型的准确性。通过单因素分析确定了胺液循环量、贫胺液进料温度及原料气温度对能耗的影响最大,将其作为优化参数建立天然气净化厂脱硫单元能耗最优化模型,采用BP神经网络及GA遗传算法相结合的方法进行优化计算。结果表明,经BP神经网络及GA遗传算法相结合的算法进行优化后,胺液循环量、贫胺液进料温度及原料气温度3个运行参数均得到了优化,将优化后的运行参数运用于现场实际生产后,工艺总能耗由10614.99 kW下降至8297.59 kW,能耗降低了21.83%。

关键词：天然气脱硫 GA遗传算法 BP神经网络能耗优化 HYSYS 数值模拟

在线全文

学校读者我要写书评

暂无评论

基于电磁辐射到达时差的电弧故障定位及精度

科学技术与工程 2024年第11期24卷 4520-4526页

作者：徐肖伟王科项恩新张贵鹏聂鼎马仪杨庆齐玥云南电网有限责任公司电力科学研究院昆明650217 云南电网有限责任公司昆明650011 重庆大学输配电装备及系统安全与新技术国家重点实验室重庆400044

为了实现利用电磁辐射信号进行配网电弧故障定位,提出了一种基于到达时差(time difference of arrival,TDOA)方法的Chan-LM协同定位算法。该算法采用Chan算法快速获得的初始点,再经过LM(Levenberg-Marquart)算法迭代修正定位结果。仿真... 详细信息

为了实现利用电磁辐射信号进行配网电弧故障定位,提出了一种基于到达时差(time difference of arrival,TDOA)方法的Chan-LM协同定位算法。该算法采用Chan算法快速获得的初始点,再经过LM(Levenberg-Marquart)算法迭代修正定位结果。仿真分析了TDOA定位算法、电磁辐射传感器配置对定位精度的影响,结果表明Chan-LM协同算法比Chan算法的定位误差减小40%,参考主站位于中心位置的Y形布站方式,传感器所在海拔高度相同时的监测区域整体定位准确度较高。利用实测电弧电磁辐射波形验证了Chan-LM协同算法能够有效改善定位精度,为基于电磁辐射TDOA的电弧定位策略应用提供参考依据。

关键词：电弧故障定位精度电磁辐射到达时差传感器配置

Contact performance analysis of pressure controller's sealing interface in deep in-situ pressure-preserved coring system

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2022年第3期19卷 1334-1346页

作者： Jia-Nan Li Jun Wang Yun-qi Hu Zhen-Xi You Meng Xu Ying-Wei Wang Zu-Jie Zou qi-yue Kang School of Mechanical Engineering MOE Key Laboratory of Deep Underground Science and EngineeringCollege of Water Resource and HydropowerSichuan UniversityChengdu610065China Guangdong Provincial Key Laboratory of Deep Earth Sciences and Geothermal Energy Exploitation and Utilization Institute of Deep Earth Sciences and Green EnergyCollege of Civil and Transportation EngineeringShenzhen UniversityShenzhen518061China State Key Laboratory of Hydraulics and Mountain River Engineering College of Water Resource and HydropowerSichuan UniversityChengdu610065China State Key Laboratory of Coking Coal Exploitation and Comprehensive Utilization Pingdingshan Tianan Coal Mining Co.LTD.Pingdingshan467000China Xi'an Research Institute China Coal Technology&Engineering Group CorpXi'an710077China

The sealing performance of contact interfaces plays the most important role in the design and operation of the in-situ pressure-preserved coring *** meet the demand of ultra-high pressure-retained coring for oil and gas exploration in deep reservoirs,a quantitative analysis of the contact mechanical behavior of the pressure controller was *** on the micro-contact theory of rough surfaces,a three-dimensional numerical model of the rough contact interface between the valve cover and the valve seat was constructed,and the micro-contact behavior of the metal contact surfaces was comprehensively *** results show that the actual contact area of the valve interface increases with the increase of surface roughness before the critical contact point,but decreases after *** with the real contact model with double rough surfaces,although the simplified hard-contact model with a single rough surface can reflect the micro-contact behavior of the rough surface to a certain extent,it cannot truly reveal the microchannel morphology between the sealing interfaces under ***,the realistic double-rough-surface model should be recommended to evaluate the sealing performance of coring tools,particularly for high pressure *** material properties of valves have a significant effect on the contact characteristics of rough surfaces,which suggested that the actual contact area decreases with the increase of the elastic modulus of the contact material under the same loading *** knowledge of this work could help to enhance the seal design of pressure controllers for in-situ pressure-preserved coring.

关键词： In-situ pressure-preserved coring Metal seal Rough surface Micro contact

Influence of Reaction Conditions on Methanol Synthesis and WGS Reaction in the Syngas-to-DME Process

在线全文

学校读者我要写书评

暂无评论

Journal of Natural Gas Chemistry 2006年第1期15卷 38-44页

作者： Ligang Wang Deren Fang Xingyun Huang Shigang Zhang yue qi Zhongmin Liu Dalian fastitute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China Graduate School of Chinese Academy of Sciences Beijing 100039 China Institute of Applied Catalysis Yantai University Yantai 264005 China

A series of CuO-ZnO catalysts （with different Cu/Zn molar ratios） were prepared, and evaluated under the reaction conditions of syngas-to-dimethyl ether （DME） with three sorts of feed gas and different space velocity. The catalysts were characterized by X-ray diffraction （XRD） and temperatureprogrammed reduction （TPR）. The experiment results showed that the reaction conditions of syngas-to- DME process greatly affected the methanol synthesis and WGS reaction. The influence caused by Cu/Zn molar ratio was quite different on the two reactions; increasing of percentage of CO2 in feed gas was unfavorable for catalyst activity, and also inhibited both reactions; enhancement of reaction space velocity heavily influenced the performance of the catalyst, and the benefits were relatively less for methanol synthesis than for the WGS reaction.

关键词： copper zinc Cu/Zn molar ratio methanol dimethyl ether water gas shift reaction syngas dehydration

三维扫描技术用于大腿脂肪抽吸术的分段体积量化研究

在线全文

学校读者我要写书评

暂无评论

中华整形外科杂志 2024年第6期40卷 597-604页

作者：李怡霏李志锋顾云鹏刘怡成吕倩雯孙晶晶齐越马桂娥中国医学科学院北京协和医学院整形外科医院综合整形科北京100144 中国医学科学院北京协和医学院整形外科医院脂肪整形科北京100144

目的采用三维扫描技术对大腿脂肪抽吸术的效果进行量化客观评估。方法回顾性分析2018年1月至2022年9月,中国医学科学院整形外科医院脂肪整形科接受大腿脂肪抽吸术患者的双腿三维扫描成像数据。术前和术后随访时对患者进行三维扫描,构建... 详细信息

目的采用三维扫描技术对大腿脂肪抽吸术的效果进行量化客观评估。方法回顾性分析2018年1月至2022年9月,中国医学科学院整形外科医院脂肪整形科接受大腿脂肪抽吸术患者的双腿三维扫描成像数据。术前和术后随访时对患者进行三维扫描,构建双侧大腿的可视化三维模型。在三维模型中将双侧大腿从上至下每隔5 cm进行分段,共分为7个节段。测量、计算手术前后大腿整体及各节段的体积、体积变化率,以验证大腿脂肪抽吸术的有效性,计算大腿各节段的吸脂效率(EOL),并比较双侧大腿手术前后的对称性。采用配对秩和检验分析手术前后大腿的体积差异;采用组内相关系数(ICC)评估双侧大腿的对称性。结果共纳入36例女性患者,年龄为(28.6±7.6)岁(18~49岁)。术后随访23~1133 d,平均274.7 d。三维扫描成像测量结果显示,大腿整体及各节段体积在手术前后有显著变化,术后明显小于术前,差异均有统计学意义(P均<0.01),其中最上段体积变化率和EOL最高,大腿各节段的体积变化率和EOL总体呈自上而下递减趋势。无论是术前还是术后,双侧大腿各节段体积的ICC值均大于0.950,提示双腿对称性较好,且双腿整体体积的ICC由术前的0.992提高至术后的0.997。结论三维扫描技术可用于大腿体积的定量测量。该研究通过量化客观评估证实了大腿脂肪抽吸术的有效性,且大腿最上段吸脂效果最显著,术后双侧大腿对称性得到进一步改善。

关键词：大腿脂肪抽吸术三维扫描技术体积测量体形塑造

Flood-illuminated adaptive optics ophthalmoscope with a single curved relay mirror

在线全文

学校读者我要写书评

暂无评论

Photonics Research 2013年第3期1卷 124-129页

作者： Ruixue Liu yue qi Xianliang Zheng Mingliang Xia Li Xuan State Key Laboratory of Applied Optics Changchun Institute of OpticsFine Mechanics and PhysicsChinese Academy of SciencesChangchunJilin 130033China University of Chinese Academy of Sciences Beijing 100039China Jiangsu Key Laboratory of Medical Optics Suzhou Institute of Biomedical Engineering and TechnologyChinese Academy of SciencesSuzhouJiangsu 215163China

For decreasing light loss and diminishing the aberrations of the optical system,an open-loop adaptive optics(AO)system for retinal imaging in vivo is *** advantage of the ability of young human eyes to accommodate,there was only one single curved mirror to make the pupil of the eye conjugate with the wavefront corrector and the wavefront sensor.A liquid crystal spatial light modulator(LC-SLM)was adopted as the wavefront corrector because the LC-SLM can be made in a small size to match the *** reduce a pair of lenses or focusing mirrors,the wavefront corrector and sensor are positioned in the noncommon *** system adopts open-loop control and the high-precision LC-SLM guarantees the effectiveness of the AO *** designed field of view is 1°on the retina(about 300μm).The image quality was simulated with different mirror surface types,including circular,parabolic,and hyperbolic.A hyperbolic mirror with conic constant−1.07,which is close to−1,could best eliminate the *** analysis showed that the optical throughput of this system was at least 22.4%higher than that of a standard transmission AO *** a practical experiment,a parabolic mirror was positioned in the optical *** of the cone photoreceptors and the capillary vessels were obtained *** system simplifies the optical setup in comparison to the commonly used 4F systems while still guaranteeing the effectiveness of AO to correct the ocular aberrations.

关键词： mirror optics curved

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

冬小麦-夏玉米轮作田沟金针虫垂直活动特征

应用气象学报 2024年第4期35卷 467-479页

作者：赵花荣任三学齐月张玲田晓丽杨超胡丽丽中国气象科学研究院北京100081 中国气象局·河南省农业气象保障与应用技术重点开放实验室郑州450003 河北固城农业气象国家野外科学观测研究站保定072656 中国气象局兰州干旱气象研究所·甘肃省干旱气候变化与减灾重点实验室·中国气象局干旱气候变化与减灾重点实验室兰州730020 甘肃省气象信息与装备保障中心兰州730020 河北省保定市气象局保定071000

基于河北固城农业气象国家野外科学观测研究站2019—2020年、2021—2022年冬小麦-夏玉米轮作田沟金针虫在土壤中分层调查数据,引入虫口重量指标,结合虫口密度指标,揭示沟金针虫在冬小麦-夏玉米轮作田为害-休眠动态变化,讨论沟金针虫在... 详细信息

基于河北固城农业气象国家野外科学观测研究站2019—2020年、2021—2022年冬小麦-夏玉米轮作田沟金针虫在土壤中分层调查数据,引入虫口重量指标,结合虫口密度指标,揭示沟金针虫在冬小麦-夏玉米轮作田为害-休眠动态变化,讨论沟金针虫在土壤中垂直活动特征、气象条件与其相关性以及对冬小麦产量影响。结果表明:沟金针虫在冬小麦-夏玉米轮作田存在3个为害期和3个休眠期,且交替出现。3个为害期出现在冬小麦返青-拔节期、夏玉米幼苗期、冬小麦秋苗期,3个休眠期出现在冬小麦越冬期、冬小麦成熟-收获期、夏玉米灌浆-成熟期,3个为害期中以冬小麦返青-拔节期最为严重。冬季偏暖及春季回暖早,沟金针虫表现出晚下早上特征,使得沟金针虫冬季休眠期缩短而为害活动期延长;土壤温度、湿度以及食源关系共同影响沟金针虫为害、休眠以及取食活动,其为害适宜土壤重量含水率约为15%~18%,适宜土壤温度为14~18℃。分析沟金针虫为害与冬小麦减产率可知,虫口密度每增加10 m^(-2)或虫口重量每增加1.0 g·m^(-2),可导致减产率增加5.1%。

关键词：沟金针虫垂直活动冬小麦夏玉米轮作田

Proteomic Analysis of the Small Intestine Reveals Adaptive Strategies for Energy Restriction of Phrynocephalus vlangalii at High Altitude

在线全文

学校读者我要写书评

暂无评论

Asian Herpetological Research 2023年第2期14卷 167-174页

作者： Yangyang ZHAO Cui YANG Yongxing HE yue qi Shuhui CAO Xue BIAN Wei ZHAO Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution School of Life SciencesLanzhou UniversityLanzhou 730000GansuChina

The environmental characteristics of hypothermia and hypoxia exert great selective pressure on the energy metabolism of high-altitude animals,especially the *** research on energy-limited adaptation of high-altitude ectotherms has focused on energy ***,the mechanisms of increasing energy intake in high-altitude ectotherms have been studied *** order to investigate the adaptation mechanism of the small intestine,the key part of energy acquisition for animals,to energy limitation at high altitude in ectotherms,the gut proteins of Phrynocephalus vlangalii from high-and low-altitude populations were compared using label free *** enrichment and KEGG pathway analysis showed that proteins associated with energy intake,such as those involved in oxidation-reduction processes,glutathione metabolism,oxidoreductase activity,cofactor binding,catalytic activity and metabolic pathways,were significantly up-regulated in high-altitude populations;while proteins associated with energy expenditure,such as immune responses and processes,membrane attack complexes,natural killer pathway and other immune-related processes,were significantly down-regulated in expression.

关键词： energy intake energy limitation high altitude label-free proteomic analysis lipid metabolism Phrynocephalus vlangalii