检索结果-南通市图书馆

Association between body mass index and in vitro fertilization/intra-cytoplasmic sperm injection outcomes:An analysis of 15,124 normal ovarian responders in China

引用

Chinese Medical Journal 2024年第7期137卷 837-845页

作者： Danlei Zheng yuanyuan Wang Lixue Chen Lin Zeng Rong Li Department of Obstetrics and Gynecology Center for Reproductive MedicinePeking University Third HospitalBeijing 100191China Research Center of Clinical Epidemiology Peking University Third HospitalBeijing 100191China

Background:High body mass index(BMI)results in decreased fecundity,and women with high BMI have reduced rates of clinical pregnancy and live birth in in vitro fertilization/intra-cytoplasmic sperm injection(IVF/ICSI).Meanwhile,ovarian responses show great heterogeneity in patients with a high *** study aimed to analyze the effects of a high BMI on IVF/ICSI outcomes in the Chinese female with normal ovarian ***:We performed a retrospective cohort study comprising 15,124 patients from the medical record system of the Reproductive Center of Peking University Third Hospital,with 3530(23.3%)in the overweight group and 1380(9.1%)in the obese group,who had a normal ovarian response(5-15 oocytes retrieved)and underwent fresh embryo transfer(ET)cycles from January 2017 to December 2018,followed by linked frozen-thawed embryo transfer(FET)cycles from January 2017 to December *** live birth rate(CLBR)was used as the primary ***,a generalized additive model was applied to visually illustrate the curvilinear relationship between BMI and the *** used a decision tree to identify the specific population where high BMI had the greatest effect on IVF/ICSI ***:High BMI was associated with poor IVF/ICSI outcomes,both in cumulative cycles and in separate fresh ET or FET *** cumulative cycles,compared with the normal weight group,obesity was correlated with a lower positive pregnancy test rate(adjusted odds ratio[aOR]:0.809,95%confidence interval[CI]:0.682-0.960),lower clinical pregnancy rate(aOR:0.766,95%CI:0.646-0.907),lower live birth rate(aOR:0.706,95%CI:0.595-0.838),higher cesarean section rate(aOR:2.066,95%CI:1.533-2.785),and higher rate of large for gestational age(aOR:2.273,95%CI:1.547-3.341).In the generalized additive model,we found that CLBR declined with increasing BMI,with 24 kg/m^(2)as an inflection *** the decision tree,BMI only made a difference in the population aged≤34.5 years,with anti-Muller

关键词： Obesity Body mass index fertilization Live birth Decision trees Normal ovarian response

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Factors Influencing Fracture Propagation in Collaborative Fracturing ofMultiple HorizontalWells

引用

Energy Engineering 2024年第2期121卷 425-437页

作者： Diguang Gong Junbin Chen Cheng Cheng yuanyuan Kou Shanxi Key Laboratory of Well Stability and Fluid&RockMechanics inOil andGas Reservoirs Xi’an Shiyou UniversityXi’an710065China The Second Oil Production Plant Petro China Changqing Oilfield CompanyQingyang745100China

Horizontal well-stimulation is the key to unconventional resource exploration and *** development mode of the well plant helps increase the stimulated reservoir ***,fracture interference between wells reduces the fracturing ***,a 2D hydro-mechanical coupling model describing hydraulic fracture(HF)propagation is established with the extended finite element method,and the effects of several factors on HF propagation during multiple wells fracturing are *** results show that with an increase in elastic modulus,horizontal principal stress difference and injection fluid displacement,the total fracture area and the reservoir stimulation efficiency are both improved in all three fracturing *** a comparison of the three technologies,the method of improved zipper fracturing is proposed,which avoids mutual interference between HFs,and the reservoir stimulation effect is improved *** study provides guidance for optimizing the fracturing technology of multiple horizontal wells.

关键词： Multi-well fracturing inter-fracture interference hydraulic fracturing hydro-mechanical coupling extended finite element horizontal well

来源：

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

Research on ozone formation sensitivity based on observational methods:Development history,methodology,and application and prospects in China

引用

Journal of Environmental Sciences 2024年第4期138卷 543-560页

作者： Wanghui Chu Hong Li yuanyuan Ji Xin Zhang Likun Xue Jian Gao Cong An State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental SciencesBeijing 100012China Environment Research Institute Shandong UniversityQingdao 266237China

Observation-based method for O_(3)formation sensitivity research is an important tool to analyze the causes of ground-level O_(3)pollution,which has broad application potentials in determining the O_(3)pollution formation mechanism and developing prevention and control *** paper outlined the development history of research on O_(3)formation sensitivity based on observational methods,described the principle and applicability of the methodology,summarized the relative application results in China and provided recommendations on the prevention and control of O_(3)pollution in China based on relevant study results,and finally pointed out the shortcomings and future development prospects in this field in *** overview study showed that the O_(3)formation sensitivity in some urban areas in China in recent years presented a gradual shifting tendency from the VOC-limited regime to the transition regime or the NO_(x)-limited regime due to the implementation of the O_(3)precursors emission reduction policies;O_(3)pollution control strategies and precursor control countermeasures should be formulated based on local conditions and the dynamic control capability of O_(3)pollution control measures should be *** are still some current deficiencies in the study field in ***,it is recommended that a stereoscopic monitoring network for atmospheric photochemical components should be further constructed and improved;the atmospheric chemical mechanisms should be vigorously developed,and standardized methods for determining the O_(3)formation sensitivity should be established in China in the near future.

关键词： Observation-based method Ozone formation sensitivity Ozone pollution prevention and control VOCs NO_(x) OBM

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

TA2工业纯钛负压下间歇式气体渗氮

引用

金属热处理 2016年第12期41卷 137-140页

作者：杨峰熊茫茫祝圆圆刘静贵州师范大学材料与建筑工程学院贵州贵阳550001

研究了负压条件下,不同氮氩混合比对TA2工业纯钛组织与性能的影响。结果表明：渗氮层主要由α-Ti、TiN_（0.3）和TiN相组成。有效硬化层深度为30~50μm,氮氩比在1∶5和1∶1时渗层硬度较高且梯度平缓。腐蚀电位随氮分压的增大先提升后降... 详细信息

研究了负压条件下,不同氮氩混合比对TA2工业纯钛组织与性能的影响。结果表明：渗氮层主要由α-Ti、TiN_（0.3）和TiN相组成。有效硬化层深度为30~50μm,氮氩比在1∶5和1∶1时渗层硬度较高且梯度平缓。腐蚀电位随氮分压的增大先提升后降低,腐蚀速率则先降低后增大。当氮氩比为1∶1时,TA2渗氮层具有最优的综合性能。

关键词： TA2工业纯钛负压氮氩比气体渗氮性能

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Investigation into the roles of interfacial H_(2)O structure in catalytic oxidation of HCHO and CO over CuMnO_(2) catalysts

引用

Journal of Environmental Sciences 2024年第3期137卷 310-320页

作者： Chunyan Ma Jushuang Pan Cheng Chen yuanyuan Dong Feng Yao Fengbang Wang Maoyong Song Key Laboratory of Environmental Nanotechnology and Health Effects Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China University of Chinese Academy of Sciences Beijing 100049China No.52 Institute of China North Industries Group Yantai Branch Co.Ltd. Yantai 264000China

The rapid deactivation of cost-effective MnO_(2)-based catalysts in humid air limits their application in practice,and the identification of the role of water in an oxidation process is significant for developing water-resistant MnO_(2)-based ***,CuMnO_(2)showed a20.3%HCHO conversion in 10 hr at room temperature in humid air with relative humidity of 40%,but deactivated in 3 hr in dry *** excellent activity and stability of HCHO oxidation in humid air were attributed to the positive effect of H_(2)O on HCHO oxidation to the H_(2)O-HOCH_(2)OH supermolecule assemblies via hydrogen bonds formed on CuMnO_(2).H_(2)O-HOCH_(2)OH supermolecule assemblies tend to be oxidized to carbonate,which is further oxidized to CO_(2).Furthermore,CuMnO_(2)exhibited a much poorer activity of CO oxidation in humid air,but the CO conversion was still 100%in 10 hr in dry air.H_(2)O showed a competitive adsorption effect to CO on CuMnO_(2).CuMnO_(2)could be applied in HCHO elimination in humid air and CO elimination in dry air.

关键词： H_(2)O-HOCH_(2)OH supermolecule HCHO oxidation Humid air CuMnO_(2) CO oxidation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Particle size dependence of the microsegregation and microstructure in the atomized Ni-based superalloy powders:Theoretical and experimental study

引用

Journal of Materials Science & Technology 2024年第4期171卷 54-65页

作者： Jikang Li Mingsheng Yang Yunfei Cai yuanyuan Zhang Qingshuai Feng Jiantao Liu Tong Liu Key Laboratory of Aerospace Materials and Performance(Ministry of Education)School of Materials Science and Engineering Beihang UniversityBeijing 100191China Central Iron and Steel Research Institute Beijing 100081China

The microstructure and microsegregation of atomized powder,which depend on their sizes,are of great importance to the mechanical properties of the consolidated bulk ***,it is necessary to reveal the relationship between particle size and powder *** effects of particle size on the so-lidification characterization of the atomized Ni-based superalloy powders were studied via finite element *** on the simulations,a model was developed to predict the microsegregation and mi-crostructure of atomized powders with different sizes and study the influence of thermal history on the powder attributes during the atomization *** radiation heat transfer and temperature gradi-ent within the rapid solidification alloy powders were taken into account in this *** validating the accuracy of the model,the predictions of the present model were compared with the microsegregation and microstructure of the specific size powder close to the screen mesh *** results showed that mi-crostructure depended primarily on the temperature gradient within the powder,while the solidification rate had a more significant effect on the *** model predicted microstructure features in agreement with the experiment,and for microsegregation,the deviations of prediction for most ele-ments were less than 10%.This work provides a new model to precisely predict the microsegregation and microstructure of the atomized alloy powders and sets a foundation to control the powder features for various engineering applications.

关键词： Particle size Solidification microstructure Microsegregation Numerical simulation

来源：

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

A Nonlinear Grey Bernoulli Model with Conformable Fractional-Order Accumulation and Its Application to the Gross Regional Product in the Cheng-Yu Area

引用

Journal of Systems Science and Information 2024年第2期12卷 245-273页

作者： Wenqing WU Xin MA Bo ZENG yuanyuan ZHANG School of Science Civil Aviation Flight University of ChinaDeyang 618307China School of Mathematics and Physics Southwest University of Science and TechnologyMianyang 621010China College of Business Planning Chongqing Technology and Business UniversityChongqing 400067China

This study considers a nonlinear grey Bernoulli forecasting model with conformable fractionalorder accumulation,abbreviated as CFNGBM(1,1,λ),to study the gross regional product in the ChengYu *** new model contains three nonlinear parameters,the power exponentγ,the conformable fractional-orderαand the background valueλ,which increase the adjustability and flexibility of the CFNGBM(1,1,λ)*** parameters are determined by the moth flame optimization algorithm,which minimizes the mean absolute prediction percentage *** CFNGBM(1,1,λ)model is applied to the gross regional product of 16 cities in the Cheng-Yu area,which are Chongqing,Chengdu,Mianyang,Leshan,Zigong,Deyang,Meishan,Luzhou,Suining,Neijiang,Nanchong,Guang’an,Yibin,Ya’an,Dazhou and *** data from 2013 to 2021,several grey models are established and results show that the new model has higher accuracy in most cases.

关键词： nonlinear grey Bernoulli model conformable fractional-order operator moth flame optimization algorithm gross regional product the Cheng-Yu area

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Secure resource allocation against colluding eavesdropping in a user-centric cell-free massive multiple-input multiple-output system

引用

Frontiers of Information Technology & Electronic Engineering 2024年第4期25卷 500-512页

作者： Na LI yuanyuan GAO Kui XU Xiaochen XIA Huazhi HU Yang LI Yueyue ZHANG College of Communication Engineering Army Engineering University of PLANanjing 210007China

We investigate the resource allocation problem of a cell-free massive multiple-input multiple-output system under the condition of colluding eavesdropping by multiple passive *** address the problem of limited pilot resources,a scheme is proposed to allocate the pilot with the minimum pollution to users based on access point selection and optimize the pilot transmission power to improve the accuracy of channel *** at the secure transmission problem under a colluding eavesdropping environment by multiple passive eavesdroppers,based on the local partial zero-forcing precoding scheme,a transmission power optimization scheme is formulated to maximize the system’s minimum security spectral *** results show that the proposed scheme can effectively reduce channel estimation error and improve system security.

关键词： Cell-free Colluding eavesdropping Limited pilot resources Access point selection Security rate

来源：

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

Heptamethine cyanines in bioorthogonal chemistry

引用

Chinese Chemical Letters 2024年第2期35卷 131-137页

作者： yuanyuan Liao Yuting Liang Yurou Huang Xiaoyan Zeng Tian He Jun Yin National Key Laboratory of Green Pesticide International Joint Research Center for Intelligent Biosensor Technology and HealthCollege of ChemistryCentral China Normal UniversityWuhan 430079China

Due to their excellent fluorescence properties and biological function,cyanine dyes have been widely applied in biological *** cyanine(Cy7)dyes,as a type of classic near-infrared(NIR)fluorescent dyes,are considered as one of the effective fluorescent tools in the living organisms due to their good biocompatibility and very low background *** reactions performed in living cells and tissues have developed by leaps and bounds in recent *** NIR fluorescent labeling technique involving cyanine has attracted widespread *** review summarizes their recent application in the field of bioorthogonal imaging,mainly concluding Cy7-type dyes,labeling strategy,bioimaging application,*** expect this work can provide some helps for the studies of NIR bioorthogonal reaction in vivo.

关键词： Fluorescent probes Heptamethine cyanines Bioorthogonal reaction Imaging Cell

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Experimental study on the effect of water absorption level on rockburst occurrence of sandstone

引用

Journal of Rock Mechanics and Geotechnical Engineering 2024年第1期16卷 136-152页

作者： Dongqiao Liu Jie Sun Pengfei He Manchao He Binghao Cao yuanyuan Yang State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and Technology(Beijing)Beijing100083China School of Mechanics and Civil Engineering China University of Mining and Technology(Beijing)Beijing100083China Institute for Deep Underground Science and Engineering China University of Mining and Technology(Beijing)Beijing100083China

To investigate the mechanism of rockburst prevention by spraying water onto the surrounding rocks,15 experiments are performed considering different water absorption levels on a single ***-speed photography and acoustic emission(AE)system are used to monitor the rockburst *** effect of water on sandstone rockburst and the prevention mechanism of water on sandstone rockburst are analyzed from the perspective of energy and failure *** results show that the higher the ab-sorption degree,the lower the intensity of the rockburst after absorbing water on single side of *** is reflected in the fact that with the increase in the water absorption level,the ejection velocity of rockburst fragments is smaller,the depth of the rockburst pit is shallower,and the AE energy is *** the water absorption level of 100%,the magnitude of rockburst intensity changes from medium to *** prevention mechanism of water on sandstone rockburst is that water reduces the capacity of sandstone to store strain energy and accelerates the expansion of shear cracks,which is not conducive to the occurrence of plate cracking before rockburst,and destroys the conditions for rockburst incubation.

关键词： Rockburst Water Prevention effect Crack evolution

来源：

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

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：