期刊文献+
共找到6,435篇文章
< 1 2 250 >
每页显示 20 50 100
Bird specimen number linked with species trait and climate niche breadth
1
作者 Xiaoyu Duan Xiongwei Huang +4 位作者 Jingya Zhang Shuo Lv Gang Song Yanping Wang Gang Feng 《Avian Research》 SCIE CSCD 2024年第1期108-115,共8页
Biological specimens are fundamental for taxonomy and flora/fauna research.More importantly,they also play crucial roles in recording environmental impacts on morphology and behavior,which is vital for biodiversity re... Biological specimens are fundamental for taxonomy and flora/fauna research.More importantly,they also play crucial roles in recording environmental impacts on morphology and behavior,which is vital for biodiversity research and conservation.However,there are few systematic studies on the patterns and drivers of bird specimen number at regional scales.This study is the first attempt to examine the relationships between bird specimen number and species traits as well as climate niche breadth in China,aiming to answer two questions:1)how do species’temperature niche breadth and precipitation niche breadth influence specimen number?2)which trait is most associated with bird specimen number?The associations between bird specimen number and explanatory variables were examined using ordinary least squares,generalized linear models,phylogenetic generalized linear mixed models,and multiple comparisons.The results showed that Muscicapidae was the family with the highest specimen number,and Passeriformes was the order with the highest specimen number.Bird specimen number significantly increased with larger temperature niche breadth and precipitation niche breadth.Specimen number was also positively associated with geographic range size,habitat specificity,hunting vulnerability and clutch size,but negatively associated with body size.These findings suggest that future bird specimen collection should pay more attention to birds with limited ecological niches,large body sizes,and small clutch sizes.This research enhances the use of bird specimen data to study and preserve biodiversity. 展开更多
关键词 Biodiversity conservation Biological specimens Bird traits Scientific collection specimen number Temperature and precipitation
下载PDF
Dynamic characteristics of coal specimens with varying static preloading levels under low-frequency disturbance load
2
作者 WEN Xiao-ze FENG Guo-rui +5 位作者 GUO Jun YU Lu-yang QIAN Rui-peng ZHANG Jie ZHANG Peng-fei FENG Wen-ming 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第8期2644-2657,共14页
The mechanical properties of residual coal pillars under the influence of upward mining disturbances significantly affect the safety of residual mining activities on working faces.This study conducted low-frequency di... The mechanical properties of residual coal pillars under the influence of upward mining disturbances significantly affect the safety of residual mining activities on working faces.This study conducted low-frequency disturbance dynamic uniaxial compression tests on coal specimens using a self-developed dynamic-static load coupling electro-hydraulic servo system,and studied the strength evolutions,surface deformations,acoustic emission(AE)characteristic parameters,and the failure modes of coal specimens with different static preloading levels were studied.The disturbance damage is positively correlated with the coal specimen static preload level.Specifically,the cumulative AE count rates of the initial accelerated damage stage for the coal specimens with static preloading level of 60%and 70%of the uniaxial compressive strength(UCS)were 2.66 and 3.19 times that of the 50%UCS specimens,respectively.Macroscopically,this behaviour manifested as a decrease in the compressive strength,and the mean strengths of the disturbance-damaged coal specimens with 60%and 70%of UCS static preloading decreased by 8.53%and 9.32%,respectively,compared to those of the specimens under pure static loading.The crack sources,such as the primary fissures,strongly control the dynamic response of the coal specimen.The difference between the dynamic responses of the coal specimens and that of dense rocks is significant. 展开更多
关键词 low-frequency disturbance dynamic response coal specimens static preloading level
下载PDF
Species’ geographical range, environmental range and traits lead to specimen collection preference of dominant plant species of grasslands in Northern China
3
作者 Jingya Zhang Cui Xiao +5 位作者 Xiaoyu Duan Xin Gao Hao Zeng Rong'an Dong Gang Feng Keping Ma 《Plant Diversity》 SCIE CAS CSCD 2024年第3期353-361,共9页
Many different factors,such as species traits,socio-economic factors,geographical and environmental factors,can lead to specimen collection preference.This study aims to determine whether grassland specimen collection... Many different factors,such as species traits,socio-economic factors,geographical and environmental factors,can lead to specimen collection preference.This study aims to determine whether grassland specimen collection in China is preferred by species traits(i.e.,plant height,flowering and fruiting period),environmental range(i.e.,the temperature and precipitation range)and geographical range(i.e.,distribution range and altitudinal range).Ordinary least squares models and phylogenetic generalized linear mixed models were used to analyze the relationships between specimen number and the explanatory variables.Random Forest models were then used to find the most parsimonious multivariate model.The results showed that interannual variation in specimen number between 1900 and 2020 was considerable.Specimen number of these species in southeast China was notably lower than that in northwest China.Environmental range and geographical range of species had significant positive correlations with specimen number.In addition,there were relatively weak but significant associations between specimen number and species trait(i.e.,plant height and flowering and fruiting period).Random Forest models indicated that distribution range was the most important variable,followed by flowering and fruiting period,and altitudinal range.These findings suggest that future floristic surveys should pay more attention to species with small geographical range,narrow environmental range,short plant height,and short flowering and fruiting period.The correction of specimen collection preference will also make the results of species distribution model,species evolution and other works based on specimen data more accurate. 展开更多
关键词 Biological specimen Collection preference Dominant plant species Environmental range Geographical range Species traits
下载PDF
Direct Pointwise Comparison of FE Predictions to StereoDIC Measurements:Developments and Validation Using Double Edge-Notched Tensile Specimen
4
作者 Troy Myers Michael A.Sutton +2 位作者 Hubert Schreier Alistair Tofts Sreehari Rajan Kattil 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第8期1263-1298,共36页
To compare finite element analysis(FEA)predictions and stereovision digital image correlation(StereoDIC)strain measurements at the same spatial positions throughout a region of interest,a field comparison procedure is... To compare finite element analysis(FEA)predictions and stereovision digital image correlation(StereoDIC)strain measurements at the same spatial positions throughout a region of interest,a field comparison procedure is developed.The procedure includes(a)conversion of the finite element data into a triangular mesh,(b)selection of a common coordinate system,(c)determination of the rigid body transformation to place both measurements and FEA data in the same system and(d)interpolation of the FEA nodal information to the same spatial locations as the StereoDIC measurements using barycentric coordinates.For an aluminum Al-6061 double edge notched tensile specimen,FEA results are obtained using both the von Mises isotropic yield criterion and Hill’s quadratic anisotropic yield criterion,with the unknown Hill model parameters determined using full-field specimen strain measurements for the nominally plane stress specimen.Using Hill’s quadratic anisotropic yield criterion,the point-by-point comparison of experimentally based full-field strains and stresses to finite element predictions are shown to be in excellent agreement,confirming the effectiveness of the field comparison process. 展开更多
关键词 StereoDIC spatial co-registration data transformation finite element simulations point-wise comparison of measurements and FEA predictions double edge notch specimen model validation
下载PDF
Perioperative outcomes of transvaginal specimen extraction laparoscopic total gastrectomy and conventional laparoscopicassisted total gastrectomy
5
作者 Zhi-Cao Zhang Wen-Sheng Wang +5 位作者 Jiang-Hong Chen Yuan-Hang Ma Qi-Fa Luo Yun-Bo Li Yang Yang Dan Ma 《World Journal of Gastrointestinal Surgery》 SCIE 2024年第6期1527-1536,共10页
BACKGROUND Natural orifice specimen extraction surgery(NOSES)has emerged as a promising alternative compared to conventional laparoscopic-assisted total gastrectomy(LATG)for treating gastric cancer(GC).However,evidenc... BACKGROUND Natural orifice specimen extraction surgery(NOSES)has emerged as a promising alternative compared to conventional laparoscopic-assisted total gastrectomy(LATG)for treating gastric cancer(GC).However,evidence regarding the efficacy and safety of NOSES for GC surgery is limited.This study aimed to compare the safety and feasibility,in addition to postoperative complications of NOSES and LATG.METHODS Dual circular staplers were used in Roux-en-Y digestive tract reconstruction for transvaginal specimen extraction LATG,and its outcomes were compared with LATG in a cohort of 51 GC patients with tumor size≤5 cm.The study was conducted from May 2018 to September 2020,and patients were categorized into the NOSES group(n=22)and LATG group(n=29).Perioperative parameters were compared and analyzed,including patient and tumor characteristics,postoperative outcomes,and anastomosis-related complications,postoperative hospital stay,the length of abdominal incision,difference in tumor type,postoperative complications,and postoperative survival.RESULTS Postoperative exhaust time,operation duration,mean postoperative hospital stay,length of abdominal incision,number of specific staplers used,and Brief Illness Perception Questionnaire score were significant in both groups(P<0.01).In the NOSES group,the postoperative time to first flatus,mean postoperative hospital stay,and length of abdominal incision were significantly shorter than those in the LATG group.Patients in the NOSES group had faster postoperative recovery,and achieved abdominal minimally invasive incision that met aesthetic requirements.There were no significant differences in gender,age,tumor type,postoperative complications,and postoperative survival between the two groups.CONCLUSION The application of dual circular staplers in Roux-en-Y digestive tract reconstruction combined with NOSES gastrectomy is safe and convenient.This approach offers better short-term outcomes compared to LATG,while long-term survival rates are comparable to those of conventional laparoscopic surgery. 展开更多
关键词 Gastric cancer Circular stapler Natural orifice specimen extraction surgery Laparoscopic-assisted total gastrectomy
下载PDF
Wireless Preamplifier for the Specimen Current Mode Detector in a SEM
6
作者 Valentin G. Dyukov 《Optics and Photonics Journal》 2024年第2期23-28,共6页
Using a scanning electron microscope (SEM) in the back-scattered electron (BSE) mode the composition of multi-element specimens may be determined based on the strong dependence of emission coefficient η on the averag... Using a scanning electron microscope (SEM) in the back-scattered electron (BSE) mode the composition of multi-element specimens may be determined based on the strong dependence of emission coefficient η on the average atomic number of elements Z. The output video signal of the usual BSE detectors is produced from their sensors, and the larger proportion of high-energy electrons with modified spectrum is added. Since η = is/ip (is and ip currents of specimen and probe), better accuracy must be achieved by direct measurements those currents on the specimen surface. Here, an experimental model of a current detector for a presented specimen is described. The cage is mounted on the carousel of the moving specimen stage. The input of the preamplifier is connected to the specimen holder in the form of a disk, the diameter of which is 12 mm. When the probe along its surface scanned, the input potential begins to pulsate with a negative polarity. The output of this preamplifier is connected to a small light-emitting diode, which creates intensity-modulated radiation in the chamber. Thus created the light video signal will be picked up by the photomultiplier of the E-T detector. The modes of true SE and BSE are set by applying tens bias volts of various polarities to the specimens or the cage itself. 展开更多
关键词 Scanning Electron Microscopy Backscattered Electron Imaging Wireless specimen Current Preamplifier Universal (SE/BSE) Dyukov Detector
下载PDF
Application Effect of Feedforward Control in Outpatient Blood Specimen Management
7
作者 Meiying Lu 《Journal of Clinical and Nursing Research》 2024年第6期177-183,共7页
Objective:To analyze the application effect of feedforward control in outpatient blood specimen management.Methods:1,200 patients who had their venous blood collected in outpatient phlebotomy room of our hospital'... Objective:To analyze the application effect of feedforward control in outpatient blood specimen management.Methods:1,200 patients who had their venous blood collected in outpatient phlebotomy room of our hospital's outpatient clinic from January 2021 to April 2021 were selected as study subjects and divided into 600 cases in the control group and 600 cases in the observation group.The two groups of patients were compared in terms of their satisfaction with the staff,the efficiency of the nurses and the quality of nursing care,turnaround time before specimen analysis,the rejection rate of the blood specimens,and the time of result reporting.Results:After the implementation of feedforward control,patients'satisfaction with staff,nurses work efficiency and quality of care,turnaround time before specimen analysis,specimen rejection rate,and result reporting time in the observation group were significantly higher than those in the control group(P<0.05).Conclusion:The application of feedforward control in the management of outpatient blood specimens has significant effect,which effectively improves patients'satisfaction,enhances the efficiency of nurses and the quality of nursing care,shortens the turnaround time of specimens before analysis and the reporting time of results,and reduces the rejection rate of specimens. 展开更多
关键词 Feedforward control Venous blood specimen Nursing management Application effect
下载PDF
Robotic natural orifice specimen extraction surgery I-type F method vs conventional robotic resection for lower rectal cancer 被引量:2
8
作者 Fang Tao Dong-Ning Liu +4 位作者 Peng-Hui He Xin Luo Chi-Ying Xu Tai-Yuan Li Jin-Yuan Duan 《World Journal of Gastrointestinal Surgery》 SCIE 2023年第10期2142-2153,共12页
BACKGROUND Robotic resection using the natural orifice specimen extraction surgery I-type F method(R-NOSES I-F)is a novel minimally invasive surgical strategy for the treatment of lower rectal cancer.However,the curre... BACKGROUND Robotic resection using the natural orifice specimen extraction surgery I-type F method(R-NOSES I-F)is a novel minimally invasive surgical strategy for the treatment of lower rectal cancer.However,the current literature on this method is limited to case reports,and further investigation into its safety and feasibility is warranted.AIM To evaluate the safety and feasibility of R-NOSES I-F for the treatment of low rectal cancer.METHODS From September 2018 to February 2022,206 patients diagnosed with low rectal cancer at First Affiliated Hospital of Nanchang University were included in this retrospective analysis.Of these patients,22 underwent R-NOSES I-F surgery(RNOSES I-F group)and 76 underwent conventional robotic-assisted low rectal cancer resection(RLRC group).Clinicopathological data of all patients were collected and analyzed.Postoperative outcomes and prognoses were compared between the two groups.Statistical analysis was performed using SPSS software.RESULTS Patients in the R-NOSES I-F group had a significantly lower visual analog score for pain on postoperative day 1(1.7±0.7 vs 2.2±0.6,P=0.003)and shorter postoperative anal venting time(2.7±0.6 vs 3.5±0.7,P<0.001)than those in the RLRC group.There were no significant differences between the two groups in terms of sex,age,body mass index,tumor size,TNM stage,operative time,intrao-perative bleeding,postoperative complications,or inflammatory response(P>0.05).Postoperative anal and urinary functions,as assessed by Wexner,low anterior resection syndrome,and International Prostate Symptom Scale scores,were similar in both groups(P>0.05).Long-term follow-up revealed no significant differences in the rates of local recurrence and distant metastasis between the two groups(P>0.05).CONCLUSION R-NOSES I-F is a safe and effective minimally invasive procedure for the treatment of lower rectal cancer.It improves pain relief,promotes gastrointestinal function recovery,and helps avoid incision-related complications. 展开更多
关键词 Robotic surgery Natural orifice specimen extraction surgery Lower rectal cancer Robotic resection using the natural orifice specimen extraction surgery I-type F method
下载PDF
Energy-dispersive X-ray Spectroscopy for the Quantitative Analysis of Pyrite Thin Specimens
9
作者 LUO Tingting GUO Yi +4 位作者 DENG Zhao LIU Xiaoqing SUN Zhenya QI Yanyuan YANG Meijun 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2023年第6期1304-1310,共7页
To explore ways to improve the accuracy of quantitative analysis of samples in the micrometer to nanometer range of magnitudes,we adopted analytical transmission electron microscopy(AEM/EDS)for qualitative and quantit... To explore ways to improve the accuracy of quantitative analysis of samples in the micrometer to nanometer range of magnitudes,we adopted analytical transmission electron microscopy(AEM/EDS)for qualitative and quantitative analysis of pyrite materials.Additionally,the k factor of pyrite is calculated experimentally.To develop an appropriate non-standard quantitative analysis model for pyrite materials,the experimentally calculated k factor is compared with that estimated from the non-standard quantitative analytical model of the instrument software.The experimental findings demonstrate that the EDS attached to a TEM can be employed for precise quantitative analysis of micro-and nanoscale regions of pyrite materials.Furthermore,it serves as a reference for improving the results of the EDS quantitative analysis of other sulfides. 展开更多
关键词 analytical transmission electron microscopy(AEM) energy dispersive X-ray spectroscopy(EDS) PYRITE thin specimen quantitative analysis
下载PDF
Statistical Analysis and Countermeasures for Specimen Rejection in the Emergency Department
10
作者 Yinhua Fan Bo Zhao 《Journal of Clinical and Nursing Research》 2023年第4期145-150,共6页
The rejected specimens from the Emergency Department of the Center of Clinical Laboratory from January 1,2022 to January 1,2023 were analyzed to reduce the specimen rejection rates and to improve the quality of inspec... The rejected specimens from the Emergency Department of the Center of Clinical Laboratory from January 1,2022 to January 1,2023 were analyzed to reduce the specimen rejection rates and to improve the quality of inspection.The results showed that there were 1488 samples of rejected specimens and the non-conforming rate was 0.58%.The departments involved were mainly the Emergency Department,the Hematology Department,the Cardiology Department,the Intensive Care Department,and the Brain Surgery Department.Among the reasons for rejection,blood hemolysis accounted for 43.15%,blood coagulation accounted for 26.61%,and the rate of insufficient specimens was 17.14%.Among them,the sample rejection rate for arterial blood gas analysis was the highest,which accounted for 1.74%;followed by specimens for coagulation test,which was 1.18%.These results indicate the main reason for producing rejected specimens is mainly due to not following the standard operating procedure.Specimen rejection can largely be avoided if the standards for specimen collection are strictly followed. 展开更多
关键词 specimen rejection Statistical analysis Quality inspection
下载PDF
公安实践教学中数字化标本库的构建与应用 被引量:1
11
作者 张婷 夏鑫鑫 《实验室研究与探索》 CAS 北大核心 2024年第1期169-173,共5页
为推进信息化教学的发展,提出在公安实践教学中建设数字化标本库的构想。以虚拟仿真教学中的毒品数字化标本库构建与教学组织应用为例,探讨公安数字化标本库建设可持续发展的路径和内涵,提出适合公安特色数字化标本库内容和标准化建设... 为推进信息化教学的发展,提出在公安实践教学中建设数字化标本库的构想。以虚拟仿真教学中的毒品数字化标本库构建与教学组织应用为例,探讨公安数字化标本库建设可持续发展的路径和内涵,提出适合公安特色数字化标本库内容和标准化建设的建议,采用资源利用、整合、共建等高效节约办法,注重数字化样本库和数据库同步开发使用的发展趋势。数字化标本库具有线上自学、线上线下教学、终身学习等优势,可启发公安教育智慧教学工作高质量发展。 展开更多
关键词 公安 实践教学 标本库 数字化构建
下载PDF
数智化全自动标本转移系统在手术病理标本前处理流程中的应用
12
作者 张颖 雷梦君 +4 位作者 玄力娟 孙碧海 司超增 陈静 牛云 《中国护理管理》 CSCD 北大核心 2024年第6期924-928,共5页
目的:探讨在数智化管理背景下,由手术室护士主导的数智化全自动标本转移系统在手术病理标本前处理流程中的应用效果,为提高手术病理标本质量提供参考。方法:构建数智化全自动标本转移系统,并将其应用于手术病理标本前处理流程中,比较系... 目的:探讨在数智化管理背景下,由手术室护士主导的数智化全自动标本转移系统在手术病理标本前处理流程中的应用效果,为提高手术病理标本质量提供参考。方法:构建数智化全自动标本转移系统,并将其应用于手术病理标本前处理流程中,比较系统应用前(2023年4月—7月)和系统应用后(2023年8月—11月)的病理标本送检效率、送检质量、手术室护士心理压力及医护人员满意度。结果:应用数智化全自动标本转移系统后,病理标本前处理流程时长较应用前平均减少3.66 min,一次性接收合格率由87.07%提高至96.42%,病理送检质量满意率较高,护士工作压力显著缓解,医务人员满意度明显提高,以上差异均具有统计学意义(P<0.05)。结论:数智化全自动标本转移系统应用于手术标本前处理流程中可有效提高手术标本前处理效率并缓解护士工作压力,保障病理标本送检质量,为医疗诊断提供可靠的依据,有效减少医务人员职业暴露,提升医护人员满意度。 展开更多
关键词 数智化 全自动标本转移系统 手术病理标本前处理 抽真空处理 冷藏
下载PDF
钢管混凝土键连接框架梁和剪力墙的受剪性能 被引量:1
13
作者 李明 刘栩邑 +2 位作者 吴潜 吴欣禹 吴永新 《沈阳建筑大学学报(自然科学版)》 CAS 北大核心 2024年第1期38-46,共9页
目的 研究钢管混凝土键连接框架梁和剪力墙的受剪性能,为工程应用提供设计依据。方法 应用有限元分析软件ABAQUS对比钢管混凝土键连接与现浇连接梁墙的结构受剪性能,分析前者受剪机理及不同因素对受剪性能的影响。结果 钢管混凝土键连... 目的 研究钢管混凝土键连接框架梁和剪力墙的受剪性能,为工程应用提供设计依据。方法 应用有限元分析软件ABAQUS对比钢管混凝土键连接与现浇连接梁墙的结构受剪性能,分析前者受剪机理及不同因素对受剪性能的影响。结果 钢管混凝土键连接梁墙的结构承载力和延性系数较现浇结构分别提高约10%和34%;钢材强度从Q235到Q390,初始刚度增加8.44%;截面高度从100 mm到120 mm,延性系数提高17.73%;截面厚度每增加2 mm,承载力提高约15%;截面长度和混凝土强度等级对承载力、初始刚度和延性系数的影响均小于15%,纵向距离对其受剪性能几乎无影响。结论 采用钢管混凝土键连接梁墙的结构总体受剪性能优于现浇结构;钢材强度和截面厚度分别是影响初始刚度和承载力的主要因素。 展开更多
关键词 钢管混凝土键 框架-剪力墙结构 梁墙试件 抗剪性能 有限元分析
下载PDF
寄生虫虫卵悬液永久封制玻片标本制作方法探索
14
作者 唐媛媛 王晓楠 +2 位作者 李京培 王林定 李群 《河南大学学报(医学版)》 CAS 2024年第3期184-188,共5页
目的:探索寄生虫虫卵液永久玻片封制标本的最佳制作方法。方法:在现有研究的基础上,改良虫卵悬液保存配方,再结合不同封片方法制作虫卵玻片标本,保存1 a后,再对其制作效果对进行观察。结果:用体积分数为50%的鸡蛋清、40%的福尔马林、10... 目的:探索寄生虫虫卵液永久玻片封制标本的最佳制作方法。方法:在现有研究的基础上,改良虫卵悬液保存配方,再结合不同封片方法制作虫卵玻片标本,保存1 a后,再对其制作效果对进行观察。结果:用体积分数为50%的鸡蛋清、40%的福尔马林、10%的甘油配制的蛋白甘油液保存虫卵,再进行石蜡圈+树胶双封片制作效果最佳。结论:经比较发现虫卵保存液中甘油的含量多少对于虫卵永久封制玻片标本效果的影响很大,其次封制方法对于虫卵液的长期保存也尤为重要。 展开更多
关键词 寄生虫虫卵 蛋白甘油液 标本制作
下载PDF
甲状腺结节大小对超声引导下细针穿刺活检标本质量影响的研究
15
作者 李龙 张苏雅 +2 位作者 吕镔 王贝贝 冷志远 《影像科学与光化学》 CAS 2024年第1期29-33,共5页
本研究旨在评估甲状腺结节大小对超声引导下细针穿刺活检(US-FNAB)标本质量的影响。回顾性分析由同一名超声医生独立完成的614例共733个甲状腺结节US-FNAB患者资料,根据甲状腺结节直径分为A组(<5 mm)、B组(5~10 mm)和C组(>10 mm)... 本研究旨在评估甲状腺结节大小对超声引导下细针穿刺活检(US-FNAB)标本质量的影响。回顾性分析由同一名超声医生独立完成的614例共733个甲状腺结节US-FNAB患者资料,根据甲状腺结节直径分为A组(<5 mm)、B组(5~10 mm)和C组(>10 mm),比较各组间标本不满意率。A组189个结节,不满意率为11.6%(22/189);B组397个结节,不满意率为10.8%(43/397);C组147个结节,不满意率为9.5%(14/147)。三组间US-FNAB标本不满意率比较差异均无统计学意义(P>0.05)。对于一名具有丰富操作经验的医生,甲状腺结节大小不会影响US-FNAB的标本质量。 展开更多
关键词 甲状腺结节 超声检查 活组织检查 细针 标本质量
下载PDF
基于加速加载试验的青川岩改沥青混合料疲劳性能研究 被引量:1
16
作者 李志 郝岩 +1 位作者 袁晓曼 庄传仪 《中外公路》 2024年第3期78-84,共7页
为评价青川岩改沥青混合料疲劳性能,该文设计了基于比例尺为1∶3的路面加速加载试验系统的动轮载三点弯曲加载疲劳试验装置,对双层沥青混合料复合车辙试件进行轮胎碾压下的三点弯曲重复加载疲劳试验,结合沥青混合料小梁试件MTS弯曲疲劳... 为评价青川岩改沥青混合料疲劳性能,该文设计了基于比例尺为1∶3的路面加速加载试验系统的动轮载三点弯曲加载疲劳试验装置,对双层沥青混合料复合车辙试件进行轮胎碾压下的三点弯曲重复加载疲劳试验,结合沥青混合料小梁试件MTS弯曲疲劳试验,评价青川岩改沥青及复合改性沥青等对沥青混合料疲劳性能的改善效果。结果表明:青川岩改沥青提高了沥青混合料承受重复弯拉荷载的能力,改善了沥青混合料的抗疲劳性能,其抗疲劳性能优于青川岩沥青与SBS复合改性沥青、SBS改性沥青和基质沥青;基于比例尺为1∶3的路面加速加载试验的动轮载三点弯曲重复加载疲劳试验,能更真实地模拟现场路面轮载作用,减少了小梁试件尺寸效应对疲劳寿命的影响,再现了轮载作用下路面结构的受力状况。 展开更多
关键词 道路工程 疲劳性能 青川岩改沥青 加速加载试验 双层沥青混合料复合试件
下载PDF
2015-2021年CHINET尿液分离菌分布和耐药性变迁
17
作者 李艳明 邹明祥 +86 位作者 刘文恩 杨洋 胡付品 朱德妹 徐英春 张小江 张峰波 季萍 谢轶 康梅 王传清 付盼 徐元宏 黄颖 孙自镛 陈中举 倪语星 孙景勇 褚云卓 田素飞 胡志东 李金 俞云松 林洁 单斌 杜艳 郭素芳 魏莲花 邹凤梅 张泓 王春 胡云建 艾效曼 卓超 苏丹虹 郭大文 赵金英 喻华 黄湘宁 金炎 邵春红 徐雪松 鄢超 王山梅 楚亚菲 张利侠 马娟 周树平 周艳 朱镭 孟晋华 董方 吕志勇 胡芳芳 沈瀚 周万青 贾伟 李刚 吴劲松 卢月梅 李继红 段金菊 康建邦 马晓波 郑燕萍 郭如意 朱焱 陈运生 孟青 王世富 胡雪飞 沈继录 汪瑞忠 房华 俞碧霞 赵勇 龚萍 温开镇 张贻荣 刘江山 廖龙凤 顾洪芹 姜琳 贺雯 薛顺虹 冯佼 岳春雷 《中国感染与化疗杂志》 CAS CSCD 北大核心 2024年第3期287-299,共13页
目的了解2015-2021年CHINET细菌耐药监测网中尿液分离菌的分布和耐药性。方法收集CHINET细菌耐药监测网51家医疗机构2015-2021年所有尿液标本临床分离菌的耐药监测数据资料,采用WHONET 5.6软件进行统计分析。结果2012-2021年尿液标本共... 目的了解2015-2021年CHINET细菌耐药监测网中尿液分离菌的分布和耐药性。方法收集CHINET细菌耐药监测网51家医疗机构2015-2021年所有尿液标本临床分离菌的耐药监测数据资料,采用WHONET 5.6软件进行统计分析。结果2012-2021年尿液标本共分离细菌261893株,其中革兰阳性菌62219株,占23.8%,革兰阴性菌199674株占76.2%。常见的分离菌依次为大肠埃希菌(46.7%)、屎肠球菌(10.4%)、肺炎克雷伯菌(9.8%)、粪肠球菌(8.7%)、奇异变形杆菌(3.5%)、铜绿假单胞菌(3.4%)、无乳链球菌(2.6%)和阴沟肠杆菌(2.1%)。上述细菌主要分离自住院患者,女性多见于男性,成人多见于儿童。大肠埃希菌、肺炎克雷伯菌和奇异变形杆菌中产超广谱β内酰胺酶(ESBL)菌株分别占53.2%、52.8%和37.0%。耐碳青霉烯类的大肠埃希菌、肺炎克雷伯菌、铜绿假单胞菌和鲍曼不动杆菌中检出率分别为1.7%、18.5%、16.4%和40.3%。粪肠球菌对氨苄西林、呋喃妥因、利奈唑胺、万古霉素、替考拉宁和磷霉素的耐药率<10%,屎肠球菌对氨苄西林、左氧氟沙星、红霉素的耐药率>90%,对万古霉素、利奈唑胺和替考拉宁的耐药率<2%。ICU住院患者分离的大肠埃希菌、肺炎克雷伯菌、铜绿假单胞菌和鲍曼不动杆菌对大部分抗菌药物的耐药率明显高于门诊患者和非ICU住院患者。结论尿液标本临床分离菌主要以大肠埃希菌、肠球菌和肺炎克雷伯菌为主,不同人群尿液标本中分离的细菌种类和耐药性不尽相同,应重视细菌耐药监测,减少抗菌药物的不合理使用。 展开更多
关键词 尿液 细菌耐药性监测 药物敏感性试验 大肠埃希菌 多重耐药菌
下载PDF
织物增强混凝土永久模板叠合试件抗氯离子渗透性能研究
18
作者 陈欣 王国杰 林颖 《混凝土》 CAS 北大核心 2024年第8期158-162,共5页
织物增强混凝土(TRC)由高性能细骨料混凝土基体与纤维网组成,TRC永久模板与核心混凝土组成叠合试件。为揭示叠合试件氯离子渗透作用规律,确定永久模板最佳厚度范围,以TRC永久厚度、耐碱纤维网层数以及界面处理方式为变量,进行叠合试件... 织物增强混凝土(TRC)由高性能细骨料混凝土基体与纤维网组成,TRC永久模板与核心混凝土组成叠合试件。为揭示叠合试件氯离子渗透作用规律,确定永久模板最佳厚度范围,以TRC永久厚度、耐碱纤维网层数以及界面处理方式为变量,进行叠合试件抗氯离子渗透性能试验研究和计算分析。结果表明:与未设置永久模板相比,当TRC永久模板厚度为10~50 mm时,叠合试件氯离子扩散系数分别降低73.2%~95.6%。耐碱纤维编网对永久模板抗氯离子渗透性能没有增强作用。水泥净浆涂刷、表面凿毛、短切纤维插入三种界面处理方式对叠合试件氯离子渗透系数和渗透深度的影响不显著。结合Duracrete模型定量分析,给出了海洋环境不同工况下TRC永久模板厚度建议范围。 展开更多
关键词 永久模板 叠合试件 氯离子扩散系数 模板厚度
下载PDF
高等农业院校普通昆虫学课程实践教学改革探索
19
作者 李俊 佟心 +4 位作者 王小云 高琼华 杨娟 郑霞林 王国全 《安徽农学通报》 2024年第19期119-122,共4页
对普通昆虫学课程标本种类、教学内容和教学深度3个方面的教学现状进行分析,探讨并提出了以提高学生实践能力为目的的实践教学改革措施。通过充分利用现代化信息技术,以线上昆虫标本馆为基础,建设教学标本资源共享平台;加强团队建设,优... 对普通昆虫学课程标本种类、教学内容和教学深度3个方面的教学现状进行分析,探讨并提出了以提高学生实践能力为目的的实践教学改革措施。通过充分利用现代化信息技术,以线上昆虫标本馆为基础,建设教学标本资源共享平台;加强团队建设,优化师资配置等措施,提高了学生的学习兴趣,增强其自主学习能力。对该课程实践教学改革效果进行分析,结果表明,该教学改革有利于培养学生的动手能力,使其做到理论和实践相结合,实践能力有所增强。为培养符合社会需要、具有创新思维和实践能力的高素质人才提供参考。 展开更多
关键词 普通昆虫学 标本种类 昆虫标本馆 标本资源共享
下载PDF
类岩石试件三轴扰动破坏特性试验研究
20
作者 王军 朱传根 +2 位作者 李勋 王波 张艺腾 《采矿与岩层控制工程学报》 EI 北大核心 2024年第2期11-24,共14页
为研究高应力围岩扰动破坏机制,开展了不同围压下类岩石试件的三轴常规压缩和三轴循环扰动试验,得到了试件的扰动应力–应变规律和变形破坏特征,并对试件开展了核磁共振(Nuclear Magnetic Resonance)成像试验,从微观角度进一步阐明了试... 为研究高应力围岩扰动破坏机制,开展了不同围压下类岩石试件的三轴常规压缩和三轴循环扰动试验,得到了试件的扰动应力–应变规律和变形破坏特征,并对试件开展了核磁共振(Nuclear Magnetic Resonance)成像试验,从微观角度进一步阐明了试件扰动破坏机理。研究结果表明:(1)试件在不同围压下均存在一个阈值强度,轴向荷载超过阈值强度后,轴向变形对扰动变得敏感,再次施加扰动会引起试件显著变形,当轴向荷载低于阈值强度时,变形对扰动不敏感。阈值强度与极限强度的比值可以反映试件的抗扰动能力,随着围压增大,该比值呈现逐步递减的规律,说明高围压下试件抗扰动能力下降,对扰动作用更敏感。(2)扰动作用下类岩石试件存在弱化效应,如常规三轴10MPa围压下试件表现出腰鼓破坏,而受扰动作用后,试件呈现斜切脆性破坏,与常规三轴5MPa围压下破坏形态相近。(3)岩石试件在高应力作用下进入塑性流动状态,内部颗粒重新排列,内部小孔隙与大孔隙的占比减少,而中孔隙的占比显著增多,试件内部孔隙率整体降低。 展开更多
关键词 类岩石试件 三轴扰动 阈值强度 破坏形态 核磁共振
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部