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Predator stress-induced depression is associated with inhibition of hippocampal neurogenesis in adult male mice 预览
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作者 Yan-Ping Wu Hua-Ying Gao +3 位作者 Shu-Hua Ouyang Hiroshi Kurihara Rong-Rong He Yi-Fang Li 《中国神经再生研究:英文版》 SCIE CAS CSCD 2019年第2期298-305,共8页
Stress has been suggested to disturb the 5-hydroxytryptamine system and decrease neurogenesis, which contribute to the development of depression. Few studies have investigated the effect of predator stress, a type of ... Stress has been suggested to disturb the 5-hydroxytryptamine system and decrease neurogenesis, which contribute to the development of depression. Few studies have investigated the effect of predator stress, a type of psychological stress, on depression and hippocampal neurogenesis in adult mice; we therefore investigated this in the present study. A total of 35 adult male Kunming mice were allocated to a cat stress group, cat odor stress group, cat stress + fluoxetine group, cat odor stress + fluoxetine group, or a control group (no stress/treatment). After 12 days of cat stress or cat odor stress, behavioral correlates of depression were measured using the open field test, elevated plus maze test, and dark-avoidance test. The concentrations of hippocampal 5-hydroxytryptamine and 5-hydroxyindoleacetic acid were measured using high-performance liquid chromatography-electrochemical detection. Neurogenesis was also analyzed using a bromodeoxyuridine and doublecortin double-immunostaining method. Cat stress and cat odor stress induced depression-like behaviors; this effect was stronger in the cat stress model. Furthermore, compared with the control group, cat stress mice exhibited lower 5-hydroxytryptamine concentrations, higher 5-hydroxyindoleacetic acid concentrations, and significantly fewer bromodeoxyuridine+/doublecortin+-labeled cells in the dentate gyrus, which was indicative of less neurogenesis. The changes observed in the cat stress group were not seen in the cat stress + fluoxetine group, which suggests that the effects of predator stress on depression and neurogenesis were reversed by fluoxetine. Taken together, our results indicate that depression-like behaviors induced by predator stress are associated with the inhibition of hippocampal neurogenesis. 展开更多
关键词 nerve REGENERATION DEPRESSIVE disorder CAT STRESS CAT odor STRESS behavioral evaluation open field TEST elevated plus maze TEST dark-avoidance TEST 5-HYDROXYTRYPTAMINE 5-hydroxyindoleacetic acid hippocampal neurogenesis neural REGENERATION
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Undrained shear strength evaluation for hydrate-bearing sediment overlying strata in the Shenhu area, northern South China Sea 预览
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作者 Yanlong Li Gaowei Hu +3 位作者 Nengyou Wu Changling Liu Qiang Chen Chen’an Li 《海洋学报:英文版》 SCIE CAS CSCD 2019年第3期114-123,共10页
The undrained shear strength of shallow strata is a critical parameter for safety design in deep-water operations.In situ piezocone penetration tests(CPTU) and laboratory experiments are performed at Site W18-19 in th... The undrained shear strength of shallow strata is a critical parameter for safety design in deep-water operations.In situ piezocone penetration tests(CPTU) and laboratory experiments are performed at Site W18-19 in the Shenhu area, northern South China Sea, where China’s first marine hydrate exploitation operation is due to be located. The validation of the undrained shear strength prediction model based on CPTU parameters. Different laboratory tests, including pocket penetrometer, torvane, miniature vane and unconsolidated undrained triaxial tests, are employed to solve empirical cone coefficients by statistical and mathematical methods. Finally, an optimized model is proposed to describe the longitudinal distribution of undrained shear strength in calcareous clay strata in the Shenhu area. Research results reveal that average empirical cone coefficients based on total cone resistance, effective resistance, and excess-pore pressure are 13.8, 4.2 and 14.4, respectively. The undrained shear strength prediction model shows a good fit with the laboratory results only within specific intervals based on their compaction degree and gas-bearing conditions. The optimized prediction model in piecewise function format can be used to describe the longitudinal distribution of the undrained shear strength for calcareous clay within all depth intervals from the mud-line to the upper boundary of hydrate-bearing sediments(HBS). The optimized prediction result indicates that the effective cone resistance model is suitable for very soft to firm calcareous clays,the excess-pore pressure model can depict the undrained shear strength for firm to very stiff but gas-free clays,while the total cone resistance model is advantageous for evaluating the undrained shear strength for very stiff and gassy clays. The optimized model in piecewise function format can considerably improve the adaptability of empirical models for calcareous clay in the Shenhu area. These results are significant for safety evaluations of proposed hydrate exploitat 展开更多
关键词 piezocone penetration TEST HYDRATE EXPLOITATION TEST UNDRAINED shear strength CALCAREOUS clay Shenhu area South China Sea
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Room-temperature test system for 162.5 MHz high-power couplers 预览
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作者 Long Chen Shen-Hu Zhang +9 位作者 Yong-Ming Li Ruo-Xu Wang Tiancai Jiang Lei Yang Chun-Long Li An-Dong Wu Shi-Chun Huang Feng Pan Xin-Meng Liu Yuan He 《核技术:英文版》 SCIE CAS CSCD 2019年第1期35-41,共7页
Fundamental power couplers are crucial components for feeding radio frequency power to accelerating cavities. Couplers must be tested and conditioned on a room-temperature test stand to evaluate and potentially improv... Fundamental power couplers are crucial components for feeding radio frequency power to accelerating cavities. Couplers must be tested and conditioned on a room-temperature test stand to evaluate and potentially improve their performance before being installed in an accelerating cavity. A new test system has been designed and is under construction at the institute of modern physics.For this test system, multiple conditioning modes, including the pulse mode, CW mode, and amplitude-sweeping mode, have been embedded in the low-level radio frequency system of the test stand. All of these conditioning modes can be run manually or automatically. In addition, a novel test cavity is proposed and has been designed, which facilitates non-contact conditioning and a multi-purpose test stand. 展开更多
关键词 COUPLERS CONDITIONING TEST STAND LLRF control system TEST CAVITY
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t检验和F检验在化学测试质控数据趋势分析中的应用 预览
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作者 沈英 《检验检疫学刊》 2019年第2期105-107,共3页
本文采用t检验和F检验对一段时期内化学测试项目(化学有害物质铅的测试)质控数据的趋势进行分析。通过比较2个不同时期的均值和标准差是否存在显著性差异,从而确认该化学测试项目的趋势是否稳定。本文采用Excel进行t检验和F检验运算,最... 本文采用t检验和F检验对一段时期内化学测试项目(化学有害物质铅的测试)质控数据的趋势进行分析。通过比较2个不同时期的均值和标准差是否存在显著性差异,从而确认该化学测试项目的趋势是否稳定。本文采用Excel进行t检验和F检验运算,最大限度减少人工运算,易于日常操作。该统计方式可用于判断单个化学测试项目长期的趋势是否稳定可控,为检测领域进行质控数据趋势分析提供一种新思路。 展开更多
关键词 T检验 F检验 趋势分析 EXCEL
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In-vivo Mutagenicity of Protein-modified Enterococcus faecalis 预览
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作者 Lijun DING Shasha ZHAO 《农业生物技术:英文版》 CAS 2019年第3期92-94,共3页
The mutagenicity of the protein-modified Enterococcus faecalis was evaluated by a mouse bone marrow micronucleus test and a mouse sperm abnormality test.The test substance was designed with three dose groups (1,2 and ... The mutagenicity of the protein-modified Enterococcus faecalis was evaluated by a mouse bone marrow micronucleus test and a mouse sperm abnormality test.The test substance was designed with three dose groups (1,2 and 5 g/kg·bw) and intragastrically administrated,with cyclophosphamide as a positive control and normal saline as a normal control.The micronucleus rate and sperm abnormality rate were measured.The results showed that the micronucleus rates and sperm abnormality rates in the different dose groups were not significantly different from those in normal control group ( P >0.05),while the positive control group was significantly higher than the normal control group ( P <0.01).The conclusion is that the protein-modified E.faecalis was tested to be negative in both the mouse bone marrow micronucleus test and mouse sperm abnormality test,suggesting that it has no mutagenicity in vivo. 展开更多
关键词 Protein-modified E.faecalis MOUSE bone marrow MICRONUCLEUS TEST MOUSE sperm abnormality TEST
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高职学生进校前使用科学计算工具的现状分析--以西安职业技术学院为例 预览
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作者 宋剑萍 李洁琼 《西安职业技术学院学报》 2019年第1期30-33,共4页
针对西安职业技术学院2018级建轨学院、电工学院系新生开展《高职学生进校前使用科学计算工具的现状》问卷调查,运用统计学原理和Spss软件对调查问卷的效度和信度,以及问卷的结果进行分析,得出此次的问卷设计科学,调查结果可信,在高职... 针对西安职业技术学院2018级建轨学院、电工学院系新生开展《高职学生进校前使用科学计算工具的现状》问卷调查,运用统计学原理和Spss软件对调查问卷的效度和信度,以及问卷的结果进行分析,得出此次的问卷设计科学,调查结果可信,在高职阶段开设科学计算工具相关课程是学生的迫切需要.提出了实施高职数学教学改革的方向为增加数学实验课程,培养学生对科学计算工具的使用能力. 展开更多
关键词 科学计算工具 效度 信度 T检验 非参数检验 数学软件
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Biochemical,Enzymatic,and Immunological Study on Antimutagenic Achillea millefolium Methanolic Extract in vivo 预览
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作者 Asmaa A.Hussein Ruqaya M.Al-Ezzy Mays T.Abdallah 《药剂与药理学:英文版》 2019年第2期69-74,共6页
Traditionally medicinal plants are used for its potential chemotherapeutic action and for safety upon the continued use of these plants.Achillea millefolium(AM)is an ancient herb which is used to treat wounds,headache... Traditionally medicinal plants are used for its potential chemotherapeutic action and for safety upon the continued use of these plants.Achillea millefolium(AM)is an ancient herb which is used to treat wounds,headaches,disorder in gastrointestinal and hepatobiliary,pain,and inflammation.This study was aimed to investigate the biochemical parameter of antimutagenic methanolic extract for AM in vivo.Plant extract together with MTX decreased the damage caused by the drug on the concentrations of total cholesterol and triglycerides(160.3±2.26 and 108.7±2.71),significant increase in total protein concentration(8.51±0.17,9.46±0.19 and 10.8±2.71 g\dL)for 100 and 200 mg\kg was observed.Also plant extracts counteract the damage caused by drug through the reduction for both creatinin and albumin concentrations to 1.57±0.03 mg\dL and 4.56±0.09 g\dL,respectively.On enzymatic level,the results of interactions indicated the ability of plant to modulating harmful effects of the drug(57.1±1.3,130±3.1 and 111.1±2.1 U\L)for GOT,GPT and ALP,respectively.On the other hand,the plant possesses the ability to enhance the concentrations of all immunoglobulin(IgM,IgA and IgG)in the two doses tested.Therefore,the results of this study indicate the antimutagenic potential of AM extract and encouraging its consumption with MTX as one of the promising therapies. 展开更多
关键词 Medicinal plants ACHILLEA millefolium liver FUNCTION TEST kidney FUNCTION TEST IMMUNOGLOBULIN
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Optimization of test resources for 3D SoC based on game theory
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作者 Shao Jingbo Zhao Yue Liu Xiaoxiao 《中国邮电高校学报:英文版》 EI CSCD 2019年第1期65-74,共10页
The ever-increasing complexity of on-chip interconnection poses great challenges for the architecture of conventional system-on-chip(SoC)in semiconductor industry.The rapid development of process technology enables th... The ever-increasing complexity of on-chip interconnection poses great challenges for the architecture of conventional system-on-chip(SoC)in semiconductor industry.The rapid development of process technology enables the creation of stacked 3-dimensional(3D)SoC by means of through-silicon-via(TSV).Stacked 3D SoC testing consists of two major issues,test architecture optimization and test scheduling.This paper proposed game theory based optimization of test scheduling and test architecture to achieve win-win result as well as individual rationality for each player in a game.Game theory helps to achieve equilibrium between two correlated sides to find an optimal solution.Experimental results on handcrafted 3D SoCs built from ITC'2 benchmarks demonstrate that the proposed approach achieves comparable or better test times at negligible computing time. 展开更多
关键词 3D SOC GAME THEORY TEST ARCHITECTURE TEST SCHEDULING
Comparison of Inspection Data by Difference in Odour Inspection Kit (Including Results of Young and Old Age) 预览
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作者 Naomi Katayama Shoko Kondo +12 位作者 Yui Nakayama Takafumi Nakada Seiya Goto Satofumi Sugimoto WakakoKinoshita Masaaki Teranisi Michihiko Sone Yasushi Fujimoto Hironao Otake Hirokazu Suzuki NaokiSaji Seiichi Nakata Tsutomu Nakashima 《健康科学:英文版》 2019年第3期160-165,共6页
The present study examined the relationship between olfactory function for ten years. A personal function test was calculated from the Nagoya Women’s University study database, and the odor stick identification test ... The present study examined the relationship between olfactory function for ten years. A personal function test was calculated from the Nagoya Women’s University study database, and the odor stick identification test and open essence identification test were administered to healthy young and elderly people. The participants were community dwellers who voluntarily participated in the Nagoya Women’s University Study and had managed everyday life by themselves. We combined data of 2018 and checked two kinds of the olfactometry result. These data were made from a consultation result list which was handed to a testee by hand. The test age was in his/her 80s from 40s and in his/her 20s from 10s. The data were compared according to the generation (young age is 20.1 ± 0.7 years old and old age is 74.5 ± 10.0 years old). We conducted two kinds of olfaction tests. The Odour Stick Identification Test (OSIT-J) was used to assess odour perception. This test possesses high reliability and validity. The OSIT-J includes 12 different odorants to be identified. The Odour Essence Identification Test was used to assess odour perception, too. It also includes 12 different odorants to be identified. We compared the answer of generation and compared the results of the two olfactory tests. As a result, there were no statistically significant differences in the total number of correct answers in young people and old people in the two olfactory test results. In addition, we compare young people and old people who increased the number of correct answer in the two kinds of olfactory examination, the same person, and those who decreased, but there was no statistically significant difference. However, there were statistically significant differences between India ink and perfume and Household (domestic) gas compared with young people and old people with two kinds of olfactory test results. From the results of this study, it was found that the results of two kinds of olfactory test can be used together as a research result for the result 展开更多
关键词 HEALTHY elderly PEOPLE HEALTHY young PEOPLE OLFACTORY function the ODOR stick TEST the open ESSENCE TEST
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定期检验对电梯试验检验项目的思考 预览
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作者 张翔 耿继波 崔婷 《起重运输机械》 2019年第1期170-172,共3页
依据电梯定期检验中所规定的试验检验内容与要求,结合对应的检验方法来判断电梯合格与否。但检验方法多为电梯制造厂家制定,维护保养单位进行试验,检验人员现场观察试验结果并确认。其检验形式存有不严谨之处,文中以轿厢上行超速保护装... 依据电梯定期检验中所规定的试验检验内容与要求,结合对应的检验方法来判断电梯合格与否。但检验方法多为电梯制造厂家制定,维护保养单位进行试验,检验人员现场观察试验结果并确认。其检验形式存有不严谨之处,文中以轿厢上行超速保护装置试验、抱闸接触器防粘连试验为探讨对象,提出合理化的检验形式,规范电梯试验检验,确保电梯安全。 展开更多
关键词 电梯 轿厢上行 超速保护装置 检验 试验 抱闸接触器 防粘连试验
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试验与仿真相结合的某结构噪声优化分析 预览
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作者 孙俊刚 《电脑知识与技术:学术版》 2019年第4X期268-270,共3页
针对某车型投产试制阶段被抱怨的轰鸣声结构噪声进行了试验优化与仿真优化。试验验证了该结构噪声来源于顶棚的局部振动,通过加装质量阻尼器可以消除该轰鸣声。但是考虑到成本,需要寻找替代方案。通过仿真,将前横梁加厚到2mm可以满足该... 针对某车型投产试制阶段被抱怨的轰鸣声结构噪声进行了试验优化与仿真优化。试验验证了该结构噪声来源于顶棚的局部振动,通过加装质量阻尼器可以消除该轰鸣声。但是考虑到成本,需要寻找替代方案。通过仿真,将前横梁加厚到2mm可以满足该结构噪声的优化需求。 展开更多
关键词 结构噪声 试验 仿真 优化
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Comparison of the Analgesic Effect of Low-Intensive Polarized Polychromatic Light and Analgesics 预览
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作者 Sergiy A. Gulyar Zynaida A. Tamarova 《美中医学:英文版》 2019年第1期1-15,共15页
On the model of formalin test in mice,the analgesic effects of low-intensity polarized light(PL)of BIOPTRON device(480-3,400 nm,polarization up to 95%,power density 40 mW/cm^2)and three pharmacological analgesics(ibup... On the model of formalin test in mice,the analgesic effects of low-intensity polarized light(PL)of BIOPTRON device(480-3,400 nm,polarization up to 95%,power density 40 mW/cm^2)and three pharmacological analgesics(ibuprofen,analgin,tramal)were compared.We used analgesics in the optimal and half-dose,as well as half-doses of analgesics combined with the application of PL to the analgesic acupuncture point(AP)E-36.Pain was induced by subcutaneous injection of a 5%formalin solution(30μL)into the back of the foot of the left hind limb of the animal.The intensity of pain was judged by duration of pain(licking of the affected limb)and non-painful(sleeping,eating,running,washing)behavioral reactions during 60 minutes of observation.In animals that immediately after the creation of the locus of tonic pain,received an injection(intraperitoneally)of ibuprofen,analgin or tramal in optimal doses(30.0;8.3 and 1.7 mg/kg),duration of the pain response reduced by 46.0;74.9 and 56.2%,respectively.Half doses of these analgesics(15.0;4.2 and 0.8 mg/kg)weakened the pain by 23.1;28.5 and 34.2%.A statistically significant reduction of pain was also observed in groups where instead of analgesics,was applied a 10-min PL session to the anti-pain AP E-36(by 27.0%)or to the locus of pain(by 35.8%).These data indicate that PL analgesic effect is comparable to the effect of moderate doses of analgesics.Combined use of analgesic and PL suppresses pain more effectively than one analgesic in the same dose.The 10-minute PL application to the analgesic AP E-36 in 1.5-2 times(statistically significantly)increased the analgesic effect of small analgesics doses.In contrast to animals in which analgesia was caused by administration of high doses of analgesics,in the case of low doses of analgesic in combination with PL,caused no disturbances in motor activity and eating behavior.Clinical significance of the presented data is to prove the possibility of reducing the dose of analgesic pharmaceuticals by applying PL,which reduces the risk of unwanted si 展开更多
关键词 POLARIZED light bioptron device pain FORMALIN test ANALGESIA IBUPROFEN analgin tramal acupuncture point
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Application-Oriented Performance Comparison of 802.11p and LTE-V in a V2V Communication System
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作者 Mengkai Shi Yi Zhang +1 位作者 Danya Yao Chang Lu 《清华大学学报自然科学版(英文版)》 EI CAS CSCD 2019年第2期123-133,共11页
In recent years,the Vehicle-to-Vehicle (V2V)communication system has been considered one of the most promising technologies to build a much safer and more efficient transportation system.Both simulation and field test... In recent years,the Vehicle-to-Vehicle (V2V)communication system has been considered one of the most promising technologies to build a much safer and more efficient transportation system.Both simulation and field test have been extensively performed to evaluate the performance of the V2V communication system.However, most of the evaluation methods are communication-based,and although in a transportation environment,lack a V2V application-oriented analysis.In this study,we conducted real-world tests and built an application-oriented evaluation model.The experiments were classified into four scenarios:static,following,face 2 face,and crossing vertically,which almost covered all the V2V communication patterns on the road.Under these scenarios,we conducted experiments and built a probability model to evaluate the performance of 802.11p and LTE-V in safetyrelated applications.Consequently,we found out that improvements are still needed in Non-Line-of-Sight scenarios. 展开更多
关键词 Vehicle-to-Vehicle (V2V)communication CONNECTED VEHICLES performance evaluation INTELLIGENT TRANSPORTATION SYSTEM application-oriented field test
基于Chroma 8000的DC/DC电源模块测试 预览
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作者 唐彩彬 《电子与封装》 2019年第3期11-13,共3页
介绍了DC/DC电源模块的通用测试方法。基于Chroma 8000测试系统,通过对DC/DC电源模块测试要求进行分析,设计了某款DC/DC电源模块测试夹具与测试外围,实现了对该DC/DC电源模块主要性能参数的测试。该方案能够作为通用测试方法为DC/DC电... 介绍了DC/DC电源模块的通用测试方法。基于Chroma 8000测试系统,通过对DC/DC电源模块测试要求进行分析,设计了某款DC/DC电源模块测试夹具与测试外围,实现了对该DC/DC电源模块主要性能参数的测试。该方案能够作为通用测试方法为DC/DC电源模块测试设计提供参考。 展开更多
关键词 DC/DC CHROMA 8000 电源模块 测试
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246例HIV感染者的流行病学特点及梅毒感染情况
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作者 王淑华 王丽俊 +4 位作者 王春馨 杨静 贾国伟 赵海元 王学晶 《中国热带医学》 CAS 2019年第5期463-467,共5页
目的分析2012—2017年北京某综合医院人类免疫缺陷病毒(human immunodeficiency virus,HIV)抗体检测阳性者的流行病学特点及梅毒感染情况,为区域性HIV筛查及防治提供依据。方法对2012—2017年北京某综合医院门诊与住院患者中经HIV抗体... 目的分析2012—2017年北京某综合医院人类免疫缺陷病毒(human immunodeficiency virus,HIV)抗体检测阳性者的流行病学特点及梅毒感染情况,为区域性HIV筛查及防治提供依据。方法对2012—2017年北京某综合医院门诊与住院患者中经HIV抗体初筛和确认的HIV感染者相关数据进行描述性流行病学分析。结果2012—2017年共进行HIV筛查222550人次,初筛阳性285例(0.13%),确证阳性246例(0.11%)。各年HIV阳性率较稳定,上升趋势不明显。HIV抗体确认阳性者以男性为主,占96.34%,男女比例26.33∶1,年龄上以20~39岁年龄段为主(82.52%),外省市户籍者(84.96%)居多,婚姻状况以已婚为主(56.50%),且已婚比例随时间有升高趋势(P<0.05);传播途径上均为性传播,以男男同性性传播为主(96.34%)。就诊科室主要分布在皮肤科(43.50%)、内科(16.67%)、外科(13.41%)和体检中心(11.79%),在整个内科来源的HIV阳性者中,消化内科占的比例为65.85%。HIV阳性者合并感染梅毒的几率很大(26.02%),且梅毒发作期患者比例高(20.33%)。结论需进一步加强对大型综合性医院就诊患者的HIV检测。性活跃期MSM(men who have sex with men)人群(尤其是双性性接触的MSM)需继续作为艾滋病防控宣传和咨询检测的重点人群,防止HIV感染由高危人群向一般人群传播。及时治疗梅毒感染,有效控制梅毒的发病率,对于控制艾滋病的流行有着重要意义。 展开更多
关键词 人类免疫缺陷病毒 筛查 检测 梅毒感染
LED综合特性的测试与分析 预览
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作者 陈丽娅 《电子测试》 2019年第11期53-55,共3页
随着LED产品的迅速发展,LED的测试设计实验也需不断完善和改进,通过更系统更优质的测试与设计,可以便于掌握LED的基本性能特征。本文借助不同的实验仪器,搭建LED综合特性测试平台,在不同环境下对小、大功率白发红LED光以及白、红、绿、... 随着LED产品的迅速发展,LED的测试设计实验也需不断完善和改进,通过更系统更优质的测试与设计,可以便于掌握LED的基本性能特征。本文借助不同的实验仪器,搭建LED综合特性测试平台,在不同环境下对小、大功率白发红LED光以及白、红、绿、蓝四色以及平头、平凹头、圆头封装工艺的LED做了全面的特性测试,并用计算机处理数据。本课题的研究可以为照明产品的测试与设计实验提供一定的思路。 展开更多
关键词 LED 综合实验 性能 测试
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勃利县马铃薯有机肥提质增效技术模式试验示范 预览
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作者 桑树鹏 《现代农业研究》 2019年第6期45-46,共2页
利用作物秸秆和畜禽粪便混配发酵制成有机肥,在粮食作物种植上进行有机肥使用方法和“替代化肥”试验示范,探索马铃薯“有机营养套餐”和“有机-无机营养套餐”施肥模式,示范作物提质增效与耕地保护相结合的可行技术措施,培育可复制、... 利用作物秸秆和畜禽粪便混配发酵制成有机肥,在粮食作物种植上进行有机肥使用方法和“替代化肥”试验示范,探索马铃薯“有机营养套餐”和“有机-无机营养套餐”施肥模式,示范作物提质增效与耕地保护相结合的可行技术措施,培育可复制、可推广的有机肥生产和施用典型。 展开更多
关键词 马铃薯 有机肥 增产 提质增效 技术 试验
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便携式傅立叶与气相色谱法测定气体中的苯系物 预览
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作者 陈广银 蔡灏兢 陆任婷 《污染防治技术》 CAS 2019年第1期52-54,60共4页
为了比较便携式傅立叶与实验气相色谱检测有机物结果的差异,文中采用两种仪器对苯系物的标准气体进行检测。结果显示:傅立叶测定标气的回收率在86.0~897%,相对标准偏差5.4~8.7%;采用活性碳吸附解析气相色谱法测标准气体时,苯系物的回收... 为了比较便携式傅立叶与实验气相色谱检测有机物结果的差异,文中采用两种仪器对苯系物的标准气体进行检测。结果显示:傅立叶测定标气的回收率在86.0~897%,相对标准偏差5.4~8.7%;采用活性碳吸附解析气相色谱法测标准气体时,苯系物的回收率为在88.5~95.2%,相对偏差在3.8~6.6%。采用t检验法对两种仪器测定苯、甲苯、乙苯、二甲苯、苯乙烯的均值进行显著性检验,当置信水平选定为a=0.05时,两种仪器对苯系物的测定均值无显著性差异,说明两种仪器测定均值的差异是随机误差造成。便携式傅立叶检测快速、操作简单、无需标准物质、维护保养简单更适合于野外环境应急监测;活性碳吸附气相色谱法操作复杂、检测速度慢、定性定量需要标准物质,更适合于对企业的环境执法检查。 展开更多
关键词 应急监测 便携式傅立叶 T检验 气相色谱
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空隙特征对砂岩水致劣化规律的影响
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作者 许宝田 张莉萍 +1 位作者 燕晓莹 邱德俊 《岩土力学》 EI CAS CSCD 北大核心 2019年第2期561-569,共9页
针对南京秦淮东河开挖后的稳定性问题,选取黄马青组(T2h)砂岩为研究对象,对砂岩在吸水-干燥循环条件下的单轴抗压、抗拉特性进行试验研究。考虑到未来边坡运营过程中水的影响,试验时分别考虑自然吸水和饱和吸水两种情况。根据试验结果... 针对南京秦淮东河开挖后的稳定性问题,选取黄马青组(T2h)砂岩为研究对象,对砂岩在吸水-干燥循环条件下的单轴抗压、抗拉特性进行试验研究。考虑到未来边坡运营过程中水的影响,试验时分别考虑自然吸水和饱和吸水两种情况。根据试验结果对所研究砂岩的空隙特征、水致劣化特征和劣化机制进行了详细分析。随着吸水-干燥循环次数增加,岩石的抗压、抗拉强度和凝聚力均呈劣化趋势,说明循环次数的增加对岩石的损伤有累积作用。岩石自然吸水条件下(小开空隙未进水时)强度和弹性模量下降速度较慢,而饱和吸水条件下(开空隙被水充满时)强度和弹性模量下降速度较快,表明岩石中小开空隙对岩石的劣化效果显著。微观结构分析结果表明,随着吸水-干燥循环次数增加,岩石中空隙率增大。结合抗剪强度特征分析认为,干-湿循环导致岩石的黏结强度不断下降,而摩擦强度变化较小,表明黏结强度劣化是岩石水致劣化的主要原因,干-湿循环导致水-岩反应,岩石颗粒胶结物发生松散,边缘发生开裂,宏观上表现为岩石劣化。该研究成果对于新开挖河道边坡稳定性分析具有较大的参考价值,为河岸边坡的长期稳定性分析提供了依据。 展开更多
关键词 砂岩 水致劣化 试验 空隙特征 自然吸水 饱和吸水 吸水-干燥循环
摩擦复充种型孔带式水稻精量排种器充种性能分析与验证 预览
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作者 刘彩玲 王亚丽 +3 位作者 都鑫 宋建农 王继承 张福印 《农业工程学报》 EI CAS CSCD 北大核心 2019年第4期29-36,共8页
为解决杂交稻工厂化穴盘育秧低播量精密播种问题,提出了一种摩擦复充种型孔带式水稻精量排种器,对种子充填过程进行了力学和运动学分析,确定影响试验指标的影响因素分别为型孔方向角、型孔带速度、型孔带倾角和种层厚度。通过EDEM离散... 为解决杂交稻工厂化穴盘育秧低播量精密播种问题,提出了一种摩擦复充种型孔带式水稻精量排种器,对种子充填过程进行了力学和运动学分析,确定影响试验指标的影响因素分别为型孔方向角、型孔带速度、型孔带倾角和种层厚度。通过EDEM离散元软件仿真分析了种子多次循环重复充种过程和充种效果,并分别分析了型孔带速度、型孔带倾角、种层厚度对充种性能的影响规律。基于仿真分析结果进行了较优组合验证试验,结果表明:在型孔方向角为90°,型孔带倾角为43°,型孔带转速为0.11m/s,种层厚度为50mm时充种合格率为96.4%,多粒率为1.4%,漏充率为2.2%,种子破碎率为0.18%,效果较优。摩擦复充种型孔带式水稻精量排种器能够满足杂交稻低播量精密播种的农艺要求,研究结果为工厂化穴盘育秧精量播种机的设计提供参考。 展开更多
关键词 机械化 农作物 计算机仿真 复充种 型孔带 精量播种 离散元 试验
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