检索结果-南通市图书馆

在线全文

学校读者我要写书评

暂无评论

采煤机截割轨迹自动跟踪系统的设计

机械管理开发 2024年第4期39卷 249-251页

作者：丁正伟山焦汾西香源煤业有限责任公司山西吕梁030500

为解决采煤机依靠人工控制存在的效率低、安全性差的问题,在对采煤机轨迹跟踪自动调高原理分析的基础上,确定了截割轨迹自动跟踪系统的采样周期和进刀方式,提出了基于多传感器对采煤机的截割状态监测的方案,并为其配套设计了自动跟踪控... 详细信息

为解决采煤机依靠人工控制存在的效率低、安全性差的问题,在对采煤机轨迹跟踪自动调高原理分析的基础上,确定了截割轨迹自动跟踪系统的采样周期和进刀方式,提出了基于多传感器对采煤机的截割状态监测的方案,并为其配套设计了自动跟踪控制模块,验证了基于速度前馈模糊PID控制策略的控制效果.

关键词：采煤机截割轨迹基于速度前馈模糊PID控制采样周期进刀方式

四象限开关磁阻电牵引系统在煤矿大倾角采煤机中的应用

在线全文

学校读者我要写书评

暂无评论

机械管理开发 2024年第3期39卷 312-314页

作者：丁正伟山焦汾西香源煤业有限责任公司山西吕梁030500

开关磁阻电机控制系统(SRD)成本低,结构简单,电流小,启动力矩大,是煤矿机械的理想选择。针对大倾角采煤机运行过程中的牵引功率及SRD低电流大扭矩的驱动性能进行了定性分析,同时,还对大倾角煤矿四象限开关磁阻电牵引系统的应用进行了探... 详细信息

开关磁阻电机控制系统(SRD)成本低,结构简单,电流小,启动力矩大,是煤矿机械的理想选择。针对大倾角采煤机运行过程中的牵引功率及SRD低电流大扭矩的驱动性能进行了定性分析,同时,还对大倾角煤矿四象限开关磁阻电牵引系统的应用进行了探讨究。经在大倾角煤层现场使用证明,四象限SRD系统能够充分满足采区采掘作业的需要,有效提高采掘设备利用率及煤炭资源的回采率。

关键词：开关磁阻 SRD 大倾角牵引系统

Confidentiality-aware message scheduling for security-critical wireless networks

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2010年第1期21卷 154-160页

作者： Wei Jiang Guangze Xiong Xuyang ding zhengwei Chang Nan Sang College of Computer Science and Engineering University of Electronic Science and Technology of China Chengdu 610054 E R. China

Without considering security, existing message scheduling mechanisms may expose critical messages to malicious threats like confidentiality attacks. Incorporating confidentiality improvement into message scheduling, this paper investigates the problem of scheduling aperiodc messages with time-critical and security-critical requirements. A risk-based security profit model is built to quantify the security quality of messages; and a dynamic programming based approximation algorithm is proposed to schedule aperiodic messages with guaranteed security performance. Experimental results illustrate the efficiency and effectiveness of the proposed algorithm.

关键词： security-critical wireless networks confidentialityaware real-time message scheduling.

Estimation and Projection of the HIV Epidemic Trend among the Migrant Population in China

在线全文

学校读者我要写书评

暂无评论

Biomedical and Environmental Sciences 2011年第4期24卷 343-348页

作者： MENGXiaoJun WANG Lu Susan CHAN Kathleen Heather REILLY PENG ZhiHang GUO Wei ding GuoWei ding zhengwei QIN QianQian National Center for AIDS/STD Control and Prevention Chinese Center for Disease Control and PreventionBeijing 102206 China Department of Public Health Nanjing Medical University Nanjing 210029 Jiangsu China

Objective The migrant population is a vulnerable group for HIV infection in *** potential epidemic trends among migrants is critical for developing HIV preventative measures in this *** The Estimation and Projection Package （EPP） model was used to process prefecture and county-level surveillance data to generate HIV prevalence and epidemic trends for migrant populations in *** The prevalence of HIV among migrants in 2009 was estimated at 0.075% （95% CI：0.042%,0.108%） in *** HIV epidemic among migrants is likely to increase over the next 5 years,with the prevalence expected to reach 0.110% （95% CI：0.070%,0.150%） by *** Although the 2009 estimates for the HIV/AIDS epidemic in China indicate a slower rate of increase compared with the national HIV/AIDS epidemic,it is estimated to persistently increase among migrants over the next 5 *** will have a strong impact on the overall future of the HIV epidemic trend in China and evidence-based prevention and monitoring efforts should be expanded for this vulnerable population.

关键词： China Transients and migrants Estimation and projection package HIV/AIDS

Bioactive Hydrogels with Pro-coagulation Effect for Hemostasis

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2024年第1期42卷 87-103,I0004页

作者： Quanshi Guo Yihang ding Lisha Yu Zongrui Tong zhengwei Mao MOE Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and EngineeringZhejiang UniversityHangzhouZhejiang 310058China Department of Hepatobiliary and Pancreatic Surgery The Second Affiliated HospitalSchool of MedicineZhejiang UniversityHangzhouZhejiang 310009China Key Laboratory of Precision Diagnosis and Treatment for Hepatobiliary and Pancreatic Tumor of Zhejiang Province HangzhouZhejiang 310009China

Hemostatic hydrogels are widely applied for wound management of damaged tissues,traumatic wounds,and surgical *** hydrogels composed of bioactive components,including fibrin and thrombin,showed great promise in the clinic due to their good pro-coagulation *** the expanding knowledge of cascade reaction of blood coagulation and emerging bioactive substances,massive bioactive hydrogels consisting of peptides,hemocoagulase,polyphosphate(polyP),etc.,have been developed as effective hemostatic *** on the coagulation process and mechanism,we summarize the role of reported bioactive hydrogels in hemostasis in this *** conclude the key points in the coagulation process,including activation of coagulation factors,fibrinogen polymerization,etc.,then discuss how to design bioactive hydrogels to accelerate coagulation targeted to these ***,we conclude the progress and propose a perspective of bioactive hydrogels with a pro-coagulation effect for hemostasis.

关键词： Hemostasis Biological activity Biomaterials Enzyme catalysis Composites

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

彝药苦刺化学成分和生物活性的研究进展

西北药学杂志 2024年第3期39卷 242-252页

作者：王瑞毛宇恒丁正伟高阳刘霞高昕张海龙张红西安交通大学药学院西安710061 陕西省中医药研究院西安710003

目的总结近年来彝族民族药苦刺的化学成分和生物活性的研究进展,为进一步开发利用该民族药提供参考。方法通过万方、维普、CNKI、SCI finder、PubMed等数据库查阅国内外有关苦刺的文献,对其化学成分和药理活性研究结果进行归纳和总结。... 详细信息

目的总结近年来彝族民族药苦刺的化学成分和生物活性的研究进展,为进一步开发利用该民族药提供参考。方法通过万方、维普、CNKI、SCI finder、PubMed等数据库查阅国内外有关苦刺的文献,对其化学成分和药理活性研究结果进行归纳和总结。结果苦刺的根、茎、叶、花和种子皆可入药;该植物所含成分结构类型多样,其中以生物碱和黄酮为主;苦刺具有抗炎、抗糖尿病、抗肿瘤、抗胃溃疡等多种药理作用。结论苦刺是一种富含生物碱和黄酮且生物活性多样的民族药,具有进一步研究开发的价值。

关键词：民族药苦刺化学成分生物碱生物活性

Toward Unified Total Synthesis of Tigliane and Daphanane Natural Products

在线全文

学校读者我要写书评

暂无评论

Toward Unified Total Synthesis of Tigliane and Daphanane Nat...

中国化学会第八届天然产物全合成青年学术研讨会

作者： zhengwei ding Zhi Liu Guanghu Tong 李鹏飞 Frontier Institute of Science and Technology Xi’an Jiaotong University

＜正＞Tiglianes and daphnanes are two bio-genetically correlated families of diterpenoids isolated from plants.1,2 Structurally, they are highly oxidized compact polycyclic compounds as shown by the representative members in Fig. 1. These molecules share a densely substituted [5,7,6] tricyclic core that features C4,C10-and C8,C9 double trans configurations at ring junctions and multiple contiguous stereocenters including three tertiary alcohols.

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

鄂药挨姆末的化学成分及细胞毒作用研究

西北药学杂志 2024年第2期39卷 1-5页

作者：刘杏王欣于春萍杨敏飞郭华黄小强王儒月荣真吉丁正伟高阳张海龙西安市高陵区妇幼保健院西安710200 西安交通大学药学院西安710061 西安市第五医院西安710082

目的研究鄂伦春族民族药挨姆末叶(Lonicera caerulea ***)的化学成分及细胞毒作用。方法用正相柱色谱、反相柱色谱、SephadexLH-20柱色谱、HPLC等现代色谱技术对挨姆末叶的提取物进行分离纯化,通过各种波谱技术结合理化性质鉴定化合物... 详细信息

目的研究鄂伦春族民族药挨姆末叶(Lonicera caerulea ***)的化学成分及细胞毒作用。方法用正相柱色谱、反相柱色谱、SephadexLH-20柱色谱、HPLC等现代色谱技术对挨姆末叶的提取物进行分离纯化,通过各种波谱技术结合理化性质鉴定化合物的结构,用HepG2细胞模型评价样品的细胞毒作用。结果从鄂药挨姆末叶中分离得到12个化合物,分别鉴定为ferna-7,9(11)-diene-3α,16α-dio(l 1);3β,23-dihydroxy-olean-12-en-28-oic acid(2);2(-3-methoxy-4-hydroxyphenyl)-propane-1,3-dio(l 3);nicotinic acid(4);4-hydroxy-5-methoxy-benzoic acid(5);3,7-dihydro-1,3,7-trimethyl-1H-purine-2,6-dione(6);caffeic acid methyl este(r 7);(2E)-2,6-dimethyl-6-hydroxy-2,7-octadienoic acid(8);syringin(9);threo-5-hydroxy-3,7-dimethoxy phenylpropane-8,9-dio(l 10);3,4,5-trimethoxyphenyl 1-α-glucofuranosid(e 11);benzyl-β-D-glucosid(e 12)。其中化合物1对HepG2细胞有一定的细胞毒作用。结论这12个化合物中包括2个三萜、2个生物碱、3个木脂素、1个不饱和脂肪酸和4个芳香族化合物,化合物3、8、10、11为首次从该属中分离得到,化合物1、2、4、6、7、12为首次从该种中分离得到。

关键词：民族药鄂药挨姆末化学成分细胞毒

HIV and syphilis infections among street-based female sex workers in China, 2010-2012

在线全文

学校读者我要写书评

暂无评论

Chinese Medical Journal 2014年第4期127卷 707-711页

作者： Li Dongmin Wang Lu Lin Wen Li Peilong Wang Lan Guo Wei Ge Lin ding zhengwei Cui Yan Wang Ning Division of Epidemiology National Center for Acquired Immune Definciency Syndrome/Sexually Transmitted Disease Control and Prevention Chinese Center for Disease Control and Prevention Beijing 102206 China Santa Clara County Public Health Department California 95126USA

Background Female sex workers （FSW） were high-risk population for HIV and other sexually transmitted diseases （STD） earlier,and now are an important driver of the HIV/AIDS epidemic in *** surveillance for FSW was set up to monitor the trend of HIV prevalence and risk behavior-related HIV *** study collected the data on street-based FSW from HIV sentinel surveillance system to understand HIV and syphilis infections,risk behaviors,and intervention in China from 2010 to *** The study population was the street-based FSW who were recruited for the national HIV integrated biological and behavioral surveillance between 2010 and *** information,HIV-related risk behaviors,and HIV and syphilis testing results were described and trend analysis was *** Between 2010 and 2012,the number of street-based FSW surveyed was 3725,3425,and 3335,*** knowledge awareness rate significantly increased from 74.6% in 2010 to 76.8% in 2011 and 82.2% in 2012 （P 〈0.01）.More FSW consistently used condom in the last month （49.0% in 2010; 51.0% in 2011; and 59.0% in 2012） and in the last commercial sex （72.0% in 2010; 78.5% in 2011; and 80.0% in 2012） over *** proportions of individuals who received HIV testing in the last year were 31.2% （2010）,37.0% （2011）,and 36.9% （2012）（P-trend 〈0.01）.HIV prevalence rate changed from 1.5% in 2010 to 1.4% in 2011 and 2.3% in 2012 （P-trend=0.01）.Syphilis prevalence rate was 6.9%,7.2%,and 7.1% in the same *** top three provinces with the highest average HIV prevalence rates over the 3 years were Guangxi （5.9%）,Yunnan （4.2%）,and Sichuan （1.2%）.Conclusions Street-based FSW are at high risk of HIV and syphilis *** efforts need to target streetbased FSW who are of old age and minority,who use illicit drugs and have syphilis infection.

关键词： street-based female sex worker HIV syphilis prevalence risk behaviors