检索结果-南通市图书馆

Extreme space weather events caused by super active regions during solar cycles 21-24

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2021年第5期21卷 296-300,302页

作者： Gui-Ming le Gui-Ang Liu Ming-xian Zhao Tian Mao Ping-Guo Xu School of Physics Science&Technology Lingnan Normal UniversityZhanjiang 524048China Key Laboratory of Space Weather National Center for Space WeatherChina Meteorological AdministrationBeijing 100081China Beijing Engineering Research Center of Smart Mechanical Innovation Design Service Beijing 100020China

Extreme space weather events including≥X5.0 flares,ground level enhancement(Gle)events and super geomagnetic storms(Dst≥-250 nT)caused by super active regions(SARs)during solar cycles 21-24 were *** total number ofX5.0 solar flares was 62,among which 41 were X5.0-X9.9 flares and 21 were≥X10.0 *** found that 83.9%of the≥X5.0 flares were produced by SARs;78.05%of the X5.0-X9.9 and 95.24%of the≥X10.0 solar flares were produced by SARs;46 Gles were registered during solar cycles 21-24,and 25 Gles were caused by SARs,indicating that 54.3%of the Gles were caused by SARs;24 super geomagnetic storms were recorded during solar cycles 21-24,and 12 of them were caused by SARs,namely 50%of the super geomagnetic storms were caused by *** ascertained that only 29 SARs produced≥X5.0 flares,15 SARs generated Gles and 10 SARs triggered super geomagnetic *** the 51 SARs,only 33 SARs produced at least one extreme space weather event,while none of the other 18 SARs could trigger an extreme space weather *** were only four SARs and each of them generated not only a≥X5.0 flare,but also a Gle event and a super geomagnetic *** of the extreme space weather events caused by the SARs appeared during solar cycles 22 and 23,especially for Gle events and super geomagnetic *** longitudinal distributions of source locations for the extreme space weather events caused by SARs were also studied.

关键词： Sun:sunspots Sun:flares Sun:particle emission Sun:solar-terrestrial relations

Mutation breeding of high 4-androstene-3,17-dione-producing Mycobacterium neoaurum ZADF-4 by atmospheric and room temperature plasma treatment

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2015年第4期16卷 286-295页

作者： Chao LIU xian ZHANG Zhi-ming RAO Ming-long SHAO le-le ZHANG Dan WU Zheng-hong XU Hui LI Key Laboratory of Industrial Biotechnology Ministry of Education School of Biotechnology Jiangnan University Laboratory of Applied Microorganisms and Metabolic Engineering School of Biotechnology Jiangnan University Laboratory of Pharmaceutical Engineering School of Pharmaceutical Science Jiangnan University

Steroid medication is used extensively in clinical applications and comprises a large and vital part of the pharmaceutical industry. However, the difficulty of separating 4-androstene-3,17-dione （AD） from 1,4-androstadiene- 3,17-dione （ADD） restricts the application of the microbial transformation of phytosterols in the industry. A novel at- mospheric and room temperature plasma （ARTP） treatment, which employs helium as the working gas, was used to generate Mycobacterium neoaurum mutants producing large amounts of AD. After treatment of cultures with ARTP, four mutants were selected using a novel screening method with a color assay. Among the mutants, M. neoaurum ZADF-4 was considered the best candidate for industrial application. When the fermentation medium contained 15 g/L phytosterols and was cultivated on a rotary shaker at 160 r/min at 30 ~C for 7 d, （6.28＋0.11） g/L of AD and （0.82＋0.05） g/L of ADD were produced by the ZADF-4 mutant, compared with （4.83＋0.13） g/L of AD and （2.34＋0.06） g/L of ADD by the original strain, Iv~. neoaururn ZAD. Compared with ZAD, the molar yield of AD increased from 48.3% to 60.3% in the ZADF-4 mutant. This result indicates that ZADF-4 may have potential for industrial production of AD.

关键词： Mycobacterium neoaurum Atmospheric and room temperature plasma (ARTP) Mutation breeding 4-Androstene-3 17-dione (AD) 1 4-Androstadiene-3 17-dione (ADD)

Investigation of Mean Glandular Dose in Diagnostic Mammography in China

在线全文

学校读者我要写书评

暂无评论

Biomedical and Environmental Sciences 2014年第5期27卷 396-399页

作者： DU xiang WANG Jin yang Chun Yong ZHOU xian Feng CHEN Wei CAO Xing Jiang ZHOU Yuan Yuan YU Ning le Department of Radiation Protection Jiangsu Provincial Center for Disease Prevention and Control

A survey of 420 exposures of mammography was performed with the parameters recorded. Entrance skin air kerma （ESAK） was measured and the mean glandular dose （MGD） was calculated according to the Dance＇s formula. Correlation analysis showed that several factors could affect the MGD level. Mann-whitney test and Non-parametric ANOVA analyses were used to compare the MGD level grouped by view type and radiographic systems, No significant difference was found in MGD between the craniocaudal （CC） group and the mediolateral oblique （MLO） group. The MGD level was higher in the CR group than in the other two groups. MGD was positively correlated with the compressed breast thickness （CBT）. MGD varied with the half value layer （HVL） and increased first then decreased, The mean MGD level in China is about 1.6 mGy and is lower than the guidance level in the International Basic Safety Standards （IBSS）.

关键词： MGD HVL Mean

Experimental Investigation on the LCF Behavior Affected by Manufacturing Defects and Creep Damage of One Selective Laser Melting Nickel-Based Superalloy at 815℃

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English letters) 2020年第4期33卷 514-527页

作者： Xiao-An Hu Gao-le Zhao Yun Jiang xian-Feng Ma Fen-Cheng Liu Jia Huang Cheng-Li Dong School of Aircraft Engineering Nanchang Hangkong UniversityNanchang 330063China Jiangxi Key Laboratory of Micro Aeroengine Technology Nanchang 330063China Sino-French Institute of Nuclear Engineering and Technology Sun Yat-Sen UniversityZhuhai 519082China National Defence Key Discipline Laboratory of Light Alloy Processing Science and Technology Nanchang 330063China School of Aeronautics and Astronautics Central South UniversityChangsha 410083China Materials Evaluation Center for Aeronautical and Aeroengine Application AECC Beijing Institute of Aeronautical MaterialsBeijing 100095China

Uniaxial tensile tests and stress-controlled low-cycle fatigue(LCF) and creep-fatigue interaction(CFI) tests of Inconel 625 alloy manufactured by selective laser melting(SLM) were performed at 815℃ in air *** microstructure was characterized by optical microscopy and scanning electron microscopy after *** results confirmed that significant embrittlement and large scatter in LCF life are resulted from manufacturing *** CFI life is decreased sharply to approximately dozens of cycles with the accumulated creep strain;however,the selected dwell time(i.e.,60 s and 300 s)exhibits low sensitivity to the fracture time and elongation to *** embrittlement of SLM Inconel 625 was proposed to be due to the low grain uniformity and precipitation of carbides at the grain *** to the quality of the SLM process,the accelerated initiation and propagation of fatigue crack are caused by the present unmelted powder particles,which result in the large dispersion of LCF ***,due to the accumulation of creep damage,cracks in the CFI test are initiated along the grain boundaries and then linked together,contributing to a significant decline in fatigue life.

关键词： Selective laser melting Low-cycle fatigue Creep-fatigue interaction Failure analysis

药用蛇及其水提物的DNA微型条形码鉴别研究

在线全文

学校读者我要写书评

暂无评论

中药材 2024年第1期47卷 51-56页

作者：冼乐尧罗宇琴宋叶魏梅孙冬梅李国卫胡绮萍广州中医药大学广东广州510006 广东一方制药有限公司/广东省中药配方颗粒企业重点实验室广东佛山528244 中国中药控股有限公司广东佛山528303

目的:建立药用蛇及其水提物的DNA微型条形码鉴别方法。方法:通过比对药用蛇及常见11种混伪品的16S rRNA序列,建立约220 bp的蛇类DNA微型条形码,并与16S rRNA标准条形码比较,对药用蛇原料及水提物进行测序鉴定。采用MEGA-X软件分析遗传... 详细信息

目的:建立药用蛇及其水提物的DNA微型条形码鉴别方法。方法:通过比对药用蛇及常见11种混伪品的16S rRNA序列,建立约220 bp的蛇类DNA微型条形码,并与16S rRNA标准条形码比较,对药用蛇原料及水提物进行测序鉴定。采用MEGA-X软件分析遗传距离并以邻接法(NJ)构建系统发育树。结果:DNA微型条形码引物对药用蛇原料及水提物的扩增率为100%,鉴定率为100%。药用蛇及其混伪品的种内平均遗传距离均小于种间平均遗传距离,且各物种在NJ系统发育树中具有良好的单系性,并与16S rRNA标准条形码原料的鉴定结果一致。结论:该研究建立的蛇类DNA微型条形码可有效实现药用蛇原料及水提物等制品的物种鉴别,为保障蛇类原料、临床汤剂及配方颗粒等药品的安全性和有效性提供了技术支撑。

关键词：乌梢蛇金钱白花蛇蕲蛇水提物 DNA微型条形码 16S rRNA

Folate and Vitamin B_(12)Status and Related Dietary Factors among the Elderly Northern and Southern Rural Chinese Population

在线全文

学校读者我要写书评

暂无评论

Biomedical and Environmental Sciences 2021年第7期34卷 552-556页

作者： LIU Zhen MAN Qing Qing JIA Shan Shan SONG Peng Kun WANG Jing Zhong WANG Xi le KANG Bing xian yang Li Gui ZHANG Jian National Institute for Nutrition and Health Chinese Center for Disease Control and PreventionBeijing 100050China Wuyuan County Center for Disease Control and Prevention Wuyuan CountyBayannaoer 015100Inner Mongoli Autonomous RegionChina Luxi County Center for Disease Control and Prevention Luxi CountyHonghe Hani and Yi Autonomous Region 661100YunnanChina

Folate and vitamin B_(12)are involved in the carbon metabolism pathway supplying essential methyl groups for DNA and protein synthesis and play a vital role in individual *** have also been shown to be associated with cardiovascular disease,especially stroke.A recent study showed that stroke was the leading cause of death and disabilityadjusted life years(DALYs)at the national level in ***,the nutritional status of folate and vitamin B_(12)in the Chinese population is a *** elderly are more prone to develop folate and vitamin B_(12)deficiencies due to poor appetite,dental defects,and issues with digestion.

关键词： synthesis vitamin

Synergistic piezoelectricity enhanced BaTiO_(3)/polyacrylonitrile elastomer-based highly sensitive pressure sensor for intelligent sensing and posture recognition applications

在线全文

学校读者我要写书评

暂无评论

Nano Research 2023年第4期16卷 5490-5502页

作者： Junbin Yu Shuai xian Zhenpeng Zhang Xiaojuan Hou Jian He Jiliang Mu Wenping Geng Xiaojun Qiao le Zhang Xiujian Chou Science and Technology on Electronic Test and Measurement Laboratory North University of ChinaTaiyuan 030051China

Designing stretchable and skin-conformal self-powered sensors for intelligent sensing and posture recognition is ***,based on a multi-force mixing and vulcanization process,as well as synergistically piezoelectricity of BaTiO_(3)and polyacrylonitrile,an all-in-one,stretchable,and self-powered elastomer-based piezo-pressure sensor(ASPS)with high sensitivity is *** ASPS presents excellent sensitivity(0.93 V/104 Pa of voltage and 4.92 nA/104 Pa of current at a pressure of 10-200 kPa)and high durability(over 10,000 cycles).Moreover,the ASPS exhibits a wide measurement range,good linearity,rapid response time,and stable frequency *** components were fabricated using silicone,affording satisfactory skinconformality for sensing *** cooperation with a homemade circuit and artificial intelligence algorithm,an information processing strategy was proposed to realize intelligent sensing and *** home-made circuit achieves the acquisition and wireless transmission of ASPS signals(transmission distance up to 50 m),and the algorithm realizes the classification and identification of ASPS signals(accuracy up to 99.5%).This study proposes not only a novel fabrication method for developing self-powered sensors,but also a new information processing strategy for intelligent sensing and recognition,which offers significant application potential in human-machine interaction,physiological analysis,and medical research.

关键词： flexible pressure sensor synergistic piezoelectricity all-in-one structure high sensitivity intelligent sensing and recognition

Mechanical Properties and Microstructure of In Situ TiB_2-7055 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

Chinese Journal of Aeronautics 2006年第B12期19卷 66-70页

作者： CHEN dong le Yong-kang BAI Liang MA Nai-heng LI xian-feng WANG Hao-wei The State Key laboratory of Metal Matrix Composites Shanghai Jiao Tong University Shanghai 200030 China

In order to fabricate a kind of high strength particulate reinforced aluminum-matrix composites, the high strength aluminum alloy 7055 was selected as a matrix. Composites reinforced with varying amounts of TiB2 particles were synthesized using the in situ method, and their mechanical properties and microstructure were analyzed. It is found that the in situ TiB2 particles sized from 50 to 400 um uniformly disperse in the matrix. With the weight fraction of TiB2 particles increasing, the elastic modulus as well as the yield strength and the ultimate tensile strength increase, while the ductility decrease. The improvement of strength could be attributed to good bonding between TiB2 and the matrix, and also the TiB2 particles act as a barrier to dislocation.

关键词： metal matrix composite in situ mechanical properties microstructure

Construction and validation of a personalized prediction model for postpartum anxiety in pregnant women with preeclampsia

在线全文

学校读者我要写书评

暂无评论

World Journal of Psychiatry 2023年第10期13卷 763-771页

作者： le-Jing Lin Hai-xian Zhou Zhi-Yun Ye Qi Zhang Shu Chen Department of Obstetrics and Gynecology Wenzhou Hospital of Integrated Traditional Chinese and Western MedicineWenzhou 325000Zhejiang ProvinceChina Department of Gynecology Wenzhou Traditional Chinese Medicine HospitalWenzhou 325000Zhejiang ProvinceChina

BACKGROUND Preeclampsia is a pregnancy-specific multi-system disease with multi-factor and multi-mechanism *** cure for preeclampsia is to terminate the pregnancy and deliver the ***,it will reduce the perinatal survival rate,prolong the pregnancy cycle,and increase the incidence of maternal *** relaxation of the birth policy,the number of elderly pregnant women has increased significantly,and the prevalence rate of preeclampsia has *** treatment can seriously affect the normal postpartum life of pregnant *** have shown that postpartum anxiety in women with preeclampsia can affect physical and mental health,as well as infant growth and *** To analyze the factors influencing preeclampsia in pregnant women complicated with postpartum anxiety,and to construct a personalized predictive *** We retrospectively studied 528 pregnant women with preeclampsia who delivered in Wenzhou Hospital of Integrated Traditional Chinese and Western Medicine between January 2018 and December *** basic data were collected,and various physiological and biochemical indicators were obtained by laboratory *** self-rating anxiety scale was used to determine whether the women had postpartum anxiety 42 d after *** independent factors influ-encing postpartum anxiety in early pregnant women with eclampsia were analyzed with multifactor logistic regression and a predictive model was *** Hosmer-lemeshow test and receiver operating characteristic(ROC)curve were used to evaluate the calibration and discrimination of the predictive *** pregnant women with preeclampsia admitted to our hospital from January 2022 to May 2022 were retrospectively selected to verify the prediction *** We excluded 46 of the 528 pregnant women with preeclampsia because of loss to follow-up and adverse outcomes.A total of 482 cases completed the assessment of postpartum anxie

关键词： Preeclampsia Postpartum anxiety Risk factors Predictive model