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

近十年国内青年研究的现状及其变迁分析

青年探索 2024年第2期 5-16页

作者：风笑天广西师范大学政治与公共管理学院南京大学社会学院

通过对四种青年核心学术期刊908篇论文的内容分析,描述近十年国内青年研究的基本状况及变迁。研究发现:近十年青年研究的对象较多地集中于青年整体和大学生群体、中小学生群体,针对各类职业青年的研究相对较少;研究主题依旧十分宽泛,传... 详细信息

通过对四种青年核心学术期刊908篇论文的内容分析,描述近十年国内青年研究的基本状况及变迁。研究发现:近十年青年研究的对象较多地集中于青年整体和大学生群体、中小学生群体,针对各类职业青年的研究相对较少;研究主题依旧十分宽泛,传统主题都有所涉及,重点在青年的“教育成才”“价值观念”“就业职业”“社会参与”与“亚文化”等五个方面;青年研究的作者主要来自高等院校;研究类型中,经验性研究的比例不到一半,反映出青年研究在深入社会、收集第一手经验资料方面有所不足。不同期刊的论文在研究对象、研究主题、研究类型、作者来源方面都存在一些明显的差别。近十年青年经验研究在研究对象上对青年整体的研究比例大幅度上升,而研究的主题总体上则相对比较稳定。这些结果对如何认识青年和研究青年都提供了有益的启示。

关键词：青年研究研究对象研究主题核心期刊

钯催化下杂芳基溴代物与偕二氟烯丙基硼试剂的交叉偶联反应

在线全文

学校读者我要写书评

暂无评论

化学学报 2024年第2期82卷 105-109页

作者：张大伟赵海洋冯笑甜顾玉诚张新刚中国科学院、中国科学院大学、上海有机化学研究所、中国科学院有机氟化学重点实验室上海200032 郑州大学化学学院与河南先进技术研究院郑州450001 Syngenta Jealott’s Hill International Research Centre BracknellRG426EYUK

使用二叔丁基苯基膦预配位的氯化钯(P(t-Bu)_(2)Ph)_(2)·PdCl_(2)为催化剂,实现了钯催化下偕二氟烯丙基硼试剂与杂芳基溴代物的偶联反应.该方法不仅体系简单,反应效率高,区域选择性优秀,可以克量级制备产物,而且具有良好的官能团兼容性... 详细信息

使用二叔丁基苯基膦预配位的氯化钯(P(t-Bu)_(2)Ph)_(2)·PdCl_(2)为催化剂,实现了钯催化下偕二氟烯丙基硼试剂与杂芳基溴代物的偶联反应.该方法不仅体系简单,反应效率高,区域选择性优秀,可以克量级制备产物,而且具有良好的官能团兼容性,适用于一系列不同类型的杂环底物,为合成偕二氟烯丙基杂芳烃化合物提供了一种高效方法.

关键词：钯催化偕二氟烯丙基化杂芳基溴代物偶联反应

Corrigendum to “Ancient DNA traces a Chinese 5400-year-old cat specimen as leopard cat (Prionailurus bengalensis)” [Journal of Genetics and Genomics (2022) 49, 1076e1079]

在线全文

学校读者我要写书评

暂无评论

Journal of Genetics and Genomics 2024年第4期51卷 466-466页

作者： Shilun Zhu Zehui Chen Songmei Hu Weilin Wang Peng Cao feng Liu Qingyan Dai xiaotian feng Ruowei Yang Wanjing Ping Qiaomei Fu Key Laboratory of Vertebrate Evolution and Human Origins Institute of Vertebrate Paleontology and PaleoanthropologyChinese Academy of SciencesBeijing 100044China Sino-Danish Center University of the Chinese Academy of SciencesBeijing 100049China University of the Chinese Academy of Sciences Beijing 100049China Shaanxi Academy of Archaeology Xi’anShaanxi 710054China School of History and Culture Shanxi UniversityTaiyuanShanxi 030006China

Effect of scanning speeds on electrochemical corrosion resistance of laser cladding TC4 alloy

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 Physics B 2019年第2期28卷 383-390页

作者： xiaotian feng Jianbo Lei Hong Gu Shengfeng Zhou Laser Technology Institute Tianjin Polytechnic University

In order to study the effect of scanning speed on the electrochemical corrosion resistance of laser cladding TC4 alloy in artificial seawater, the x-ray diffraction analysis, microstructure of cross-section, microhardness variation, and impedance spectrum have been studied in comparison with the TC4 titanium alloy. The results show that the main phase of cladding coating is α-Ti, and the change of scanning speed has no obvious effect on it; therefore, the supersaturated α-Ti solid solution is formed, and the acicular α martensite is obtained. As the scanning speed increases, the microstructure of cladding coating is orthogonal basket-weave, the crystal surface spacing decreases, and the average microhardness of laser cladding TC4 alloy slightly increases. When the scanning speed increases to 10 mm/s, the microhardness is about 14.71%higher than that of the substrate, and the electrochemical corrosion resistance of laser cladding TC4 alloy is also improved,which is about 2.48 times more than the substrate. Grain refinement has a great effect on enhancing the anti-electrochemical corrosion.

关键词： laser cladding TC4 alloy grain refinement electrochemical corrosion

Expression and functional characterization of odorant-binding protein 2 in the predatory mite Neoseiulus barkeri

在线全文

学校读者我要写书评

暂无评论

Insect Science 2023年第5期30卷 1493-1506页

作者： Yixia Wu Yaying Li Wenqiang Chu Tiandi Niu xiaotian feng Rongjiang Ma Huai Liu Key Laboratory of Entomology and Pest Control Engineering College of Plant ProtectionSouthwest UniversityBeibei DistrictChongqing400715 China

Olfaction plays a crucial role for arthropods in foraging,mating,and *** odorant-binding protein(OBP)gene is considered one of the most important olfactory ***,little is known about its functions in predatory ***,we used Neoseiulus barkeri,an important commercialized natural pest control,to explore the chemosensory characteristics of *** this study,*** was attracted by methyl salicylate(MeSA)and showed higher crawling speeds under MeSA ***,we identified and cloned an OBP gene named Nbarobp2 and analyzed its expression profiles in the predatory ***2 was 663 bp,was highly expressed in larval and nymphal stages,and was significantly upregulated in *** under MeSA ***2 encoded 202 amino acid residues with a molecular weight of 23 kDa(after removing the signal peptide).Sequence comparisons revealed that the OBPs in Arachnida shared 6 conserved cysteine sites,but were distinguishable from the OBPs of Insecta on the phylogenetic *** interference,Western blotting,and binding affinity assays further proved that Nbarobp2 was involved in volatile perception in predatory *** study shed light on the functional characteristics of OBPs in predatory mites,providing a new insight for better biological control.

关键词： binding affinity crawling speed heterologous expression methyl salicylate olfactory behavior RNA interference

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

基于GF-2面向对象土地利用分类研究

山西建筑 2024年第7期50卷 171-174页

作者：郝旋捷冯晓天赵燕伶张巧玲自然资源陕西省卫星应用技术中心陕西西安710082

高分辨率遥感技术发展迅速,传统技术已经无法满足信息提取的要求,严重影响提取精度和效率。以秦岭北麓长安区与鄠邑区交界处北部部分区域为实验区,高分二号影像为数据源,采用面向对象分类法进行土地利用分类研究,并进行监督分类做对比... 详细信息

高分辨率遥感技术发展迅速,传统技术已经无法满足信息提取的要求,严重影响提取精度和效率。以秦岭北麓长安区与鄠邑区交界处北部部分区域为实验区,高分二号影像为数据源,采用面向对象分类法进行土地利用分类研究,并进行监督分类做对比实验。结果表明,采用面向对象分类法分类结果总体精度为90.05%,Kappa系数为0.857,比监督分类方法精度高出14.55%,Kappa系数高出0.288。面向对象分类方法总体分类效果较好,有效提高了分类精度。

关键词：高分二号影像面向对象分类秦岭北麓 eCognition 土地利用

基于遥感技术的韩城市燎原煤矿矿山地质灾害监测与分析

在线全文

学校读者我要写书评

暂无评论

陕西地质 2024年第1期42卷 82-90页

作者：赵燕伶蒙利郑晨郝旋捷冯晓天陕西省地质调查院西安710054 自然资源陕西省卫星应用技术中心西安710068

以获取的韩城市龙门镇燎原煤矿2013、2018、2022年等3个年度的卫星影像作为主要数据源,并辅以矿区范围内30m的ALOS高程数据,通过对影像和高程数据进行处理,根据影像特征建立了研究区矿山地质灾害遥感解译标志,利用ArcGIS平台重点解译了... 详细信息

以获取的韩城市龙门镇燎原煤矿2013、2018、2022年等3个年度的卫星影像作为主要数据源,并辅以矿区范围内30m的ALOS高程数据,通过对影像和高程数据进行处理,根据影像特征建立了研究区矿山地质灾害遥感解译标志,利用ArcGIS平台重点解译了采空区范围内出现的地裂缝、地面塌陷、落水洞及沟谷边缘疑似出现的滑坡、崩塌等地质灾害。结果表明:①研究区地质灾害数量偏高,共解译滑坡、崩塌、地面塌陷、地裂缝灾害点总计42处;②研究区地质灾害发生与人类工程活动(采矿活动)、区内地形条件、地质背景、物候条件密切相关;且灾害点大多形成于2013年之后,主要发生在坡度15°30°和30°45°之间。

关键词：燎原煤矿矿山地质环境地质灾害遥感监测

Ancient DNA traces a Chinese 5400-year-old cat specimen as leopard cat(Prionailurus bengalensis)

在线全文

学校读者我要写书评

暂无评论

Journal of Genetics and Genomics 2022年第11期49卷 1076-1079页

作者： Shilun Zhu Zehui Chen Songmei Hu Weilin Wang Peng Cao feng Liu Qingyan Dai xiaotian feng Ruowei Yang Wanjing Ping Qiaomei Fu Key Laboratory of Vertebrate Evolution and Human Origins Institute of Vertebrate Paleontology and PaleoanthropologyChinese Academy of SciencesBeijing 100044China Sino-Danish Center University of the Chinese Academy of SciencesBeijing 100049China University of the Chinese Academy of Sciences Beijing 100049China Shaanxi Academy of Archaeology Xi'anShaanxi 710054China School of History and Culture Shanxi UniversityTaiyuanShanxi 030006China

Now,widely distributed modern cats are the descendant of wildcat(Felis silvestris lybica),which are assumed to have originally taken advantage of resources in human settlements,before being tamed in the Near East via ... 详细信息

关键词： assumed settlement Fuller

Removal of pathogenic indicator microorganisms during partial nitrification:the role of free nitrous acid

在线全文

学校读者我要写书评

暂无评论

Frontiers of Environmental Science & Engineering 2024年第3期18卷 93-102页

作者： Jiaojiao Xu xiaotian Chen Rui Tang Jingwei feng Shoujun Yuan Wei Wang Zhen-Hu Hu Anhui Engineering Laboratory of Rural Water Environment and Resource School of Civil EngineeringHefei University of TechnologyHefei 230009China Hefei 168 High School Hefei 230025China Shanghai Key Laboratory of Materials Protection and Advanced Materials in Electric Power Shanghai University of Electric PowerShanghai 200090China

Digested wastewater contains pathogenic microorganisms and high ammonia concentrations,which can pose a potential risk to public *** removal of pathogens and nitrogen is crucial for the post-treatment of digested *** nitrification-anammox is an energy-saving nitrogen removal *** nitrous acid(FNA),an intermediate product of partial nitrification,has the potential to inactivate ***,the efficiency and mechanisms of FNA-related inactivation in pathogens during partial nitrification remains *** this study,Enterococcus and Escherichia coli(***)were selected to investigate the efficiency and mechanisms of FNA-related inactivation in partial nitrification *** results revealed that 83%±13%and 59%±27%of *** and Enterococcus were removed,respectively,in partial nitrification process at FNA concentrations of 0.023−0.028 mg/*** the concentration of FNA increased from 0 to 0.5 mg/L,the inactivation efficiencies of *** and Enterococcus increased from 0 to 99.9%and 89.9%,*** exhibited a higher resistance to FNA attack compared to ***.3D-laser scanning microscopy(3D-LSM)and scanning electron microscopy(SEM)revealed that FNA exposure caused the surface collapse of *** and Enterococcus,as well as visible pore formation on the surface of *** cells.4',6-Diamidino-2-phenylindole dihydrochloride n-hydrate(DAPI)/propidium iodide(PI)and biomolecule leakage confirmed that inactivation of *** and Enterococcus occurred due to breakdown of cell walls and cell *** findings indicate that partial nitrification process can be used for the removal of residual pathogenic microorganisms.

关键词： Partial nitrification Free nitrous acid Pathogenic indicator microorganism Inactivation Cell structure