检索结果-南通市图书馆

Metal release/accumulation during the decomposition of Potamogeton crispus in a shallow macrophytic lake

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2016年第4期28卷 71-78页

作者： Huanguang Deng Ju Zhang Shiyue Chen Liwei Yang Dongqi Wang shiyong yu School of Environment and Planning Liaocheng University School of Geographical Sciences East China Normal University Institute for Cultural Heritage Shandong University

Changes in metal concentrations in the litter of Potamogeton crispus were monitored during a consecutive 40-day in situ decomposition experiment using the litterbag *** accumulation index was calculated and used to indicate the changes in the metals in *** results showed that the concentrations of Al,Cd,Cr,Fe,Mn,and Pb in litter increased significantly during the decomposition,while Cu and Zn concentrations decreased *** positive correlations were found between the concentrations of Al,Cr,Fe,and Mn and between Cu and ***,Cu and Zn both negatively correlated with Al and *** remaining dry mass was negatively correlated with Al and Fe concentrations but positively correlated with Cu and Zn *** the accumulation index values of metals other than Al were less than one,indicating that the litter of *** acted as a source of metals to the surrounding water *** was the only metal that showed continuous net accumulation in *** net accumulation of Fe and Mn in litter during the last 10 days of the experiment may indicate the precipitation of Feand *** was estimated that 160 g/m^2（dry weight）*** was decomposed in40 *** was equivalent to releasing the following amounts of metals：0.01 mg Cd,0.03 mg Cr,0.71 mg Cu,0.55 mg Mn,0.02 mg Pb and 13.8 mg Zn into surrounding water,and accumulating 149 mg Al and 11 mg Fe,in a 1 m^2 area.

关键词： Litter decomposition Metal release/accumulation Metal stocks Accumulation index Potamogeton crispus Lake Dongping

Ancient water wells reveal a prolonged drought in the lower Yellow River area about 2800 years ago

在线全文

学校读者我要写书评

暂无评论

Science Bulletin 2018年第20期63卷 1324-1327页

作者： shiyong yu Xuexiang Chen Xiuling Liu Zhen Fang Junfeng Guo Senyang Zhan Hui Fang Fahu Chen School of Geography Geomaticsand PlanningJiangsu Normal UniversityXuzhou 221116China Joint International Research Laboratory for Environmental and Social Archaeology 5handong Universityfinan 250100China Jinan Municipal Institute of Archaeology jinan 250062China Institute of Tibetan Plateau Research Chinese Academy of SciencesBeijing 100101China

Proxy records from the North Atlantic realm reveal that large and rapid cooling known as the Bond events continued into the Holocene [1],repeatedly punctuating what is conventionally thought to have been a relatively stable *** that the Holocene is the most recent interglacial period that has spurred the development of modern societies,scrutinizing climate variabil- ity during this period is important not only for predicting the trend of future climate changes,but also for better understanding the driving forces behind the rise and fall of ancient civilizations.

关键词： water wells drought Yellow River area

Factors Influencing Farmers' Willingness to Participate in the New Vocational Training

在线全文

学校读者我要写书评

暂无评论

Asian Agricultural Research 2014年第3期6卷 55-59页

作者： shiyong yu Jia WANG College of Economics and Management Southwest University School of Public Finance and Taxation Southwestern University of Finance and Economics

Probit model is applied to analyze some key factors influencing farmers' willingness to participate in the new vocational training for farmers based on 683 questionnaires from 8 districts in Chongqing. The results show that individual and family factors significantly affect farmers' participation will. These factors are age,family scale and years of education. Age is the most important factor,family scale is of secondary importance and years of education are the third one. Meanwhile,years of education positively affect farmers' participation willingness;there is a negative correlation among age,family scale and this willingness. Organizer,rural economic development level and training experience have no significant influence on this willingness.

关键词： New vocational training for farmers Willingness to

Cerium Oxide Coating of Titanium Dioxide Pigment to improve the weatherability

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

Cerium Oxide Coating of Titanium Dioxide Pigment to improve ...

中国化学会第九届全国无机化学学术会议

作者： Zhao Li shiyong yu Inner Mongolia Key Laboratory of Physics and Chemistry of Rare Earth Materials School of Chemistry and Chemical Engineering Inner Mongolia University

Titanium dioxide is the best white pigment, but it does not have good weatherability if it is not properly coated. The untreated Titanium dioxide has photocatalytic activity,it can make the degradation of organic produce, resulting in loss of light, yellowing, chalking phenomenon. The function of the coated film was to capture electrons and holes of the Ti O2 particles produced by the ultraviolet irradiation that otherwise could produce free radicals on the Ti O2 surface. As a change from the conventional coating with silicon or aluminum oxide, its weatherability after coating with the oxides of cerium was investigated. A new more effficient, easier and more accurate method that used rhodamine-B degradation was used to evaluate the weather-stability of the coated Ti O2 particles. The photocatalytic activity of titanium dioxide particles coated with cerium oxide decreases largely. It means a large improvement in the weatherability of titanium dioxide particles coated with cerium oxide was obtained even with a tinycoating amount of 1 wt %, and the pigments were more stable with the 10 wt % film coating of cerium dioxide.

关键词： weatherability titanium dioxide cerium oxide

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

急性肺栓塞介入治疗现状及展望

中华心血管病杂志 2024年第4期52卷 439-444页

作者：李丽于世勇陆军军医大学新桥医院心内科重庆400037

急性肺栓塞是临床常见致死性心血管疾病,依据当前指南对于高危患者和抗凝治疗过程中血流动力学恶化的中高危患者,静脉溶栓是首选再灌注治疗方案,溶栓禁忌或者失败可以考虑经导管介入治疗。介入治疗是建立在导管技术基础上的再灌注治疗... 详细信息

急性肺栓塞是临床常见致死性心血管疾病,依据当前指南对于高危患者和抗凝治疗过程中血流动力学恶化的中高危患者,静脉溶栓是首选再灌注治疗方案,溶栓禁忌或者失败可以考虑经导管介入治疗。介入治疗是建立在导管技术基础上的再灌注治疗措施之一,目的是通过介入技术快速解除血栓对肺动脉主干或主要分支的阻塞,促进右心室功能恢复,减轻症状和提高生存率。介入治疗近年来发展迅速,其优点在于可以减少或者不用溶栓药物,方法包括经导管血栓碎解、局部溶栓、血栓抽吸和(或)机械取栓等。该文针对急性肺栓塞的介入治疗现状进行综述,重点介绍现有的介入治疗方法以及适用人群,并展望未来的发展方向。

关键词：肺栓塞介入治疗局部溶栓血栓抽吸机械取栓

Relationship between autonomic nervous system function and acute mountain sickness

在线全文

学校读者我要写书评

暂无评论

Journal of Medical Colleges of PLA(China) 2008年第5期23卷 276-282页

作者： Long Min Huang Lan Tian Kaixin yu shiyong yu Yang Qin Jun Department of Endocrinology Xinqiao Hospital Third Military Medical University Chongqing 400037 China Cardiovascular Diseases Research Center Xinqiao Hospital Third Military Medical University Chongqing 400037 China

Objective: To elucidate the role of the autonomic nervous system (ANS) in acute mountain sickness (AMS) during the initial phase at acute high-altitude exposure. Methods: Ninety-nine healthy sea-level residents rapidly ascended to Tibet plateau (3 675 m altitude) by airplane from Chengdu plain (560 m altitude). ANS function was tested in plain and day 2–4 in Tibet by heart rate variability (HRV), cold pressor test (CPT). AMS was evaluated by clinic symptomatic scores. All subjects were divided into non-AMS group (57, scores≤4) and AMS group (42, scores>4). Results: Compared with non-AMS group, AMS group had higher standard deviation of normal to normal intervals (SDNN), root mean square of delta RR (rMSSD), low-frequency (LF) power, and normalized low-frequency (LFnu) power in plain (P50 ms(PNN50), rMSSD (P<0.01) and SDNN, LF, total power (TP) (P<0.05). Although no significant differences in the increase of SP and DP during CPT were found between 2 groups in plain, the SP increase during CPT of AMS group was less than non-AMS group (P<0.05) at 3 675 m altitude. AMS symptomatic scores was not only positively correlated with SDNN, rMSSD, LF/HF in plain (P<0.05), but also negatively correlated with HFnu in plain (P<0.05). Conclusion: During the initial high altitude exposure, ANS modulation is generally blunted, but the relatively predominant sympathetic control is enhanced, and this characteristic change of ANS function is positively correlated with the development of AMS.

关键词： High altitude Autonomic nervous system Acute mountain sickness Heart rate variability Cold pressor test

Changes of autonomic nervous system function in healthy young men during initial phase at acute high-altitude exposure

在线全文

学校读者我要写书评

暂无评论

Journal of Medical Colleges of PLA(China) 2008年第5期23卷 270-275页

作者： Qin Jun Huang Lan Tian Kaixin yu shiyong yu Yang Long Min Cardiovascular Diseases Research Center Xinqiao Hospital Third military medical university Chongqing 400037 China Department of Endocrinology Xinqiao Hospital Third military medical university Chongqing 400037 China

Objective: To investigate the changes of autonomic nervous system (ANS) function during the initial phase at acute high-altitude exposure. Methods: Ninety-nine healthy sea-level male residents were studied in Chengdu plain and then Tibet plateau. Heart rate variability (HRV), cold pressor test (CPT), resting heart rate (HR) and blood pressure (BP) were measured at baseline (560 m altitude) and in 2 to 4 d after arriving at Tibet plateau (3 675 m altitude) to assess the ANS function. Results: Compared with baseline, on day 2 in Tibet the standard deviation of normal to normal intervals (SDNN), high-frequency (HF) power, total power (TP), root mean square of delta RR (rMSSD), percentage of delta RR>50 ms (PNN50), normalized high-frequency (HFnu) and fractal dimension (FD) decreased significantly (SDNN, HF, TP P<0.01, rMSSD, PNN50, HFnu, FD P<0.05), while the normalized low-frequency (LFnu) and LF/HF increased significantly (P<0.01). During day 3–4 in Tibet, SDNN, rMSSD, HF, TP and HFnu tended to rebound while LFnu and LF/HF decreased towards baseline day by day. In addition, in Tibet the increase in systolic pressure (SP) and diastolic pressure (DP) during CPT decreased significantly (P<0.01, 0.05), but resting HR increased compared with baseline (P<0.01). Conclusion: ANS modulation is generally blunted, and the relatively predominant sympathetic control is enhanced originally, then it reverts to the sea level states gradually during the initial days of acute high-altitude exposure.

关键词： Autonomic nervous system High altitude Heart rate variability Cold oressor test

在线全文

学校读者我要写书评

暂无评论

三峡库区生态与经济同步建设的难点及对策

生态经济 2012年第6期28卷 64-66页

作者：余世勇西南大学经济管理学院重庆400715

三峡库区地处长江咽喉地带,是我国极为重要的敏感生态经济区。三峡库区的战略地位决定了生态与经济必须同步建设、同时优化和协调发展。三峡库区生态与经济同步建设面临人地矛盾突出、财政困难和资金缺乏、科技创新和人才不足、地方政府... 详细信息

三峡库区地处长江咽喉地带,是我国极为重要的敏感生态经济区。三峡库区的战略地位决定了生态与经济必须同步建设、同时优化和协调发展。三峡库区生态与经济同步建设面临人地矛盾突出、财政困难和资金缺乏、科技创新和人才不足、地方政府的"经济人"行为、管理体制不完善等难点。推进三峡库区生态与经济同步建设必须牢固树立科学发展观,发展兼具生态与经济的双功能产业,加大国家投入力度,建立有效的激励与约束机制,强化科技支撑与人才支持、完善库区综合统一的管理体制等。

关键词：三峡库区生态与经济同步建设对策

Effects of the precursor size on the morphologies and properties of γ-Ce_2S_3 as a pigment

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2014年第6期32卷 540-544页

作者：于世泳王东日高小龙苏海全 Inner Mongolia Key Laboratory of Chemistry and Physics of Rare Earth Materials School of Chemistry and Chemical Engineering Inner Mongolia University

Ceria spheres with different sizes and sulfurized products with corresponding morphology were prepared by hydro-thermal and gas-solid reaction method at 600-800℃ under CS2 atmosphere for a short time, respectively. Dimensional effect in preparation ofγ-Ce2S3 was firstly investigated by means of techniques such as scanning electron microscopy （SEM）, X-ray dif-fraction （XRD）, thermal gravimetric analysis （TGA） and spectrophotometer. The results showed that when ceria nanoparticles with small size were used as precursors, theγ-Ce2S3 could be prepared at the lower temperature and the badly sintered products were obtained; when ceria nanoparticles with large size were employed as precursors, pureγ-Ce2S3 was difficultly obtained even if the temperature was up to 800℃ and the products tended to keep their original size. The heat-resistance property of theγ-Ce2S3 with large size was better than the smaller one, and the pureγ-Ce2S3 prepared from precursor with small size had a good pigmen-tary performance.

关键词： ceria sphere size γ-Ce2S3 low temperature pigmentary performance rare earths