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621.
Zhao Yaxin Tian Huafeng Ouyang Yuge Xiang Aimin Luo Xiaogang Shi Xingwei Ma Songbai 《Journal of Polymers and the Environment》2022,30(10):4193-4200
Journal of Polymers and the Environment - Although polyvinyl alcohol (PVA) membranes are commonly used for CO2 separation, there is still large development space in mechanical properties and high... 相似文献
622.
623.
采用甲酸对天然沸石改性,通过测定其比表面积和XRD图谱评定其结构变化;并在不同浓度的K+、Cu2+、HPO42-存在条件下,比较了天然沸石及改性加工后对沙门氏菌K533的吸附性能.结果表明:天然沸石经甲酸改性后,BET比表面积增加;由XRD图谱可见,改性沸石表面杂质减少;在离子浓度相同的条件下,改性沸石对沙门氏菌K533的吸附量极显著高于天然沸石(P<0.01),且在一定离子浓度范围内,天然沸石、改性沸石的吸附量随离子浓度的增加而增大.综上所述,甲酸改性沸石对沙门氏菌K533的吸附性能优于天然沸石. 相似文献
624.
大都市传统工业区休闲旅游转型发展研究综述 总被引:1,自引:0,他引:1
传统工业区休闲旅游转型是大都市城市功能和产业空间优化的关键问题,目前该方面研究尚未形成系统性的理论研究体系.论文梳理了国内外相关研究成果,从休闲旅游转型趋势,转型价值,转型空间演化,转型要素,转型模式,转型效应和转型策略等方面进行了研究内容和研究结果的总结,评述了国内外在研究时间,研究内容,研究方法上的差异.最后认为现有研究缺乏从人地关系视角对传统工业区转型背景,要素,动力,空间演化的系统分析,今后应针对中国大都市发展特点,重点关注传统工业区休闲旅游转型发展模式,转型过程,机制以及综合效应等方面的研究,从理论性和可操作性上指导我国城市传统工业区的休闲旅游改造. 相似文献
625.
通过分子生物学技术构建2种不同RAD54启动子调控的yEGFP重组报告载体pRAD54 ̄yEGFP和pRAD54S ̄yEGFP,前者启动子DNA为1.8 kb,后者为0.5 kb,分别转入W303 ̄1A酵母细胞,构建2种启动子调控的发光酵母细胞,用不同化学诱变原作用后,用流式细胞仪和多功能发光仪测定酵母的发光强度。结果发现2种启动子调控的酵母细胞的发光强度均与化学诱变原(甲磺酸甲脂、4 ̄硝基 ̄N ̄氧化喹啉和5 ̄氟尿嘧啶)有明显的剂量效应关系,但是W303 ̄1A/RAD54 ̄yEGFP剂量效应关系较为明显,产生的最大诱导倍数(5.96、2.19和2.71)明显高于W303 ̄1A/RAD54S ̄yEGFP所产生的最大诱导倍数(2.53、1.50和1.91),可能与启动子序列中转录因子的数量以及转录因子间协同增效作用有关。同时发现,流式细胞仪测定效果明显优于发光仪测定效果。所以在构建RAD54启动子调控重组酵母细胞筛选诱变时,选用全启动子序列效果较好。 相似文献
626.
Ningning Zhang Mazhan Zhuang Jie Tian Pengshan Tian Jieru Zhang Qiyuan Wang Yaqing Zhou Rujin Huang Chongshu Zhu Xuemin Zhang Junji Cao 《Frontiers of Environmental Science & Engineering》2016,10(5):17
Ambient PM2.5 samples were collected at four sites in Xiamen, including Gulangyu (GLY), Hongwen (HW), Huli (HL) and Jimei (JM) during January, April, July and October 2013. Local source samples were obtained from coal burning power plants, industries, motor vehicles, biomass burning, fugitive dust, and sea salt for the source apportionment studies. The highest value of PM2.5 mass concentration and species related to human activities (SO4 2–, NO3 –, Pb, Ni, V, Cu, Cd, organic carbon (OC) and elemental carbon (EC)) were found in the ambient samples from HL, and the highest and lowest loadings of PM2.5 and its components occurred in winter and summer, respectively. The reconstructed mass balance indicated that ambient PM2.5 consisted of 24% OM (organic matter), 23% sulfate, 14% nitrate, 9% ammonium, 9% geological material, 6% sea salt, 5% EC and 10% others. For the source profiles, the dominant components were OC for coal burning, motor vehicle, biomass burning and sea salt; SO4 2– for industry; and crustal elements for fugitive dust. Source contributions were calculated using a chemical mass balance (CMB) model based on ambient PM2.5 concentrations and the source profiles. GLY was characterized by high contributions from secondary sulfate and cooking, while HL and JM were most strongly affected by motor vehicle emissions, and biomass burning and fugitive dust, respectively. The CMB results indicated that PM2.5 from Xiamen is composed of 27.4% secondary inorganic components, 20.8% motor vehicle emissions, 11.7% fugitive dust, 9.9% sea salt, 9.3% coal burning, 5.0% biomass burning, 3.1% industry and 6.8% others. 相似文献
627.
Tian Shi 《国际发展与全球生态学杂志》2013,20(3):195-210
Past decades have witnessed the rise of sustainable agriculture movements throughout the world. In parallel with this international trend, ecological agriculture (with essential goals of food security, rural employment, poverty alleviation, natural resource management and environmental protection) has been advocated as a workable approach for the realization of sustainable agriculture in China. Two decades of ecological agricultural development have shown that it not only gained legitimacy at the senior policy level but also became a focus of scientific research in fields such as ecological economics, ecology, and agricultural and environmental sciences. However, this endeavour is hardly known in the West and little attention has been paid so far to examining the broader politico-economic and sociocultural contexts within which it has evolved. This paper attempts to provide a general review of the emerging background, development history, policy initiatives and recent tendencies of ecological agriculture. In addition, the extant problems and potential contributions of this alternative practice to China's sustainable agricultural development are discussed. The purpose of this study is to identify the gap between the policy rhetoric and practical implementation of Chinese ecological agriculture and therefore to facilitate its moving towards sustainable development. 相似文献
628.
海洋石油降解酵母的分离鉴定与降解特性 总被引:1,自引:0,他引:1
以原油为唯一碳源,采用富集培养、平板涂布分离、平板划线纯化及摇瓶复筛等方法,从表层海水或海泥中分离得到2株具有较强石油降解能力的菌株SYB-5和SYB-2. 根据菌落及菌体形态、生理生化特征和分子生物学分析、鉴定显示,SYB-5为季也蒙毕赤酵母(Meyerozyma guilliermondii/Pichia guilliermondii),SYB-2为长孢洛德酵母(Lodderomyces elongisporus). 对2株酵母菌的石油降解性能的研究结果表明,SYB-5和SYB-2以原油组分作为碳源,以(NH4)2SO4和(NH4)3PO4作为氮源,在ρ(NaCl)为30g/L、氧气充足的条件下,生长的最适温度分别为36和32℃,pH均为7.0. 在最适生长条件下,培养5d后的原油降解率分别达到45.8%和34.4%. 当2株菌混合培养时,培养5d的原油降解率可提高到53.9%,培养8d时达到56.4%,说明2株菌利用原油作碳源生长时具有协同作用. 相似文献
629.
环境内分泌干扰物(environmental endocrine disruptors,EEDs)是一类可以改变生物体内激素的合成、释放、运输、代谢、结合、作用或清除等一系列生物过程的外源物质。性激素的生物合成需要一系列酶的参与,体内和体外研究表明,性激素合成途径中的类固醇生成酶是EEDs通过非性激素受体介导途径发挥内分泌扰乱作用的重要靶点,性激素合成途径的扰乱可能导致生物体生殖系统受损。本文综述了EEDs对鱼类性激素合成底物和类固醇生成酶的影响、信号转导机制及其生殖危害;并对性激素合成途径中促性腺激素调控机理、多种转录因子间的相互作用、不同物种间类固醇生成酶的差异以及各内分泌轴线的相互作用研究进行了展望,以期为EEDs通过非性激素受体介导途径发挥内分泌干扰效应的机制研究提供思路。 相似文献
630.
Effect of nitrogen deposition on China's terrestrial carbon uptake in the context of multifactor environmental changes 总被引:7,自引:0,他引:7
The amount of atmospheric nitrogen (N) deposited on the land surface has increased globally and by nearly five times in China from 1901 to 2005. Little is known about how elevated reactive N input has affected the carbon (C) sequestration capability of China's terrestrial ecosystems, largely due to the lack of reliable data on N deposition. Here we have used a newly developed data set of historical N deposition at a spatial resolution of 10 km x 10 km in combination with other gridded historical information on climate, atmospheric composition, land use, and land management practices to drive a process-based ecosystem model, the dynamic land ecosystem model (DLEM) for examining how increasing N deposition and its interactions with other environmental changes have affected C fluxes and storage in China's terrestrial ecosystems during 1901-2005. Our model simulations indicate that increased N deposition has resulted in a net C sink of 62 Tg C/yr (1 Tg = 1012 g) in China's terrestrial ecosystems, totaling up to 6.51 Pg C (1 Pg = 10(15) g) in the past 105 years. During the study period, the N-induced C sequestration can compensate for more than 25% of fossil-fuel CO2 emission from China. The largest C sink was found in southeast China, a region that experienced the most significant increase of N deposition in the period 1901-2005. However, the net primary productivity induced by per-unit N deposition (referred to as ecosystem N use efficiency, ENUE, in this paper) has leveled off or declined since the 1980s. This indicates that part of the deposited N may not be invested to stimulate plant growth, but instead leave the ecosystem by various pathways. Except shrubland and northwest/southwest China, signs of N saturation are apparent in the rest major biome types and regions, with ENUE peaking in the 1980s and leveling off or declining thereafter. Therefore, to minimize the excessive N pollution while keeping the N-stimulated C uptake in China's terrestrial ecosystems, optimized management practices should be taken to increase N use efficiency rather than to keep raising N input level in the near future. 相似文献