基于泵吸效应的电磁驱动配气机构温升抑制方案研究

根据动圈式电磁驱动配气机构的结构特点和工作原理提出了一种温升抑制方案:利用动圈的泵吸效应,以环形切片作为开关阀片,在无需额外动力源驱动的前提下能够提升动圈与永磁体之间气隙内的气体流量与速度,从而有效强化气隙表面的对流传热效果。通过建立流动区域的数值模型,仿真分析了电磁驱动配气机构工作循环中阀片的响应规律以及气体流动状态,据此对方案结构进行了改进,通过更换材质减轻了阀片的质量并优化了阀片行程。最后开展了配气机构长时间工作下的温升测试试验,结果表明,改进后的方案对执行器温升抑制效果明显,在测量工况下各测量点中最高温升下降12.1℃。     

深圳市游憩资源现状及建设对策研究

文中采用问卷调查的方式结合对游憩资源的空间分布研究,对深圳市目前游憩资源的供给能力、使用状况、服务能力以及公众满意度与影响原因进行分析,结果表明:1)深圳总体的游憩资源类型供给能力排序为滨海风光类 > 都市观光类 > 休闲娱乐类 > 人文历史类 > 自然郊野类,同时各区的供给能力及其对总体资源供给能力的贡献不相同,盐田海滨风光类供给能力强且贡献最大,南山、福田、罗湖都市观光类供给能力强且对贡献相对次之,龙岗自然资源供给能力最强但贡献较小;2)海滨风光、都市观光、自然郊野游憩资源具有较高的吸引力与使用度;3)深圳总体自然郊野游憩资源的服务压力最大,其次为都市观光、滨海风光、休闲娱乐、人文历史,同时不同区的游憩资源本地服务能力存在差异;4)公众对深圳总体游憩地的满足度还不够高,主要源自建设内容与形式、特色创新、亲和融入性、体验参与性、方便可达性5个方面存在的问题。最后基于这一结果归纳出各区游憩资源开发提升的主题并提出多样丰富性、特色创新性、亲和融入性、体验参与性、方便可达性5项建设原则。     

大型抽水蓄能电站地下厂房环境测试方案

为了评估大型抽水蓄能电站地下厂房温湿度控制的效果,提高运行环境的舒适性及其对机电设备安全性的设计水平,分析了宜兴抽水蓄能电站地下主厂房、母线洞、主变洞、排风道的结构特点,结合地下厂房及主要洞室的通风、内部空气循环以及各自不同的温湿度性能参数分析要求,选用合适的温度、湿度、噪声环境参数测量仪表,分别设计了厂房和不同洞室的通风除湿性能测试方案.经过初步的测试及分析可以得到,选用的测试仪表具有价格适中、精度高和使用方便的特点;制定的测试系统和方案可以全面而系统地测试地下厂房温湿度控制效果.选用的仪器仪表和测试方案结合了厂房和通风空调系统的特点与要求,可以为同类电站通风空调系统测试和性能分析提供参考.     

Genetic Variation in Cadmium Accumulation and Tolerance among Wheat Cultivars at the Seedling Stage

Exploitation of genetic differences to select wheat cultivars’ pollution-safe from cadmium (Cd) contamination requires better understanding of Cd uptake and translocation patterns. For this purpose, 15 wheat cultivars were grown in nutrient solution and exposed to four levels of Cd, i.e., 0, 15, 30, and 45 µM. The plants were harvested after 2 weeks of Cd exposure. Root and shoot relative dry matter (DM) was decreased in most of the cultivars, but some cultivars did not exhibit any toxic symptoms. The lowest Cd concentration in shoots was recorded for Lasani-2008 and Iqbal-2000 while the highest for Sehar-2006 and Inqlab-91. Both root absorption and translocation accounted for regulating Cd concentration in shoots. There was no relationship between relative DM and Cd concentrations in roots and shoots. The results suggest that wheat cultivars with low shoot Cd concentration but higher tolerance, i.e. Lasani-2008 and Iqbal-2000, could be used in breading programs for low Cd wheat.     

Comparison of the distribution of mineral nutrients and active substances in dehydration- and salinity-stressed Aloe vera L.

Changes in growth and distribution of inorganic mineral elements and organic active substances in seedlings of A. vera were examined under treatments of ?0.44 and ?0.88 MPa polyethylene glycol 6000 (PEG) and corresponding isosmotic sodium chloride (NaCl). All stress treatments inhibited plant growth, with NaCl severely inhibiting the growth of the seedlings than PEG. However, leaf biomass did not change significantly. The nitrogen concentration under PEG was maintained higher than that under NaCl. Salinity caused more severe ionic imbalance than dehydration. However, when the concentration of NaCl was increased, ion homeostasis was maintained. Stressors induced an increase in aloin concentration in leaves, especially in young leaves. Polysaccharide concentrations in leaves did not change under dehydration. However, the polysaccharide concentration decreased in the middle and base leaves under NaCl. A. vera exhibited high adaptability to suitable osmotic stress, which increases its main active ingredients in leaves.     

Comparison of single and competitive metal adsorption by pepper stem biochar

Carbon-based sorbents have been proven to be cost-effective in removing pollutants from wastewater. Biochar from plant residue and agricultural waste is an emerging treatment technology. However, there is a limited number of studies on the effects of various biochar sources on metal adsorption. The aim of this study was using batch experiment to evaluate the adsorption of heavy metals in single- and multi-metal conditions onto pepper stem biochar. The maximum adsorption capacities (mg g^?1) of metals by pepper stem biochar were in the order of Pb (131) ? Cr (76) > Cd (67) > Cu (48) > Zn (31) in the single-metal adsorption isotherm and Pb (91) ? Cu (39) > Cr (29) > Zn (20) > Cd (13) in the multi-metal adsorption isotherm. Lead was the most retained cation, whereas Cr and Cd could be easily exchanged and substituted by other metals (Pb or Cu). For pepper stem biochar, the Langmuir model provided a slightly better fit than the Freundlich model. Results from the batch experiments show that competitive adsorption among metals increases the mobility of these metals. Particularly, Cd adsorption capacity in multi-metal conditions was significantly reduced. Overall, the results suggested that competitive adsorption studies are necessary for obtaining an accurate estimation of the metal retention capacity of pepper stem biochar in natural environments.     

湘早籼46号在湖南益阳的种植表现及高产栽培技术

湘早籼46号是湖南省贺家山原种场选育的常规早籼迟熟水稻新品种,2009年通过湖南省农作物品种审定委员会审定。2011-2012年在湖南省益阳市多点引种试种,表现为丰产性好、熟期适宜、性状优良、抗性好、米质较优、售价高、效益好。为此,研究了一套与湘早籼46号配套的高产栽培技术措施,以期帮助农民增产增收。