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101.
我国是世界上最大的农业生产国,每年生产各类作物秸秆约7亿吨,其中有约50%未得到有效的处理和利用。不仅浪费了资源,而且还由于大量秸秆的露天焚烧,导致了严重的环境污染、火灾频发、高速公路和民航的运输安全受到影响及威胁。秸秆的处理和利用已成为我国目前面临的一个主要问题之一,但是由于缺乏经济可行的技术,秸秆焚烧和综合利用问题一时难以解决。  相似文献   
102.
从普施特生产厂的污泥和长期施用普施特的土壤中筛选获得了4株能以普施特为唯一碳源生长,且对普施特具有较好降解功能的细菌(降解率均在80%以上).对其进行形态特征、生理生化及16S rDNA序列分析。结果表明,zx2和zx7为芽孢杆菌属(Bacillus sp.),zx5是产碱杆菌科(Alcaligenaceae bacterium)菌,zx6是无色杆菌属(Achromobacter sp.).  相似文献   
103.

从数字图书馆与知识产权的概念、数字图书馆的建设和数字图书馆的合理使用等 几个方面对数字图书馆建设中的知识产权保护问题进行了探讨与分析。

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104.

以SCIE数据库为资料来源,统计1998-2005年蛋白质组学研究 论文的高产国家、机构、发表论文期刊及文献主题等相关指标,揭示蛋白质组学的研究现状 ,并对论文数量和影响力进行比较,以衡量我国在蛋白质组领域的研究实力。

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105.
Taking the extended Mindlin solution of a vertical point load acting in the interior of a multi layered elastic medium as the basic solution, an indirect boundary element method (BEM) was adopted to analyze pile foundations embedded in a multi layered elastic soil. The numerical analysis was carried out by the compiled program for a pile foundation in an homogeneous soil and a pile foundation in a multi layered soil. Reasonably good agreement is obtained between the present and existing solutions. Compared with the FEM software ABAQUS, the computational speed of BEM is much faster than that of FEM. Applying BEM in practice is convenient. It is pointed out that the exact measurement of elastic modulus is the key factor for applying BEM in geotechnical engineering.  相似文献   
106.
To solve the key problems of the electric drive system, a controller area network(CAN) based electric drive system for electric vehicles was designed. The system was composed of two parts: a CAN communication module and a motor control module. The newest transceiver (TJA1040) and a stand alone CAN controller were used during the design of the CAN communication module, and anti jamming measures were employed to guarantee communication stability. The fuzzy vector control method and direct speed control were applied to realize highly robust control functions. This system has high compatibility. It can be installed in electric vehicles as an independent module and be extended through CAN Bus.   相似文献   
107.
Methods of IF difference detection combined with rapid acquisition synchronization and tracking principle by parallel processing methods were proposed in order to quickly achieve synchronous digital capture and tracking in π/4 DQPSK demodulation.Field program grid array (FPGA) technology to achieve rapid detection of synchronous capture and symbol tracking was adopted by using the improved algorithm in parallel with signal acquisition and frequency offset acquisition. This adoption took into account the characteristics of π/4 DQPSK and was in accordance with the detection of rapid acquisition synchronization and the tracking principle. The experimental results show that clock synchronization signals can be restored stably in eight symbol bit, accurately realize bit timing, and possess strong anti interference capability without affecting frequency differences. This proposed algorithm is suited for frequency hopping communication systems with high transmission rates.  相似文献   
108.
Three typical commercial buildings in Chongqing, P.R. China were selected to study the actual summertime operation and energy situations of heating ventilating and air conditioning (HVAC) systems in commercial buildings. Based on tests of energy consumption of HVAC systems in these three buildings, we analyzed the electricity consumption of the main components of the air conditioning systems. The energy efficiency of the chillers and air conditioning water distribution systems were studied. The indoor thermal environment in these three buildings were also tested and discussed. It is concluded that problems exist in the air conditioning systems of commercial buildings. Among the problems are over sized system design, low equipment operating efficiencies, poor operation management, and lack of indoor temperature controls. To reduce energy consumption of HVAC systems in commercial buildings, we propose energy efficient strategies such as sizing systems based on accurate load calculation and automatic control under partial load conditions.  相似文献   
109.
葡萄酒香气成分萃取中固相微萃取纤维的选择   总被引:1,自引:0,他引:1  
【目的】针对葡萄酒香气成分气相色谱分析的要求,比较了3种固相微萃取纤维萃取葡萄酒香气成分的效果。【方法】选用常用的PA、PDMS/DVB、PDMS 3种固相微萃取纤维进行葡萄酒香气成分的富集、浓缩处理,然后用GC-MS检测香气成分。通过对不同固相微萃取纤维萃取香气成分的数量、化学种类以及各类化合物累积峰面积标准化值的比较,评价供试固相微萃取纤维萃取葡萄酒香气成分的效果。【结果】3种固相微萃取纤维萃取出的葡萄酒香气成分中,高级醇、化学酯和有机酸是主要成分,萜烯醇、β-大马酮、挥发性酚和呋喃酮等是微量成分。不同固相微萃取纤维萃取的化合物存在明显差异,PA萃取出化合物49种,PDMS萃取出53种,PDMS/DVB仅萃取出38种。累积峰面积标准化值分析表明,PA萃取高级醇、有机酸、3-甲硫基-1-丙醇、2(3H)-二氢呋喃酮、2,4-二季丁基苯酚的灵敏度高;PDMS萃取化学酯类、萜烯醇和β-大马酮的灵敏度高;PDMS/DVB几乎萃取各类化合物的灵敏度都低。【结论】在供试的3种固相微萃取纤维中,PDMS是萃取富集绝大多数葡萄酒挥发性成分的最佳纤维。  相似文献   
110.
通过对网络医学学术信息资源的分类及其评价分析,提出建立 网络医学学术信息资源检索导航系统的初步设想,帮助用户提高对网络医学学术信息资源 的甄别与应用能力。  相似文献   
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