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991.
论现代高校图书馆员的服务理念 总被引:1,自引:0,他引:1
探讨新时期网络条件下高校图书馆服务工作的特点,树立全新的服务理念。首先要转变服务观念,从被动的“等读者“变为主动的“送信息“,不断扩大传统载体的服务范围,随着电子载体的大量需求使服务向多元化发展。其次积极提高馆员的综合素质,以塑造馆员良好的职业形象为前提,加强馆员的自主学习意识,树立敬业精神,全面、多元的为读者服务。 相似文献
992.
Impacts of climate warming on heating energy consumption and southern boundaries of severe cold and cold regions in China 总被引:2,自引:0,他引:2
CHEN Li FANG XiuQi LI Shuai 《科学通报(英文版)》2007,52(20):2854-2858
Impacts of climate warming on heating energy consumption and southern boundaries of severe cold and cold regions of China in the past 20 years are analyzed by using daily and monthly average tem- perature data from 590 weather stations in China and based on regulations of Heating Ventilation and Air Conditioning Design Rules (GB50019-2003) and Thermal Design Rules for Civil Building (GB50175-93) (China National Standard). The contribution of climate warming to coal saving for heating during cold seasons in major cities is calculated according to indices of coal consumption for heating in major cities during cold seasons defined in Energy Conservation Design Standard for New Heating Residential Buildings (JCJ26-95). Comparing with the period before 1980, southern boundaries of se- vere cold and cold regions shift toward north up to 2 degrees in latitude since the mid-1980s. Theo- retically, climate warming could contribute to 5%―10% coal savings for heating since the mid-1980s in major cities, and even more since the mid-1990s. 相似文献
993.
ZHANG Jian HUANG Min HAN Guoqiang 《武汉大学学报:自然科学英文版》2007,12(3):442-446
For the encoding bit-rate problem in H.264 wireless video communication,this paper analyzes the bit-rate computation model and the Mean Square Error distortion model,establishes the relation between the quantization parameter of the encoding bit-rate and the intra frame refresh rate of the macro block,and put forward a new ideal about the coding rate on the basis of general binomial computation model theory. Furthermore,this method not only can adaptively adjust the bit allocation and quantization parameter and prevents buffer from overflowing downward or upward under given network bandwidth,but also can apply the rate-distortion to optimize the solution method,control the encoding bits accurately and optimizes the allocation between the intra and inter frame encoding macro block. 相似文献
994.
LI Huili LUE Bingnan WANG Dan LIU Xinyue 《武汉大学学报:自然科学英文版》2007,12(3):548-552
An expanded granular sludge bed (EGSB) reactor was adopted to study the influence factors and rule of enhancing granular sludge concentration and performance. The experiment was performed at 33 ℃, pH 6.0-8.0 with continuous flow by adding proper quantity of nutritional trace elements. The results show that SLR was the key of steady operation of EGSB reactor. The increment of the granular sludge was influenced by volume loading rate (VLR), liquid up-flow velocity and sludge loading rate (SLR). Concentration of granular sludge increased rapidly when liquid up-flow velocity was over 0.94 m · h^-1 with SLR being at 1.0-2.0 d ^-1. With the propriety parameters: liquid up-flow velocity 2.52 m · h^-1, SLR 1.0-2.2 d^-1 and VLR 8.2-13.1 kg · m ^3 · d^-1, 23 days' continuous operation resulted in an increment by over 80% of granular sludge concentration in the EGSB reactor, plus good granular sludge property. 相似文献
995.
WU Hua TAO Heping LU Yuan 《武汉大学学报:自然科学英文版》2007,12(4):715-720
The eco-environmental frangibility is studied by choosing the factors of land use class change and vegetation cover rate, and the equation of eco-environmental frangibility and its evaluation system are established based on remote sensing (RS) and geographic information system technology (GIS). Four different years of TM images are selected to calculate land use change grads and vegetation cover rate, and the relationship between the two factors and eco-environment frangibility index are build, taking Fuzhou as an example. The character of times change and space distribution of eco-environment frangibility are described. The result indicates the area of eco-environment frangibility increased 2.6% in Fuzhou during twelve years, and expands from the region between infield and forest land to forest land in space distribution. 相似文献
996.
Nickel accumulation and its effects on the survival rate of Spodoptera litura Fabricius under continuous nickel stress 总被引:2,自引:0,他引:2
SUN HongXia SHU YingHua TANG WenCheng WANG Qi ZHOU Qiang ZHANG GuRen 《科学通报(英文版)》2007,52(14):1957-1963
The artificial diets mixed with various concentrations of nickel were offered to the larvae of the phytophagous insect Spodoptera litura Fabricius for 3 generations. Nickel accumulations in the 6th instar larvae, pupae and newly emerged adults of the corresponding generations of S. litura were investigated by Inductively Coupled Plasma-Atomic Emission Spectrometer (ICP-AES), and the effects of nickel accumulations on the survival rate of S. litura were also evaluated by individual rearing. The results showed that nickel accumulated in the 6th instar larvae, pupae and adults of S. litura, and the accu- mulated nickel in all the tested developmental stages within a generation increased with the increase of the nickel doses in the treated diets and showed significant dose-dependent relationship with the nickel doses in the artificial diets. The results also indicated that the nickel accumulations in the 6th instar larvae, pupae, and newly emerged adults from the 3rd generation were higher than those from the 2nd generation, which were also higher than those from the 1st generation. Nickel concentrations in pupae and adults were significantly lower than those in larvae, which indicated that the excessive nickel might be excreted during metamorphosis. Furthermore, larval survival rate, pupation rate and eclosion rate of S. litura in the tested three generations all decreased with the increase of the nickel doses in the treated diets. 相似文献
997.
加热率对比及大气加热性质的研究 总被引:1,自引:0,他引:1
首先对比分析了气候平均的ERA与NCEP再分析的全球加热率资料,以及两套资料在青藏高原地区的差异。发现在全球范围内,主要差异在于ERA的总加热率比NCEP的总加热率普遍要大,NCEP资料优于ERA资料。再利用NCEP资料分析高原的加热性质及加热的季节变化规律,发现对于青藏高原主体(80-100°E、27.5-37.5°N)而言,平均的辐射冷却全年少变;高原在夏季表现为强大的热源主要由潜热加热引起,感热加热次之,冬季的冷源则以辐射冷却为主,过渡季节的急剧变化主要因感热的变化引起。 相似文献
998.
通过在马弗炉内以及循环流化床内对单元垃圾(土豆块)进行干燥试验,分别获得了其在炉内的干燥特性曲线.试验结果显示,在马弗炉内低温区干燥温度对垃圾干燥过程的影响较大;在同一干燥温度下,随着垃圾厚度的增加,干燥时间近似呈指数形式增加;在干燥的大部分阶段,土豆块内温度随含湿量减少呈逐渐上升趋势.在循环流化床内,土豆块的整个干燥过程中只有降速段,而不存在恒速段和初始段,垃圾厚度对干燥过程有显著影响. 相似文献
999.
1000.
针对信号自适应chirplet分解未知参数多、实现起来比较困难的特点,提出了一种新的chirplet分解快速算法.该算法利用计算信号的二次相位函数,得到其能量分布集中于信号的调频率曲线上的结论,此时通过谱峰检测可同时获得chirplet调频率、时间中心和幅度的估计;然后通过解线性调频技术获得其初始频率和宽度的估计.仿真结果验证了本文算法的有效性. 相似文献