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991.
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
992.
YU DanMi XIAO SuYao TONG ChunYi CHEN Lin LIU XuanMing 《科学通报(英文版)》2007,52(21):2913-2918
Dialdehyde starch nanoparticles (DASNP) were prepared by the redox reaction of NaIO4 and starch in water-in-oil microemulsion. IR spectrum showed that DASNP had aldehyde groups, and quantitative alkali consumption showed that its dialdehyde content was about (50±5)%. The average diameter of DASNP determined by SEM was about 100 nm. TGA-DTA showed that its thermal stability was better than starch nanoparticle (StNP) and dialdehyde starch (DAS). Its low biological toxicity was detected by cell experiment. Also the best mass ratio of doxorubicin (DOX) to combined DASNP detected by UV-VIS was 15 : 1, and the product was effective for controlled release of DOX. The cell experiment showed that the drug-carrier particle (DOX-DASNP) can release DOX for a long time and strengthened the effect of the anticancer drug. This work demonstrates that the DASNP, which has good thermal stability, small particle size, low biological toxicity, and slowly anticancer drug-releasing to strengthen drug effect, is a potentially useful carrier for anticancer drug. 相似文献
993.
DONG Dong ZHOU Bing Jing-Dong J. HAN 《科学通报(英文版)》2007,52(21):2938-2944
Protein-protein interaction networks serve to carry out basic molecular activity in the cell. Detecting the modular structures from the protein-protein interaction network is important for understanding the organization, function and dynamics of a biological system. In order to identify functional neighbor- hoods based on network topology, many network cluster identification algorithms have been devel- oped. However, each algorithm might dissect a network from a different aspect and may provide dif- ferent insight on the network partition. In order to objectively evaluate the performance of four com- monly used cluster detection algorithms: molecular complex detection (MCODE), NetworkBlast, shortest-distance clustering (SDC) and Girvan-Newman (G-N) algorithm, we compared the biological coherence of the network clusters found by these algorithms through a uniform evaluation framework. Each algorithm was utilized to find network clusters in two different protein-protein interaction net- works with various parameters. Comparison of the resulting network clusters indicates that clusters found by MCODE and SDC are of higher biological coherence than those by NetworkBlast and G-N algorithm. 相似文献
994.
From deep basin gas to diagenetic trap—An example from the Yulin Gas Field in the Ordos Basin 总被引:1,自引:0,他引:1
ZHANG LiuPing LUO XiaoRong MA XinHua CHEN MengJin WU MingHui 《科学通报(英文版)》2007,52(21):2973-2983
In the updip portion of the Yulin Gas Field in the Ordos Basin, there are no any structural, stratigraphic and sedimentary lithologic seals. Using thin-section petrography, ultraviolet fluorescence microscopy, micro-thermometry and Raman microspectrometry, this paper finds out the diagenetic trap and studies the diagenetic history of this field. It was revealed that three phases of diagenesis and hydrocarbon charging happened in late Triassic, late Jurassic and the end of early Cretaceous respectively. In the first two phases, acid geofluid entered the reservoir and caused dissolution and cementation. Although the porosities had been increased, further compaction accompanying re-subsidence resulted in tight sandstone and conglomerates. Till the end of the early Cretaceous, bulk of gas migrated into the tight reservoir. Cementation, however, kept on in the updip portion of this field due to low gas saturation and formed the diagenetic trap. The mechanism for gas accumulation was changed from deep basin gas to diagenetic trap, which offers a sealing condition that can retain gas for much longer time. 相似文献
995.
Phylogenetic position of sponges in early metazoan evolution and bionic applications of siliceous sponge spicules 总被引:1,自引:0,他引:1
Werner E G MULLER WANG XiaoHong ZENG LingSen Heinz C SCHRODER 《科学通报(英文版)》2007,52(22):3029-3040
Sponges are the oldest and the simplest but not primitive multicellular animals. They represent the earliest evolutionary metazoan phylum still extant. It was a long and painful scientific process to posi-tion the most enigmatic and mysterious metazoan,the Porifera,into their correct phylogenetic place among the eukaryotes in general and multicellular animals in particular. As living fossils,sponges provide the best evidence for the early evolution of Metazoa. More recently,interest has been focused on the bionic applications of sponges' siliceous spicules,after the discovery of their unique structure and high fiber performance. In this review,the emergence of sponges,evolutionary novelties found in sponges,and the phylogenetic position of sponges in early metazoan evolution are highlighted. In ad-dition,the present state of knowledge on silicatein-mediated "biosilica" formation in marine sponges,including the involvement of other molecules in silica metabolism and their potential application in nanobiotechnology and medicine,is given. 相似文献
996.
TIAN He ZHANG YunDong WANG Nan YUAN Ping 《科学通报(英文版)》2007,52(22):3047-3050
In order to control group velocity,an annular chain of microring coupled-resonator optical waveguides was analyzed,and its transmission spectra were obtained using the transfer matrix method. The result showed that the curvature of the chain caused the dispersion curves to shift and the resonance fre-quency got fixed. It is therefore concluded that the group velocity of light in the annular chain of mi-croring coupled-resonator optical waveguides can be controlled by adjusting the curvature of the chain. We believe that such an annular chain can be used as an optical buffer or signal retarder for optical communication. 相似文献
997.
以职业能力为目标的软件专业实践教学改革 总被引:2,自引:0,他引:2
通过软件专业的职业能力分析,围绕软件专业职业能力设计实施实践教学环节,体现工学结合思想,强化职业技能和职业素质的培养。 相似文献
998.
HE Xiaoxia MING Ruixing HU Yijun 《武汉大学学报:自然科学英文版》2007,12(3):412-416
Let u ∈ R ,for any ω 〉 0, the processes X^ε = {X^ε(t); 0 ≤ t≤ 1} are governed by the following random evolution equations dX^ε(t)= b(X^ε(t),v(t))dt-εdSt/ε, where S={St; 0≤t≤1} is a compound Poisson process, the process v={v(t); 0≤t≤1} is independent of S and takes values in R^m. We derive the large deviation principle for{(X^ε,v(.)); ε〉0} when ε↓0 by approximation method and contraction principle, which will be meaningful for us to find out the path property for the risk process of this type. 相似文献
999.
Wavelet Numerical Solutions for Weakly Singular Fredholm Integral Equations of the Second Kind 总被引:1,自引:0,他引:1
TANG Xinjian PANG Zhicheng ZHU Tonglin LIU Jian 《武汉大学学报:自然科学英文版》2007,12(3):437-441
Daubechies interval wavelet is used to solve numerically weakly singular Fredholm integral equations of the second kind. Utilizing the orthogonality of the wavelet basis,the integral equation is reduced into a linear system of equations. The vanishing moments of the wavelet make the wavelet coefficient matrices sparse,while the continuity of the derivative functions of basis overcomes naturally the singular problem of the integral solution. The uniform convergence of the approximate solution by the wavelet method is proved and the error bound is given. Finally,numerical example is presented to show the application of the wavelet method. 相似文献
1000.
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