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991.
根据消防车活荷载的作用特征分析指出,该项活荷载应取荷载的偶然组合参与结构构件的承载能力极限状态验算;应取荷载的频遇组合参与结构构件的正常使用极限状态验算。以常用的柱网尺寸为8.4m×8.4m的全埋式地下车库为例,讨论了地下室顶板分别采用单向板、双向板和无梁楼盖方案时消防车轮压的最不利布置方式。并采用SAP2000有限元软件中的薄板单元模型分析推导出相应的消防车活荷载的等效均布荷载值。与规范将消防车活荷载视为一般活荷载而提供的建议值相比,本文提供的意见无论在荷载组合概念上,还是在消防车等效均布荷载取值上更显科学合理,且其在工程上的应用具有较大的经济效益与社会效益。 相似文献
992.
<正>都江堰虹口距成都市约80km,因避暑及漂流而成为成都的旅游胜地,生态旅游中心选址于虹口风景区深溪沟。项目分两期,一期为深溪沟接待点,由香溪行馆(别墅区)和香溪堂(服务配套建筑,190m~2)组成,二期为虹口旅游服务中心及酒店。香溪堂作为接待、休闲之用,规模很小,功能简单,但业主极为重视,把它作为二期启动前的形象展示,希望设计理念先进,独具个性。业主于2007年10月正式委托我们设计一期工程,原计划2008年6月动工。5月12日突如其来的汶川大地 相似文献
993.
Wei Dai Milenkovic O. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》2009,55(5):2215-2229
We introduce a new family of codes, termed weighted superimposed codes (WSCs). This family generalizes the class of Euclidean superimposed codes (ESCs), used in multiuser identification systems. WSCs allow for discriminating all bounded, integer-valued linear combinations of real-valued codewords that satisfy prescribed norm and nonnegativity constraints. By design, WSCs are inherently noise tolerant. Therefore, these codes can be seen as special instances of robust compressed sensing schemes. The main results of the paper are lower and upper bounds on the largest achievable code rates of several classes of WSCs. These bounds suggest that, with the codeword and weighting vector constraints at hand, one can improve the code rates achievable by standard compressive sensing techniques. 相似文献
994.
Qiu Tong Wu Qingzhi Dai Honglian Wang Xinyu Wang Youfa Li Shipu Li Junli 《Journal of materials science. Materials in medicine》2014,25(8):1915-1923
A comparative study was performed to investigate the ultrastructural and biomolecular properties of osteoblasts induced by three types of single-walled carbon nanotubes (SWNTs). The results on cellular uptake and ultrastructural alteration indicate that SWNTs enter osteoblasts by endocytosis. SWNTs-COOH and SWNTs-OH particles were freely dispersed in the cytoplasm, while pristine SWNTs were localized to the periphery of the cell. Both SWNTs-OH and SWNTs-COOH promoted cell changes in cell activity regarding mRNA expression at doses of 50 and 100 μg/mL in the first 24 h. When treated with 50 μg/mL SWNTs-COOH for 48 h, the expression of type I collagen increased by 6.3-fold (for MG63) or 9.1-fold (for primary osteoblasts) compared with the control group. The present study observed for the first time that SWNTs-COOH initiated the prompt and the maximum upregulation of type I collagen gene expression, and simultaneously induced the expansion of the endoplasmic reticulum for increased protein synthesis, which in turn accelerated the mineralization process. However, impaired cell properties and mitochondrial injury were detected following treatment with SWNTs at 100 μg/mL after 48 h. In conclusion, we believe that SWNTs-COOH is a good candidate for the fabrication of biomedical scaffolds for bone regeneration. 相似文献
995.
螺旋管中间介质气化器可行性研究 总被引:1,自引:0,他引:1
A novel intermediate fluid vaporization (IFV) technology for LNG re-gasification process with spiral-wound heat exchanging tubes is proposed. The new IFV project combines the advantage of running the shell and tube heat exchangers at high pressure with the advantage of compact space of heat exchangers. Thermal analysis on the two processes of forced convection and vaporization type heat transfer in the spiral wound tubes and vapor condensation /re-boiling type of heat transfer via intermediate fluid in shell side shows the feasibility of this promising technology. 相似文献
996.
目的:建立血液中佐匹克隆全自动固相萃取高效液相色谱-三重四级杆串联质谱(LC/MS/MS)检测方法。方法:采用全自动固相萃取进行提取,用Oasis HLB固相萃取柱,使用二氯甲烷洗脱。洗脱物浓缩后用Eclipse Plus C18柱(3.5μm×2.1×100mm)分离,LC/MS/MS分析。结果:采用本文方法检测血液中佐匹克隆的检出限为0.1ng/ml,回收率大于90.0%。结论:本方法具有操作简单、灵敏度高和重现性好等优点,可应用于血液中佐匹克隆的检验鉴定。 相似文献
997.
998.
999.
Shiru Jia Baoqing Fan Yujie Dai Guoliang Wang Peng Peng Yuanyuan Jia 《Food science and biotechnology》2010,19(2):361-366
ɛ-Poly-l-lysine (ɛ-PLL) produced by Streptomyces albulus CGMCC 1986 was fractionated using ultra-filtration technique with 2 and 5 kDa cut-offs of membrane. The number-average molecular
weight of each fraction was determined by 1H nuclear magnetic resonance (NMR) method. The number-average molecular weights of the cutoffs of 5 and 2 kDa and the filtrate
are 4,230.95, 3,687.80, and 1,900.82 Da, respectively. 1H NMR indicates the chemical shifts of α-H, β-H, γ-H, δ-H, and ɛ-H are very similar to all the fractions. Fourier transform-infrared
(FTIR) spectra showed that the ɛ-PLL solid samples obtained by freeze-drying at pH 5 with molecular weights higher than 2
kDa take on a β-turn conformation, however, the fraction with molecular weight smaller than 2 kDa adopts random coil structure.
The antibacterial test proved that the fraction between 2 and 5 kDa of membranes behaves the highest antibacterial activity
than other fractions for the test strains of Staphylococcus aureus, Micrococcus luteus, Bacillus subtilis, Escherichia coli, and Shigella. 相似文献
1000.
Shelly Hogan Hyun Chung Lei Zhang Jianrong Li Yongwoo Lee Yumin Dai Kequan Zhou 《Food chemistry》2010,118(2):208-214
An anthocyanin-rich extract, generated from açai (AEA), was investigated for its antioxidant properties and antiproliferative activity against C-6 rat brain glioma cells and MDA-468 human breast cancer cells. AEA has an ORAC value of 2589 μmoles trolox equivalents (TE)/g dried powder and a DPPH radical-scavenging activity of 1208 μmoles TE/g, suggesting that AEA is an exceptional source of natural antioxidants. In addition, AEA remarkably suppresses proliferation of C-6 rat brain glioma cells, but has no effect on the growth of MDA-468 human breast cancer cells. Further experiments demonstrated that the AEA treatment dose-dependently inhibited the growth of C-6 rat glioma cells with an IC50 of 121 μg/ml. The DNA ladder fragmentation results indicated that AEA induced apoptosis of C-6 rat brain glioma cells. To compare açai with other anthocyanin-rich extracts, a number of berry extracts, including blueberry, strawberry, raspberry, blackberry and wolfberry, were assessed for potential antiproliferative activity against C-6 rat brain glioma cells. However, none of them showed suppressing effect. The results suggest that the active antiproliferative constituents in AEA are unlikely to be anthocyanins normally found in common berries. 相似文献