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741.
742.
Delphi自版本4就开始提供一组新的构件MIDAS,使用它,可以方便地开发具有三层体系结构的数据库应用程序。本文分析了MIDAS构件组的开发原理,并以起重机为例,论述了开发基于三层结构的起重机零部件管理系统的基本步骤,并详细讨论了开发中三层结构的实现过程。 相似文献
743.
对履带式推土机行走机构的振动特性进行测试 ,建立起推土机缓冲系统模型 ,经对模型特性参数对传递率影响的分析 ,确定出参数的合理值域。把阻尼材料诺模图曲线数字化 ,做到了计算机对诺模图动态曲线的自动查询 ,实现了阻尼缓冲结构的动态优化。掌握了阻尼缓冲结构的设计理论和方法 ,已应用于 2 4 2kW履带式推土机粘弹性悬挂机构的开发。 相似文献
744.
基于多层前馈型神经元网络模型的摄像机定标算法 总被引:2,自引:0,他引:2
针对传统线性、非线性摄像机定标算法的鲁棒性,提出了基于多层前馈型神经元(MLFN)网络模型来替代传统精确的摄像机定标数学模型,MLFN网络模型作为层状网络可实现任意维复杂的输入/输出映射,对于无需计算摄像机构,外参数的应用场合,该模型提供了一种实用且有较好鲁棒性的摄像机定标算法,同时为了补偿摄影机非线性畸变,把图像按畸变程度分割成两个区域,分别建立各自基于MLFN网络的摄像机定标模型,实验表明,该方法有效补了畸变,并提高了模型精度,给出了基于MLFN网络模型摄像机定标算法实验,验证了该模型的有效性。 相似文献
745.
746.
Li Jin |chai Guo Huai |xi Lu Xian |feng Zhang Zhi |hong Ye Ming |sheng School of Physics Technology Wuhan University Wuhan Hubei China 《武汉大学学报:自然科学英文版》2003,8(3):821-824
0 IntroductionArtificialarthrosiseshavebeenwidelyusedintheoperatorsclinicalsurgeriesforthepatientswhosearthrosiseswerese riouslyseverelydamaged.Butmostofartificialarthrosisescanon lybeusedforabouttenyearslongduetotheseriousabrasion .Forthisreason ,theimprovementofthelongevityofartificialarthrosisbecomesanimportantsubjectofstudy .TheartificialarthrosisesbeingmadeupofTialloyTC4(Ti 6Al 4V)andthepolythenewithultrahighmolecularweighthavegreatpotentialitiesonim provinglongevitybecauseTC4canreac… 相似文献
747.
Iron in surface seawater has been demonstrated to be the limiting nutrient factor for primary productivity in certain oceanic regions where other major nutrients are abundant[1—5]. The available Fe to the phytoplankton in seawater is related to the uptake of carbon dioxide through the ocean and, in turn, to the global greenhouse effect[6—11]. Recent reports showed that the available Fe in the seawater is closely correlative to nitrogen fixation in the ocean[12—17]. Understanding which Fe s… 相似文献
748.
<Emphasis Type="Italic">In situ</Emphasis> generation and detection of methyl radical by voltammetry
The chemistry of free radicals is one of the advanced subjects of fundamental sciences such as biomedicine, environment protection, new energy sources and new material. The detection technique of free radicals is an essential tool for studying free radicals. Methyl radical is one of the representatives of alkyl radicals and the studies on it attract more attention. The current approaches to obtaining methyl radical are based on pulse radiolysis of organic substances that contain the methyl gro… 相似文献
749.
TANG Zhiwen WANG Kemin TAN Weihong LI Jun LIU Lingfeng GUO Qiuping MENG Xiangxian HUANG Shasheng LI Du & LUO Weifang State Key Laboratory of Chemo/Biosensing Chemometrics Institute of Biological Technology College of Chemistry Chemical Engi-neering Hunan University Changsha China Correspondence should be addressed to Wang Kemin 《科学通报(英文版)》2003,48(12):1215-1218
The replication, ligation and repair of nucleic acids are essential life processes that based the survival, pro-creation and evolution of creatures. These interactions involving proteins (enzymes) and nucleic acids have fas-cinated great interest of scientists[1]. The nucleic acids ligation has been revealed that it is catalyzed by ligase and co-enzyme (ATP or NAD)[2—4]. Along with in-depth re-search, the nucleic acids ligation becomes a significant and common tool employed in bioengineerin… 相似文献
750.
The effect of sodium nitroprusside (SNP), a donor of nitric oxide, on meiotic maturation of mouse oocytes was studied by injecting Nw-nitro-L-arginine methyl ester (L-NAME) intra-peritoneal (ip), a nitric oxide synthase inhibitor, or culturing oocytes in the medium supplemented with L-NAME or hypoxanthine (HX) to arrest the spontaneous oocyte maturation in vitro. The results showed that the inhibitory effect of L-NAME by injecting 10 mg/kg ip on extrusion of the first polar body only could be reversed by injecting 2.5 mg/kg SNP with L-NAME simultaneously (P < 0.05). Half an hour later ten mice died when given 10 mg/kg SNP ip. The treatment of some concentrations of SNP (10–7, 10–6, 10–5mol/L) significantly stimulated meiotic maturation to metaphase Ⅱ stages in cumulus enclosed oocytes in the presence of HX. However, other concentrations of SNP (10–8, 10–4, 10–3 mol/L) had no effect on HX-arrested oocyte meiotic maturation. The optimal concentration of SNP on CEOs had no effect on DOs. The dose of 10–3 mol/LL-NAME demonstrated a significant suppression in formation of PB1, but not in GVBD. This inhibition was reversed by the addition of SNP. These results indicated that the physiological levels of NO produced by cumulus cells could stimulate meiotic maturation of mouse oocytes both in vivo and in vitro. 相似文献