一种基于神经网络和遗传算法的桥梁加速度传感器优化布置方法

为实现桥梁加速度传感器的优化布置, 提出一种基于神经网络和遗传算法的布置方法。利用ANSYS软件建立桥梁模型并获得模态数据,通过随机生成大量布置方案及对应MAC值形成数据集,并建立双隐藏层的神经网络模型进行训练,将训练好的模型利用遗传算法搜索出最优值及对应的布置方案,最后对结果进行了分析,表明该方法可行。     

直激式压电风能捕获器的性能分析与实验

提出一种由压电梁及其端部附加质量构成的直激式压电风能捕获器。在考虑了压电振子静平衡变形的基础上,根据涡激振动理论建立了柔性压电振子的自激振动理论模型并进行了仿真分析,获得了压电梁厚度比、附加质量及风速对其发电性能的影响规律。结果表明,存在最佳的压电梁厚度比使输出电压、电能及功率最大,电压/电能/功率所对应的最佳厚度比分别为0.5/0.65/0.65。其它参数确定时,存在最佳风速/附加质量使输出电压最大,且最佳风速随附加质量增加而降低、最佳质量随风速增加而降低。制作了风能捕获器样机并进行了试验测试,风速为4.8/7.2/10m/s时,对应的最佳附加质量及最大电压分别为15/11/7g和1.9/3.94/6.18V;风速为10m/s时,10g附加质量下的输出电压为0/20g附加质量下的4.1/1.2倍。结果证明根据实际风速范围确定合理的附加质量可提高发电能力。     

基于数值模拟的级进模筒形拉深工步工艺分析

在带有拉深工步的级进模设计中，用数值模拟技术对其拉深工步进行工艺分析是非常重要的。由于级进模中的拉深工步要受到其他工步的牵制，其拉深成形比单个零件的拉深要困难一些，因此在对拉深工步的工艺性进行数值模拟时，所建立的毛坯几何模型、边界条件和压边条件等也都与单工序模有差别。结合某工厂的攻关项目，运用ANSYS对级进模中筒形拉深工步的成形性能和数值模拟的关键技术进行了研究，经生产实际验证，该分析过程合理、准确。     

Controlling Reaction Pathways for Alcohol Dehydration and Dehydrogenation over FeSBA-15 Catalysts

The iron location in FeSBA-15 strongly influences the selectivity to dehydrogenation and dehydration in ethanol conversion. At low iron loading, Fe is present as isolated $\hbox{Fe}^{3+}The iron location in FeSBA-15 strongly influences the selectivity to dehydrogenation and dehydration in ethanol conversion. At low iron loading, Fe is present as isolated species in the amorphous silica phase. At higher loading additional aggregated forms of iron oxide exist. Isolated species in the silica matrix imply Br?nsted acidity resulting in selective formation of ethylene, whereas clusters catalyze formation of ethylene and aldehyde.     

各类CAPP比较及混合法探讨

CAPP有自动化型CAPP和工具型CAPP两大类,前者侧重于研究工艺创成的技术,后者侧重于发展实用化、商品化的CAPP产品。本文着重叙述了各类CAPP的工作原理,比较了它们的优点,举例说明了各类CAPP的局限性。在此基础上,探讨了混合式CAPP模型。混合式CAPP兼有智能性和易实现性的特点,能充分发挥工艺人员和计算机各自的特长。     

风力作用下大气颗粒物凝聚生长Monte Carlo模拟

在扩散限制凝聚(DLA)模型的基础上,考虑风力作用对大气颗粒物凝聚生长过程的影响,建立了关于风力作用下大气颗粒物凝聚生长模拟模型。在VC++6.0下成功实现了大气颗粒物凝聚生长的模拟,并对结果进行了分析和讨论。实验表明,模拟方法能在普通微机上较好实现大气颗粒物凝聚生长过程的模拟,能动态观察大气颗粒物凝聚生长过程,实时性较好。     

Electrochemical and optical properties of biphenyl bridged-dicarbazole oligomer films: Electropolymerization and electrochromism

4,4′-Di(N-carbazoyl)biphenyl monomer (CBP) was synthesized and coated onto ITO–glass surface by electrochemical oxidative polymerization. Its CV shows two distinct one-electron and stepwise oxidation processes occurred at 1.29 and 1.61 V. By using this property, the monomer was electrochemically polymerized separately at these oxidation states and thus, two different oligomer films were obtained afterwards. Their spectro-electrochemical and electrochromic properties were also investigated. Switching ability of the oligomers was evaluated by kinetic studies upon measuring the percent transmittance (%T) at their maximum contrast point, indicating that these oligomers were found to be suitable material for electrochromic devices.     

Calcium-sensing receptor gene polymorphisms and cardiac valvular calcification in patients with chronic renal failure: A pilot study

Cardiac valvular calcification (VC) is a frequent finding in chronic hemodialysis patients. In addition to demographic and metabolic factors, genetic susceptibility may also influence the occurrence and severity of these abnormalities and account for interindividual variability among patients. In this report, we studied the relation of calcium-sensing receptor (CaSR) gene polymorphisms to the development of VC in chronic hemodialysis patients. A total of 41 chronic hemodialysis patients (26 male, mean age 47.23 ± 11.36 years vs. 15 females, mean age 48.13 ± 14.66 years) undergoing treatment for more than 1 year were evaluated with transthoracic echocardiography. In patients with and without VC, CaSR gene polymorphisms (A990G, C1011G) were investigated by PCR, using allele-specific primers. In randomly chosen subjects, PCR analysis was verified by DNA sequencing. Cardiac valve calcification was detected in 21 patients (51.2%). Five of these patients (12.2%) had mitral valve calcification, 4 (9.75%) had aortic valve calcification, and 12 (29.27%) had both. In patients with VC, the frequency of the A/G genotype was slightly higher than those with no VC with a borderline P value (42.9% vs. 15%, χ²=3.840, P=0.050). The frequency of the C/C genotype was similar in patients with and without VC (90.5% vs. 85%, P>0.05). The results of this study are not enough to prove the role of CaSR gene polymorphisms in the development of VC. There is a need for large-scale studies on this topic.     

Sectoral analysis for international technology development and transfer: Cases of coal-fired power generation,cement and aluminium in China

The sector-based decisions in Bali Action Plan have made “cooperative sectoral approaches and sector-specific actions” one of the most promising ways to achieve substantial progress in technology transfer. This paper makes a more fundamental examination of the intrinsic characteristics, ongoing mitigation efforts, and mitigation difficulties and barriers in China's principle energy-intensive sectors, hoping to lay a foundation of using “cooperative sectoral approaches and sector-specific actions” to enhance international technology development and transfer. It is found that great mitigation achievements had been made in coal-fired power generation, cement and aluminium sectors through various policies. About 420 million tons (Mt), 234 and 48 Mt of CO₂-e have been reduced, respectively, from 2001 to 2007. However, factors such as fast-growing development needs, low-quality resources and carbon-intensive energy mix, huge disparities within sector, poor technology, equipment and financial status of plants, low level of employers’ abilities as well as huge social costs are causing big difficulties and barriers to further mitigate sectoral greenhouse gas in China. Therefore it is strongly advocated that the existing and possible new sectoral approaches try to consider these factual barriers as comprehensively as possible. Finally the paper concludes with two fields of future work to do.     

Analysis of the economic impact of different Chinese climate policy options based on a CGE model incorporating endogenous technological change

Abatement cost is the main concern for climate change mitigation and the key factor for mitigation cost is technological change. This study established an integrated economic, energy, environmental, dynamic, computable general equilibrium (CGE) model representing endogenous technological change for China's climate change policy analysis. This study analyzed and compared the economic impact of different approaches to mitigation commitments as well as the potential role of technological change in the formulation of mitigation targets and commitments, taking into account China's climate policy-making needs based on the current international climate negotiation process. The results show that, absolute emission limits similar to the Kyoto Protocol will seriously impede the future economic development of China, while the impact of an 80% reduction in carbon intensity, forecast for 2050 based on the 2005 level, is relatively small. Technological change can promote economic growth, improve energy efficiency and reduce carbon intensity per unit of output through the substitution of production factors. Consequently it can reduce marginal abatement cost and related GDP loss by mitigation. At the same time it can increase mitigation potentials and extend the emission reduction amount, showing that consideration of the impact of technological change when deciding the emission reduction targets is necessary.