Role of humidity on the structures and properties of regenerated silk fibers

Silk fiber was processed from highly concentrated spinning dope to solid fibers along with water removal. To understand the mechanism of water removal during silk fiber spinning process, a microfluidic chip was designed and applied to investigate the structures and mechanical properties of two kinds of regenerated silk fibroin fibers dry-spun at different relative humidity. The experimental results showed that the diameters of the fibers spun at 40% RH are always larger than the fibers spun at 50% RH due to different removal rates of water. The fibers spun at low humidity contain more β-sheet structure and lower degree of chain orientation and crystalline orientation. These results indicate that the fast phase transition of silk fibroin from sol–gel to silk fiber undergoes with rapid water removal and higher fiber orientation relates to more residue water and drawing force.     

基于SEM建模的后效能写作授受建构轨迹研究

以写作教学为切入点,通过对平行班40名学生为期1年半的实验,研究了教师指导下后效能写作授受建构的效能性.实验借助在期初、期末及期后分别进行的相关测试和问卷分析进行因子设定和建模测算,来测试创新模式对ESL习得者写作力后效能作用的轨迹.研究表明,本写作授受建构通过形成良好课堂环境和提高习得者写作思辨力,对ESL习得者写作能力提高确具较高效能.实验模式能在期后继续有效整体提高平行班ESL习得者写作能力,对习得者写作素质提高颇有裨益.研究表明此模式对学生整体写作素质提高具有长效性,特别是对中高级习得者效果明显;SEM介入性研究可以为相关研究提供有益借鉴.     

Modeling Default Dependence with the Mixture of Calendar Time and Business Time

Evaluating default correlation between securities in a portfolio is very important for credit derivatives pricing and risk management. Under the framework of the structural model proposed by Black and Cox, we assume that the asset values of companies are driven by Brownian motions in the worlds of the calendar time and the business time; they then could evolve continuously or by leap. We build the dynamic default correlations using the time-varying correlated Brownian motions in these processes. The sensitivity of default correlations to the key parameters is explored in the paper by numerical examples, and we apply the model to risk management as well. Because default times are unpredictable in the proposed model, the defaults might occur suddenly. Independent defaults and complete correlated defaults can be described in the model as well.     

基于EPR的供应链治理机制博弈分析

研究了生产者责任延伸(EPR)制度背景下的供应链系统中主体决策影响因素和治理机制的融合问题,基于供应链治理和博弈的理论视角,构造了个体生产者责任(IPR)模式下的非合作博弈模型和集体生产者责任(CPR)模式下的合作博弈模型,分别得出了IPR和CPR模式下企业污染治理技术的最佳决策.研究结果表明,企业的污染治理决策主要取决于企业之间生产技术的差距,以及相互依赖程度.强技术差距和强依赖性更容易导致CPR模式的产生;反之,IPR模式更容易出现在低依赖性和实力相当的企业当中.最后总结了EPR制度下供应链系统动态均衡治理的内部效率机制和外部合法性机制.     

IKONOS影像融合技术对比研究

本文以赣州市章贡区工业园某时期IKONOS影像数据为基础,采用Brovey变换,G-S变换,PC变换,P-S变换4种方法进行融合比较,然后通过主观和客观两方面对融合效果进行对比评价。通过实验对比分析可得,4种融合方法均提高了影像的纹理光谱信息,但P-S变换法融合的IKONOS影像效果突出,较高程度地保持了纹理和分辨率的空间信息,是保持空间信息综合效应的最佳方法。     

陕北志丹地区长6低电阻率油层成因机制研究

低电阻率油藏作为一种非常规油藏已被人们所认知,由于成因机制复杂,识别难度大,常被人们遗漏或错判。为了详细研究陕北志丹地区低电阻率油层的成因机制,以长6储层为研究目的层位,采用实验分析、测井曲线重叠法、交会图等方法,建立相关的平、剖面图,并结合研究区试油试采成果,对长6储层低电阻率油层的成因机制进行了深入分析。认为志丹油区低阻油层发育众多,资源潜力大,约占其总储量的40%,分布广泛,成因机制复杂,很难用常规方法进行识别;多数油层电阻率主要介于2~21Ω·m之间,甚至小于0.6Ω·m.最终得出沉积砂体控制作用、岩性细,束缚水饱和度高、粘土附加导电性和高放射性砂岩是长6低电阻率油层发育的主要因素;由于区域地质状况的差异,初步探索出了适合研究区的低电阻率油层识别标准,以便为以后研究低阻油藏提供参考与借鉴。     

TDLAS湿度传感器与维萨拉湿度传感器性能对比研究

水汽含量对于诸如文物保护、气象、工业生产等领域都有明确标准并需要严格控制,因此能够精确和快速的实现环境湿度监测已成为一大研究热点.现在常用的湿度传感器为芬兰VAISALA生产的湿度传感器系列,但是其测湿部分采用聚合物高分子薄膜电容传感器,存在响应时间长,褪湿慢等缺点,已经不能满足用户需求.基于TDLAS技术的湿度传感器使用半导体激光器作为光源,参考气室提供光谱调节反馈,构成了一种高精度水汽含量检测系统,响应速度快,灵敏度高,可以克服传统湿度传感器的不足.该文以米歇尔露点仪为标准,对比测试了TDLAS湿度传感器与传统的VAISALA电容传感器响应时间、测量精度等性能.证明了TDLAS湿度传感器具有更好的测量准确度与灵敏度.     

基于交通信号灯信息的混合动力汽车节能预测控制方法

针对传统混合动力汽车控制方法不考虑已知道路交通信号灯信息对车辆能量管理影响的问题,提出了基于交通信号灯信息的混合动力汽车节能预测控制智能优化策略。通过建立混合动力汽车系统的简化模型,并采用连续广义最小残量方法求解模型预测控制问题。运用MATLAB/Simulink进行仿真,仿真结果验证了交通信号灯信息模型的有效性,以及所设计的模型预测控制算法大幅度提高混合动力汽车的燃油经济性的能力和实时控制性能。研究结果表明所提出的控制策略可以实现车辆行驶轨迹的优化控制,显著提高了车辆的燃油经济性,并满足系统的实时最优控制要求。     

刚果盆地的棘管轮属(轮虫门;单巢亚纲;棘管轮科)

研究了2010年4月到5月和2012年6月二次采集自刚果盆地的水样，共发现棘管轮属Mytilina Bory de St. Vincent 1826的8个种，其中2个种 M. crassipes (Lucks, 1912) 和 M. trigona (Gosse, 1851) 是非洲新纪录种； M. macrocera (Jennings, 1894)和 M. bisulcata (Lucks, 1912)是刚果盆地多个样点的常见种； M. ventralis (Ehrenberg, 1830)和M. trigona,在刚果盆地个别样点比较多见；M. michelangllii Reid     

PRICE AND SERVICE COMPETITION WITH MAINTENANCE SERVICE BUNDLING

In many equipment manufacturing industries,firms compete with each other not only on products price,but also on maintenance service.More and more traditional products oriented firms are offering their customers products bundled with maintenance service(P&S bundles).In this study,we examine firms’ incentive to offer customers products bundling with long-term maintenance or repair support service in a duopoly competitive environment.When providing P&S bundles,a firm need to determine the service level(in terms of average response time guarantee for the service in this paper) to offer and needs to build a service facility to handle the maintenance service requirements.Based on the analysis of three sub-game models,we characterize the market conditions in which only one firm,both firms or neither firm will offer P&S bundles.Finally,we analyze the affects of serval market factors on firms’ strategy choices.