汽车空气滤清器数值仿真分析与结构改进设计

降低空气滤清器流动阻力是提高滤清效率、延长滤清器寿命、提高发动机动力性与经济性的主要方法。利用计算流体力学(Computational Fluid Dynamic,CFD)数值仿真分析方法对某型号汽车空气滤清器进行流动阻力仿真分析与研究。通过调整滤清器的进气角度以及圆角设计,提高了滤清器内部气流流动的均匀性,有效降低了滤清器的流动阻力。     

软聚硅酮泡沫吸收敷料(美皮康)治疗压疮的循证药物经济学研究

目的 综合评价软聚硅酮泡沫吸收敷料(美皮康)在压疮治疗中的有效性与经济性.方法 通过文献研究,进 行规范化系统评价,结合临床治疗数据,应用决策树模型进行成本效果分析.结论 研究结果表明美皮康在产品疗效、综合成本和改善患者疼痛等诸多因素上的表现与传统的无菌纱布相比存在明显优势.     

论中西部农村土地承包经营权流转的制约因素与破解对策——以湖北、贵州两省的实证调研为依据

通过实证考察湖北、贵州两省近几年农村土地承包经营权流转的现状及对其成因的探析可以发现,中西部地区的农村要达致土地承包经营权规模化经营的理想状态,还有诸多制约因素有待克服。破解之道主要在于应构建有利于促进土地承包经营权流转的配套制度,营造有利于土地承包经营权流转的社会条件和经济环境。     

Mapinfo在区域城市环境质量评价中的应用

本文探讨了基于Mapinfo的城市环境质量评价研究思路,在明确评价单元划分和评价方法的基础上,以各个省区地级以上城市作为分析样本,通过对评价区城市环境质量状况的综合评价实证研究,结果表明:Mapin-fo的应用可以有效支持这一评价过程,它能够将数值计算与图形处理有机的结合起来,使评价工作更加简洁、直观、高效和易于操作。     

人口老龄化背景下提升我国城镇职工养老保险统筹层次分析及建议

我国自2000年起进入人口老龄化社会,近年来人口老龄化趋势持续上升,提升基本养老保险制度的保障能力成为急需,其中,提高基本养老保险的统筹层次为完善养老制度的步骤之一.2011年,中共中央在"十二五"规划中做出明确指示,由社会统筹账户中的基础养老金部分率先实行全国统筹,但在具体实施过程中却有一定困难.实现城镇职工养老保险的全国统筹需要突破当前存在的瓶颈问题,采取切实可行的举措.     

Exchange and refund of complementary products

A common dilemma a consumer faces during product return pertains to the decision of exchanging the product or obtaining a refund. This issue becomes even more salient for durable goods, when the initial purchase involves complementary products from different categories. This research examines consumer’s trade-off decision between returning and keeping complementary products by exploring various retail actions (using umbrella branded products (UBP)) and customer characteristics. We also investigate the trade-off between product exchange and refund when consumer returns a product. We find interesting extensions to past research wherein UBP are returned less and result in greater exchange than refund. Furthermore, an interesting caveat is that higher degree of complementarity between UBP intensifies the impact of various factors on exchange as opposed to refund of products. Implications for retail managers and sales teams are explored.     

Guanxi,political connections and resource acquisition in Chinese publicly listed private sector firms

In this study, we examined the role of guanxi as entrepreneurs’ resource-obtaining mechanism in private sector firms, using a data-set of 184 publicly listed firms in China. We found that guanxi indeed played a positive role that helped private sector firms gain easier access to resources. We also found that guanxi exerted even a greater positive effect on private sector firms’ resource obtaining compared to entrepreneurs’ political participation, due to being the lifeblood of business conduct and social interaction in Chinese culture.     

Do ongoing networks block out new friends? Reconciling the embeddedness constraint dilemma on new alliance partner addition

Research Summary: This study addresses a theoretical dilemma regarding how alliance network constraint (reflected by network cohesion) affects a firm’s alliance formation with new partners. Using a network pluralism approach, we separate a firm’s ego alliance network into two activity‐based networks—an exploratory network and an exploitative network—based on the primary value chain activity involved in each alliance. We argue that the cohesion of exploratory or exploitative networks has an inverted U‐shaped effect on the addition of new partners in the same activity‐based network, and a positive effect on the addition of new partners in the other network. Results based on data from the biotechnology industry largely support our predictions with one exception. Our study contributes to both scholarly understanding of network embeddedness and alliance practice. Managerial Summary: The structure of firms’ ongoing alliance networks may have paradoxical implications for their efforts to search for and form alliance with new partners. That is, when a firm’s alliance partners are tightly connected with each other, the cohesive network tends to both encourage and impede the focal firm to add new partners. We resolve this dilemma by showing that when a firm is deeply entrenched in a cohesive alliance network conducting a certain type of activities (e.g., R&D activities), it may not easily add new R&D alliance partners. However, it may still be able to escape from the cohesive R&D alliance network by seeking new partners conducting other activities (e.g., manufacturing activities).     

Box-Behnken响应面法优化徐长卿配方颗粒挥发油-β-CD包合物制备工艺

为了解决徐长卿挥发油加油难及加入后的稳定性问题,采用Box-Behnken响应面法,优选出徐长卿配方颗粒挥发油-β-CD包合物的制备工艺。在单因素试验的基础上,采用3因素3水平Box-Behnken设计对徐长卿配方颗粒挥发油-β-CD包合工艺进行优选,以挥发油包合率及包合物收率为考察指标,考察挥发油与β-CD比例、包合温度、包合时间对结果的影响。结果表明:优选的包合工艺条件为挥发油与β-CD质量比为1∶8.34,包合温度为50.2℃,包合时间为2.17 h。在此条件下,挥发油包合率为72.19%,包合物收率为75.06%,综合评分为96.41,RSD值为1.1%。优选的包合工艺包合率高,工艺稳定可行,可为配方颗粒挥发油的工业化生产提供数据支持。