西气东输工程用感应加热弯管技术条件探讨

在对国外X70管线弯管技术条件进行调查分析与研究的基础上，对其中的几个关键技术问题包括母管成分，弯管的制造工艺和技术路线，强度与韧性要求，屈强比，Cu污染问题等进行了讨论。一些观点在西气东输感应加弯管技术条件中得到应用。     

75kW中频感应加热电源的研制

针对中频感应加热电源对油田油井加热问题,本文采用PWM控制技术实现了功率可调。为使系统的功率因数较高,采用串联谐振和频率跟踪技术。中频感应加热电源采用IGBT作为开关器件,可工作在10 Hz-10 kHz频段。它充分利用中频趋肤效应、邻近效应和圆环效应原理,通过感应加热器和油管柱,使电能有效的转化为热能,从而达到原油降粘降稠、稳产高产的目的。     

Modeling and Measuring Economic Reality: Reply to the Reviews

To begin with, we'd like to express our appreciation to our three commentators for their thoughtful and helpful reviews. Like the founders of the subject, we believe, and our reviewers seem to agree, that structural econometrics has the potential to enable us to develop serious working models of how different economies actually operate, and also to tell us something about the changing patterns of their growth and transformation. But both we and our reviewers agree that there is a great deal wrong with the way econometrics is practiced today.     

Does foreign investment benefit the exporting activities of Vietnamese firms?

Using firm-level data, this paper examines the effects of foreign investment on the exporting behaviour of domestic firms in the Vietnamese manufacturing and service sectors. Applying the Heckman selection model on panel data and following the Wooldridge approach, we find that investment by foreign firms has a significant positive effect on the decision of domestic firms in the same and upstream sectors to export. The proportion of exports of domestic firms declines through horizontal and forward linkages, but increases through backward linkages in the manufacturing sector. However, there is only weak evidence in support of export spillovers on domestic firms in the service sector. We also find that the presence of foreign firms has differing effects on the exporting activities of low- versus high-tech firms in the manufacturing sector.     

Optimal investment-consumption-insurance with random parameters

This paper discusses an optimal investment, consumption, and life insurance purchase problem for a wage earner in a complete market with Brownian information. Specifically, we assume that the parameters governing the market model and the wage earner, including the interest rate, appreciation rate, volatility, force of mortality, premium-insurance ratio, income and discount rate, are all random processes adapted to the Brownian motion filtration. Our modeling framework is very general, which allows these random parameters to be unbounded, non-Markovian functionals of the underlying Brownian motion. Suppose that the wage earner’s preference is described by a power utility. The wage earner’s problem is then to choose an optimal investment-consumption-insurance strategy so as to maximize the expected, discounted utilities from intertemporal consumption, legacy and terminal wealth over an uncertain lifetime horizon. We use a novel approach, which combines the Hamilton–Jacobi–Bellman equation and backward stochastic differential equation (BSDE) to solve this problem. In general, we give explicit expressions for the optimal investment-consumption-insurance strategy and the value function in terms of the solutions to two BSDEs. To illustrate our results, we provide closed-form solutions to the problem with stochastic income, stochastic mortality, and stochastic appreciation rate, respectively.     

落后小经济实体的产业结构协调——以四川省南充为例

落后小经济实体的特性与其所处的大环境决定了其产业结构的不协调。就业困难成为落后小经济实体的一大隐患。南充作为小经济实体的典型代表 ,其现期产业结构的逆转 ,预示着其不可能跨过“第二产业 >第三产业 >第一产业”的阶段。轻型工业和服务业是解决其就业矛盾的关键。从某种意义上说 ,轻型工业起到了一个桥梁的作用 ,它使第一产业的人口顺利流向第三产业。     

新疆旅游业投入产出分析

本文以新疆2002年和2007年投入产出表为依据,从直接消耗系数和完全消耗系数、感应度系数和影响力系数以及投入产出乘数效应这三方面对新疆旅游业进行投入产出分析后发现,新疆旅游业对新疆经济的推动作用有限,旅游业自身的发展依赖于交通运输业、批发零售业、住宿餐饮业及交通运输设备业的发展,且旅游业的发展并未带来交通运输业的显著发展。     

农村区域性公共品有效供给的新视角——基于浙江村级公共品供给的调研

实现农村公共品有效供给一直是三农问题关注的焦点,而且政府承担着主要的供给责任。对于具有需求偏好差异的农村区域性公共品而言,政府完全主导的供给模式却是导致效率损失的主要原因。正是基于这一点考虑,并结合浙江省村级公共品的调研,本文提出实现农村区域性公共品有效供给的新模式———政府诱导供给模式,即通过税收惠免、财政奖补等激励政策,诱导私人或村集体积极参与农村区域性公共品供给,弥补县级政府效率损失。     

基于价格折扣的物流服务供应链协调模型研究

在一个物流服务集成商与一个物流服务提供商及一个客户构成的物流服务供应链中,文章建立了各个利益主体的利润模型及物流服务供应链的整体利润模型,并分别求解了其最优解,通过对模型的分析和求解,得出各个利益主体与整体供应链的最优解存在矛盾。为了协调这个利益矛盾,提出了利用价格折扣契约来对物流服务供应链进行协调,并计算得出价格折扣系数的取值范围,最后给出了算例以证明这种契约对物流服务供应链的协调具有有效性。