Congestion and Fiscal Policy in a Two-Sector Economy with Public Capital: A Quantitative Assessment

This paper analyzes the role of public capital when the services it yields is subject to two forms of congestion, which we characterize as relative and aggregate. We employ a two-sector growth model in which there are conventional profit-maximizing private firms, together with “public firms”, whose objective is to produce a specified quantity of government investment goods – determined by government policy – at minimum cost. We characterize the equilibrium dynamics, and analyze two forms of fiscal disturbances – an increase in public investment, and a decrease in the tax on capital income – by simulating a calibrated economy. We contrast the effects of these two types of congestion on both the existing steady-state equilibrium, as well as for the effectiveness of fiscal policy.     

营养液低氧胁迫对网纹甜瓜幼苗生长和生理代谢影响

在水培条件下,研究了营养液低氧胁迫对网纹甜瓜幼苗生长指标、光合作用和生理代谢物质含量的影响。结果表明,低氧处理显著抑制了幼苗的生长,鲜重、干重等生长指标和叶绿素含量、净光合速率等光合指标均显著降低;低氧胁迫诱导幼苗不定根和根系活力显著增加;低氧胁迫下幼苗MDA、H2O2含量显著增加,但是幼苗体内可溶性糖、氨基酸、游离态多胺和热稳定蛋白含量也显著提高。与西域一号相比,星光生长较快,较高的光合速率、根系活力和生理代谢物质含量,缓解了低氧胁迫对幼苗的伤害。     

Nano‐emissive display technology for large‐area HDTV

Abstract— Using nano‐emissive display (NED) technology, Motorola labs has successfully developed 5‐in. full‐color display prototypes. Carbon‐nanotube‐based field‐emission displays with a pixel size of 0.726 mm for a 42‐in. HDTV exhibit video image quality comparable to CRT displays and demonstrate a luminance of 350 cd/m². These novel low‐drive‐voltage NEDs take advantage of selective growth of CNTs to obtain the desired electron‐emission performance while maintaining inexpensive manufacturing due to a simple self‐focusing and self‐regulating planar structure. Improved video image quality and color purity are achieved with very low power consumption and without the need for an expensive focusing grid.     

Assessing the validity of self-reported stress-related growth.

The purpose of these studies was to assess the validity of self-reported stress-related growth (SRG). In Study 1, individuals with breast cancer (n = 70) generally did not report greater well-being than a matched comparison group (n = 70). In Study 2, there were no significant differences in well-being between undergraduate students who said that something positive had come out of their worst stressor (n = 34) and those who reported no positives (n = 34). In Study 3, specific domains of SRG assessed in undergraduate students (n = 96) generally were not uniquely related to corresponding well-being measures. Thus, the authors found fairly little evidence for the validity of self-reported SRG. Future research directions are highlighted. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

10Cr9Mo1VNb钢冲击断裂机理

采用小能量示波冲击法和金相法，研究了10Cr9Mo1VNb钢冲击断裂时裂纹的萌生、生长与扩展．结果表明：10CrgMo1VNb钢裂纹生长机理是裂纹前沿和孔洞之间以颈缩聚合的方式相连，裂纹生长速率缓慢；裂纹扩展其机理是裂纹前沿和孔洞之间以剪切裂纹的方式相连，裂纹扩展速率很快．裂纹的临界破断为尺寸2mm左右，临界冲击功为114J左右。     

分形图像物理机制的系统研究

分形的物理机制是非线性科学研究的重要课题．为了解决这一难题，笔者以广义进化综合理论为基础，以雪花生长模型为研究对象，结合曼德尔布罗特的分形理论，提出了分形图像形成过程的基本原理，即惯性原理，适应性原理，全息原理，二次叠加原理，优化选择原理．从而解释了分形图像生成的成因，为分形的生成机制和分形图像的具体应用提供了理论基础．分形形成过程的这种机制，比其它机制更具体化、更系统化；而且，和相关的实验结果也符合．     

培养条件对褐黄孢链霉菌发酵合成纳他霉素的影响

对褐黄孢链霉菌摇瓶发酵合成纳他霉素的研究表明: 种龄、接种量和装液量对纳他霉素合成的影响显著;在实验范围内,随着种龄、接种量和装液量的增加,纳他霉素产量均表现出先增加后减少的趋势,而菌体干重则变化很小.最适宜产物合成和菌体生长的发酵培养基初始pH值各不相同,分别为7.5～8.0和6.5～7.0.当发酵温度从31℃下降到25℃时,纳他霉素产量大幅度增加,而菌体干重在31℃达到最大值.在种龄48 h、接种量10%、25℃、初始pH值 7.6、装液量10%的优化条件下,纳他霉素最高产量达到1.5 g/L, 基于菌体干重的产率为4.917%.     

加氢反应器接管裂纹的疲劳扩展分析

为了预测焊接构件在中温环境下的疲劳裂纹扩展寿命，提出了一组新的疲劳裂纹扩展方程.采用紧
凑拉伸（CT）试样，对2.25Cr1Mo钢在室温和420℃时的疲劳裂纹扩展速率进行了测试研究，通过速率试验
值的回归分析，推导了两种温度下疲劳裂纹扩展速率方程，并利用该方程计算了一台加氢反应器接管焊缝
部位浅长表面裂纹的疲劳扩展量和表面裂纹临界长度，对扩展后的裂纹进行了安全评估.研究结果表明，
420℃时2.25Cr1Mo钢的疲劳裂纹扩展速率高于室温，反应器接管焊缝处的裂纹疲劳扩展不会威胁其使用安
全性，该扩展方程的计算结果具有较好的准确性和可靠度，可用于该钢种的裂纹疲劳扩展预测和安全评估     

基于虚拟植物生长模型的农业专家系统研究

针对传统农业专家系统存在着缺少动态预测功能及机理性解释的缺点,提出一种虚拟植物生长模型和农业专家系统的集成框架.详细介绍了虚拟植物生长模型的研究概况,着重论述了基于虚拟植物生长模型的农业专家系统体系结构以及各组成部分的功能.在此基础上,进一步讨论了新型农业专家系统的开发原则.虚拟植物生长模型和农业智能系统的有机集成,可以帮助推理机获得推理决策所必需的数据;此外,模型的预测结果与专家经验知识进行有效协同融合,可以实现定性决策与定量决策推理的有机结合,降低系统决策的风险性.     

互联电力系统新增发电装机同用电量增长的优化模型及实证研究

如何以最小发电装机增长来换取最大社会用电量增长是电力供需形势紧张环境下值得研究的问题。对于孤立系统而言,问题研究相对简单;而在多区域互联电力系统中,问题的研究变得相对复杂。在构建模型的基础上提出一种新的研究方法,即通过联网输送到某地区的电量或在已联网基础上增加的外送电量可等效为该地区当年新增发电量,将这部分新增电量累积到实际新增发电机组发电量上,则相当于提高了这些新增发电机组的年平均利用小时数。年平均利用小时数提高有效缓解了电量短缺矛盾,更大程度地满足用电需求。多区域互联电力系统中,各子系统之间互为备用,系统总容量备用率呈下降趋势。最后通过实例分析验证了该方法的可行性,此方法在联网论证和后评估工作中具有一定实用价值。