船舶结构焊接结晶裂纹的产生与防止

焊接结构中焊接裂纹经常出现,其中结晶裂纹是最容易产生的一种裂纹。本文介绍了焊接结构中结晶裂纹产生的原因,并提出了有效的预防措施。     

How much can we trust China’s investment statistics?

Abstract

Building upon recent research into the underestimation of China’s official final consumption expenditure, this paper investigates the quality of China’s investment data. We strictly follow the official method to estimate the annual gross fixed capital formation (GFCF) expenditure from 2004 to 2012, and the resulting figures are significantly different from the official statistics. This implies that the ‘total investment in fixed assets’ data, which are the primary source for the estimation of GFCF, grossly exaggerate actual investments, and that the official GFCF figures are not, strictly speaking, independently estimated, as they are purported to be. We deduce that the official gross capital formation figure is more or less a residual item obtained by subtracting final consumption and net exports from the official GDP figure that is calculated based on the production-cum-income approach. As a result, the underestimation of China’s consumption expenditure automatically translates into overestimation of investment expenditure. We conclude that China’s official consumption and investment statistics cannot be trusted as the basis for policy discussions and academic research.     

Internal habits formation and optimality

In a very influential model with internal habits, Carroll et al., (2017, 2000), establish that an increase in economic growth may cause a positive change in savings. The optimality of this result, and of many other contributions using a similar framework, has been questioned by some authors who have observed that the parametrization used in these models always implies a utility function not jointly concave in consumption and habits. In this paper, we revisit the optimality issue and, using advanced techniques in Dynamic Programming, we answer the following long-standing open questions: (i) Is the solution found in Carroll et al., (2017, 2000) optimal? (ii) Is it also unique or do other optimal solutions exist?     

Partner‐diversity effects on alliance termination in the early stage of green alliance formation: Empirical evidence from carbon‐emission reduction projects in Latin America

Partner diversity is a key influencer in interorganizational alliances, and several empirical studies have shown that its outcomes are contingent on alliance‐specific factors. We extend this research as well as the growing literature on green alliances, in which partner diversity is uniquely high. Specifically, we examine partner‐diversity effects on alliance termination in the early stage of green alliance formation. We hypothesize that in this context, size disparity increases termination likelihood, whereas organizational variety and cultural separation have the opposite effect. To test our hypotheses, we use a sample of 366 alliance projects located in Latin America and submitted to the Kyoto Protocol's Clean Development Mechanism for evaluation, validation, and registration from 2004 to 2014. Our findings contribute to several research streams and provide practical guidance for successful formation of alliances focused on environmental protection.     

A one-sided many-to-many matching problem

This study discusses a one-sided many-to-many matching model wherein agents may not be divided into two disjoint sets. Moreover, each agent is allowed to have multiple partnerships in our model. We restrict our attention to the case where the preference of each agent is single-peaked over: (i) the total number of partnerships with all other agents, and (ii) the number of partnerships that the agent has with each of the other agents. We represent a matching as a multigraph, and characterize a matching that is stable and constrained efficient. Finally, we show that any direct mechanism for selecting a stable and constrained efficient matching is not strategy-proof.     

Migration,Friendship Ties,and Cultural Assimilation

We study immigrant assimilation by analyzing whether friendship with natives is a measure of cultural assimilation, and by investigating the formation of social ties. Using the German Socio‐Economic Panel, we find that immigrants with a German friend are more similar to natives than those without German friends, along several important dimensions, including concerns about the economy, an interest in politics, and a host of policy issues. Turning to friendship acquisition, we find that becoming employed, time spent in the host country, the birth of a child, residential mobility, and additional education acquired in the host country are significant drivers of social network variation.     

重复扰动下富含水地层的加固技术

随着城市地铁、地下空间、铁路和公路隧道的大规模建设和发展,工程中要面对的各种复杂地层的地基处理及松软地层改良问题越来越多。文章结合广州市轨道交通5号线(大坦沙～中山八盾构区间)2#联络通道塌方后,在重复扰动的富含水地层进行加固处理的成功经验,详细地介绍了采用无收缩双液二重管注浆技术在重复扰动下富含水地层中的注浆加固方法。     

Labor Income Taxation,Human Capital,and Growth: The Role of Childcare*

In this paper, we examine the effects of labor income taxation on growth in an overlapping generations model in which schooling and childcare play a role in the production of human capital. We compare such effects with those obtained in a model in which only schooling matters for skill formation. We show that the omission of childcare from the technology of skill formation can bias the results related to the impact of labor income taxation on growth.     

金融发展与中国的经济增长——从储蓄动员型向市场配置的消费型经济转变

隐形税收机制瓦解后,储蓄动员型的金融发展模式取代了财政投资的主导地位,通过金融支持政策为公有经济部门融资,支撑了经济的高速增长。然而,随着市场约束机制的变化,金融支持政策的收益逐渐下降,成本却在递增。本文认为储蓄动员型的金融支持政策在一定阶段促进了经济的发展,但是也伴随着一系列经济发展的成本,比如降低了资本配置效率,过度投资产生的宏观经济成本和经济持续增长的外部风险加大等。因此,中国金融体制应深化改革,提高金融体系的资本配置效率,促进技术进步和生产效率的改进。同时,通过发展消费信贷和商业保险,减少信贷约束和不确定性,推动消费型经济的增长。     

高校财务风险的形成机理及防范机制分析

大量举债、资金运营以及学费拖欠等给高校财务管理带来极大风险。构建高校财务风险防范机制必须发挥政府主导作用,在加大教育经费投入的基础上规范高校办学规模;引导社会力量进入办学领域,在营造社会办学环境的基础上拓宽筹资渠道;建立现代大学制度,在规范管理的基础上强化内部监督;提高银行向高校贷款的门槛,在严格控制贷款规模的基础上落实还款渠道。