女性时代风貌与“剩女”择偶模式——基于传统择偶模式的社会学分析

随着传媒的推波助澜,＂剩女＂话题日益成为关注的焦点,既展现出女性择偶变迁的事实,又呈现了女性的择偶窘境。这一现象需要遵循社会学研究的社会事实——逻辑诊断——范式建构——策略选择这一技术路径,探究当代＂剩女＂现象的生成机理、现实运行与调适机制。通过对传统择偶模式的社会学梳理,可以揭示其对都市女性择偶适用的现代症结,从科学发展观视界探寻当代女性择偶模式的变革。     

Residential Location,Job Location,and Wages: Theory and Empirics

I develop a stylized partial on‐the‐job equilibrium search model that incorporates a spatial dimension. Workers reside on a circle and can move at a cost. Each point on the circle has a wage distribution. Implications about wages and job mobility are drawn from the model and tested on Danish matched employer–employee data. The model predictions hold true. I find that workers working farther away from their residence earn higher wages. When a worker is making a job‐to‐job transition where he/she changes workplace location he/she experiences a higher wage change than a worker making a job‐to‐job transition without changing workplace location. However, workers making a job‐to‐job transition that makes the workplace location closer to the residence experience a wage drop. Furthermore, low‐wage workers and workers with high transportation costs are more likely to make job‐to‐job transitions, but also residential moves.     

KCLO3晶体偏光干涉特性的测试研究

通过对KCLO3晶体的110生长晶面的透射光谱的测试,发现在平行检偏的情况下,KCLO3晶体的偏光干涉会随其厚度和入射角的增加而逐渐消失,并且存在消偏光干涉特性的平面。这些现象表明,KCLO3晶体中的双折射光束电矢量的振动方向与入射的线偏振光电矢量的振动方向间夹角,随晶体的方位而改变。     

磷酸体系的平衡计算及磷酸银生成条件的探索

本论文对0.100mol/LNa_3PO_4、Na_2HPO_4、NaH_2PO_4三种盐溶液与AgNO_3溶液反应生成Ag_3PO_4沉淀时,所需AgNO_3溶液的最低浓度进行了理论计算和实验探索。     

FIRM DEFAULT AND AGGREGATE FLUCTUATIONS

This paper studies the relationship between macroeconomic fluctuations and corporate defaults while conditioning on industry affiliation and an extensive set of firm‐specific factors. By using a panel data set for virtually all incorporated Swedish businesses over 1990–2009, a period which includes a full‐scale banking crisis, we find strong evidence for a substantial and stable impact from aggregate fluctuations on business defaults. A standard logit model with financial ratios augmented with macroeconomic factors can account surprisingly well for the outburst in business defaults during the banking crisis, as well as the subsequent fluctuations in default frequencies. Moreover, the effects of macroeconomic variables differ across industries in an economically intuitive way. Out‐of‐sample evaluations show that our approach is superior to models that exclude macro information and standard well‐fitting time‐series models. Our analysis shows that firm‐specific factors are useful in ranking firms’ relative riskiness, but that macroeconomic factors are necessary to understand fluctuations in the absolute risk level.     

DOES IDIOSYNCRATIC BUSINESS RISK MATTER FOR GROWTH?

Several imperfections can prevent entrepreneurs from diversifying away the idiosyncratic risk of their business. As a result idiosyncratic risk discourages entrepreneurial activity and hinders growth, with the effects being stronger in economies with lower risk diversification opportunities. In accordance with this prediction, we find that OECD countries with low levels of risk diversification opportunities (as measured by the relevance of family firms or of widely held companies) perform relatively worse (in terms of productivity, investment, and business creation) in sectors characterized by high idiosyncratic risk. Differently from previous literature, we allow risk to be country specific. Since risk is endogenous to risk diversification opportunities, we instrument its value using sectoral risk in the United States, a country where idiosyncratic business risk can be more easily diversified away. Tackling the endogeneity of risk and recognizing that it varies by country magnifies the estimated effects of risk on growth.     

WHY DO EMERGING ECONOMIES BORROW SHORT TERM?

We argue that one reason why emerging economies borrow short term is that it is cheaper than borrowing long term. This is especially the case during crises, as during these episodes the relative cost of long‐term borrowing increases. We construct a unique database of sovereign bond prices, returns, and issuances at different maturities for 11 emerging economies from 1990 to 2009 and present a set of new stylized facts. On average, these countries pay a higher risk premium on long‐term than on short‐term bonds. During crises, the difference between the two risk premia increases and issuance shifts towards shorter maturities. To illustrate our argument, we present a simple model in which the maturity structure is the outcome of a risk‐sharing problem between an emerging economy subject to rollover crises and risk‐averse international investors.     

专业化·互联化·平台化：5G时代县级融媒体深度融合发展路径

推动县级融媒体深度融合发展是加强和改进新闻舆论工作的现实需要,也是完善国家治理体系和提升国家治理能力的必然要求。5G技术的应用为推动县级融媒体深度融合发展创造了历史性机遇。以增强型移动宽带、低功耗大连接、高可靠低时延等为特征的5G技术对媒体融合会产生革命性影响。这种影响主要体现在生产流程重塑、呈现方式升维、用户需求预知、媒介场域扩张四个方面。在5G时代,专业化、互联化和平台化将成为县级融媒体深度融合发展的必由之路。要真正实现此“三化”发展,县级融媒体建设应该解决好思维转型、破圈融合和平台治理三个关键问题,即要避免智能技术与专业理念的脱钩,打破连接至上与技术壁垒的迷关以及规制权利博弈与隐私使用的问题。     

Fe_3O_4@SiO_2-TiO_2磁性介孔复合材料光催化降解亚甲基蓝的性能研究

染料废水处理是水污染治理中非常重要内容之一,针对染料废水带有极高的色度、可生化性差和含"三致"物等特点。本文采用水热法制备复合材料用于染料废水处理。通过XRD、TEM、SBET等表征手段证实制备材料为核-壳Fe3O4@SiO2-TiO2复合材料。将此材料用于染料废水处理,选用亚甲基蓝(Methylene Blue,简称MB)作为染料废水典型目标物,测定催化剂Ti:Si摩尔比、催化剂用量、染料溶液pH值和催化剂重复利用对染料废水降解效果影响。研究结果表明,染料废水浓度为14mg/L,双氧水用量为2mL,催化剂用量为2g/L,脱色90min时,溶液脱色率能达到98.6%。催化剂重复使用4次,其脱色效果仍然保持在90%左右。由此可见,用此方法制备的核-壳材料是比较有效且实用的一种染料废水处理非均相Fenton催化剂。     

CLUSTERING IN N‐PLAYER PREEMPTION GAMES

We study a complete information preemption game in continuous time. A finite number of firms decide when to make an irreversible, observable investment. Upon investment, a firm receives flow profits, which decrease in the number of firms that have invested. The cost of investment declines over time exogenously. We characterize the subgame‐perfect equilibrium outcome, which is unique up to a permutation of players. When the preemption race among late investors is sufficiently intense, the preemption incentive for earlier investors disappears, and two or more investments occur at the same time. We identify a sufficient condition in terms of model parameters: clustering of investments occurs if the flow profits from consecutive investments are sufficiently close. This shows how clustering can occur in the absence of coordination failures, informational spillovers, or positive payoff externalities.