对B_2H_6、B_3H_5和B_4H_6分子结构的对比研究

为了正确理解氢桥键的本质,采用MP2/6-31＋＋（D,P）方法对B2H6,B3H5和B4H6分子的结构进行了研究。比较了这3种分子中处于分子平面上下方的两个氢原子的距离变化引起的各原子带电情况的变化图和分子轨道图,结果显示,在某种程度上,B3H5和B4H6中分子平面上下方的两个氢原子具有类似B2H6分子中两个桥氢原子的性质,并在此基础上通过B2H6,B3H5和B4H6的分子轨道图得出了这3种分子中的氢桥键结构均可以看成π键电子云吸附两个带正电的质子构成的结论。     

从格式塔“场”理论谈选项安排对考生的心理影响——基于大学英语四、六级分题选择MC

从格式塔"场"原理看大学英语过级考试中完形填空的选项安排对考生的心理影响.并通过问卷调查证实该现象存在的现实性和正确性.试图通过此类调查和研究对我国过级考试中完形填空的命题提出自己的看法.     

小麦-簇毛麦端体附加系中6V端体的细胞遗传学行为及其在Moisson 6MV/6B中的传递

簇毛麦6V染色体上携有抗白粉病基因Pm21.本研究利用抗白粉病小麦-簇毛麦单端体和双端体附加系(2n=42+1t和2n=42+2t)为材料,通过自交,观察后代植株6V端体出现频率,以评价外源染色体在小麦背景中的遗传平衡程度及稳定性,为利用培育小麦-簇毛麦导入系提供理论依据.通过对自交群体植株根尖细胞染色体数观察,发现在双端体附加系(2n=42+2t)自交群体(F2)中,2n=42+2t,2n=42+1t,2n=42的出现频率分别为51.92%,40.38%和7.7%;在单端体附加系(2n=42+1t)的F2群体中,2n=42+2t,2n=42+1t,2n=42的出现频率分别为1.85%,17.59%和80.56%.χ2检验表明(χ20.01=0.000),两自交群体问6V端体传递能力存在显著差异,6V端体的传递能力与亲本携带的端体数密切相关,双端体附加系在减数分裂时主要形成n+t配子,而单端体附加系则形成n和n+t两种配子,n+t配子参与受精的竞争能力主要取决于6V端体的遗传平衡程度,单端体附加系自交群体中的6V端体出现频率较低.这表明6V端体可能携有较多的不利基因导致n+t配子竞争能力较差.小麦-簇毛麦6V双端体附加系Pana(2n=42+2t)6VS在Moisaon 6MV/6B中通过雌雄配子传递频率研究发现,6VS通过雌配子的传递频率(33.33%)远高于通过雄配子的传递频率(4.87%).这也与其抗病性鉴定结果一致.此外,还发现以Pana(2n=42+21)为母本获得了小麦-偏凸山羊草-簇毛麦三属杂种,而以Pana(2n=42+2t)为父本却未能获得小麦-偏凸山羊草-簇毛麦三属杂种,暗示Pana(2n=42+2t)附加端体可能对花粉育性有一定不利影响.     

A note on the queue with a random set-up time under a restricted admissibility policy with a Bernoulli vacation schedule

This paper deals with the queue size distribution of an M^x/G/1 queue with a random set-up time and with a Bernoulli vacation schedule under a restricted admissibility policy. This generalizes the model studied by Madan and Choudhury [Sankhyá 66 (2004) 175–193].     

适当浓度的调节剂和活性炭对粉蕉组培的影响

粉蕉组培中,以MS为基本培养基,附加6-BA 6mg/L,NAA 0.4mg/L的配比可获4倍的月增殖率,且瘤状芽率较低;生根培养基添加活性炭有效抑制褐变.     

Do greater amounts of FDI cause higher pollution levels? Evidence from OECD countries

Using an ARDL model for a panel of 15 OECD countries, this work analyses the impact that FDI, both jointly and by sector, has on CO₂ emissions. The findings reveal that these countries are yielding to the pressure on the trade sector. Unexpectedly, gross fixed capital formation shrink pollution, excluding in the mining sector. With findings supporting the Pollution Haven Hypothesis, policymakers must pay attention to FDI inflows, ensuring that FDI place high importance on the transfer of green technologies to improve the efficiency. These goals could be achieved through an increase in the stringency of environmental laws within the host countries, especially the ones related to FDI.     

促进3-6岁儿童人格特质培育的微型戏剧游戏活动设计与实施

3-6岁儿童人格品质的发展对于幼儿一生的可持续发展具有重要作用,本研究尝试以微型戏剧游戏为载体,通过确立人格特质培育目标,创编有人格陶冶意义的戏剧故事,遵循重视情境导入、引导感受音乐、互动创编故事、组织戏剧表演和反思提升的五步骤活动流程,以及营造故事情境、优化游戏环节、树立典型榜样、巧设两难情境、发挥正向激励、践行人格行为六类实施策略来帮助幼儿发展积极人格特质。研究表明,微型戏剧游戏作为开展人格培育活动的有效载体,对促进幼儿自护、勇敢、交往、关怀、诚信、合作等积极人格特质的养成具有积极成效。     

Extending social security coverage to the rural sector in China

In late 2009 China launched an innovative, voluntary programme that by 2011 had extended pension coverage to 326.4 million people in the rural sector, including contributors and beneficiaries. It requires one contribution per year and provides a flat‐rate benefit and a contributions‐related benefit through a contributory individual account, with a government guarantee that the benefit will continue for life. The programme encourages participation of persons who do not pay income taxes, and thus have no tax incentive to participate, by providing substantial government subsidies. As a further incentive, old‐age benefits are provided to older parents when all their adult children participate in the contributory programme.     

Does trust increase willingness to pay higher taxes to help the needy?

The article studies the causal effect of trust on the willingness to pay higher taxes to help the needy in a sample of 29 countries of Eastern and Southern Europe, and the former Soviet Union and Mongolia. It is hypothesized that interpersonal trust leads to a greater willingness to pay taxes to help the needy since (i) trust increases the likelihood of helping strangers; (ii) trust fosters solidarity and cooperation when working to solve common problems in society; and (iii) trust reduces suspicion with respect to the perceived misuse of redistributed money. Three key findings are that the more people trust each other, the more they are ready to support the welfare state; the effect of trust on welfare state support holds even in a contextual environment characterized by rather lower levels of trust and relatively underdeveloped systems of redistribution; and higher individual‐level trust fosters tax morale and helps deter tax evasion.     

An optimal design for process quality improvement: modelling and application

Existing research works on process quality improvement focus largely on the linkages between quality improvement cost and production economics such as set-up cost and defect rate reduction. This paper deals with the optimal design problem for process improvement by balancing the sunk investment cost and revenue increments due to the process improvement. We develop an optimal model based on Taguchi cost functions. The model is validated through a real case study in automotive industry where the 6-sigma DMAIC methodology has been applied. According to this research, the management can adjust the investment on prevention and appraisal costs on quality improvement that enhances process capability, reduces product defect rate and, as a result, generates remarkable financial return.