转轴上裂纹的产生及其应力分析

转轴运转时由于应力的作用而产生裂纹，裂纹扩展、加深易使轴断裂，通过对裂纹的产生和扩展分析，确定危险截面，运用断裂力学理论对裂纹处的应力强度因子和应力状况进行分析，计算出转轴的临界裂纹。防止突然断裂。并举例验证．     

大断面黄土隧道加宽过渡段变形特性三维数值分析

针对三车道公路隧道加宽段空间跨度大,加宽过渡段设计难度大的难题。以某三车道黄土隧道为依托,采用三维有限元仿真的方法,对加宽过渡段的支护结构和围岩的变形规律进行了研究。研究结果表明：加宽过渡段处初支结构的变形呈现不对称性。距过渡段10 m范围以外加宽段围岩变形趋于对称。加宽段施工对正常段的围岩变形影响较小,对加宽段围岩的影响范围约为10 m。故在三车道公路隧道的加宽段施工过程中,除加强支护外,距离过渡断面的前10 m加宽段施工应提高监控量测频率。     

在全球化进程中融合:基于高校大学生洋节与中华传统节日的对比

洋节和传统节日并非完全对立的矛盾,是全球化进程中一种必然的碰撞和融合现象。通过问卷调查和数据分析,将大学生过洋节与过传统节日行为进行对比,深入挖掘大学生对中西方节日的了解和重视程度,大学生过节的行为习惯,探索根本原因。研究发现:第一,对大学生而言,我国节日文化的教育和传承情况没有我们想象中的那么糟糕,有一定问题存在。第二,西方节日虽在我国大学生中有着普遍高的认知和参与程度,但是未与传统节日文化产生冲突。第三,正确引导大学生培养节俭朴实节日消费观,不要奢侈浪费,要重视节日文化传承意义。第四,面对新潮的西方节日,我们也不应一味抵制,应该正确引导,培养大学生正确的节日观念,让洋节成为传统节日的一种有效补充。     

VARIANCE ESTIMATION IN THE ERROR COMPONENTS REGRESSION MODEL

ABSTRACT

In a regression model with a random individual and a random time effect explicit representations of the nonnegative quadratic minimum biased estimators of the corresponding variances are deduced. These estimators always exist and are unique. Moreover, under normality assumption of the dependent variable unbiased estimators of the mean squared errors of the variance estimates are derived. Finally, confidence intervals on the variance components are considered.     

欠发达地区农业产业化经营的模式与对策选择

从发达国家和地区农业发展的经验角度,提出欠发达地区农业发展的新机制是实现产业化经营,并分析了农业产业化经营的经济结构调整、组织模式选择以及基层政府在农业产业化经营过程中的职能转变,特别是有利于推动农业产业化经营的农地制度创新和提供农村公共产品等问题.     

劳动经济学研究的新进展

作为经济学的主要分支学科,劳动经济学近年来在就业失业理论、人力资本投资理论、劳动力市场的分割与歧视、收入分配理论和工会与罢工理论等方面,在理论、实证和政策研究方面都取得了不少研究成果.国内学者的研究在研究方法上逐渐完成与国际的接轨,并在对转轨时期的中国劳动力市场的分析与研究上逐步形成自己的特色,其研究成果对发展中国家和经济转型国家具有一定的启示意义.     

Midwives’ views of an evidence-based intervention to reduce caesarean section rates in Ireland

ProblemA worldwide increase of caesarean section (CS) rates has been estimated at a rate of 4% per year and numerous interventions to reduce the rates have not been successful, perhaps because they are not acceptable to clinicians.BackgroundA caesarean section (CS) can be a life-saving operation, but has been associated with short- and long-term risk factors and shown to affect subsequent pregnancies.AimTo explore midwives’ views on CS rates and evaluate the feasibility and acceptability of an evidence-based intervention programme (REDUCE) designed to decrease overall CS rates in Ireland by 7%.MethodsFollowing ethical approval, a qualitative exploratory design was used to seek midwives’ views of the evidence-based intervention. A total of 28 midwives from one large tertiary maternity hospital took part in four focus group interviews. Data were analysed using thematic analysis.FindingsFive themes emerged, illustrating the midwives’ views of what could be improved in the present system and how CS rates could be reduced in future. The themes included: (i) Induction of labour; (ii) Education; (iii) Auditing of practice; (iv) Clinical practice; (v) Midwife-Obstetrician collaboration.DiscussionThis study noted a rising CS rate year on year, with a rate of 37% at the time of the study, and the midwives voiced their very real concerns over the increased high rates.ConclusionThe study provided support for the evidence based ‘REDUCE’ intervention, which now needs to be tested empirically within this Irish population.     

椭圆气缸内燃机的稳流试验及其性能预测

本次稳流试验用来预测新颖的椭圆气缸往复式内燃机的性能。实测数据和分析结果表明,椭圆截面气缸内燃机此起等容积正圆截面气缸内燃机,增大了进、排气门,从而提高了充气效率;或在充气效率不减的条件下,大幅度提高转速或增压,以实现发动机的高强化。     

Midwifery continuity of care and vaginal birth after caesarean section: A randomised controlled trial

Problem and backgroundCaesarean section (CS) rates in Australia and many countries worldwide are high and increasing, with elective repeat caesarean section a significant contributor.AimTo determine whether midwifery continuity of care for women with a previous CS increases the proportion of women who plan to attempt a vaginal birth in their current pregnancy.MethodsA randomised controlled design was undertaken. Women who met the inclusion criteria were randomised to one of two groups; the Community Midwifery Program (CMP) (continuity across the full spectrum — antenatal, intrapartum and postpartum) (n = 110) and the Midwifery Antenatal Care (MAC) Program (antenatal continuity of care) (n = 111) using a remote randomisation service. Analysis was undertaken on an intention to treat basis. The primary outcome measure was the rate of attempted vaginal birth after caesarean section and secondary outcomes included composite measures of maternal and neonatal wellbeing.FindingsThe model of care did not significantly impact planned vaginal birth at 36 weeks (CMP 66.7% vs MAC 57.3%) or success rate (CMP 27.8% vs MAC 32.7%). The rate of maternal and neonatal complications was similar between the groups.ConclusionModel of care did not significantly impact the proportion of women attempting VBAC in this study. The similarity in the number of midwives seen antenatally and during labour and birth suggests that these models of care had more similarities than differences and that the model of continuity could be described as informational continuity. Future research should focus on the impact of relationship based continuity of care.