我院近7年剖宫产率及剖宫产指征变化的临床分析

目的：总结我院近7年剖宫产率及剖宫产指征的变化。方法：回顾性分析我院近7年来剖宫产孕妇的临床资料。结果：剖宫产率逐年升高,2000年为29%,2006年为54.30%,增加1.87倍;2000年-2003年剖宫产的指征难产排第一位,而近3年,社会因素占第一位。结论：剖宫产率升高主要与社会因素有关,降低剖宫产率的关键是严格掌握剖宫产指征,尽量减少因社会因素而行剖宫产术。     

工程哲学与神东亿吨矿区创新实践

工程哲学指导工程实践。神东矿区在煤矿开发建设创新实践中遵循“系统性、客观性、时效性”的理性思维，系统思考，整体推进，寻找主客观最佳结合，及时掌握和集成新技术、新材料、新装备、新工艺，建设了不同于传统模式的千万吨矿井，建成世界上首个亿吨级煤炭生产基地。全员工效、生产规模、安全、环保水平、资源回收率等指标达到国际领先水平。     

Φ12LMQ型钢筋冷拉机原理及主要参数选择

介绍了一种新型钢筋冷拉机的工作原理和主要参数：变形速度Ｖ△Ｌ、单位时间伸长率ε、送进速度Ｖ２、冷拉速度Ｖ１及其之间的关系．这种冷拉机具有生产率高、冷拉质量稳定等特点．     

Subset threshold autoregression

We develop in this paper an efficient way to select the best subset threshold autoregressive model. The proposed method uses a stochastic search idea. Differing from most conventional approaches, our method does not require us to fix the delay or the threshold parameters in advance. By adopting the Markov chain Monte Carlo techniques, we can identify the best subset model from a very large of number of possible models, and at the same time estimate the unknown parameters. A simulation experiment shows that the method is very effective. In its application to the US unemployment rate, the stochastic search method successfully selects lag one as the time delay and five best models from more than 4000 choices. Copyright © 2003 John Wiley & Sons, Ltd.     

新电位溶出分析方法研究

本文对新电位溶出分析方法进行了综述和研究,并着重讨论了流动注射电位溶出分析和间断多次扫描流动注射电位溶出分析.     

缓凝砂浆螺旋输送理论研究

缓凝预应力筋包覆装置是将新型独特的缓凝材料应用于预应力混凝土体系的一种施工设备．通过对缓凝砂浆的流变性能分析，建立了螺旋输送物理模型，运用粘性流体力学的运动微分方程研究缓凝砂浆螺旋输送的速度场和流率，从而对其装置的设计和运行参数的合理选择提供了理论依据．     

试论外币报表折算方法的选择

作为当今国际会计领域公认的三大难题之一，随着经济全球化的迅猛发展，外币报表折算方法的选择显得越来越重要，这也成为了目前会计理论界和实务界一直探讨的焦点之一。在时态法和现行汇率法的争议中，现行汇率法暂时占据上风，也成为我国企业外币报表折算方法的现行选择。     

森林面积分布系统的最优控制存在性问题

本文研究森林面积分布系统的最优控制问题。本文将林木总和长消率作为控制变量，以“范数最小”来衡量其最优性，利用空间Ｌ＾２（０，Ｔ）Ｔ〉０的自反、光滑和严格凸性，给出了森林面积分布系统最优控制的一个存在性定理。     

Juvenile hormone titre and regulation in the cockroachDiploptera punctata

Summary Titres of juvenile hormone (JH) have been determined in both hemolymph and whole body extracts of femaleDiploptera punctata during the first gonotrophic cycle using a method employing gas chromatography/mass spectrometry for qualitative and quantitative analysis. JH III is the sole JH found in both adult and last instarD. punctata. Maximum values of 1500 ng/ml (6M) were observed at the middle of the gonotrophic cycle, when basal oocyte growth rate was greatest. Changes in rates of JH release in vitro by corpora allata paralleled closely the changes in JH titre, suggesting that biosynthesis is a major regulator of titre. JH levels per animal were calculated from observed JH titres, and at certain time points in the gonotrophic cycle JH levels obtained from analysis of whole bodies were significantly greater than those predicted from hemolymph titres. These results suggest the existence of a nonhemolymph JH pool inD. punctata. Decay in JH titre after allatectomy of 5 day females has also been studied. Following a rapid initial decline, the rate of decay slowed appreciably 4 h post-operation. Thus, use of a first-order rate constant to estimate half-life of JH significantly underestimated the longevity of the hormone. The apparent persistence of JH following allatectomy may be due to the existence of a nonhemolymph JH pool.     

一种改进的树形矢量量化编码算法

矢量量化中的一个最严重的问题是在一本码本中搜索最近码字的高计算复杂度。本文在研究树形矢量量化的基础上提出了一种改进的树形矢量量化编码算法。实验结果表明,本文提出的编码算法相对于树形矢量量化算法可大大改善峰值信噪比（ＰＳＮＲ）。