导体旋转双曲面电学量的原模型计算方法

建立带电导体旋转双叶双曲面的原模型,利用原模型计算了导体旋转双曲面的电场、电势和面电荷密度分布,并得到相应的解析表达式.     

2-苯基-5-（6-哒嗪酮-3-基）-1,3,4-噁二唑的分子结构、光谱及热力学性质的理论研究

在B3LYP/6-31＋G＊水平对2-苯基-5-（6-哒嗪酮-3-基）-1,3,4-噁二唑分子进行几何构型优化和频率的计算,得到红外光谱、拉曼光谱和不同温度下的热力学性质.结果显示：该分子的哒嗪环、噁二唑和苯基环在同一个平面上,整个分子不具有对称性;该分子的气态热容、熵、焓等热力学性质与温度之间存在很好的函数关系式.     

不同密度与施肥量对龙花243产量的影响

采用四因子五水平正交回归旋转组合设计,研究龙花243产量与不同种植密度、氮磷钾施肥量(N、P、K)间的关系,建立了各因素与产量指标的优化数学模式,确立了高产优化栽培方案,各因素对产量的影响程度为磷肥>氮肥>钾肥>密度。     

基于能量密度的地图线性要素提取改进算法

在地理图形中,线性特性目标的能量密度与背景图像的能量密度不同,根据这一特性,分析了基于能量密度对线性目标识别算法的不足,提出基于多个模板搜索目标算法,不同的模板应用不同的规则以及自适应的算法,通过仿真实验,该算法能较好地识别出地理图像的目标要素.     

Parzen窗核密度估计的模式分类隐私保护方法

针对大规模数据集上的模式分类任务,提出了一种基于Parzen窗核密度估计的模式分类隐私保护算法。该算法首先利用Parzen窗算法对原始大规模训练集服从的概率密度进行估计,然后根据估计的概率密度函数构造la个替换训练样本,其中l为原始样本的数目,a通过10折交叉验证方式确定。最后发布替换训练样本进行模式分类,以实现原始数据上的隐私保护。在Adult数据集上的仿真实验充分验证了该算法的有效性。     

二甲基硅油的乳化实验

乳化硅油作为消泡剂,在实际的生活生产中有着广泛的应用。在实验的过程中,我们发现硅油的乳化实验受到多种因素的影响,比如各种物质的用量、搅拌的速度等等。     

集群企业技术创新能力的外部影响因素——基于组织间网络的视角

本文运用社会网络理论,以中国高新技术园区中187家企业为样本,分析不同类型的网络联结关系、网络的结构特征以及它们间的交互作用,如何影响企业技术创新能力。研究发现,在企业集群中,企业在供应链网络内的位置中心性对其技术创新能力有正向影响,而企业在连锁董事网络和相互持股关系网络内的位置中心性正向调节纵向供应链网络中心性与技术创新能力的关系。同时,这两类网络的网络密度也对供应链网络与企业技术创新能力的关系起到调节作用。     

Does oligomenorrhoea/amenorrhoea and underweight imply athlete triad syndrome in young female dancers?

Abstract

The aim of this study was to compare the bone mineral density (BMD) of young dancers suspected of suffering from the female athlete triad syndrome and eumenorrhoeic/normal weight dancers with eumenorrhoeic non-exercising controls. Full-time dance students from a collegiate academy of performing arts were recruited. The female athlete triad syndrome was suspected when oligo/amenorrhoea was present together with underweight (body mass index below 18.5 kg · m^?2). The non-exercising group consisted of eumenorrhoeic age-matched patients presenting to an adolescent gynaecology clinic. All participants had a full hormonal profile, pelvic ultrasound, bio-impedance estimation of body fat, together with dual energy X-ray absorptiometry (DXA) and quantitative peripheral computed tomography scans (pQCT) to determine bone mineral density. A total of 47 dancers aged 17–20 years were recruited, of whom 14 (29.7%) fell within the criteria for suspected female athlete triad syndrome. Comparing the dancers with suspected female athlete triad with 36 non-exercising controls showed no significant differences in BMD at most sites between the two groups. Comparing the normal dancers (n=33) with the same control group showed the dancers had significantly higher BMD at the hip sites (P<0.005), as well as higher core tibial volumetric BMD (P=0.04) than the controls. Young dancers with oligo/amenorrhoea and apparent under-nutrition that fitted the clinical diagnosis of female athlete triad syndrome did not have lower BMD than non-exercising eumenorrhoeic controls, while eumenorrhoeic dancers actually had higher BMD. In addition, no significant differences were seen between eumenorrhoeic dancers and those with suspected female athlete triad. The risk of osteoporosis was apparently offset by the benefits of regular intensive weight-bearing exercises in those participants with suspected female athlete triad.     

Hydrostatic Weighing during Different Stages of the Menstrual Cycle

Abstract

This study compared the physiological responses (oxygen consumption and energy expenditure) of Nordic Walking to regular walking under field-testing conditions. Eleven women (M age = 27.1 years, SD = 6.4) and 11 men (M age = 33.8 years, SD = 9.0) walked 1,600 m with and without walking poles on a level, 200-m track. For women, Nordic Walking resulted in increased oxygen consumption (M = 14.9 ml·kg¹·min^?1 , SD = 3.2 vs. M = 17.9 ml·kg¹·min^?1 , SD = 3.5; p < .001), caloric expenditure (M = 4.6 kcal·min^?1 , SD = 1.2 vs. M = 5.4 kcal·min^?1 , SD = 1.2; p < .001), and heart rate (M = 113.7 bpm, SD = 12.0 vs. M = 118.7 bpm, SD = 14.8; p < .05) compared to regular walking. For men, Nordic Walking resulted in increased oxygen consumption (M = 12.8 ml·kg¹·min^?1 , SD = 1.8 vs. M = 15.5, SD = 3.4 ml·kg¹·min^?1; p < .01), caloric expenditure (M = 5.7 kcal·min^?1 , SD = 1.3 vs. M = 6.9 kcal·min^?1 , SD = 1.8; p < .001), and heart rate (M = 101.6 bpm, SD = 12.0 bpm vs. M = 109.8 bpm, SD = 14.7; p < .01) compared to regular walking. Nordic Walking, examined in the field, results in a significant increase in oxygen use and caloric expenditure compared to regular walking, without significantly increasing perceived exertion.     

辽河流域与辽东半岛新石器遗迹及其稻作、贝丘、积石冢、大石棚文化

在紧邻辽河干流的左翼,突出于黄、渤二海之间,有一块特殊的地域,由于其三面环海,地处辽河之东,故有辽东半岛之称。又因为辽东半岛地域实际上是夹在东有鸭绿江口,西有辽河河口的地域之间,其文化的面貌既具有辽河特征也具有鸭绿江流域特点,因此学术界常常把辽东半岛的文化作为独立的单元加以研究。文章提出辽东半岛的新石器时代至青铜时代的文化面貌一直不是孤立的。从总体上来看,其依然属于辽河流域文明的研究范畴。因此,文章把辽河流域与辽东半岛新石器时代及青铜时代具有特点的文化遗迹联系起来,并对其进行比较和研究。其目的就是希望学术界,把辽东半岛的早期文化也纳入到辽河流域文明范畴的视野中。因篇幅有限,文章只选择了辽东半岛的稻作文化、贝丘文化、积石冢和大石棚这四种文化予以概要的介绍。