课程文献中心 更多>>

关键词： 前列腺增生   F8测压管   压力-流率测定   尿流率  

摘要： 目的探究前列腺增生患者尿道内置F8测压管在压力-流率测定中对尿流率的影响。方法 63例前列腺增生患者,均在尿道内放置F8测压管,在放置测压管前后进行压力-流率测定,比较放置测压管前后患者的最大尿流率和平均尿流率。结果放置测压管后,患者最大尿流率和平均尿流率分别为(7.58±2.57)、(5.29±1.98)ml/s,均明显低于放置测压管前的(8.80±2.95)、(6.27±2.11)ml/s,差异具有统计学意义(P<0.05)。结论前列腺增生患者尿道内置F8测压管会影响压力-流率测定中的尿流率。

关键词： 马来酸酐   1H,1H,7H-十二氟庚醇   含氟烷基磺酸盐   表面活性剂   表面张力  

摘要： 以马来酸酐、1H,1H,7H-十二氟庚醇和环氧乙烷作为原料,用亚硫酸氢钠磺化得到一种新型含氟烷基磺酸盐表面活性剂,为顺丁烯二酸单-(1H,1H,7H-十二氟庚基乙氧基)乙醇酯磺酸钠H(CF2)6CH2OCH2CH2OCOCH(SO3Na)CH2COOH(简称FEOS-1),通过FT-IR、1HNMR和19FNMR等方法对结构进行表征。研究了含氟表面活性剂的热稳定性,结果表明:FEOS-1开始热降解温度为240℃,并最终在340℃降解完全。说明含氟烷基磺酸盐表面活性剂具有相当高的热降解温度,能够适用于温度较高的环境,并且有较高的表面活性和较好的水溶性。

关键词： 涡量-流函数法   方腔流动   粘性旋涡   主涡   次级涡  

摘要： 本文采用MATLAB编程,利用涡量-流函数法求解二维顶板驱动方腔内流动,对比分析了不同雷诺数时,二维顶板驱动方腔内涡旋的变化情况.采用有限差分法对二维顶板驱动方腔内不可压黏性流动的连续性方程和动量方程进行离散求解计算,得到了方腔内的流函数和涡量分布,以此分析方腔内涡旋随雷诺数的变化.结果表明:雷诺数对二维顶板驱动方腔内流函数分布影响较大.随着雷诺数的增大,方腔内流动的复杂度增加,表现为次级涡旋数量增加,且各个次级涡旋的涡心位置和涡面面积也呈现各异的规律变化.主涡涡面变化较小,但涡心随着雷诺数的增大而向方腔中心移动;由于二维方腔流动为带奇性流动,主涡涡心最终均未位于方腔中心.

关键词： 河南平原区   地热流体   同位素   氘过量参数   成生环境   年龄  

摘要： 河南省东部平原地区蕴藏着丰富的地热资源,不同构造单元、不同时代的天然地热流体,其水化学特征及成生环境有较大差异。本次采用稳定同位素数据研究地热流体来源、迁移特征;采用放射性同位素数据,研究地热流体年龄。结果表明:①河南平原区地热流体主要源于大气降水且多为滞留古水;②不同时代热储之间水力联系微弱;③同时代热储赋存的地热流体年龄,山前区远小于平原区,揭示其由山前向平原迁移。

关键词： 地质特征   成矿流体特征   板仓萤石矿   湖北  

摘要： 湖北省大悟县板仓大型萤石矿床位于秦岭褶皱系桐柏-大别褶皱带东部,是典型的中低温热液充填型矿床,该矿床至今未开展成矿流体的相关研究。本文在进一步研究矿床地质特征的基础上,系统开展了矿床流体包裹体研究,了解其流体包裹体形态、温度、盐度、密度和成分特征,推断其成矿流体主要为低温低盐度、较低密度的含Na2SO4-NaCl-H2O成矿流体体系的热液流体。本文认为板仓萤石矿床的形成与燕山晚期三大岩体侵入时形成的岩浆热液有密切关系,矿床属于断裂控矿、中低温热液裂隙充填型萤石矿床。

关键词： 稠油   表面张力   Turbiscan   Lab型分散稳定性分析仪   动力学不稳定性   S分离值  

摘要： 稠油开采具有黏度高、开采困难、耗费资金高等特点,本文对两种稠油乳化降黏剂AOS和MES开展评价,通过Attension表面张力仪分析了高温处理前后的表面张力变化。以降黏率与破乳脱水率为指标进行了乳化降黏效果评价,接着利用Turbiscan Lab型分散稳定性分析仪测定了高温处理前后的动力学不稳定性参数TSI,并采用STDEV函数处理求得S分离值。实验结果表明:AOS在高温处理前后表面张力变化仅为0.86%,MES则为12.38%;两种降黏剂的降黏率均达到97%以上,浓度0.3%的AOS沉降脱水率为86.67%,1.0%的MES为81.67%;两种浓度的AOS在高温处理前后的TSI变化量为0.02和0.27,MES对应为0.13和0.64。AOS对应的S分离值为0.0668和0.1300相对小于MES的0.1874和0.2364,AOS总体上稳定性均优于MES。

关键词： 表面活性剂   竹溶解浆   反应性能   黏胶过滤性能   表面张力  

摘要： 采用太古油(TRO)、聚氧乙烯蓖麻油(PCO)、聚醚多元醇(PP)3种表面活性剂对竹溶解浆原料进行处理,以改善竹溶解浆的反应性能;考察了不同表面活性剂及其用量对竹溶解浆Fock反应性能及黏胶过滤性能的影响,得到竹溶解浆反应性能改善效果最佳的表面活性剂及其优化用量,并研究了Fock反应性能与黏胶过滤性能的关系;分析及比较了上述3种表面活性剂在最优条件下对竹溶解浆的孔隙结构及比表面积、碱液的表面张力、黏胶流变行为的影响,揭示了表面活性剂改善竹溶解浆反应性能的机理。结果表明,TRO对竹溶解浆反应性能的改善效果最优,最佳用量为1.5%,此时,Fock反应性能及黏胶过滤值分别为81.7%和96.9 s,且当Fock反应性能超过77%时,所得的黏胶均能够达到过滤要求;TRO对竹溶解浆比表面积及孔隙结构的改善效果最好,并显著降低碱液的表面张力和提高黏胶的表观黏度,这与竹溶解浆反应性能的改善一致。

关键词： Surface energy flux   SEBAL   Local climate zone   Urban area   Remote sensing  

摘要： In this study, the surface energy flux distribution within Akure city, Nigeria, was assessed using a remote sensing-based model. The Surface Energy Balance over Land (SEBAL) model was used to estimate the net radiation, soil heat flux, sensible and latent heat flux over the city. The estimated fluxes were extracted based on Local Climate Zones (LCZ) and the intensity of each component was assessed. Results showed that LCZ_3 and LCZ_6 with the highest impervious surface cover (above 50%) had higher sensible heat flux intensities, while other zones with lower percentage of impervious surface cover such as LCZ_6(c) and LCZ_9 had lower sensible heat flux intensities. The derived mean sensible heat flux at the built-up zones ranged between 196 W/m(2) and 349 W/m(2) while the latent heat flux ranged between 78 W/m(2) and 295 W/m(2). The latent heat flux was lower over the built-up zones compared to the zones with intense vegetation which recorded as high as 415 W/m(2). The urban surface characteristics were shown to have impact on the surface energy flux distribution within the city as the components were altered differently and at dissimilar intensities at each zone.

关键词： bolus   esophagus   optical flow   swallowing   ultrasound video  

摘要： Video endoscopy (VE) and video fluorography (VF) are the classic inspection methods used for evaluating the function of swallowing, but are disadvantageous as they are invasive. Therefore, we have proposed a noninvasive method that uses pharyngeal ultrasound videos to estimate the internal flow characteristics of foods and evaluates the swallowing function level quantitatively. We are proposing a new method that combines optical flow with Maximally Stable Extremal Regions (MSERs) to extract the movement velocity and position of esophagus and bolus. The results showed that the movement velocity could be used as an indicator to quantify the internal flow characteristics of foods. The displacement of the esophagus indicates the esophageal opening;this could be used as an indicator to evaluate the swallowing. In this study, we confirmed that a classification of esophageal and bolus movements should be performed automatically by the developed method to decrease the evaluation time.

关键词： Gate turn-off thyristors (GTOs)   neutron irradiation   silicon carbide   static and dynamic characteristics  

摘要： Silicon carbide (SiC) has shown substantial promise in the fabrication of high-power devices, and SiC Schottky diodes and field-effect transistors (FETs) have been considered as potential candidates for outerspace and sensors applications. Due to the multipolar structure, SiC gate turn-off thyristor (GTO) device is relatively sensitive to the irradiation-induced point defects. However, how SiC GTOdevices performunder neutron irradiation still needs to be clarified. In this paper, the effects of neutron irradiation on the static and dynamic switch characteristics of highvoltage 4H-SiC GTOs are investigated for the first time. For the static electrical properties, it is found that the forward current significantly decreases with the increasing neutron irradiation fluence. While the cathode leakage current in the blocking characteristics shows an insignificant change up to a neutron fluence of 1.0 x 10(13) n/cm(2). For the switching characteristics, both the pulse peak current and di/dt show substantial reductionas the neutronfluenceincreaseswhile the delay time increases after irradiation. The degraded performance of the static and dynamic characteristics of SiC GTO devices was then analyzed and attributed to the weakened conductivitymodulation and reduced carrier injection efficiency into the drift layer. These two aspects originate from the significantly reduced carrier lifetime and deteriorated forward characteristics of anode-gate diodes, respectively.