便携式地质刻槽取样机

针对目前地质勘查中刻槽取样工作存在的问题 ,从地质大调查的需要出发 ,研制了便携式地质刻槽取样机 ,介绍了其主要技术指标、基本结构。

Clinical analysis of 322 cases of placenta previa

In recent years, the incidence of placenta previa has been increasing. According to the literature, it is mainly related to induced labor, artificial abortion, cesarean section, high aging pregnancy, multipara or smoking. The placenta previa is the chief cause of bleeding in late pregnancy and threatens the lives of mother and infant, resulting in a high risk problem in obstetrics. This article studies 322 cases of placenta previa from my hospital and Dalian Obstetrics and Gynecological Hospital from January, 2002 to July, 2009, on the basis of clinicretrospective analysis, in order to deepen our understanding and art of treating placenta previa. The study revealed that: 1. With 322 cases of placenta previa, the incidence was 0.73%. It was higher than the incidence 0.3% reported abroad and lower than the incidence 0.94% reported in our country. The data were from sampling survey and did not prove relations between placenta previa and ages, different from the result obtained abroad in which placenta previa had relation with pregnancy ages. The outcome needs further study. But artificial abortion, induced labor, cesarean section and multipara clearly influence the incidence. The study did not analyze the relation between smoking and placenta previa, but there was external data proving that smoking was related to placenta previa; 2. Ultrasound-B is a better method for examination at present; 3. In cases of vaginal childbirth there was a higher incidence of lateral placenta previa and partial placenta previa. The conservative temporization and timely cesarean section can greatly decrease the mortality of mother and infant.

Inversion of river-bottom sediment parameters using mechanically sampled specimens and subbottom profiling data

The study of river dynamics requires knowledge of physical parameters, such as porosity, permeability, and wave propagation velocity, of river-bottom sediments. To do so, sediment properties are determined on mechanically sampled specimens and from subbottom profiling. However, mechanical sampling introduces disturbances that affect test results, with the exception of grain-size distribution. In this study, we perform inversion of acoustic data using the grain-size distribution of mechanically sampled specimens and the relation between porosity and permeability from the Kozeny-Carman equation as prior information. The wave reflection coefficient of the water-silt interface is extracted from the raw subbottom profile. Based on the effective density fluid model, we combine the Kozeny-Carman equation and the wave reflection coefficient. We use experimental data from two Yellow River reservoirs to obtain the wave velocity and density of multiple sections and their spatial variations, and find that the inversion and testing results are in good agreement.

On the Dimension for Multivariate Weak Spline Function Spaces

In this paper, the dimension formulaes of multivariate weak spline are discussed. The dimension formulaes of non-degree multivariate weak spline on a vertex are presented. The dimension formulaes on triangulation are also discussed. At last, the local supported bases of W31(I1Δ) are presented.