液体火箭发动机带有隔板和无隔板的两相冷态解数值模拟

本文对液体火箭发动机燃烧室内带有隔板和无隔板的两种情况进行了两相冷态解数值模拟，气相控制方程用欧拉坐标系下的Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程组描述，液相控制方程在Ｌａ－ｇｒａｎｇｉａｎ坐标系下进行描述。气、液两相作用通过方程组的源项互相耦合，通过计算比较了有隔板和无隔板时发动机内部流场的参数值，表明了隔板体的数值处理方法对计算两相冷态解的有效性。

Morphological and ultrastructural changes in rat ovarian tissues after cryopreservation

Objective: The aim of the study was to observe and compare the effects of cryopreservation and thawing meth- ods on rat ovarian tissues. Methods: Twenty 5-6 weeks old SPF-SD female rats were randomly divided into two groups, with ten rats in each group. Freshly isolated ovaries saved as a control (group 1: fresh ovaries) in formalin-fixed or vitrified immediately after dissection (group 2: vitrified ovaries). Ovaries in vitrified group were processed into thin slices then cryo- preserved, stored in liquid nitrogen for 21 days, rapidly thawed and grossly examined. All of the collected ovaries underwent hematoxylin and eosin-stained paraffin serial sections and observed the microscopic evaluation in vitrified ovaries. Results: Grossly the vitrified ovaries turned pale color and the size was same as before freeze. The vitrified ovarian tissue had normal anatomical structures of cortex and medulla under the microscope and had no difference with the fresh control ovarian tis- sue. The number and distribution of the follicles were similar with the fresh ovarian tissue, but had smaller size and the gap between oocyte and the surrounding granulosa cells was increased. Few ooctyes were in irregular appearance however the morphology of follicular cells did not give a different appearance as compared to the fresh control ovarian tissue. Conclusion: Cryopreservation of ovarian tissues by vitrification method has some detrimental effect on the morphology of follicles but does not induce negative impact on the number, density and survival of the primordial ovarian follicles. However the whole follicle anatomical structures also had no significant changes.

Morphology and survival of cryopreserved-thawed ovarian tissues after heterotopic autotransplantation

Objective： The aim of our study was to observe the survival and morphological changes of thawed ovarian tis- sues after heterotopic transplantation. Methods： Twenty SPF-SD female rats （5-6 weeks old） were equally randomized into the control group and experimental group. In control group, the freshly isolated ovaries were fixed in formalin. In experimental group, the freshly isolated ovaries were vitrified immediately and cut into thin slices. After stored in liquid nitrogen for 21 days, the tissues of experimental group were rapidly thawed and transplanted into back muscles of rats for 2 or 4 weeks, respectively. After that, all rats in experimental group were sacrificed and the ovarian tissues were collected and fixed in 4% formaldehyde solution. Then the ovarian tissues were stained with HE and observed under the light confocal microscope. Re- suits： With the naked eyes, there was no specific alteration except the size reduction with color changing. Under microscopy, we found normal cortex and medulla in the ovary, and the primordial follicles and follicles in various stages were observed in the cortex. The normal oocytes in ovarian tissues of experimental group were significant decreased than in the control group. Conclusion： The ovarian tissues survive well in experimental group and there is no significant difference in the proportion of follicles between different times （2 and 4 weeks） after grafting. Our results suggest that thawed ovarian tissues could survive after heterotopic transplantation into back muscles of rat models and maintain their morphology and function.

Morphology and structure evolution of metallic nanowire arrays prepared by die nanoimprinting

Metallic nanowire arrays （NWAs） possess wide application prospects due to their unique property, and the tailoring of NWAs＇ structure and morphology is of importance since it would significantly influence the per- formance of NWAs. In the present work, the morphology and structure evolution of the NWAs prepared by the newly developed die nanoimprinting technique has been investigated in detail. It was found that increasing pro- cessing temperature, time and pressure could increase the length of the nanowires and change the NWAs＇ morphol- ogy from monodispersed form to aggregated form. Increasing processing time and temperature within the supercooled liquid region would promote crystallization, while increasing processing pressure could suppress the crystallization. This work provided important insights into the structure and morphology evolution, and therefore, the tailoring of metallic NWAs prepared by die nanoimprinting through adjusting the process parameters.

The Spatio-temporal Pattern of Regional Land Use Change and Eco-environmental Responses in Jiangsu, China

Land use change and its eco-environmental responses are foci in geographical research. As a region with uneven economic development, land use change and eco-environmental responses across Jiangsu Province are relevant to China＇s overall development pattern. The external function of regional land use changes during different stages of economic development. In this study, we proposed a novel classification system based on the dominant function of land use according to ＂production-ecology-life＂, and then analyzed land use change and regional eco-environmental responses from a functional perspective of regional development. The results showed that from 1985 to 2008, land use change features in Jiangsu were that productive land area decreased and eco- logical and living land areas increased. Land use changes in southern Jiangsu were the most dramatic. In southern and central parts of Jiangsu the agricultural production function weakened and urban life service function strengthened; in northern Jiangsu, the mining production function＇s comparative advantage highlighted that the rural life service function was weakening. Ecological environmental quality decreased slightly in Jiangsu and its three regions. The maximum contribution rate to ecological environmental change occurred in southern Jiangsu and the minimum rate was located in the north. Eco-environmental quality deteriorated in southern and central Jiangsu, related to expanding construction land in urban and rural areas. Ecological environmental quality deterioration in northern Jiangsu is probably due to land development and consolidation. The main reason for improvements in regional ecological environments is that agricultural production land was converted to water ecological land across Jiangsu.