黄河某水电站库区泥石流特征及工程影响研究

黄河某水电站库区泥石流沟道发育,对该水电站运行安全带来不利影响。结合国内外有关研究成果,根据库区内泥石流的具体特征,以杏儿沟、官亭沟和喇家沟为重点研究对象,分析研究了这几条沟泥石流的形成条件及运动特征,包括泥石流的流速、流量等,并将泥石流对工程的危害作出评价。研究成果对水电站建设具有重要指导意义。     

汶川地震极震区震后高川乡泥石流降雨警戒模式

以汶川地震极震区绵阳市安县高川乡泥石流为例,在对其爆发历史及相应降雨资料的详细调查、收集基础之上,研究了高川乡泥石流发生的临界雨量特征,得到了该乡泥石流临界雨量Ic-R关系式,进而建立了高川乡泥石流发生的降雨警戒模式,得到该乡泥石流发生不同几率下的警戒基准线,并验证了该警戒模式具有较高可信度,可用于研究区泥石流预警分析中。     

Photovoltaic characteristics of phosphorus-doped amorphous carbon films grown by r.f. plasma-enhanced CVD

The phosphorus-doped amorphous carbon (n-C:P) films were grown by r.f. power-assisted plasma-enhanced chemical vapor deposition at room temperature using solid phosphorus target. The influence of phosphorus doping on material properties of n-C:P based on the results of simultaneous characterization are reported. Moreover, the solar cell properties such as series resistance, short circuit current density (J_sc), open circuit current voltage (V_oc), fill factor (FF) and conversion efficiency (η) along with the spectral response are reported for the fabricated carbon based n-C:P/p-Si heterojunction solar cell were measured by standard measurement technique. The cells performances have been given in the dark I–V rectifying curve and I–V working curve under illumination when exposed to AM 1.5 illumination condition (100 mW/cm², 25 °C). The maximum of V_oc and J_sc for the cells are observed to be approximately 236 V and 7.34 mA/cm², respectively for the n-C:P/p-Si cell grown at lower r.f. power of 100 W. The highest η and FF were found to be approximately 0.84% and 49%, respectively. We have observed the rectifying nature of the heterojunction structures is due to the nature of n-C:P films.     

微机械可变电容制作工艺中的牺牲层释放和残余应力分析

运用高选择比的特别配方来释放MEMS可变电容制作工艺中的牺牲层,以保护上级板金属铝层,同时很好地释放牺牲层磷硅玻璃。探讨了上级板的粘附问题,对工艺中影响成品率的关键因素残余应力进行了模拟,当温度T为350℃时,平面应力P为811.6 MPa;当温度T为500℃时,平面应力P为1 185.9 MPa。分析了残余应力对上级板的影响和对悬臂梁的等效弹性系数的影响。     

Macroinvertebrate assemblages of littoral habitats in the Macquarie and Mersey rivers,Tasmania: Implications for the management of regulated rivers

Littoral habitats in large rivers are influenced to varying degrees by changes in discharge. Irrigation abstractions can increase the amount of habitat that would naturally be dewatered during low flow periods and therefore it is important to have some knowledge of the potential impact this may have on riverine macroinvertebrates. The macroinvertebrate assemblages of common littoral habitats in riffles, pools and runs in two reaches each of the Macquarie and Mersey Rivers, northern Tasmania, Australia were compared from samples collected during the low flow and irrigation season, between December 1991 and April 1992. The area under water of these habitats, riffle substrata, macrophyte beds and coarse woody debris, responded differently to changes in discharge. Within a reach, the same taxonomic groups often dominated the total number of macroinvertebrates for all habitats, but there were differences in the proportions contributed by these taxa to the different habitats. In general, taxa characteristic of slow-flowing or lentic habitats, such as ostracods and amphipods, were dominant in macrophyte beds in pools and runs, whereas taxa such as larval elmid beetles and hydropsychid caddisflies were dominant in riffles. A substantial component of the fauna from each habitat within a reach was unique to that habitat, but there was always a similar number of taxa common to all habitats. Classification and ordination grouped samples from both rivers firstly by habitat and secondly by month and reach. Total density and family richness of invertebrates differed by reach, habitat and month in both rivers, except for richness in the Mersey River where habitat was not significant. Differences in densities and numbers of invertebrate families among habitats were not consistent between reaches for each river. This study has highlighted the differences in macroinvertebrate assemblages of several littoral habitats in two lowland rivers in Tasmania. Differences in taxonomic composition, density and richness among habitats within reaches strongly imply the uniqueness of these habitats in terms of the invertebrate faunas that occupy them. We suggest that if maintenance of biotic diversity is an aim of instream flow management, water allocations that address low flows should place a high priority on the maintenance of a diversity of habitats.     

Fabrication of excimer laser annealed poly-Si thin film transistor by using an elevated temperature ion shower doping

We have investigated the effect of an ion shower doping of laser annealed poly-Si films at elevated substrate temperatures. The substrate temperature was varied from room temperature to 300°C when the poly-Si film was doped with phosphorus by a non-mass-separated ion shower. Optical, structural, and electrical characterizations have been performed in order to study the effect of the ion shower doping. The sheet resistance of the doped poly-Si films was decreased from 7 × 10⁶ Ω/sq to 700 Ω/sq when the substrate temperature was increased from room temperature to 300°C. This large change in sheet resistance is due to the fact that the doped films do not become amorphous but remain in the polycrystallinephase. The mildly elevated substrate heating appears to contribute mainly to reduction of ion damages incurred in the poly-Si films in addition to the activation of dopants during the ion shower doping. From the fabricated n-channel poly-Si TFTs, the current crowding effect do not occur because of the low contact source-drain resistance and the field effect mobility of 120 cm²/(V s) has been obtained.     

食用油脂物理精炼和化学精炼诸多因素的比较

目前,在我国具有一定规模的禽用油脂精炼工厂（车间）中,以物理精炼或化学精炼的方法加工着不同品种的植物油脂,或以此两种不同的方法加工着同一品种的油脂。这两种方法的优缺点已成为多年来争议的焦点之一。列举了物理精炼和化学精炼中的许多因素,并加以对照、比较,以期对它们有更好的了解。     

甘蓝型油菜对干旱和低磷双重胁迫的生理反应Ⅰ：叶片气体交换参数及产量

通过对气体交换参数及产量的测定和分析,研究了干旱和低磷双重胁迫对油菜不同生育期叶片光合特性的影响。结果表明：油菜在不同生育期受到干旱和低磷胁迫后,叶片净光合速率（Pn）、气孔导度（Gs）、蒸腾速率（Tr）会明显降低。在干旱和低磷双重胁迫下,苗期油菜Ci降低、Ls升高,表明气孔限制是导致Pn降低的主要原因;而蕾薹期和花期Ci升高、Ls降低,表明非气孔限制是导致Pn降低的主要原因。对单一的胁迫而言,低磷胁迫对油菜叶片Pn影响最大的时期是蕾薹期,而干旱胁迫对油菜叶片Pn影响最大的时期则是花期;与对照相比,它们均显著降低了油菜的株高、每角粒数、单株有效角果数和单株产量。     

云南省耿马县蔗区土壤主要养分状况分析研究及对策

对云南省耿马县蔗区耕作层土壤养分的测定表明，该县土壤的有机质含量为中等，氮素营养中上，钾素供给中下，磷素供给中下。各村片差别较大，部分土壤养分严重缺乏，土壤明显酸化。土壤主要养分的供给总体上处于中下水平。根据该蔗区土壤养分状况提出相应对策。