镁合金真空低压消失模铸造充型特征

采用摄影法和电触点法对薄壁镁合金零件的充型特征进行了系统研究．实验结果表明,在低真空度条件下,镁合金呈拱形层状推进,其充型速度随充气流量的变化而变化．过小的充气流量会造成金属液充型速度较小,产生浇不足缺陷,而充气流量过大则会使金属液流动前沿不平稳,产生气孔缺陷．真空度有利于砂型紧实和热解产物的传输,但过高的真空度使金属液呈凹槽形推进,不利于热解产物的溢出,在铸件末端产生集中性气孔缺陷．因此,镁合金真空低压消失模铸造最佳的充气流量范围为3～4m^3／h,真空度低于0．02MPa．     

Cause analysis of gully erosion in Yuanmou basin of Jinshajiang valley

Some factors （i.e. lithology, topography, climate, the change of population as well as land use during the past 50 years） that could have great influence on the development of gully in the arid-hot basin of Jinshajiang valley were investigated. The results show that the factors leading to the strong gully erosion in this area include： the widely distributed Yuanmou group stratum, which promotes the development of gully erosion; the unique geomorphologic configuration that is prone to rock fall and gully erosion; the strong and time-concentrated rainfall; the arid-humid alternate climate characteristics that prepares the ground for the development of fissures in soils; the arid-hot climate that goes against the growth and recovery of vegetation; and the unreasonable and abusive human activities.     

企业核心能力生成机理的研究

企业获得长久竞争优势的途径是提高核心能力,运用企业能力结构图来阐述企业学习、核心能力与长久竞争优势之间的联系,构建了多层回路模型来阐明规范、能力与战略三个学习回路之间的逻辑关系,指出各学习回路内部要素之间的相互作用促进了企业核心能力的形成。     

甲基绿对水丝蚓超氧化物歧化酶活性的影响

采用急性毒性实验方法研究了不同浓度的甲基绿溶液对水丝蚓急性毒性(LC50),测定了经甲基绿胁迫后水丝蚓超氧化物歧化酶(SOD)的变化.结果表明:(1)甲基绿对水丝蚓24、48、72 h LC50分别为37.6、31.6、29.3 mg/L.(2)24 h实验,28、32、35 mg/L甲基绿溶液对水丝蚓SOD起诱导作用,与对照组比较,32、35 mg/L SOD活性升高,变化显著(P<0.05);40、45、50 mg/L高浓度试液对水丝蚓SOD起抑制作用,与对照组比较,45、50 mg/L动物SOD活性降低,变化显著(P<0.05);(3)48 h实验,28、32、35 mg/L甲基绿溶液对水丝蚓SOD起诱导作用,与对照组相比较,SOD活性升高,变化显著(P<0.05);40、45、50 mg/L高浓度试液对动物SOD起抑制作用,与对照组比较,SOD活性降低,变化显著(P<0.05);(4)72 h实验,水丝蚓SOD活性总体呈下降趋势.其中28 mg/L药剂对动物SOD活性与24 h相比有所升高.作为核染色剂的甲基绿溶液在一定浓度范围内对水丝蚓造成胁迫,影响动物正常行为及生理现象以至危害生命.     

松北地区人工湖藻类植物的群落组成

2007年的春季、夏季和秋季分别在松北地区人工湖的四个采样点采集藻类标本进行研究,经过鉴定发现69个分类单位,分别隶属于6个门的41个属.藻类植物群落结构的分析结果是:种类数以绿藻门最多,其次是硅藻门和蓝藻门.藻类植物春季以硅藻占优势,夏季则以蓝藻和绿藻占优势,秋季蓝藻所占比例减少,基本以绿藻为主.     

黑龙江省资源经济发展探讨

黑龙江省资源丰富,地大物博,但在多年资源依赖型发展模式的影响下,经济发展已有衰退之势,出现了资源衰竭、生态环境破坏、产业结构单一、接续产业不足等资源经济多方面的问题.针对这些问题本文提出了要以科学发展观为根本理念,大力发展接续产业,并以循环经济发展模式保证资源的可持续利用,以求资源型城市的顺利转型,保证黑龙江省经济的可持续发展.     

空芯纳米氧化亚铜颗粒的制备及其光学性质

采用微波辐照法,以葡萄糖为还原剂还原Cu^2＋离子,制备出空芯纳米氧化亚铜颗粒,并研究了表面活性剂六次甲基四胺对颗粒形貌的影响．制得的样品利用X射线衍射仪（XRD）、扫描电镜（SEM）及紫外分光光度计（UV-vis）进行表征．结果表明,用微波辐照法制备的氧化亚铜颗粒具有空芯球状结构;随着表面活性剂浓度的减少,构成空芯球的纳米颗粒由球状过渡为片状,且粒径逐渐增大．氧化亚铜颗粒属于立方晶型,其吸收峰出现在430nm附近,对应的禁带宽度约为2．58eV,尺寸效应导致了明显的蓝移现象．     

东莞理工学院学生身高与四肢长度关系的研究

了解东莞理工学院在校学生的身高与四肢长度的关系,为临床、体育训练、体育选材、法医学、人类学提供参考资料．采用邵象清的人体测量学方法,对东莞理工学院学生300名（男156名,女144名）身高、上肢长度、肩宽、下肢长度和骨盆宽进行测量．得出了身高、上肢长、肩宽、下肢长和骨盆宽的均值及相关系数,全部相关系数介于0．39至0．85之间,上肢长与身高之间相关系数男性0．79,女性0．39,二者高度相关,下肢长与身高之间相关系数男性0．85,女性0．84．东莞理工学院学生形态发育具有显著的性别差异,其形态发育基本稳定,各年龄组之间无显著性差异．     

Orbit determination of Chang＇E-3 and positioning of the lander and the rover

Chang＇E-3 landed on the east of Sinus Iridum area on December 14, 2013, performing China＇s first successful soft landing on the lunar surface. We present the results on precision orbit determination and positioning of the lander and the rover. We and methods used to achieve period December 2-21, 2014. describe the data, modeling, position knowledge over the In addition to the radiometric X-band range and Doppler tracking data, delta differential one-way ranging data are also used in the calculation, which show that they strongly improve the accuracy of the orbit reconstruction. Total position overlap differences are about 20 and 30m for the 100km × 100km and 100 kmx 15 km lunar orbit, respectively, increased by ,- 50 % with respect to CE-2 and at the same level as other lunar spacecrafts of recent era such as SELENE and lunar reconnaissance orbiter （LRO）. The position error of the soft landing trajectory is less than 100 m. A kinematic statistical method is applied to determine the position of the lander and relative position of the rover with respect to the lander. The position difference of the lander is better than 50 m compared to LRO photograph result. Compared with the delta very long baseline interferometry （VLBI） group delay between the lander and the rover, the delta VLBI phase delay can improve the relative position of the rover from ～ 1,000 to ～1 m.     

Synthesis of BiOCl photocatalyst by a low-cost,simple hydrolytic technique and its excellent photocatalytic activity

A novel photocatalyst, bismuth oxychloride (BiOCl) micro-nano particles with a fine ferrite plate structure, was prepared by a low-cost, simple hydrolytic method. The as-prepared BiOCl was characterized by scanning electron microscopy (SEM), thermogravimetric analysis-differential thermal analysis (TGA-DTA), X-ray diffraction (XRD), and UV-vis diffuse reflectance spectra (DRS). The effects of preparation conditions such as sodium dodecyl benzene sulfonate (SDBS) dispersant, HCl concentration, and heat treatment temperature on BiOCl performances were investigated. Moreover, its photocatalytic activity was evaluated on the degradation of methylene orange (MO) and was compared with that of TiO₂ (P25). The experimental results confirmed that BiOCl micro-nano particles prepared with SDBS, the HCl concentration of 1.5 mol/L, and the heat treatment temperature of 80℃ exhibited the best performance for the photodegradation of MO solution, and they showed good stability and better photocatalytic activity than P25 photocatalyst.