Influence of galvanic interaction between chalcopyrite and some metallic materials on flotation

Galvanic interactions between the grinding media and the ground mineral inside a ball mill could not only accelerate the media wear but also adversely affect the flotation response of the ground mineral. Rest potential, combination potential and galvanic current measurements were carried out to understand the probable electrochemical interactions between chalcopyrite and several metallic electrodes such as platinum, stainless steel, hyper steel, mild steel and cast iron. Flotation recovery of chalcopyrite was found to be significantly lowered when contacted with hyper steel, mild steel or cast iron prior to flotation unlike with platinum or stainless steel. The influence of the presence of collector during galvanic interaction as well as the effect of relaxation for fresh and galvanically interacted chalcopyrite samples were also studied with respect to its floatability. AES and ESCA analyses indicated that galvanic coupling of chalcopyrite with a hyper steel grinding medium resulted in the formation of hydroxide or oxide species of iron on the mineral surface. An electrochemical mechanism is proposed to explain the mineral-grinding media interaction and its effect on flotation.     

四种别藻蓝蛋白三聚体的时间分辨荧光光谱研究

研究了从Ａｎａｂａｎａｖａｒｉｂｉｌｉｓ中提取的４种别藻蓝蛋白ＡＰＣＩ，ＡＰＣＩＩ，ＡＰＣＩＩ及ＡＰＣＢ三聚体的稳态光谱和皮秒荧光光谱。采用Ｍｏｎｔｅ－Ｃａｒｌｏ方法对瞬态荧光光谱进行拟合，实验结果表明：ＡＰＣＩ荧光有两个带，其中第一个带位于６６２ｎｍ，有两个时间组分：３５．８ｐｓ和１．６７ｎｓ；第二个带位于６８０ｎｍ，有两个时间组分：３４．２ｐｓ和１．６４ｎｓ；ＡＰＣＩＩ瞬态荧光位于６６０ｎｍ，有两个时间组分：２０．４ｐｓ和１．６４ｎｓ；ＡＰＣＩＩ瞬态荧光位于６６０ｎｍ，有两个时间组分：２３．８ｐｓ和１．７６ｎｓ；ＡＰＣＢ瞬态荧光有两个带，其中第一个带位于６６２ｎｍ，有两个时间组分：３６．６ｐｓ和１．４５ｎｓ；第二个带位于６８０ｎｍ，有两个时间组分：２５．８ｐｓ和１．６２ｎｓ。实验结果一方面说明了藻胆体核内４种别藻蓝蛋白形成能量传递的两条途径；另一方面瞬态荧光解叠结果揭示了ＡＰＣＩ和ＡＰＣＢ三聚体内能量传递的超快过程。     

波浪在水流作用下的变形

本文通过实验研究，分别观测了规则、波单向不规则波和多向不规则波在不同流速条件下的情况，同进利用静水中的实测波浪资料通过理论计算，分析了在水流中的波浪，并将计算值与实测值做了对比。比较表明，当波浪主方向与水流、法线方向的夹角不过大时，计算与实验吻合较好，表明所推荐的理论方法是可行的。     

Effect of steam distillate extract of resistant wild riceOryza officinalis on behavior of brown planthopperNilaparvata lugens (Stal) (Homoptera: Delphacidae)

Rice plant volatiles extracted as steam distillates significantly affected the behavior of the brown planthopperNilaparvata lugens (Stal). In a choice test, significantly more females settled and fed on tillers of a susceptible rice variety, Taichung Native 1 (TN 1), sprayed with acetone or untreated TN 1 plants than on TN 1 tillers sprayed with the extracts of resistant wild riceOryza officinalis. O. officinalis steam distillate was highly toxic to first-instar nymphs ofN. lugens. Ingestion and assimilation of food by females was significantly reduced on TN 1 plants sprayed withO. officinalis distillate compared to TN 1 plants sprayed with acetone. Application of0. officinalis distillate on TN 1 plants adversely affected hatchability of eggs ofN. lugens.     

Lowland rice response to potassium fertilization and its effect on N and P uptake

Not much is known about the response of lowland rice to K fertilization under Brazilian conditions. A field experiment was conducted during four consecutive years to determine the response of three lowland rice (Oryza sativa L.) cultivars to K fertilization on a Low Humic Gley soil. In the first two years, K was broadcast at rates of 0, 42, 84, 126, and 168 kg K ha^–1. In the last two years K rates were reduced to 0, 25, 50, 75, and 100 kg K ha^–1 and applied in a band. Potassium significantly (P < 0.01) increased grain yields but the response varied from cultivar to cultivar and year to year. Yield responses to K fertilization were superimposed on a general trend of increasing grain yields across the four growing seasons. Mean grain yields increased 14.3% with broadcast application of K in the first two years and 10.4% with banded application of K in the last two years when compared to the control treatments. Extractable soil K increased with K application rate and decreased with soil depth. Potassium was rapidly removed from the soil and yearly broadcast or banded application of K can be expected to result in a significant increase in grain yield of lowland rice in these soils.     

Hydrodynamic constraints on evolution of chemically mediated interactions between aquatic organisms in unidirectional flows

Two hydrodynamic habitats can be defined in unidirectional flow: (1) A boundary where molecular diffusion dominates is found within roughly 1 mm of solid substrates. The actual thickness of this diffusion boundary is a function of current velocity and topography of the substrates. (2) A zone of turbulent flow is present outside the diffusion boundary where chemicals are rapidly diluted and transported downstream. The mode of chemically mediated interaction between organisms in streams is constrained differently depending on which of these two habitats they occupy. Within a diffusion boundary, reciprocal interaction between small organisms is possible because mixing is low, diffusion flux high, and organisms share the same water. Outside a diffusion boundary, in unidirectional flow, organisms unable to move effectively against flow are only chemically influenced by upstream organisms and can only influence downstream organisms. Organisms that are able to move upstream can interact reciprocally with other organisms, even if one or both organisms are found primarily in areas of turbulent mixing.     

增强现实研究进展与核心技术(上)

介绍了增强现实概念及其研究进展,阐述了增强现实的显示技术、交互技术、注册技术等核心技术,最后分析了用户界面等限制增强现实技术发展的要素。     

基于Kinect体感技术开发幼儿认知系统技术可行性研究

基于Kinect体感器开发一套幼儿认知系统,以激发幼儿认知的兴趣,陶冶幼儿的情操,促进幼儿的智力发展,提高幼儿的认知能力。幼儿认知系统是基于Kinect的体感技术,借助Kinect感应系统来定位捕捉幼儿动作及识别幼儿的语音信息,通过Kinect体感设备与计算机系统连接,将动作及语音信息输入系统,实现幼儿与系统之间互动,带幼儿进入模拟真实的认识环境中,沉浸在虚拟现实中进行认知训练,在娱乐中提高幼儿认知能力。     

基于MODBUS协议的触摸屏与MCU通信实例设计

为了提高陆轨两用电动汽车的可操控性,在MODBUS协议的基础上,设计实现以单片机为例的MCU与步科触摸屏MT4523T通讯的人机交互系统,并给出了设计方法与部分软件及其流程图.通过实际验证,该系统稳定可靠,能够简便地控制电动汽车的运行与换轨动作.在一定程度上为触摸屏与带串行接口的其他MCU间的通讯提供了参考.     

三阶孤子传输和相互作用的数值研究

用分步富里叶变换法求解三阶孤子传输的NLS方程,得到了在此条件下孤子传输的数值图形,发现三阶孤子在传输中被压缩和裂变,三阶孤子的相互作用加速了孤子的裂变。通过增加二阶色散系数可抑制孤子的裂变和孤子在传输中的相互作用。