硫化铜精矿制备硫酸铜的试验研究

本文介绍了用内蒙古炭窑口硫铁矿的硫化铜精矿经硫酸化焙烧，硫酸浸出制备硫酸铜的工艺研究，着重阐述了酸浸过程中影响铜浸出率的多种因素。     

三角形取样鉴相数字合成器锁相环中的混沌

研究三角形取样鉴相数字合成器锁相环中的混沌现象。其方法是先对三角形取样鉴相数字合成器锁相环系统作离散化处理,得到相应的离散化系统模型;系统中的环路滤波器采用RC积分滤波器,鉴相器采用三角形鉴相特性;通过验证离散化系统相应的低维系统存在快返反射点,证明了当系统方程满足一定条件时,原系统有混沌输出。最后导出了混沌与系统参数间的关系式。     

关子非闭合回路中的感应电动势和感应电流的几点讨论

本文从一般的电磁理论和费曼等物理学家近年来这方面的研究成果出发,讨论了电磁感应中常见的二种感应电动势.然后,对许多书中叙述的“当回路不闭合时,有感应电动势而无感应电流”的结论进行一般意义上的讨论,论证了非闭合回路有感应电动势的同时也可有持续的感应电流,并且还伴随电磁辐射现象.     

Wind,coal, and copper: the politics of land grabbing,counterinsurgency, and the social engineering of extraction

ABSTRACT

The multiplicity of violent techniques employed to impose land control and extraction remains under acknowledged. This article reviews research conducted between the years 2014 and 2018 and draws on three case studies: wind energy development in Mexico, coal mining in Germany, and copper mining in Peru. The idea of 'engineering extraction' is advanced through counterinsurgency to acknowledge the extent of extractive violence, arguing that the term ‘land grabbing’ is indeed a more appropriate term than ‘land deals’. Engaging with the land grabbing literature, the three cases seek to advance discussions around ‘the political reactions “from below”’ by emphasizing ‘insurrectionary’ positions with resistance movements fighting land deals and extractive projects. This is followed by offering a typology of ‘hard’ coercive techniques and ‘soft’ technologies of social pacification that surfaced in each case. The conclusion reflects on the social technologies of resource extraction, recognizing how social discord, ecological and climate crises are engineered and enforced.     

光伏发电在电动阀门中的应用

为了克服电动阀门在沙漠和其他地区供电难的问题,提出了用光伏电池为蓄电池充电,用蓄电池的电能为电动阀控制系统供电,并用DSP实现全数字软件锁相环(DSPLL)控制直流电机可逆调速的脉冲宽度调节(PWM)。试验证明光伏电池能满足电动阀门的开、关所需要的电能,该方法不仅能实现整个系统的功能,而且其性能稳定可靠,减少系统的谐波和纹波成分,使整个控制系统能实时地遥控、数据采集和传输、液晶显示电机转矩,使直流电机稳速高精度控制阀门的流量。     

一种新型CdTe量子点关于测定铜离子的研究

本文以半胱氨酸和谷胱甘肽为稳定剂,在温和条件下制备了CdTe半导体量子点(或称纳米晶),基于荧光淬灭原理,实现了对Cu2+的定量检测。系统考察了影响量子点光学性质的各种因素,在pH值为6.2的磷酸盐缓冲溶液中,量子点的浓度(以Cd2+计)为1.013×10-4mol/L时,此方法对浓度在2-260μg/L范围内的Cu2+淬灭程度呈很好的线性关系,该方法的检出限为0.15μg/L。在同类方法中,目前尚无如此低的检出限和如此宽的线性响应区间。最后对这种新型量子点监测的高灵敏度的原因和淬灭机理进行了初步推测。     

Response to the COVID-19: Understanding implications of government lockdown policies

The rising number of COVID-19 cases and economic implications of lockdown measures indicate the tricky balancing act policy makers face as they implement the subsequent phases of 'unlock'. We develop a model to examine how lockdown and social distancing measures have influenced the behavioral conduct of people. The current situation highlights that policy makers need to focus on bringing awareness and social restraint among people rather than going for stringent lockdown measures. We believe this work will help the policy makers gain insights into the troubled COVID-19 times ahead, and based on the estimates, they can frame policies to navigate these wild waves in the best possible way.     

新型注射机控制系统设计

介绍了用S5－115U型PC对注射机实行闭环控制的原理，软件、硬件组成等内容，用本系统控制的注射机具有控制功能多、精度多、可靠性强、灵活方便等特点。     

酞菁铜硅胶固定相的合成及在嘧啶核苷分析中的应用

以大孔微球硅胶 (30 μm ,8μm)作基体 ,经γ -氨丙基三乙氧基硅烷活化 ,再与已磺酰化的酞菁铜键合构成液相色谱固定相 .在该固定相上 ,利用反相HPLC条件 ,成功实现对嘧啶核苷的分离     

新型全电动式注塑机直拉式电动射移机构

采用射移丝杠安装于机架方式的全电动式注塑机电动射移机构,易造成推力块的力臂结构长度过长。当喷嘴顶 靠于模具时,由于过大偏载力矩的作用而产生上翘现象。针对性地设计开发了新型直拉式电动射移机构。该机构将注 射单元通过直拉式射移机构直拉于定模板上,大大减小了全电动式注塑机射移力系的封闭回路里出力机构的射移丝杠 中心线与机筒中心线的距离,使机架不再需要承受原有设计由于射移最终阶段喷嘴顶紧模具浇口产生的顶靠力,从而大 大改善了射移机构和喷嘴的受力情况,同时也简化了机架结构,进而减轻了机架的结构重量。