A structure/function study of polyaminoamide dendrimers as silica scale growth inhibitors

Dendrimers have attracted immense attention during the last decade due to their interesting properties both from a basic and an applied research viewpoint. Encapsulation of metal nanoparticles for catalysis, drug delivery and light harvesting are only some applications of dendrimers that are breaking new ground. A novel application of dendrimer technology is described in the present paper that relates to industrial water treatment. Industrial water systems often suffer from undesirable inorganic deposits. These can form either in the bulk or on metallic surfaces, such as heat exchangers or pipelines. Silica (SiO₂) scale formation and deposition is a major problem in high‐silica‐containing cooling waters. Scale prevention rather than removal is highly desired. In this paper, benchtop screening tests on various silica inhibition chemistries are reported, with emphasis on materials with a dendrimeric structure. Specifically, the inhibition properties of commercially available STARBURST^® polyaminoamide (PAMAM) dendrimers generations 0.5, 1, 1.5, 2, and 2.5 are investigated in detail together with other commonly‐used scale inhibitors. Experimental results show that inhibition efficiency largely depends on structural features of PAMAM dendrimers such as generation number and nature of the end groups. PAMAM dendrimers are effective inhibitors of silica scale growth at 40 ppm dosage levels. PAMAM dendrimers also act as silica nucleators, forming SiO₂–PAMAM composites. This occurs because the SiO₂ formed by incomplete inhibition interacts with cationic PAMAM‐1 and ‐2. The general scope of silica formation and inhibition in industrial waters is also discussed. Copyright © 2005 Society of Chemical Industry     

转炉煤气风机叶轮故障诊断及处理措施

对转炉煤气风机叶轮故障进行诊断,分析了故障产生的原因,提出了处理措施,延长了设备使用寿命。     

应用遥感图像分析九江瑞昌地区构造与金铜成矿的关系

九瑞地区是长江中下游重要的金铜成矿区,遥感图像分析认为,北东东向断裂是主要的控矿构造,与北西向断裂的交汇部位是金铜成矿的有利地段。此外,环形构造又是另外一种控矿构造,目前所发现的金铜矿床均有物化探异常显示,并形成于环形构造的边缘。     

硫脲法从低品位含金硫化矿及其焙砂酸浸渣中回收金

本工作采用硫脲法从钴铜硫化矿及其经硫酸化焙烧,酸浸钴铜后的渣中对低品位金进行了浸取研究.直接浸取硫化矿,金的溶出率低,操作参数如电位、pH值等不稳定,试剂耗量大;而从酸浸渣中浸取金的溶出率高,可达91.0%以上,数据重现性好,试剂消耗大大降低,操作稳定.优化了浸取条件,从而降低了硫脲消耗,耗量是1.78kg/t矿.最后,用还原铁粉和活性炭从硫脲浸取富液中回收金进行了探索,效果良好.试验结果表明,硫脲法具有潜在的工业性应用推广价值.     

新疆东昆仑地区金矿成矿地质条件及找矿方向初探

东昆仑地区是昆仑巨型成矿带中２个重要的成矿区之一，从大地构造背景、沉积建造、岩浆活动等成矿地质条件的分析入手，对东昆仑地区的求勉雷克成矿远景区、鸭子泉成矿远景区、库木巴彦成矿远景区和石雪尖成矿远景区的金矿成矿条件进行了初步的探讨，指出了找矿方向。     

从含有机物的金废料中提取纯金的研究

物料的经蒸发、燃烧和焙烧除去有机物。焙渣用硝酸浸出可溶性杂质，金富集在渣中。用正水溶解金。金溶液用Ｈ２ＳＯ４和ＮａＯＨ进行纯化处理，用亚硫酸钠沉积金。金粉洗至无Ｃｌ＾－反应后，加稀硝酸煮沸３０￣６０ｍｉｎ，得到纯度９９．９５％以上的海锦金。     

NH4SCN从ROH-CTMAB-C12H26载金有机相中反萃金

研究了硫氰酸铵（NH4SCN）从混合醇（ROH）－十六烷基三甲基溴化铵（CTMAB）－正十二烷（C12H26）载金有机相中反萃金，考察了平衡时间，PH值，反萃剂浓度，温度等因素对反萃率的影响及有机相的循环使用，绘制了反萃等温曲线，结果表明，NH4SCN对金具有较高反萃率，可顺利实现金的反萃。     

A “Golden Age” for the discovery of new antileishmanial agents: Current status of leishmanicidal gold complexes and prospective targets beyond the trypanothione system

Leishmaniasis is one of the most neglected diseases worldwide and is considered a serious public health issue. The current therapeutic options have several disadvantages that make the search for new therapeutics urgent. Gold compounds are emerging as promising candidates based on encouraging in vitro and limited in vivo results for several Au^I and Au^III complexes. The antiparasitic mechanisms of these molecules remain only partially understood. However, a few studies have proposed the trypanothione redox system as a target, similar to the mammalian thioredoxin system, pointed out as the main target for several gold compounds with significant antitumor activity. In this review, we present the current status of the investigation and design of gold compounds directed at treating leishmaniasis. In addition, we explore potential targets in Leishmania parasites beyond the trypanothione system, taking into account previous studies and structure modulation performed for gold-based compounds.     

Micron-Scale Soft Actuators Fabricated from Multi-Shell Polystyrene Particle-Gold Nanoparticle Nanohybrids

Actuators made of soft matter are needed for a variety of fields ranging from biomedical devices to soft robotics to microelectromechanical systems. While there are a variety of excellent methods of soft actuation known, the field is still an area of intense research activity as new niches and needs emerge with new technology development. Here, a soft actuation system is described, based on a core-multi-shell particle, which moves via photothermal expansion. The system consists of a novel polystyrene-based thermally expandable microsphere, with a secondary shell of a silicate-silane graft copolymer, to which gold nanoparticles are covalently linked. The gold nanoparticles act as photothermal nano-transducers, converting light energy into the thermal energy necessary for microsphere expansion, which in turn results in material movement. Actuation is shown in isolated particles in thermal and photothermal regimes using metal ceramic heaters or 520 nm laser illumination, respectively. Macroscale actuation is demonstrated by making a composite material of particles suspended in the transparent elastomer polydimethylsiloxane. The sample demonstrates an inchworm-like movement by starting from an arched geometry. Overall, this work describes a new particle-based actuation method for soft materials, and demonstrates its utility in driving the movement of a composite elastomer.