Fixed-bed column study for deep removal of copper(Ⅱ) from simulated cobalt electrolyte using polystyrene-supported 2-aminomethylpyridine chelating resin

This study presents the deep removal of copper (Ⅱ) from the simulated cobalt electrolyte using fabricated polystyrene-supported 2-aminomethylpyridine chelating resin (PS-AMP) in a fixed-bed.The effects of bed height (7.0–14.0 cm),feed flow rate (4.5–9.0 mL/min),initial copper (Ⅱ) concentration of the feed (250–1000 mg/L),feed temperature (25–40 ℃) and the value of pH (2.0–4.0) on the adsorption process of the PS-AMP resin were investigated.The experimental data showed that the PS-AMP resin can deeply eliminate copper (Ⅱ) from the simulated cobalt electrolyte.The bed height,feed flow rate,initial copper (Ⅱ) concentration of the feed,feed temperature and feed pH value which corresponded to the highest removal of copper (Ⅱ) were 7.0 cm with 35 mm of the column diameter,4.5 mL/min,40℃,1000 mg/L and 4.0,respectively.The breakthrough capacity,the saturated capacity of the column and the mass ratio of Cu/Co (g/g) in the saturated resin were correspondingly 16.51 mg/g dry resin,61.72 mg/g dry resin and 37.67 under the optimal experimental conditions.The copper (Ⅱ) breakthrough curves were fitted by the empirical models of Thomas,Yoon-Nelson and Adam-Bohart,respectively.The Thomas model was found to be the most suitable one for predicting how the concentration of copper (Ⅱ) in the effluent changes with the adsorption time.

A thermal stress loading technique for large-sized hot dry rock mechanical tests

Testing of large-sized specimens is becoming increasingly important in deep underground rock mechanics and engineering.In traditional mechanical loading,stresses on large-sized specimens are achieved by large host frames and hydraulic pumps,which could lead to great investment.Low-cost testing machines clearly always have great appeal.In this study,a new approach is proposed using thermal expansion stress to load rock specimens,which may be particularly suitable for tests of deep hot dry rock with high temperatures.This is a different technical route from traditional mechanical loading through hydraulic pressure.For the rock mechanics test system of hot dry rock that already has an investment in heating systems,this technology may reduce the cost of the loading subsystem by fully utilizing the temperature changes.This paper presents the basic principle and a typical design of this technical solution.Preliminary feasibility analysis is then conducted based on numerical simulations.Although some technical details still need to be resolved,the feasibility of this loading approach has been preliminarily confirmed.

Study on the shear strength of deep reconstituted soils

Based on analytical methods of strength studies for deep soils, direct shear tests were carried out to investigate the shear strength of deep reconstituted soils at different initial dry densities and amounts of water.The results indicate that the shear strength of deep reconstituted soils for identical amounts of water below the plastic limit is enhanced with increasing dry density and but reduced sharply at the critical density, the point at which coarse particles break down.Moreover, the shear strength for identical dry density decreases with additional amounts of water and the rate of degradation is the greatest at the critical density.This is because the friction resistance between coarse particles reduces with increasing amounts of water higher than the plastic limit.In order to obtain reliable strength of deep reconstituted soils, suitable dry densities and amounts of water are necessary.

用改进的干法取土的灌注桩作基坑挡土结构

圆型截面灌注桩用于基坑挡土结构其配筋设计是不合理的。用改进的干法取土的灌注桩作基坑挡土结构可以克服这一缺点,达到节约钢筋的目的。

公路路床常见处理措施

通过对汽车荷载作用下路床的受力分析,探讨不同的路床处理方法的适用性。设计中常用的处理方法有翻挖晾晒、掺灰处理、换填及深层处理。翻挖晾晒和掺灰处理主要对原土的含水量进行改良,掺灰处理还可以降低土的膨胀性;换填是将路床范围的不良地层超挖,然后分层回填合格的路基填料;深层处理常常将路床及路床以下地基一并处理。良好的路床对路面的稳定性和耐久性起到至关重要的作用,故在设计中应重视路床部位的处理。

挂面产业现状及其产品深加工方向

挂面作为中国的传统食品,其加工工艺主要包括和面、压片、切条、干燥等步骤。近年来,人们越来越关注饮食的营养和健康,精深加工的高品质挂面产品越来越受到人们的欢迎。本文从原辅料选择、营养素预处理、产品形式设计和生产工艺控制4个方面对营养强化挂面产业进行探索,从而研发生产具有中国特色的挂面新产品。

Co-Processing Sewage Sludge in Cement Kiln in China

Sewage sludge is the by-product from municipal waste water treatment plant and is highly polluted. How to treat the SS in a solid environmental friendly way is strictly concerned in China. In this article, the SS situation and also the treatment methods in China have been introduced. The advantage and some related issues of co-processing SS in cement kiln have been discussed. The technical model and projects of Huaxin cement for co-processing SS in cement kiln also have been introduced.

A New Approach to Cleave MEMS Devices from Silicon Substrates

Dicing of fabricated MEMS （microelectromechanical system） devices is sometimes a source of challenge, especially when devices are overhanging structures. In this work, a modified cleaving technique is developed to precisely separate fabricated devices from a silicon substrate without requiring a dicing machine. This technique is based on DRIE （deep reactive ion etching） which is regularly used to make cleaving trenches in the substrate during the releasing stage. Other similar techniques require some extra later steps or in some cases a long HF soak. To mask the etching process, a thick photoresist is used. It is shown that by applying different UV （ultraviolate） exposure and developing times for the photoresist, the DRIE process could be controlled to etch specific cleaving trenches with less depth than other patterns on the photoresist. Those cleaving trenches are used to cleave the wafer later, while the whole wafer remains as one piece until the end of the silicon etching despite some features being etched all the way through the wafer at the same time. The other steps of fabricating and releasing the devices are unaffected. The process flow is described in details and some results of applying this technique for cleaving fabricated cantilevers on a silicon substrate are presented.

利用低品位难选铁矿生产高品质直接还原铁

针对国内某低品位难选铁矿,采用深度还原磁选分离技术对其进行处理。研究结果表明:随还原温度升高,产物的金属化率先增大后降低,1275℃时的金属化率最高;随时间延长,产物金属化率增加明显,但超过60min后金属化率增加缓慢。对最优条件下还原产物进行磨矿、磁选、粒度分级处理,结果显示磁选精矿粒度越粗,铁品位越高。粒度>0.1mm的精矿铁品位>94%,占磁选精矿的75.2%,可以作为优质还原铁使用;粒度<0.1 mm的精矿铁品位在80%左右,可以作为炼铁炼钢添加剂使用。

黄土高原生态林耗水深度和深层耗水量研究

【目的】探讨黄土高原生态林耗水深度和深层耗水量,以明确黄土高原生态林的耗水规律。【方法】选取延安地区16年生的侧柏、沙棘和刺槐三种常见的黄土高原生态林种,以土钻法获取不同生态林和草地的土壤水分含量。首先基于年际的土壤水分含量确定生态林的土壤水分活跃层;其次,基于>25 m深剖面的土壤水分数据来确定三种生态林的耗水深度和深层耗水量,并分析不同土层的耗水速率。【结果】依据年际土壤水分含量变化,2 m土层为该地区土壤水分活跃层。侧柏、沙棘和刺槐的最大耗水深度分别为12.0 m、12.2 m和23.2 m,其16年内耗水总量分别为304 mm、664 mm和1763 mm。刺槐的深层土壤耗水速率最大,为110 mm a^(−1);其次为沙棘,为42 mm a^(−1);最小为侧柏,为19 mm a^(−1)。在2~10 m土层刺槐的耗水量仅占总耗水量的44%。【结论】探究黄土高原生态林的耗水量需要根据生态林物种的耗水特性选择合适取样土层深度。

Research on the Performance of Supercritical CO_2 Dry Gas Seal with Different Deep Spiral Groove

The performance of supercritical CO_2(SCO_2) dry gas seal(DGS) with different deep spiral groove is investigated with the thermal-fluid-solid coupling method. The performance parameters of DGSs with five different kinds of grooves are obtained. The influence of inlet temperature, inlet pressure, velocity and film thickness on performance is analyzed compared with air DGS. The average film pressure, open force and leakage decrease while the average face temperature and flow velocity increase as the spiral groove number increases. The average film pressure, average face temperature, open force and leakage of DGS with radial different deep groove are higher than those of DGS with circumferential different deep groove respectively under the same spiral groove number while the average flow velocity is the opposite. SCO_2 DGS can generate larger average film pressure, open force and leakage with lower average face temperature than air DGS. SCO_2 DGS could maintain better sealing performance despite larger leakage with the variations of inlet temperature, inlet pressure, velocity and film thickness. The variables hold a more remarkable influence on SCO_2 DGS compared with air DGS.

Eyelid margin cleaning using Deep Cleaning Device for the treatment of meibomian gland dysfunction-associated dry eye: a preliminary investigation

Objective: To evaluate the safety and effectiveness of eyelid margin cleaning using Deep Cleaning Device for the treatment of meibomian gland dysfunction-associated dry eye. Methods: This was a prospective, randomized, open-label, investigator-masked, and self-controlled study. We randomly assigned one eye of patients with meibomian gland dysfunction-associated dry eye to the treatment group, and the other eye to the control group. Both groups received artificial tears and lid warming;the treatment group received an additional one-time in-office eyelid margin cleaning using Deep Cleaning Device. Non-invasive tear break-up time(NITBUT) and tear meniscus height(TMH) of each eye, and Standard Patient Evaluation for Eye Dryness II(SPEED II) score of each patient were evaluated before and at one week after treatment. Results: Thirty eyes of 15 patients were enrolled. No adverse effects occurred during the treatment. Compared with the baseline values, the SPEED score decreased significantly at one week after treatment(mean±95% confidence interval, 11.00±0.99 vs. 5.67±1.67, P<0.0001), the NITBUT-first in the treatment group increased significantly at one week after treatment((4.74±1.27) s vs.(7.49±2.22) s, P=0.01). The NITBUT-first was significantly longer in the treatment group((7.49±2.22) s) than in the control group((5.17±0.91) s) at one week after treatment(P=0.042). No significant differences were found in other tear film parameters between the two groups. Conclusions: Eyelid margin cleaning using the novel Deep Cleaning Device is a convenient, effective, and safe treatment for patients with meibomian gland dysfunction-associated dry eye.

冷冻、冻干、辐照对骨诱导活性的影响

[目的]研究冻干、冷冻、辐照对骨诱导活性的影响。[方法]收取胫骨上段松质骨,加工成大小约0.5 cm×0.5 cm×0.5 cm的骨块,随机分为五组:新鲜骨组、冷冻组、冻干组、冻干+辐照组以及冷冻+辐照组,用免疫组化法测定骨细胞因子BMP、bFGF、β-TGF含量的变化。[结果]新鲜骨及冷冻骨、冻干骨均有细胞因子表达,但冻干骨表达的程度着色较深,表达阳性的细胞位于骨小梁的表面。辐照后,BMP、bFGF、β-TGF表达减少。[结论]辐照可减少骨的诱导活性,但仍保留部分骨诱导成分。

陕北黄土区具干表土层的极陡坡绿化技术研究

黄土地区基础设施建设形成的裸露陡峭坡面(坡度45°～80°)是水土流失和地质灾害的易发区,需要恢复植被覆盖,但其干表土层限制了植被自然恢复,需探索合适的人工促进植被恢复方法.本研究以凋萎湿度作为坡面干表土层判定标准,探索分析了陕北黄土区半阴坡、半阳坡和阳坡的典型裸露陡峭坡面的干表土层;选择本地植物柠条、柽柳及外来植物金叶莸,基于坡面干表土层的分析结果,实验了陡坡深植绿化技术,并调查评价了绿化效果.得出以下结论:(1)黄土区裸露极陡坡面存在一定厚度的干表土层,形成时间2年的半阴坡和半阳坡的干表土层厚度约20cm,形成时间4～5年的阳坡约30～35cm;(2)深植绿化效果理想,苗木栽植成活率及3年后保存率均可达93%以上;(3)本地植物长势优于外来植物;植被长势随坡度增加而变弱;柽柳在半阴坡和半阳坡的高度和地径均最高,在阳坡的长势最好.本研究提出的极陡坡深植绿化技术可有效加快黄土区人工促进植被恢复的进程.

Investigation of Influencing Parameters for Tribological Conditions in Dry Forming Processes

Environmental awareness and a growing demand for efficient resource utilization encourage the realization of lubricant-free forming processes. A first step in accomplishing dry sheet metal forming is to gain knowledge about the changing tribological conditions and to identify the relevant influencing parameters. The commonly used flat strip drawing test was selected to investigate the tribological conditions in the flange area of deep drawing processes. The influencing factors of contact pressure and varying drawing velocities were analyzed under dry and lubricated conditions. Additionally,the tool and workpiece surfaces were characterized. Besides lubrication, the contact pressure mainly determines the tribological conditions. In lubricated tests higher normal pressure reduces friction, whereas without lubrication higher pressure results in slightly increasing friction. A changing drawing velocity affects the friction when lubricant is applied. In dry experiments, no influence of velocity was found. Results of surface characterization reveal adhesion as main wear mechanism under dry conditions. Based on the investigated influence of the process parameters, an increase in process understanding for dry forming operations is derived.

污泥深度脱水协同垃圾焚烧生产性试验研究

针对北方某城市200 t/d污泥集中处置项目进行模拟工业化生产的试验研究,以探索污泥深度脱水协同生活垃圾焚烧相关工艺条件及其稳定性。考察了不同工况下污泥脱水速率、泥饼含水率、低位热值以及冬季严寒环境下脱水泥饼的物理性能。结果表明,使用厢式隔膜压滤机,采用聚合氯化铝(PAC)和石灰作为调理剂,通过调整药剂投加比例,在PAC投加量为污泥干基的5%~7%、石灰投加量为污泥干基的10%~20%的情况下,经厢式隔膜压滤机深度脱水后,泥饼含水率可以达到44. 0%~58. 5%,低位热值为3. 25~4. 22 MJ/kg,脱水周期为2. 6~4 h,化学调理药剂成本为37~57元/t(含水率约为80%),泥饼低位热值可以满足垃圾焚烧炉入炉要求;泥饼在有条件储存或晾晒时可显著降低含水率,提高低位热值。