铜电解液杂质控制:短床离子交换技术和PHELPS DODGE公司EL PASO冶炼厂案例研究综述

本文探讨了短床离子交换技术在铜电解液开路中去除金属污染物的应用,并论述了硫酸、砷、锑、铋、铁选择性去除工艺。同时,本文也对菲尔普斯道奇公司的埃尔帕索冶炼厂进行了案例研究,描述了短床除硫酸系统+两段选择性沉淀系统生产碳酸镍副产品的工艺史。

Classification of conditions for short-wall continuous mechanical mining in shallowly buried coal seam with thin bedrock

The room and pillar method is usually used to extract coal from shallowly buried seams with thin bedrock. This results in a very low production efficiency and in a low degree of extraction. In recent years short-wall continuous mechanical mining has been extensively used in many situations except shallowly buried coal seams with thin bedrock. The principles governing movement of the overlying strata above the 2-2 coal seam were deduced from in-situ experience, laboratory data, calculations and computer simulations. The thicknesses of the bedrock in the Shendong Coal Field where the coal is shallowly buried are classified into 5 types: <10 m, 10–15 m, 15–25 m, 25–35 m and >35 m, which was done using fuzzy clustering results. A series of reasonable, relative parameters in each category have been calculated and analyzed. One proposed way to perform short-wall continuous mechanical mining in shallowly buried coal seams is given. This is significant for coal mines with similar geological conditions.

Effect of proximal femoral osteoporosis on cementless hip arthroplasty: A short-term clinical analysis

Objective： The aim of this retrospective investigation was to explore the influence of femoral osteoporosis on short-term curative effects ofcementless hip arthroplasty and to evaluate the femoral metaphyseal bone mineral density （BMD） for femoral osteoporosis in order to guide prosthesis choice and rehabilitation. Methods： We performed 127 total arthroplasty operations between June 1999 to February 2003 and investigated 49 cementless hip replacements with the Metalcancellous cementless Lubeck Ⅱ system being used in all hips. There were twenty men and twenty-nine women whose mean age at the time of the operation was 60 years （range, 52-81 years）. The patients were divided into osteoporosis or normal groups according to the femoral metaphyseal BMD measured preoperatively. The average duration of follow-up was 30 months （range, 8-52 months）. We evaluated all of the patients from a clinical standpoint with use of a standard-terminology questionnaire with respect to the short-term curative effects and patients＇ satisfaction. Hip pain status and functional ability were important indicators of treatment efficacy. Results： Harris hip score and patients＇ satisfaction in femoral osteoporosis patients who underwent noncemented hip arthroplasty were lower （P=0.004, P=0.03） while the incidence of thigh pain was higher （P=0.03） than the patients with non-osteoporosis. Conclusion： The higher incidence of pain, as well as the decrease in function experienced by the patients in osteoporosis group, supports the case that cementless arthroplasty is not a better choice for those patients and that we had better select prosthesis based on the femoral metaphyseal BMD.

Firebird stent for the treatment of patients with coronary heart disease： short-term clinical outcome

Objective The sirolimus-eluting stent （SES） has dramatically reduced the rate ofrestenosis in comparison to that with the baremetal stent （BMS）.This study aimed to evaluate the short-term efficacy and safety of Firebird stent implantation for patients with coronary heart disease （CHD）. Methods From Apri12006 through July 2007, 155 patients （mean age 58.93±10.27 years ） with CHD were implanted with Firebird stent or Cypher select stent at Daxing Hospital. Patients were followed up for one year. All-cause mortality, major adverse cardiac events （MACE, including cardiac death, myocardial infarction, recurrence of angina pectoris, heart failure, revascularization, and adverse arrhythmia） and stent thrombosis were compared between the 2 groups. Results Of the 155 consecutive patients, 147 patients were revascularized completely. Of these patients, 48 （with 59 lesions） were treated with Firebird stent, 59 patients （with 75 lesions） with Cypher select stent. The demographic characteristics were similar in the 2 groups. All the angiographic and procedural results were not significantly different between the 2 groups. All-cause mortality, myocardial infarction, recurrence of angina pectoris, MACE and stent thrombosis were almost identical between the 2 groups before discharge, at 6 months and at one year .Conclusion The short-term efficacy and safety of Firebird stent are similar to that of the cypher select stent for the treatment of patients with CHD （J Geriatr Cardlo12009; 6：157-161）.

Robust tracking control for micro machine tools with load uncertainties

The quality of the micro-mechanical machining outcome depends significantly on the tracking performance of the miniaturized linear motor drive precision stage. The tracking behavior of a direct drive design is prone to uncertainties such as model parameter variations and disturbances. Robust optimal tracking controller design for this kind of precision stages with mass and damping ratio uncertainties was researched. The mass and damping ratio uncertainties were modeled as the structured parametric uncertainty model. An identification method for obtaining the parametric uncertainties was developed by using unbiased least square technique. The instantaneous frequency bandwidth of the external disturbance signals was analyzed by using short time Fourier transform technique. A two loop tracking control strategy that combines the p-synthesis and the disturbance observer （DOB） techniques was proposed. The p-synthesis technique was used to design robust optimal controllers based on structured uncertainty models. By complementing the/z controller, the DOB was applied to further improving the disturbance rejection performance. To evaluate the positioning performance of the proposed control strategy, the comparative experiments were conducted on a prototype micro milling machine among four control schemes： the proposed two-loop tracking control, the single loop μ control, the PID control and the PID with DOB control. The disturbance rejection performances, the root mean square （RMS） tracking errors and the performance robustness of different control schemes were studied. The results reveal that the proposed control scheme has the best positioning performance. It reduces the maximal errors caused by disturbance forces such as friction force by 60% and the RMS errors by 63.4% compared with the PID control. Compared to PID with DOB control, it reduces the RMS errors by 29.6%.

NEUTROPHILIC TRANSIENT ACIDIFICATION AND SUPEROXIDE PRODUCTION IN PERITONEAL DIALYSATE

Aim. To elucidate whether an inhibited superoxide production(O 2 ) of neutrophils induced by commercial lactate based peritoneal dialysates(PDS) could be corrected after a transient intracellular acidosis. Methods. The intracellular pH([pHi]) of human neutrophils incubatd in PDS was monitored with a spectrofluorometer with a pH sensitive dye (BCECF AM). Neutrophilic O 2 stimulated by zymosan was determined in PDS with the superoxide dismutase inhibitable ferricytochrome c reduction, using a spectrophotometer. Results. The severe intracellular acidosis induced within 5 min by PDS at an extracellular pH of 5.2 could be promptly and completely recovered by a neutralization of the pH of media. However, O 2 by neutrophils exposed to the PDS for as little as 5 min was drastically and persistently inhibited, even the acidic [pHi] of cells had been fully returned for 1h. Conclusions. The intracellular acidification of cells in the initial phase could be transient and reversible, but impaired cell functions, at least in part including O 2 generating system, might be consistent and irreversible in the early stage of the cellular acidosis in the peritoneal cavity of CAPD patients. The findings above may be of particular importance in both clinic and cell biology.

Effects of neurofeedback on the short-term memory and continuous attention of patients with moderate traumatic brain injury： A preliminary randomized controlled clinical trial

Purpose： There are some studies which showed neurofeedback therapy （NET） can be effective in clients with traumatic brain injury （TBI） history. However, randomized controlled clinical trials are still needed for evaluation of this treatment as a standard option. This preliminary study was aimed to evaluate the effect of NET on continuous attention （CA） and short-term memory （STM） of clients with moderate TBI using a randomized controlled clinical trial （RCT）. Methods： In this preliminary RCT, seventeen eligible patients with moderate TBl were randomly allo- cated in two intervention and control groups. All the patients were evaluated for CA and STM using the visual continuous attention test and Wechsler memory scale-4th edition （WMS-IV） test, respectively, both at the time of inclusion to the project and four weeks later. The intervention group participated in 20 sessions of NFT through the first four weeks. Conversely, the control group participated in the same NF sessions from the fifth week to eighth week of the project. Results： Eight subjects in the intervention group and five subjects in the control group completed the study. The mean and standard deviation of participants＇ age were （26.75 ~ 15.16） years and （2Z60 ＋_ 8.17） years in experiment and control groups, respectively. All of the subjects were male. No significant improvement was observed in any variables of the visual continuous attention test and WMS-IV test between two groups （p _~ 0.05）. Conclusion： Based on our literature review, it seems that our study is the only study performed on the effect of NET on TBl patients with control group. NET has no effect on CA and STM in patients with moderate TBI. More RCTs with large sample sizes, more sessions of treatment, longer time of follow-up and different orotocols are recommended.