1.5m2高频振动筛结构改进

针对目前在矿棉板备浆生产线上广泛使用的高频振动筛存在的噪音大、动力消耗大、筛板易堵塞、除渣效果差等 问题,对高频振动筛筛框结构、筛板形状和减震弹簧等进行了优化改进,对振动频率、振幅、筛板的孔径通过理论计算得 出几个基本数值范围,再通过对基本数值范围内的不同数值的实际测试,确定最佳数值。新设计的振动筛经实际使用表 明运行稳定,浆料利用率高,能耗低,噪音小,取得了很好的经济效果。     

宋代矿冶业中的厢兵生产

宋代从事矿冶业生产的厢兵虽然由官府召募而来 ,但他们对封建国家仍然有很强的人身隶属关系 ,生产条件十分恶劣 ,其中 ,还有一部分人是因犯罪而被配入军队。由于厢兵生产可以解决人手不足的问题 ,并可以为统治阶级带来高额利润 ,因此 ,长期以来一直是官府经营生产的方式之一     

采矿用地使用权的取得——以地役权解“采矿用地”之结

采矿权是矿业的核心权利,但我国采矿权的客体仅为特定的矿产,于是,矿地使用权的享有成为采矿权行使的前提。然而,当采矿权和矿地使用权分别属于不同主体时,如何取得矿地使用权？立法上没有予以明确规定,实务中现行的取得方式弊端诸多。为了合理、合法地最大限度地实现矿产资源所有者的经济利益,又基于采矿权民事权利性质的确定,应以地役权解“采矿用地”之结。     

Benzene Inhalation by Parts Washers: New Estimates Based on Measures of Occupational Exposure to Solvent Coaromatics

Questions persist regarding assessment of workers’ exposures to products containing low levels of benzene, such as mineral spirit solvent (MSS). This study summarizes previously unpublished data for parts‐washing activities, and evaluates potential daily and lifetime cumulative benzene exposures incurred by workers who used historical and current formulations of a recycled mineral spirits solvent in manual parts washers. Measured benzene concentrations in historical samples from parts‐washing operations were frequently below analytical detection limits. To better assess benzene exposure among these workers, air‐to‐solvent concentration ratios measured for toluene, ethylbenzene, and xylenes (TEX) were used to predict those for benzene based on a statistical model, conditional on physical‐chemical theory supported by new thermodynamic calculations of TEX and benzene activity coefficients in a modeled MSS‐type solvent. Using probabilistic methods, the distributions of benzene concentrations were then combined with distributions of other exposure parameters to estimate eight‐hour time‐weighted average (TWA) exposure concentration distributions and corresponding daily respiratory dose distributions for workers using these solvents in parts washers. The estimated 50th (95th) percentile of the daily respiratory dose and corresponding eight‐hour TWA air concentration for workers performing parts washing are 0.079 (0.77) mg and 0.0030 (0.028) parts per million by volume (ppm) for historical solvent, and 0.020 (0.20) mg and 0.00078 (0.0075) ppm for current solvent, respectively. Both 95th percentile eight‐hour TWA respiratory exposure estimates for solvent formulations are less than 10% of the current Occupational Safety and Health Administration permissible exposure limit of 1.0 ppm for benzene.     

A four-year efficacy and safety study of the long-acting parenteral testosterone undecanoate

Introduction. This is a four-year follow-up of 25 men who received parenteral testosterone undecanoate (TU), 1000 mg every 12 weeks for at least four years. This study was a continuation of a 30-week study wherein the effects of TU had been compared to those of parenteral testosterone enanthate.

Methods & Results. Plasma testosterone (T) trough values of the injection interval of 12 weeks): median 11.9 – 15.9 nmol/L (N 10.0–30.0). E2 and SHBG were stable. Body weight, BMI, waist-to-hip ratio remained stable. Total cholesterol, and triglycerides were unchanged but plasma LDL declined while HDL, after an initial reduction over the first 30 weeks, had increased significantly after three years. Leptin levels, bone mineral density, blood pressure, liver function tests, haemoglobin and haematocrit levels remained stable without values above the upper limit of normal. Over the first 12 months of the study there was an increase in prostate volume from 19.7 ± 8.8 mL to 22.0 ± 8.4 mL (p < 0.05) but thereafter volumes remained stable, paralleled by an increase in PSA from 0.67 ± 0.38 µg/dL to 0.75 ± 0.35 µg/dL (p < 0.05) without any further changes after 12 months.

Conclusion. TU appears to be a stable and safe treatment modality of hypogonadal men.     

Effects of oral testosterone undecanoate therapy on bone mineral density and body composition in 322 aging men with symptomatic testosterone deficiency: a 1-year,randomized, placebo-controlled,dose-ranging study

Abstract

Objective: We investigated the effects of oral testosterone undecanoate (TU) on bone mineral density (BMD), lean body mass (LBM) and body fat mass (BFM) in aging men with symptomatic testosterone deficiency (TD).

Methods: Three hundred twenty-two men ≥50 years with TD symptoms and calculated free testosterone <0.26?nmol/L participated in a multicenter, double-blind, placebo-controlled trial. Patients were randomized to placebo, oral TU 80?mg/d, oral TU 160?mg/d, or oral TU 240?mg/d, administered as divided doses with normal meals. BMD of the hip and lumbar spine were evaluated by dual energy X-ray absorptiometry (DEXA), and body composition (LBM and BFM) by whole body DEXA.

Results: Oral TU significantly increased BMD at Month 12 at the lumbar spine (240?mg/d), total hip (240?mg/d), and trochanter and intertrochanter (160 and 240?mg/d) compared with placebo. Oral TU significantly increased LBM at Months 6 and 12 for all oral TU groups compared with placebo. BFM significantly decreased at Month 6 (all oral TU groups) and Month 12 (160?mg/d) compared with placebo. The effects on BMD and body composition showed a clear dose response.

Conclusions: Treatment with oral TU led to improvement in BMD, LBM and BFM in aging men with symptomatic TD.     

矿物加工工程专业学分制培养方案特色探讨——以安徽理工大学为例

在对国内主要矿物加工专业的本科培养方案进行分析基础上,对安徽理工大学矿物加工专业学分制培养方案中的专业培养特色进行了探讨,提出注重学科交叉性与应用性课程开设、改革教学方法与手段及加强实践教学环节是人才培养的关键.     

区域矿产资源战略评价:以新疆为例

从战略管理的角度出发,以区域可持续发展为基本原则,探讨矿产资源开发利用与区域可持续发展的内在作用机理,以寻求强化区域工业化进程中的矿产资源评价基础理论研究与开发利用途径,实现缓解区域人地关系矛盾与区域经济社会可持续发展的基本任务。这也正是矿产资源战略评价的目的与意义所在。基于矿产资源战略评价的基本原理,本文构建了矿产资源战略评价分析框架与指标体系,以新疆为例,在分析新疆矿产资源现状的基础上,对新疆矿产资源进行了整体优势与竞争力评价,得出了总体评价结论,并提出了相应的政策建议。     

矿产资源最适耗竭经济分析

矿产资源是自然界中有限、稀缺的可耗性资源,其开采利用无疑会导致最终可采储量为零,从理论上讲是达不到持续利用。那么如何界定矿产资源的可持续利用,已经引起理论界的关注。本文根据非再生资源的最佳开采条件、最佳存量条件,从经济学角度对矿产资源耗竭过程进行了定量分析,为进一步研究矿产资源的代际间公平配置奠定了理论基础,对矿产资源的保护利用具有重要理论与实践意义。     

实物期权价值忽视与国有资产流失--我国现行矿业权价值评估方法评述

国内外研究表明矿业权价值除了投资开发的正常收益以外,还包括多种实物期权价值,而在分析了目前国土资源部推荐的7种矿业权价值评估方法以后,我们发现这些方法都存在忽视期权价值的现象.评估与拍卖矿业权的实例进一步表明当前评估方法所得出的价格与实际价值之间存在显著差异,很多造成国有资产流失,而且这种流失倾向不会因为矿业权拍卖制度的建立而消失,加强以实物期权为基础的矿业权评估方法研究与应用是解决这一问题的方向.