钨精矿中钡、锶含量的连续测定

研究了火焰原子吸收光谱仪连续测定钨精矿中钡、锶含量的方法。试样经碳酸钠—过氧化钠熔融,熔融物用硝酸溶液提取,在仪器最佳工作条件下,快速、准确地连续测定钨精矿中钡、锶含量。实验表明该方法操作简便,灵敏度高,干扰少,钡的回收率为94.2%～96.3%;锶的回收率为94.0%～102.5%。     

Availability and cost-centered preventive maintenance scheduling of continuous operating series systems using multi-objective genetic algorithm: A case study

This article presents a multi-objective (maximization of availability and minimization of maintenance cost) preventive maintenance (PM) scheduling model for a continuous operating series system (COSS) which do not provide an off-working period for PM. The objective functions are optimized by using a Multi-Objective Genetic Algorithm (MOGA). The effectiveness of the model is demonstrated through a coal-fired boiler-tube. The case study shows that the model can improve the availability along with profound reduction of the maintenance cost, i.e., increases the profit of the plant.     

A high-Nb TiAl alloy with highly refined microstructure and excellent mechanical properties fabricated by electromagnetic continuous casting

In the present research, microstructure refinement of a high-Nb TiAl alloy(Ti-48Al-8Nb-0.15B) was realized by means of the electromagnetic continuous casting(EMCC) technique. The microstructure of an ingot obtained by EMCC was analyzed using scanning electron microscopy(SEM). As compared with the raw as-cast al oy, the obtained EMCC alloy presented a much finer microstructure with lamellar colonies with a mean size of about 50-70 μm because the electromagnetic stirring broke initial dendrites and enhanced the heterogeneous nucleation. As the grains were refined, the properties of the TiAl alloy were improved significantly. This implies that the EMCC technique could offer the possibility of application for high-Nb TiAl alloys with a refined microstructure and excel ent properties to be used as a structural material.     

Development of slope mass rating system using K-means and fuzzy c-means clustering algorithms

Classification systems such as Slope Mass Rating(SMR) are currently being used to undertake slope stability analysis. In SMR classification system, data is allocated to certain classes based on linguistic and experience-based criteria. In order to eliminate linguistic criteria resulted from experience-based judgments and account for uncertainties in determining class boundaries developed by SMR system,the system classification results were corrected using two clustering algorithms, namely K-means and fuzzy c-means(FCM), for the ratings obtained via continuous and discrete functions. By applying clustering algorithms in SMR classification system, no in-advance experience-based judgment was made on the number of extracted classes in this system, and it was only after all steps of the clustering algorithms were accomplished that new classification scheme was proposed for SMR system under different failure modes based on the ratings obtained via continuous and discrete functions. The results of this study showed that, engineers can achieve more reliable and objective evaluations over slope stability by using SMR system based on the ratings calculated via continuous and discrete functions.     

Efficient Evaluation of Monitoring Top-t Most Influential Places

The continuous top-t most influential place (CTtMIP)query is defined formally and solved efficiently in this paper.A CTtMIP query continuously monitors the t places with the maximum influence from the ...     

Severe carbamazepine intoxication unresponsive to albumin‐enhanced continuous venovenous hemodiafiltration with low dialysate flow

Carbamazepine (CBZ) intoxication can be associated with severe toxicity, including neurological and cardio‐respiratory abnormalities. Highly protein‐bound, CBZ is not removed efficiently through conventional hemodialysis. Charcoal hemoperfusion is the most effective extracorporeal elimination therapy for CBZ intoxication. Recent reports have indicated that continuous venovenous hemodiafiltration (CVVHDF), albumin‐enhanced continuous venovenous hemodialysis, high‐flux hemodialysis and plasma exchange can be as effective as charcoal hemoperfusion. In contrast to recent reports, which demonstrated the effectiveness of CVVHDF with high dialysate flow in CBZ intoxication, we observed that serum CBZ level was decreased minimally by albumin‐enhanced CVVHDF with low dialysate flow. Therefore, albumin‐enhanced CVVHDF with high dialysate flow should be considered in severe CBZ intoxication, if hemoperfusion is unavailable because of the lack of facilities or if it cannot be performed.     

Efficient purchaser incentive when dealing with suppliers implementing continuous improvement plans

This paper presents incentive schemes in the framework of a collaborative purchasing cost reduction process with a supplier implementing a continuous improvement plan. Using a stochastic decision process formulation, we analyze the structure of the optimal policy and characterize its numerical robustness through numerical applications solved by dynamic programming. Then, we analyze two purchaser incentive schemes observed in practice. First, we describe some theoretical properties of the policies associated with these two schemes (schemes I and II) and show that these policies exhibit nonoptimal structures. Second, we estimate the quantitative loss for typical parameter values and, in particular, we show that for certain businesses this loss is significant. Then, we propose two easy‐to‐implement improvements (schemes III and IV), which result in near‐optimal solutions and a significant impact on purchasing cost performances.     

浅析履带浸涂质量影响因素

履带由于其外形复杂,对漆膜要求较低,目前普遍采用浸涂工艺,由于工艺简单,涂装往往不被重视,容易引发一些外观质量问题。从浸漆设备、涂料种类、工艺参数、前处理4个方面探讨了影响浸涂质量的因素。     

对桥梁预应力施工技术的研究

文章结合某大桥的实际工程对施工过程中连续梁的悬拼技术进行了分析,在施工过程中严格把控其工序和要点,保证了工程顺利的进行.