The effect of CaF<Subscript>2</Subscript> on thermodynamics of CaO-CaF<Subscript>2</Subscript>-SiO<Subscript>2</Subscript>(-MgO) slags

To address the role of CaF₂ in the CaO-CaF₂-SiO₂(-MgO) slag system employed for the production of low-pressure rotor steels, the thermodynamic aspects of the slag were investigated by equilibrating it with liquid iron at 1873 K in CaO or MgO crucibles. Presaturation of slag with an oxide block piece of CaO or MgO in a Pt crucible and application of a carbon paste to the outside of an oxide crucible were designed to prevent crucible failure during the slag-metal experiments. The liquidus isotherm and phase boundary of the preceding slag system were investigated using the slag-metal equilibria. Also, the effect of CaF₂ on the sulfide capacity and the activity coefficient of Fe _t O were of particular interest in controlling the sulfur level and cleanliness of low-pressure rotor steels.     

基于非均匀星座的改进ARQ方案及其性能分析

本文针对调制阶数大于4的MPSK和MQAM调制，在重传中采用非均匀星座图和符号比特重新排序，提出了一种改进的ARQ方案。通过对AWGN信道下ARQ方案进行理论分析和数值仿真，表明基于非均匀星座的新方案在信道条件较差时能有效地提高重要比特的可靠性，若重传中结合符号比特重排和分组合并，则可使接收端解调合并后的比特可靠性趋于均匀且总体得到提高，从而有效地减少重传次数，提高系统的吞吐率。由于本文所提方案并不改变调制解调规则和数据分组长度，故容易实现和控制。     

Using classification techniques for informal requirements in the requirements analysis-supporting system

In order to efficiently develop large-scale and complicated software, it is important for system engineers to correctly understand users’ requirements. Most requirements in large-scale projects are collected from various stakeholders located in various regions, and they are generally written in natural language. Therefore, the initial collected requirements must be classified into various topics prior to analysis phases in order to be usable as input in several requirements analysis methods. If this classification process is manually done by analysts, it becomes a time-consuming task. To solve this problem, we propose a new bootstrapping method which can automatically classify requirements sentences into each topic category using only topic words as the representative of the analysts’ views. The proposed method is verified through experiments using two requirements data sets: one written in English and the other in Korean. The significant performances were achieved in the experiments: the 84.28 and 87.91 F1 scores for the English and Korean data sets, respectively. As a result, the proposed method can provide an effective function for an Internet-based requirements analysis-supporting system so as to efficiently gather and analyze requirements from various and distributed stakeholders by using the Internet.     

Verification of submodeling technique in thermomechanical reliability assessment of flip-chip package assembly

In this paper we verified the submodeling technique applied in the thermomechanical reliability assessment of a flip-chip BGA under accelerated thermal cycling test conditions. Since the steady-state creep model was implemented for the solder bump to better represent its realistic mechanical behavior, submodeling procedures developed specifically for path-dependent thermomechanical problems were considered. A detailed global model for the flip-chip BGA was built up to verify submodeling solutions. This model also served as a benchmark to examine solution discrepancies caused by different simplifications of the global model.     

传感技术与RFID在血液管理分析中的运用

由于血液管理对于环境条件的特殊要求，针对血液管理分析提出了将传感技术与RFID技术结合后应用于其中的想法。简要介绍了RFID传感器标签的设计，分析了将其运用于血液管理分析后对加强流程监控、提高工作效率的好处，并主要从血液的出入库管理、跟踪管理、质控管理三个方面详细描述，阐明了方法的可行性。     

Preparation and characterization of cuprous iodide nanoparticles

A new technique for the preparation of CuI nanoparticles from CuSO₄ and KI ethanol solutions has been developed. Preparation conditions were optimized through a series of experiments. Under these conditions, the yield of CuI reached 95.39%. The product was characterized and the reaction kinetics was studied. The results show that the product takes a roughly spherical shape with an average particle size of less then 50 nm. The activation energy of the formation of CuI is found to be E _a = 0.58 × 10² kJ/mol, and the preexponential factor in the Arrhenius equation is k ₀ = 7.43 × 10¹⁶ mol/(l s). The text was submitted by the authors in English.     

国外尾矿坝安全与环境研究综述

安全与环境一直是国外尾矿坝研究的重点。笔者综述了自1990年以来国外涉及尾矿坝安全与环境方面有代表性的文献 ,内容包括尾矿坝溃坝、溃坝理论研究、安全管理、环境污染、污染监测、污染治理、污染理论研究及生态复垦 ,这些对提高我国尾矿坝管理、工程技术水平都有较好的参考价值     

Developing Cost Response Models for Company-Level Cost Flow Forecasting of Project-Based Corporations

The difficulty in applying the standard curve (S-curve) and cost-schedule integration (CSI) techniques for company-level cost flow forecasting in a project-based industry is the prerequisite of forecasting future unknown individual projects and contract classifications. By analyzing cost flows at the company level through a pool of macroeconomic and internal financial data, this paper proposes an innovative approach to firm-specific model estimation. First, a series of data transformations introduce linear relationships between cost, macroeconomic, and internal financial variables. Second, multivariate regression analysis is employed for initial model building. Third, for the purposes of model restructuring, a subsequent application of Yule–Walker estimates and incomplete principal component analysis is used. This paper uses a sample of four project-based construction firms to demonstrate model performance. Using this methodology, mean absolute percentage error (MAPE) values of the forecasting models range from 0.27 to 0.60%. As such, the transformed cost, macroeconomic, internal financial data could strongly predict company-level cost flow forecasting. While converting the predicted cumulative cost data to periodic cost flows, the MAPE values were augmented, ranging from 7.04 to 17.55%, thus, requiring future research.     

中国石油石蜡基橡胶油系列产品在橡胶工业中的应用

中国石油研制生产的健康环保型石蜡基橡胶填充油系列产品，具有浅颜色、低芳烃、高饱和烃含量等特征，是中国石油的优质特色产品。该系列产品在国内橡胶行业中已得到广泛应用，其中，KP6025、KP6030石蜡基橡胶油通过了2001年中国石油润滑油公司的鉴定，该产品的研制成功，填补了这一领域的国内空白，产品性能优于国外同类产品，为国内橡胶企业的产品结构调整创造了条件，推动了我国橡胶产业向国际先进水平的发展，具有重大的经济和社会效益。主要综述了中国石油石蜡基橡胶油的应用与评价情况。