Influence Of Chemical Elements Research Articles

Recent progress of machinability and surface integrity for mechanical machining Inconel 718: a review

Inconel 718 (IN-718) has excellent mechanical and chemical properties at high temperature, which has been widely applied in aerospace, ocean, and chemical industries. Meanwhile, the super high temperature properties lead to its poor machinability and machined surface integrity. Good machinability and surface integrity of IN-718 have always been challenging topics in the field of mechanical machining. The machinability and surface integrity of IN-718 was reviewed in this paper. The influences of chemical elements, microstructure, cutting parameters, and cutting environments on machinability were discussed. Cutting force, specific energy, and tool wear were analyzed as the main factors of machinability evaluation index. The characteristics of machined surface integrity including surface morphology (such as surface defects and surface roughness), microstructure modifications (such as plastic deformation, grain size, and white layer) and mechanical properties (such as microhardness and residual stress) related to IN-718 were presented. The state-of-the-art of machining IN-718 showed that most current research focused on its poor machinability and surface integrity in the aspect of material characteristics. There is lack of research on machinability from the viewpoint of geometrical structure of the part to be machined. Therefore, it is important to further study the manufacturability (the difficulty of the process from material to part) of IN-718 components with complex geometrical surface and profiles to achieve shape control and precise design.

基于文献计量的凋落物研究现状及热点分析

PDF HTML阅读 XML下载 导出引用 引用提醒 基于文献计量的凋落物研究现状及热点分析 DOI: 10.5846/stxb201903260578 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（41271064） Research Status and Hot Spot Analysis of Litter Based on Bibliometrics Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:在生态学中，凋落物作为过渡层的研究价值日趋重要。为进一步探究凋落物的现存特征以及热点问题，基于文献计量学的相关方法分析，分别以中国知网数据库（CNKI）和Web of Science核心数据库集合中的文献作为基础数据源。运用Bibexcel、Ucinet、和Netdraw等软件得出研究文献中的高频词共词矩阵和关键词网络化图谱。再利用SPSS进行聚类分析，将研究内容分为五大群集，据此分析枯落物的特性及未来研究方向。研究结果表明：①就文献发文量来看国内外对凋落物的研究，国际上开始的时间较早，国内的研究比国际滞后10年左右，但国内的发文量和增长速度要明显高于国际上；两者都在21世纪开始趋于成熟稳定发展。②国内的凋落物研究以森林生态系统内部的各因子之间的联系为主；国外更偏向于把研究凋落物的分解、土壤营养元素归还以及化学元素转变所带来的气候改变和对环境的污染程度作为该领域研究热点。③经过共现网络化可视分析得出，国内凋落物研究中一定程度上可将凋落物、凋落物分解、生物量、人工林、土壤养分、氮沉降等词作为该领域研究热点和未来延伸发展方向。④通过聚类分析，国内外的研究有相近的部分，都涉及到凋落物的分解方面，化学元素与凋落物、土壤质地的影响。但二者不同的是国内侧重于研究森林生态系统内部的各因子之间的联系，而国际上着重上研究凋落物的分解、土壤营养元素归还以及化学元素转变，所带来的气候改变和对环境的污染程度。由此可以得出，有关凋落物的研究在国内外都是重点，今后应加强国际间的合作，着重研究枯落物特性的变化对气候改变和环境污染的影响。 Abstract:Abstract: In ecology, the research value of litter as a transition layer is increasingly important. In order to further explore the existing characteristics and hotspots of litter, this paper analyzes the relevant methods of bibliometrics, and uses the literature in the China Knowledge Network Database (CNKI) and Web of Science core database collection as the basic data sources. High-frequency word co-word matrices and keyword networked maps in the research literature were obtained using software such as Bibexcel, Ucinet, and Netdraw. Then use SPSS for cluster analysis, the research content is divided into five clusters, based on which the characteristics of the litter and future research directions are analyzed. The results show that: (1) The research on litter at home and abroad is based on the amount of literature published. The international start time is earlier. The domestic research is about 10 years behind the international, but the growth rate of domestic publications and speed is significantly higher than that. Internationally; both have begun to mature and develop in the 21st century. 2 Domestic litter research is mainly based on the links among various factors within the forest ecosystem; foreign countries are more inclined to study the decomposition of litter, the return of soil nutrients and the transformation of chemical elements, resulting in climate change and environmental The degree of pollution is a hot spot in this field. 3 Through co-occurrence network visualization analysis, the litter, litter decomposition, biomass, plantation, soil nutrient, nitrogen deposition and other words can be used as research hotspots and future extensions in the field. Direction of development. 4 Through cluster analysis, there are similar parts in domestic and foreign research, all related to the decomposition of litter, the influence of chemical elements and litter, soil texture. But the difference between the two is that the domestic focus is on the study of the linkages between the various factors within the forest ecosystem, while the international focus on the decomposition of litter, the return of soil nutrients and the transformation of chemical elements, the climate change and The degree of environmental pollution. It can be concluded that the research on litter is the focus at home and abroad. In the future, international cooperation should be strengthened, focusing on the impact of changes in litter characteristics on climate change and environmental pollution. 参考文献 相似文献 引证文献

Development of Modeling Algorithm of the Characteristics of the Steels in the Subsystem of Management of the Production Resources of Steel Production

The article is devoted to the development of an algorithm for modeling the characteristics of steels in accordance with customer requirements. A mathematical model is presented that takes into account the optimal levels of the main factors and their interaction, providing the required values of the characteristics. The next step in the study of the mathematical model was modeling by means of functional modeling methodology IDEF0. Input and output data, as well as normative documents of model management and mechanisms of this management for building a functional model are defined. The control mechanism was the software product OptimalSostav, developed using the object-oriented programming language Delphi. The software product is designed to simulate the characteristics of steels using the specified limits of permissible minimum and maximum values of mechanical properties. The algorithm of realization of the control mechanism, which is based on the fractional factor analysis, is described. The presented algorithm allows to identify the influence of chemical composition on the mechanical properties of steels in the form of mathematical and graphical dependencies and to determine the specified mechanical properties that meet the requirements of the customer. The main possibilities and the scope of the software product, which allows to solve the problem of predicting the optimal chemical composition, providing the required mechanical characteristics, as well as to adjust the process of steel melting within a given chemical composition to achieve the desired set of properties. The application of the software product on the example of the analysis of the influence of chemical elements on the mechanical properties of 75HMF roll steel is shown. The results of modeling in the form of mathematical and graphic dependences are given and the estimation of efficiency of application of the software product is given. The results of solving the problem of approximation of the obtained graphic dependences of the influence of chemical elements on the mechanical properties of the studied steel grade by means of Microsoft Excel are presented. It is established that the developed mathematical and algorithmic software of the software product allows to study the percentage of chemical elements in relation to the total composition of the alloy, based on the obtained pie charts and dependency graphs. The adequacy of the model is confirmed by experimental results.

Application of artificial neural network in medical geochemistry.

For the evaluation of various adverse health effects of chemical elements occurring in the environment on humans, the comparison and linking of geochemical data (chemical composition of groundwater, soils, and dusts) with data on health status of population (so-called health indicators) play a key role. Geochemical and health data are predominantly nonlinear, and the use of standard statistical methods can lead to wrong conclusions. For linking such data, we find appropriate the use method of artificial neural networks (ANNs) which enable to eliminate data inhomogeneity and also potential data errors. Through method of ANNs, we are able to determine the order of influence of chemical elements on health indicators as well as to define limit values for the influential elements at which the health status of population is the most favourable (i.e. the lowest mortality, the highest life expectancy). For determination of dependence between the groundwater contents of chemical elements and health indicators, we recommend to create 200 ANNs. In further calculations performed for identification of order of influence of chemical elements as well as definition of limit values, we propose to work with median or mean values from calculated 200 ANNs. The ANN represents an appropriate method to be used for environmental and health data analysis in medical geochemistry.

Charge transfer mobility of naphthodithiophenediimide derivative: Normal-mode and bond length relaxation analysis

In this letter, the charge transfer mobility of naphthalenediimide (NDTI) derivative is investigated. By employing the normal-mode analysis and bond length relaxation analysis, the influences of chemical elements on reorganization energies and intermolecular electronic couplings are investigated in NDTI derivative. The results show that the introduction of atom O would decrease reorganization energy in hole-hopping process and increase electronic coupling. This analysis encourages the molecular and material design in organic semiconductors.