分散剂在陶瓷废料悬浮试验中的应用研究

陶瓷废料是陶瓷行业中所产生的最主要的污染之一,大部分废料被填埋,少部分应用在坯料制备中。为实现资源的循环应用,将废料更多地应用于现代工业,产生经济效益,形成循环经济。本文根据陶瓷废料的特性进行了基础研究,主要是对陶瓷废料的悬浮性能,对水玻璃、NaOH、甲基纤维素等分散剂的敏感性展开研究。     

基于软件度量的Solidity智能合约缺陷预测方法

随着区块链技术的兴起,智能合约安全问题被越来越多的研究者和企业重视,目前已有一些针对智能合约缺陷检测技术的研究.软件缺陷预测技术是软件缺陷检测技术的有效补充,能够优化测试资源分配,提高软件测试效率.然而,目前还没有针对智能合约的软件缺陷预测研究.针对这一问题,提出了面向Solidity智能合约的缺陷预测方法.首先,设计了一组针对Solidity智能合约特有的变量、函数、结构和Solidity语言特性的度量元集(smart contract-Solidity, SC-Sol度量元集),并将其与重点考虑面向对象特征的度量元集(code complexity and features of object-oriented program, COOP度量元集)组合为COOP-SC-Sol度量元集.然后,从Solidity智能合约代码中提取相关度量元信息,并结合缺陷检测结果,构建Solidity智能合约缺陷数据集.在此基础上,应用了7种回归模型和6种分类模型进行Solidity智能合约的缺陷预测,以验证不同度量元集和不同模型在缺陷数量和倾向性预测上的性能差异.实验结果表明,相对于COOP度量元集...     

Computational analysis of diffuser-augmented wind turbines

Diffuser-augmented wind turbines are suitable candiates for the generation of electricity from jet-stream winds. A blade element, computational analysis is developed that includes wake rotation effects and blade Reynolds number effects. The influence of the diffuser is allowed for by introducing empirical values for the diffuser efficiency and exit-plane pressure coefficient. Good agreement is obtained for power coefficient and turbine axial velocity with experimental results. The use of screens to simulate the turbine is found to overestimate the turbine output by neglecting blade profile drag but to underestimate turbine output by neglecting favourable rotational influences on diffuser efficiency. Maximum power is delivered with a solidity ratio of 0.10 to 0.15 depending on the aerofoil section used.     

黄酒固形物实验室形态学观察研究

将黄酒采取离心分离获取其固形物成分,置于目镜×物镜=16×100的光学显微油镜下直接观察,视野内清晰可见形态各异、含量不等、视感不一的"有机类、结晶类、杂质类”三种性状结构形态.以此作为黄酒产品质量控制、优劣鉴定及污染识别等手段,其方法简便,快速准确,结果满意.值得推广应用.     

Quantitative measure of local solidity/liquidity in metallic glasses

Metallic glasses are viscoelastic materials that contain a wide spectrum of local configurations that range from more “solid-like” to more “liquid-like” varieties. To quantitatively characterize the local solidity (or liquidity) in metallic glasses, here we present a robust method and a universal materials parameter. The new parameter, solidity (liquidity) index, is based on the evaluation of bond orientational anisotropy. The usefulness of the proposed index in assessing the varying degrees of solidity (or liquidity) is demonstrated in metallic glass models produced via molecular dynamics simulations. The spectrum of local solidity is also analyzed in terms of its dependence on local structural features, particularly on the basis of different types of Voronoi polyhedra and atomic volume.     

Factors affecting preference ratings of prohibitive symbols

A sign consisting of a pictorial overlaid with a red circle-slash (i.e., a red circle with a red slash) is used ubiquitously to convey the message that some activity is prohibited. The purpose of this study was to investigate the effects of pictorial solidity, size, and direction of elongation (DE) of the pictorial and orientation and thickness of the red circle-slash on the preference ratings for prohibitive symbols.

Solid (filled) pictorials were rated better than pictorials in outline form. Pictorials with a size equal to or greater than 75% of the length of the inner diameter of the circle-slash were rated higher than pictorials 50% in size. The effect of pictorial DE was not significant: pictorials with a greater vertical DE (i.e., tall/thin pictorials) did not differ from pictorials with a greater horizontal DE (i.e., short/wide pictorials), in terms of their preference ratings. However, pictorial DE interacted with slash orientation. Diagonal slashes were rated better than vertical or horizontal ones. Further, symbols were rated better when the thickness of the red circle-slash was such that its resulting area comprised 25% of the total area inside its outer circle at least. Moreover, the interaction of pictorial size and slash thickness indicated that the preference for prohibitive symbols of thicker slash and smaller pictorial size might be degraded drastically.

Implications of the results for the design of prohibitive symbols were discussed.     

便携式型砂紧实率快速智能测试仪

简述型砂紧实率快速智能测试仪的技术原理,介绍了测试仪的设计、标定以及应用效果。     

基于网络度量元的Solidity智能合约缺陷预测

针对现有智能合约缺陷预测方法未考虑合约代码内部结构对缺陷产生的影响的不足,提出了一种基于网络度量元的Solidity智能合约缺陷预测方法。首先,通过Solidity-Antlr4工具构建Solidity智能合约的抽象语法树(abstract syntax tree, AST);其次,根据抽象语法树构建合约网络,网络中的节点代表函数和属性,边代表函数间的调用关系和函数对属性的操作关系;然后,引入复杂网络领域的知识,构建了一套针对Solidity智能合约的网络度量元;最后,基于多种回归模型和分类模型构建智能合约缺陷预测模型,进而比较不同类型的度量元在Solidity智能合约缺陷预测方面的性能。数据实验表明,结合了网络度量元的缺陷预测模型的预测性能比相应没有结合网络度量元的模型要好。     

Experimental investigation of the influence of solidity on the performance and flow field aerodynamics of vertical axis wind turbines at low Reynolds numbers

This paper shows the results of an experimental investigation into the effect of changes in solidity on the performance of a Vertical Axis Wind Turbine. Two VAWT configurations are used, one of solidity σ = 0.26 (chord C = 0.03 m) and the other with σ = 0.34 (C = 0.04 m). The turbine performance coefficient (C_p) was measured over a range of tip speed ratios and Particle Image Velocimetry (PIV) was used to determine the flow field around both turbine configurations.Performance (C_p–λ) curves for the two VAWTs are compared at the same Reynolds numbers to investigate the effects of solidity alone on the performance and aerodynamics of each configuration. The higher solidity (σ = 0.34) VAWT attained a similar maximum C_p but with a narrower C_p–λ curve than the lower solidity VAWT. The performance differences between the two VAWT configurations at two tip speed ratios are explained in detail using PIV around both VAWT rotor blades. This allows the linking of detailed aerodynamics to the performance and it was shown that the generation and shedding of stall vortices started earlier on the lower solidity VAWT than the higher solidity VAWT, thus limiting the rotor efficiency.     

Applying blockchain-based method to smart contract classification for CPS applications

Smart contract has been the core of blockchain systems and other blockchain-based systems since Blockchain 2.0. Various operations on blockchain are performed through the invocation and execution of smart contracts. This leads to extensive combinations between blockchain, smart contract, Internet of Things (IoT) and Cyber-Physical System (CPS) applications, and then many blockchain-based IoT or CPS applications emerge to provide multiple benefits to the economy and society. In this case, obtaining a better understanding of smart contracts will contribute to the easier operation, higher efficiency and stronger security of those blockchain-based systems and applications. Many existing studies on smart contract analysis are based on similarity calculation and smart contract classification. However, smart contract is a piece of code with special characteristics and most of smart contracts are stored without any category labels, which leads to difficulties of smart contract classification. As the back end of a blockchain-based Decentralized Application (DApp) is one or several smart contracts, DApps with labeled categories and open source codes are applied to achieve a supervised smart contract classification. A three-phase approach is proposed to categorize DApps based on various data features. In this approach, 5,659 DApps with smart contract source codes and pre-tagged categories are first obtained based on massive collected DApps and smart contracts from Ethereum, State of the DApps and DappRadar. Then feature extraction and construction methods are designed to form multi-feature vectors that could present the major characteristics of DApps. Finally, a fused classification model consisting of KNN, XGBoost and random forests is applied to the multi-feature vectors of all DApps for performing DApp classification. The experimental results show that the method is effective. In addition, some positive correlations between feature variables and categories, as well as several user behavior patterns of DApp calls, are found in this paper.