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Causal Analysis of Futures Sugar Prices in Zhengzhou

Acta Mathematicae Applicatae Sinica 2012年第1期28卷 39-48页

作者： Fang wang Xing-wei TONG Jing xu Jian-ping chen school of Mathematical science Beijing Normal UniversityBeijing 100875China school of Information technology and Management Engineering University of International Business and EconomicsBeijing 100029China china International science and technology Convention Center No.12 Yumin RoadChaoyang DistrictBeijing 100029China

In this paper, we are interested in investigating the causal relationships among futures sugar prices in the Zhengzhou futures exchange market （ZF）, the spot sugar prices in Zhengzhou （ZS） and the futures sugar prices in New York futures exchange market （NF）. A useful tool called Bayesian network is introduced to analyze the problem. Since there are only three variables in our Bayesian network, the algorithm is straightforward： we display all the 25 possible network structures and adopt certain scoring metrics to evaluate them. We applied five different scoring metrics in total. Firstly, for each metric, we obtained 24 scores, each calculated from one of the 24 possible structures i.e. a Directed Acyclic Graph （DAG）. Then we eliminated the network structure which represents the independence of the three variables according to our prior knowledge concerning the futures sugar market. After that, the optimal network structure which implies the causal relationships was selected according to the corresponding scoring metric. Finally, after comparing the results from different scoring metrics, we obtained the relatively affirmative conclusion that ZS causes ZF from both the Bayesian Dirichlet （BD） metric, Bayesian Dirichlet-Akaike Information Criterion （BD-AIC） metric, Bayesian Dirichlet-Bayesian Information Criterion （BD-BIC） metric and Bayesian Information Criterion （BIC） metric. The conclusions that NF causes ZF and ZF causes ZS from the Akaike Information Criterion （AIC） metric and ZF causes ZS from the BIC metric were useful and significant to our investigation.

关键词： causal relationship Bayesian network BD metric AIC metric BIC metric

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线性代数中的线性方程组方法

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高等数学研究 2024年第1期27卷 62-65,84页

作者：王丽莎陈媛徐运阁湖北大学网络空间安全学院武汉430062 湖北大学数学与统计学学院应用数学湖北省重点实验室武汉430062

本文从齐次线性方程组的同解理论、非零解的判定、解空间的维数公式、解空间与系数矩阵行空间的正交性等角度,阐述线性方程组方法在线性代数中的广泛应用.

关键词：齐次线性方程组同解矩阵的秩正交

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Optimized Mid-bond Order for 3D-Stacked ICs Considering Failed Bonding

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Chinese Journal of Electronics 2015年第2期24卷 223-228页

作者： LIANG Huaguo CHANG Hao LI Yang wang Wei chen Tian xu Hui school of Electronic science & applied Physics Hefei University of Technology school of Computer and Information Hefei University of Technology Department of Computer science & technology Anhui University of Finance & Economics

One notable difference between 3D test flow and 2D test flow mainly lies in the mid-bond test, in which the stacking yield can be further enhanced through optimized bonding arrangement. In contrast to the existing sequential stacking, this paper proposes a novel rearranged stacking scheme which estimates the probability and cost of failed bonding in each stacking step and optimizes the mid-bond order to screen out the failed component as early as possible. The effect of the rearranged stacking has been extensively analyzed using the yield model and cost model of 3D-SICs considering different process parameters such as die yield, stacking size, failure rate and redundancy degree of TSVs. Experimental results demonstrate that the proposed rearranged stacking method is only a half of the sequential stacking in terms of Failed area ratio(FAR).

关键词： 3D-Stacked ICs Through silicon via(TSV) 3D-SICs test Sequential stacking Rearranged stacking Abort on fail

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硝化污泥富集及其强化高氨氮冲击的中试研究

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环境科学 2018年第4期39卷 1697-1703页

作者：盛晓琳崔灿灿王家德刘锐徐峰陈吕军浙江清华长三角研究院生态环境研究所浙江省水质科学与技术重点实验室嘉兴314006 浙江工业大学环境学院杭州310014 嘉兴绿野环境工程有限责任公司嘉兴314006 清华大学环境学院北京100084

采用膜生物反应器(MBR)为富集装置,以预处理后的城市污水外加硫酸铵为培养基质,研究了温度、溶解氧、氨氮容积负荷、游离氨(FA)和游离亚硝酸(FNA)等因子对硝化污泥富集的影响并核算富集成本,同时考察了该硝化污泥用于强化废水生物系统... 详细信息

采用膜生物反应器(MBR)为富集装置,以预处理后的城市污水外加硫酸铵为培养基质,研究了温度、溶解氧、氨氮容积负荷、游离氨(FA)和游离亚硝酸(FNA)等因子对硝化污泥富集的影响并核算富集成本,同时考察了该硝化污泥用于强化废水生物系统抗氨氮冲击能力的效果.结果表明,MBR中富集培养182 d后,污泥的硝化活性达到98.41 mg·(L·h)^(-1),比启动时提高约30倍,硝化菌产量为14.96 mg·(L·d)^(-1),富集1 kg硝化污泥成本为3.52元.温度是影响硝化污泥活性的主要因素,低于15.0℃时污泥的硝化活性降至最高值的三分之一,降低氨氮容积负荷在一定程度上可以减轻低温的影响.此外,溶解氧不足时,亚硝氮积累减缓了硝化菌富集速度.把上述富集的硝化污泥应用于受高氨氮负荷冲击的生物处理中试系统中,投加2%硝化污泥后,系统对氨氮的去除率由29.4%提高至88.4%;此后该系统在水温降至(13.3±1.6)℃时,氨氮去除率也能高达99.0%.上述中试结果显示了硝化污泥富集后用于生物强化废水生物处理系统、提高其硝化功能启动与恢复速度的可能性.

关键词：城市污水膜生物反应器硝化污泥富集硝化强化氨氮冲击

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3D bioprinting of complex biological structures with tunable elastic modulus and porosity using freeform reversible embedding of suspended hydrogels

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生物设计与制造(英文) 2023年第5期6卷 550-562页

作者： Zhuang chen Chuanzhen Huang Hanlian Liu xu Han Zhichao wang Shuying Li Jun Huang Zhen wang Centre for Advanced Jet Engineering technology(CaJET) Key Laboratory of High-Efficiency and Clean Mechanical Manufacture(Ministry of Education)National Experimental Teaching Demonstration Center for Mechanical Engineering(Shandong University)School of Mechanical EngineeringShandong UniversityJinan 250061China school of Mechanical Engineering Yanshan UniversityQinhuangdao 066004China

Three-dimensional(3D)bioprinting has been used widely for the construction of hard tissues such as bone and ***,constructing soft tissues with complex structures remains a *** this study,complex structures characterized by both tunable elastic modulus and porosity were printed using freeform reversible embedding of suspended hydrogels(FRESHs)printing methods.A mixture of alginate and gelatin was used as the main functional component of the *** analysis showed that this bioink possesses shear thinning and shear recovery properties,supporting both cryogenic and FRESH printing *** printing capabilities and limitations of cryogenic and FRESH printing were then analyzed by printability tests.A series of complex structures were printed by FRESH printing methods which could not be realized using conventional *** tests and scanning electron microscopy analysis showed that the printed structure is of excellent flexibility and could be applied in various conditions by adjusting its mechanical modulus and porosity.L929 fibroblast cells maintained cell viability in cell-laden-printed structures,and the addition of collagen further improved the hydrogels’***,all results provided useful insight into the building of human soft tissue organ blocks.

关键词： Bioink Freeform reversible embedding of suspended hydrogels(FRESHs)printing 3D extrusion cell-laden printing Tissue engineering Tunable elastic modulus and porosity

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Boosting the Capacitive Performance of Cobalt(Ⅱ) Phthalocyanine by Non-peripheral Octamethyl Substitution for Supercapacitors

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Chinese Journal of Chemistry 2021年第5期39卷 1265-1272页

作者： Minzhang Li Rajendran Ramachandran Yu wang Qian chen Zong-Xiang xu school of Chemistry and Chemical Engineering Harbin Institute of TechnologyHarbinHeilongjiang 150001China Deportment of Chemistry Southern University of Science and TechnologyShenzhenGuangdong 518055China Guangdong-Hong Kong-Macao Joint Laboratory for Photonic-Thermal-Electricol Energy Materials and Devices Southern University of Science and TechnologyShenzhenGuangdong 518055China

In this paper,pristine cobalt(Ⅱ)phthalocyanine(CoPc)and non-peripheral octamethyl substituted CoPc(N-CoMe_(2)Pc)are the focus of electrochemical *** and N-CoMe_(2)Pc nanorods(NR)were synthesized by a facile precipitation process from sublimated bulk phthalocyanine powders and their electrochemical properties were *** to the large specific surface area,the capacitance performance of the nanorods was significantly higher than that of the sublimated powder sample.N-CoMe_(2)Pc powder exhibited better pseudocapacity compared with CoPc powder and CoPc NR,which is attributed to enhanced charge transfer rate and im-proved redox activity after the introduction of octamethyl substituents on phthalocyanine *** maximum specific capacitance value was achieved by N-CoMe_(2)Pc NR based electrode,exhibiting 210.2 F g^(-1) capacitance at 5 mV s^(-1) scan rate and 156.1 F g^(-1) at 0.25 A g^(-1) current density,and also showing high efficiency and satisfactory *** results indicate that according to proper molecular design,N-CoMe_(2)Pc NR could be applied as the potential candidate for electrode material in supercapacitors.

关键词： Phthalocyanines Methylation Nanostructures Supercapacitors Electrochemistry

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Peripheral octamethyl-substituted nickel(Ⅱ)-phthalocyanine-decorated carbon-nanotube electrodes for high-performance all-solid-state flexible symmetric supercapacitors

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Journal of Energy Chemistry 2023年第1期76卷 214-225,I0006页

作者： Yu wang Minzhang Li Rajendran Ramachandran Haiquan Shan Qian chen Anxin Luo Fei wang Zong-Xiang xu Department of Chemistry Southern University of Science and TechnologyShenzhen 518055GuangdongChina Guangdong-Hong Kong-Macao Joint Laboratory for Photonic-Thermal-Electrical Energy Materials and Devices Southern University of Science and TechnologyShenzhen 518055GuangdongChina school of Microelectronics Southern University of Science and TechnologyShenzhen 518055GuangdongChina SUSTech Academy for Advanced Interdisciplinary Studies Southern University of Science and TechnologyShenzhen 518055GuangdongChina Engineering Research Center of Integrated Circuits for Next-Generation Communications Ministry of EducationShenzhen 518055GuangdongChina

Construction of advanced electrode materials with unique performance for supercapacitors(SCs)is essential to achieving high implementation in the commercial ***,we report a novel peripheral octamethyl-substituted nickel(Ⅱ)phthalocyanine(Ni Me_(2)Pc)-based nanocomposite as the electrode material of all-solid-state *** highly redox-active NiMe_(2)Pc/carboxylated carbon nanotube(CNTCOOH)dendritic nanocomposite provides rapid electron/electrolyte ion-transport pathways and exhibits excellent structural stability,resulting in high-capacity activity and impressive cycling *** composite prepared with the optimized weight ratio of Ni Me_(2)Pc:CNT-COOH(6:10)showed the highest specific capacitance of 330.5 F g^(-1)at 0.25 A g^(-1).The constructed NiMe_(2)Pc/CNT-COOH-based all-solid-state symmetric SC device showed excellent performance with a maximum energy density of 22.8 Wh kg^(-1)and outstanding cycling stability(111.6%retained after 35,000 cycles).Moreover,flexible carbon cloth significantly enhanced the energy density of the NiMe_(2)Pc/CNT-COOH all-solid-state symmetric device to 52.1 Wh kg^(-1)with 95.4%capacitance retention after 35,000 cycles,and it could be applied to highperformance flexible electronics *** findings provide a novel strategy to design phthalocyanine-based electrode materials for next-generation flexible SC devices.

关键词： Nickel phthalocyanine Carbon nanotubes Nanocomposites Flexible supercapacitors Cycling stability

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Two-dimensional Multiple-Relaxation-Time Lattice Boltzmann model for compressible and incompressible flows

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Frontiers of physics 2014年第2期9卷 246-254页

作者： Feng chen Ai-Guo xu Guang-Cai Zhang Yong-Long wang school of Aeronautics Shan Dong Jiaotong University Jinan 250357 China . .. National Key Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics P. O. Box 8009-26 Beijing 100088 China Institute of Condensed Matter Physics School of Science Linyi University Linyi 276005 China

In the paper we extend the Multiple-Relaxation-Time （MRT） Lattice Boltzmann （LB） model pro- posed in [Europhys. Lctt., 2010, 90： 54003] so that it is suitable also for incompressible flows. To decrease tile artificial oscillations, the convection term is discretized by the flux linfiter scheme with splitting technique. A new model is validated by some well-known benchmark tests, including Rie- mann problem and Couette flow, and satisfying agreements are obtained between the sinmlation results and *** ones. In order to show the merit of LB model over traditional methods, the non-equilibrium characteristics of system are solved. The simulation results are consistent with the physical analysis.

关键词： lattice Boltzmann method multiple-relaxation-time flux limiter technique Prandtlnumbers effect non-equilibrium characteristic

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A Searchable Encryption Scheme Based on Lattice for Log Systems in Blockchain

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Computers, Materials & Continua 2022年第9期72卷 5429-5441页

作者： Gang xu Yibo Cao Shiyuan xu Xin Liu Xiu-Bo chen Yiying Yu Xiaojun wang school of Information science and technology North China University of TechnologyBeijing100144China school of Information Engineering Inner Mongolia University of Science and TechnologyBaotou014010China Information Security Center State Key Laboratory of Networking and Switching TechnologyBeijing University of Posts and TelecommunicationsBeijing100876China school of Electronic Engineering Dublin City UniversityDublinIreland

With the increasing popularity of cloud storage,data security on the cloud has become increasingly *** encryption has the ability to realize the privacy protection and security of data in the ***,with the continuous development of quantum computing,the standard Public-key Encryption with Keyword Search(PEKS)scheme cannot resist quantumbased keyword guessing ***,the credibility of the server also poses a significant threat to the security of the retrieval *** paper proposes a searchable encryption scheme based on lattice cryptography using blockchain to address the above ***,we design a lattice-based encryption primitive to resist quantum keyword guessing ***,blockchain is to decentralize the cloud storage platform’s jurisdiction of *** also ensures that the traceability of keyword retrieval process and maintains the credibility of search result,which malicious platforms are prevented as much as possible from deliberately sending wrong search *** but not least,through security analysis,our proposed scheme satisfies the credibility and unforgeability of the keyword *** comprehensive performance evaluates that our scheme has certain advantages in terms of efficiency compared with others.

关键词： Lattice cryptography searchable encryption blockchain privacy protection log system information security applied cryptography

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Phase Selection and Microhardness of Directionally Solidified AlCoCrFeNi_(2.1) Eutectic High-Entropy Alloy

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Acta Metallurgica Sinica(English Letters) 2022年第8期35卷 1281-1290页

作者： Peng Peng Shengyuan Li Weiqi chen Yuanli xu xudong Zhang Zhikun Ma Jiatai wang school of Materials science and Energy Lanzhou UniversityLanzhou 730000China Gansu Institute of Metrology Lanzhou 730071China school of Physics and Electronic Information Engineering Qinghai Normal UniversityXining 810000China

In the present work,the solidification behaviors and microhardness of directionally solidified AlCoCrFeNi_(2.1) eutectic highentropy alloy(EHEA)obtained at different growth velocities are *** microstructure of the as-cast AlCoCrFeNi_(2.1) EHEA is composed of bulky dendrites(NiAl phase)and lamellar eutectic structures,indicating that the actual composition of the alloy slightly deviates from the eutectic ***,it is interesting to observe that the full lamellar structure of this alloy is obtained through directional *** order to explain this phenomenon,the maximum interface temperature criterion and the interface response function(IRF)theory are applied to calculate the velocity range of the transition from the primary phase to the eutectic,which is 1.2–2×10^(4)μm/***,microhardness is one of the important parameters to measure the mechanical properties of ***,the microhardness test is performed,and the test result indicates that the microhardness(HV)increased with increasing growth velocity(V)or decreased with increasing lamellar spacing(λ).The dependences ofλand HV on V are determined by using a linear regression *** relationships between theλ,V and HV are given as:λ=11.62V^(-0.48),HV=305.5V 0.02 and HV=328.1λ^(0.04),*** microhardness of the AlCoCrFeNi_(2.1) EHEA increases from 312.38 HV to 329.54 HV with the increase in growth velocity(5–200μm/s).Thus,directional solidification is an effective method to improve the mechanical properties of alloys.

关键词： Directional solidification Eutectic high-entropy alloy Phase selection Microstructure Microhardness

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