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Synthesis and characterization of PMMA/Al_2O_3 composite particles by in situ emulsion polymerization

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Particuology 2008年第3期6卷 207-213页

作者： Hui liu hongqi Ye Tianquan Lin Tao Zhou College of Chemistry and Chemical Engineering Central South University Changsha 410083 China

In order to improve its dispersibility, superfine alumina （A1203） was encapsulated with poly（methyl methacrylate）（PMMA） by in situ emulsion polymerization. It was found that only when the concentration of sodium dodecyl sulfate （SDS） was much higher than its critical micelle concentration, could PMMA/Al2O3 composite particles with high percentage of grafting （PG） be prepared. The same results were obtained between the experimental and stoichiometric amounts of tris（dodecylbenzenesulfonate） isopropoxide （NDZ）, indicating that single-molecule-layer adsorption had taken place between NDZ and Al2O3. Analysis using FTIR, TEM and XPS showed that PMMA/Al2O3 composite particles with core-shell structure had been successfully synthesized by in situ emulsion polymerization. Compared to Al2O3, thermal stability and dispersibility of the composite particles showed marked improvement.

关键词： PMMA Alumina Composite particle Encapsulation Dispersibility

Time-frequency analysis and detecting method research on milling force token signal in spindle current signal

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Science China(Technological Sciences) 2009年第10期52卷 2810-2813页

作者： MAO XinYong liu hongqi LI Bin National NC System Engineering and Research Center Huazhong University of Science and TechnologyWuhan 430074China State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China

The vast majority of tool condition monitoring systems use the motor current instead of the cutting force as the predictor signal. The measured motor current signal is time-dependant and instable. It is difficult to detect the cutting force token signal from such motor current signal. This paper presents a method that uses the wavelet transforms to reconstruct the cutting force token signal from the current signal based on the time frequency analysis of the cutting force signal. The result of the cutting force measurement experiment shows that the proposed reconstruct method could be used to analyze the spindle current and monitor the time-varying cutting force.

关键词： tool monitoring spindle current cutting force wavelet transform

Study of Fractal Characteristics of the Cementation Index in Shale Gas

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Acta Geologica Sinica(English Edition) 2020年第2期94卷 456-466页

作者： liu hongqi liu Shiqiong LUO Xingping SUN Yangsha TIAN Jie LIANG Lixi liu Xiangjun School of GeoScience and Technology Southwest Petroleum UniversityChengdu 610500China Institute of exploration and development Petrochina Xinjiang oilfield company.Junggar road 29#.KaramayXinjiangChina College of Petroleum Engineering.Southwest Petroleum University Chengdu 610500China

The description of pores and fracture structures is a consistently important issue and certainly a difficult problem, especially for shale or tight rocks. However, the exploitation of so-called unconventional energy, such as shale methane and tight-oil, has become more and more dependent on an understanding of the inner structure of these unconventional reservoirs. The inner structure of porous rocks is very difficult to describe quantitatively using normal mathematics, but fractal geometry, which is a powerful mathematical tool for describing irregularly-shaped objects, can be applied to these rocks. To some degree, the cementation index and tortuosity can be used to describe the complexity of these structures. The cementation index can be acquired through electro-lithology experiments, but, until now, tortuosity could not be quantitatively depicted. This research used the well-logging curves of a gas shale formation to reflect the characteristics of the rock formations, and the changes in the curves to indicate the changes of the rock matrix, the pores, the connections among the pores, the permeability, and the fluid type. The curves that are affected most by the rock lithology, such as gamma ray, acoustic logging, and deep resistivity curves, can provide significant information about the micro-or nanostructure of the rocks. If the rock structures have fractal characteristics, the logging curves will also have fractal properties. Based on the definition of a fractal dimension and the Hausdorff dimension, this paper presents a new methodology for calculating the fractal dimensions of logging curves. This paper also reveals the deep meaning of the rock cementation index, m, through the Hausdorff dimension, and provides a new equation to calculate this parameter through the resistivity and porosity of the formation. Although it represents a very important relationship between the saturation of hydrocarbons with pores and resistivity, the Archie formula was not availa

关键词： fractal geometry nano-scale well-logging curve cementation index tight rocks gas shale

Multi-models associated with process information-driven process autonomous digital twin for multi-variety production of intelligent machines

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Science China Technological Sciences 2024年第12期67卷 3825-3842页

作者： ZHANG Lu WANG Xiao HE SongPing MAO XinYong LI Bin liu hongqi State Engineering Research Center of Digital Manufacturing and Equipment Huazhong University of Science and Technology Wuhan Heavy Duty Machine Tool Group Corporation National NC System Engineering Research Center Huazhong University of Science and Technology

The intelligent development of machines, as one of the essential research components of smart manufacturing, is urgently needed to improve the intelligent production of product manufacturing processes within product families. The uncertainty of the process requirements within a product family and the time-varying nature of the processing performance of machines pose significant challenges for intelligent manufacturing. Digital twins(DTs) have proven to be very effective architectures for intelligent manufacturing; DTs support dynamic modeling capabilities in time and space and can provide effective technical support for manufacturing intelligence under multi-variety production. Therefore, a process autonomous digital twin(PADT) framework driven by characterization, prediction, and evaluation-based multi-models(CPEM) associated with process information is constructed to realize intelligent production. First, the multidimensional information contained in the machining process is analyzed to accurately locate the features of machining precision, and a machine performance characterization model is ***, a machine capacity prediction model based on time-scale information fusion is established to predict the processing capacities of machines under different production demands. Finally, a product distribution evaluation model based on the 3σ rule is established, which provides an effective evaluation index for the optimization of processing parameters. The application of CPEM-driven PADT in a commutator machining machine provides predictive manufacturing intelligence within a product family.

关键词： process autonomous digital twin precision performance characterization performance prediction model distribution evaluation model manufacturing intelligence

Short sellers' accusations against Chinese reverse mergers: Information analytics or guilt by association?

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China Journal of Accounting Research 2015年第2期8卷 111-131页

作者： hongqi liu Nan Xu Jianming Ye Southwestern University of Finance and Economics Baruch College City University of New York Xiamen University

This paper studies short sellers' trading strategies and their effects on the financial market by examining their accusations of fraud against Chinese reverse merger firms(CRMs) in the US. We find that short sellers rely on firms' fundamental information, especially relative financial indicators, to locate their "prey." Specifically, they compare a target firm's financial indicators(e.g., growth and receivables) with both the industry average and the firm's history. We find no evidence that short sellers accuse CRMs simply because of their reverse merger label. Additionally, we test the accuracy of short sellers' accusations in the long run and find that accused firms are more likely to delist and less likely to recover from price plunges. Our results also indicate that CRMs' high exposure to short sellers' accusations stem from adverse selection problems: firms with high litigation risk are more likely to choose reverse mergers to access the US capital market. Overall, our results support the view that short sellers are sophisticated investors and shed some light on their decision processes.

关键词： Chinese reverse mergers Fraud accusation Guilt by

Tight Carbonate Microstructure and its Controls: A Case Study of Lower Jurassic Da'anzhai Member, Central Sichuan Basin

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Acta Geologica Sinica(English Edition) 2020年第2期94卷 305-321页

作者： LI Bo WANG Xingzhi liu hongqi WANG Yongjun TIAN Jie HUO Fei GAO Zhaolong State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Chengdu 610500China School of Geoscience and Technology Southw est Petroleum UniversityChengdu 610500 China Research Institute of Petroleum Exploration&Development Beijing 100083China The Institute of Exploration and Development of Southwest Oil and Gas Field Branch.PetroChina.Chengdu 610059 China

Cast thin section observation, scanning electron microscopy(SEM), high-pressure mercury injection(HPMI), and nuclear magnetic resonance(NMR) were used to examine the microstructure of tight carbonate reservoirs in the Lower Jurassic Da’anzhai Member, the central Sichuan Basin. The pore space in the Da’anzhai Member is classified into 2 types and 17 subtypes, with nano-scale pore throats of ‘O’, ‘S’, ‘Z’, and ‘I’ shapes. Poorly sorted pore throats vary greatly in diameter;thus, it is difficult for fluid flow to pass through these pore throats. There are three classes of pore throats in carbonate reservoirs, i.e. isolated pores, pores coexisting with fractures, and large pores and fractures. Isolated pores may provide some pore space, but the permeability is low. Pores and fractures coexisting in the reservoir may have a great impact on porosity and permeability;they are the major pore space in the reservoir. Large pores and fractures have a great impact on reservoir properties, but they only account for a limited proportion of total pore space. The microstructure of Da’anzhai reservoirs, which dominates fluid mobility, is dependent on sedimentary environment, diagenesis, and tectonic process. Pore structure is related to sedimentary environment. The occurrence of microfractures, which may improve reservoir properties, is dependent on tectonic process. Diageneses are of utmost importance to pore evolution, cementation and growth of minerals have played an important role in destroying reservoir microstructure.

关键词： tight carbonate rocks microscopic pore structure diagenesis Da'anzhai Member Lower Jurassic Sichuan Basin

Advanced Flexible Carbon‑Based Current Collector for Zinc Storage

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Advanced Fiber Materials 2022年第6期4卷 1500-1510页

作者： Hao Jia Minghui Qiu Chunxia Tang hongqi liu Jinlin Xu Benjamin Tawiah Shou‑xiang Jiang Xiangwu Zhang Key Laboratory of Eco‑Textiles Ministry of EducationJiangnan UniversityWuxiJiangsuPeople’s Republic of China Institute of Textiles and Clothing The Hong Kong Polytechnic UniversityHong KongPeople’s Republic of China Department of Industrial Art(Textiles) Kwame Nkrumah University of Science and TechnologyKumasiGhana Fiber and Polymer Science Program Department of Textile EngineeringChemistry and ScienceWilson College of TextilesNorth Carolina State UniversityRaleighNC 27695‑8301USA

Carbon cloth(CC)-based electrodes have attracted extensive attention for next-generation wearable energy-storage devices due to their excellent electrical conductivity and mechanical ***,the application of conventional CC-based electrodes for zinc(Zn)storage severely hinders Zn ion transport and induces deleterious Zn dendrite growth,resulting in poor electrochemical ***,a novel oxygen plasma-treated carbon cloth(OPCC)is rationally designed as a current collector for flexible hybrid Zn ion supercapacitors(ZISs).The modified interface of OPCC with abundant oxygenated groups enables enhanced electrolyte wettability and uniform superficial electric field distribution.A prolonged working lifespan for Zn electrodeposition is achieved by the OPCC due to the improved interfacial kinetics and homogenized ion *** as-prepared hybrid ZIS also delivers excellent cycling endurance(98.5%capacity retention for 1500 cycles)with outstanding operation stability under various extreme *** facile surface modification strategy provides a new way for developing future flexible electrodes for wearable electronic products.

关键词： Zinc ion supercapacitor Carbon cloth Oxygen plasma treatment Interface kinetics

A multi-step induced strategy to fabricate core-shell Pt-Ni alloy as symmetric electrocatalysts for overall water splitting

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Nano Research 2022年第2期15卷 965-971页

作者： Wenjuan Xu Jinfa Chang Yinggang Cheng hongqi liu Jifan Li Yongjian Ai Zenan Hu Xinyue Zhang Yiming Wang Qionglin Liang Yang Yang Hongbin Sun Department of Chemistry Northeastern UniversityShenyang 110819China NanoScience Technology Center Department of Materials Science and EngineeringUniversity of Central FloridaOrlandoFL 32826USA Key Laboratory of Bioorganic Phosphorus Chemistry&Chemical Biology(Ministry of Education) Department of ChemistryCenter for Synthetic and Systems BiologyTsinghua UniversityBeijing 100084China

Devising an electrocatalyst with brilliant efficiency and satisfactory durability for hydrogen production is of considerable demand,especially for large-scale ***,we adopt a multi-step consequential induced strategy to construct a bifunctional electrocatalyst for the overall water *** oxide(GO)was used as a carbon matrix and in situ oxygen source,which was supported by the octahedral PtNi alloy to form the PtxNiy-GO *** calcinating in Ar atmosphere,the oxygen in GO induced the surface segregation of Ni from the PtNi octahedron to form a core-shell structure of Ptx@***,the surface-enriched Ni continuously induced the reformation of C in reduced graphene oxide(rGO)to enhance the degree of *** multi-step induction formed a nanocatalyst Pt_(x)@Ni_(y)-rGO which has very high catalytic efficiency and *** optimizing the feeding ratio of PtNi(Pt:Ni=1:2),the electrolytic overall water splitting at 10 mA·cm^(-2) can be driven by an electrolytic voltage of as low as 1.485 V,and hydrogen evolution reaction(HER)only needs an overpotential of 37 mV in 1.0 M KOH aqueous ***,the catalyst exhibited consistent existence form in both HER and oxygen evolution reaction(OER),which was verified by switching the anode and cathode of the cell in the electrolysis of *** work provides a new idea for the synthesis and evaluation of the bifunctional catalysts for water splitting.

关键词： continuous induction core-shell structured Pt@Ni graphene oxide hydrogen evolution reaction alkaline water splitting

Reverse genetics in virology:A double edged sword

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Biosafety and Health 2022年第5期4卷 303-313页

作者： Hongyu Chen hongqi liu Xiaozhong Peng Institute of Medical Biology Chinese Academy of Medical Sciences and Peking Union Medical SchoolKunming 650118China Institute of Basic Medical Sciences Chinese Academy of Medical Sciences and Peking Union Medical SchoolBeijing 100051China Institute of Laboratory Animals Science Chinese Academy of Medical Sciences and Peking Union Medical SchoolBeijing 100021China

Reverse genetics via targeted modification of gene sequences to obtain a phenotype and the inference of a gene's function or regulatory mechanism is widely used as a potent tool in viral biology and ***,while reverse genetics has contributed significantly to our understanding of molecular biology and the pathogenesis of viruses,its accessibility(operation)and openness(data)have raised many concerns regarding biosafety and *** this review,we retrospectively examine the development of reverse genetics and its applications in virology,then emphasize global biosafety and biosecurity concerns regarding reverse genetics,and summarize global regulations,governance,and laws on reverse *** review seeks to enhance our understanding and rational application of reverse genetics technology for the benefit of humankind.

关键词： Reverse genetics Virology Dual use research of concern Biosafety Biosecurity Regulation