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Y_(2)O_(3) nanosheets as slurry abrasives for chemical-mechanical planarization of copper

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Friction 2013年第4期1卷 327-332页

作者： Xingliang HE Yunyun CHEN Huijia ZHAO Haoming SUN Xinchun LU Hong LIANG Department of Mechanical Engineering Texas A&M UniversityCollege StationTX 77843-3123USA Materials Science and Engineering Texas A&M UniversityCollege StationTX 77843-3123USA Department of Precision Instruments and Mechanology Tsinghua UniversityBeijing 100084China

Continued reduction in feature dimension in integrated circuits demands high degree of flatness after chemical mechanical *** we report using new yttrium oxide(Y_(2)O_(3))nanosheets as slurry abrasives for chemical-mechanical planarization(CMP)of *** showed that the global planarization was improved by 30%using a slurry containing Y_(2)O_(3) nanosheets in comparison with a standard industrial *** CMP,the two-dimensional square shaped Y_(2)O_(3) nanosheet is believed to induce the low friction,the better rheological performance,and the laminar flow leading to the decrease in the within-wafer-non-uniformity,surface roughness,as well as *** application of the two-dimensional nanosheets as abrasive in CMP would increase the manufacturing yield of integrated circuits.

关键词： Y_(2)O_(3)nanosheets chemical-mechanical planarization(CMP) nanoabrasives slurry flow wafer-pad contact

Synergistic effects of zeolitic imidazolate frameworks(ZIFs)with different transition metals on intumescent flame-retarded polypropylene composites:A comparative study

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Journal of Materials Science & Technology 2023年第24期155卷 102-110页

作者： Yufeng Quan Ruiqing Shen Christian Schweizer Pradeep Parajuli Zhuoran Zhang Waruna Kulatilaka Qingsheng Wang Artie McFerrin Department of Chemical Engineering Texas A&M University College Station TX 77843-3122 USA J. Mike Walker ’66 Department of Mechanical Engineering Texas A&M University College Station TX 77843-3123 USA

The use of intumescent flame retardants(IFRs)is considered an environmentally friendly and cost-effective strategy to suppress potential fire hazards from synthetic ***,some conventional IFRs are neither efficient in developing a thermally stable char layer nor reducing the release of toxic byproducts during polymer *** this work,we aim to discuss the effects of zeolitic imidazolate frameworks(ZIFs)on synergistically improving the flame retardancy behaviors in polypropylene(PP)composites,including thermal degradation(evolved gas analysis),free radical reactions in the gaseous phase(in-situ chemiluminescent image analysis),and carbonaceous structure in the condensed phase(micro-morphology and composition analysis).It is found that the transition metals in ZIFs can catalytically accelerate the crosslinking reaction at a lower initial temperature and decrease the amount of hydrocarbon volatiles in the gaseous *** ignited,the embedded ZIFs can firstly bridge adjacent phosphorus chains in the polymer matrix to expand crosslinking degrees and then they are anchored in the developed N-doped phospho-carbonaceous networks after *** a result,more compact char residue structures are observed in the condensed phase for ZIF-reinforced *** example,by replacing 2 wt%of IFR with ZIF-67,the peak heat release rate,peak smoke production rate,and peak CO production rate are reduced by 69%,80%,and 72%,respectively,when compared to the conventional *** results indicate an excellent solution to resolve inherent fire hazards associated with IFRs in polymers and achieve necessary efficiency for industrial *** also provides a new strategy for determining flammability characteristics and combustion mechanisms of polymer composites using in-situ chemiluminescence analysis.

关键词： Polymer flammability Intumescent flame retardants Zeolitic imidazolate frameworks Thermal degradation Free radical analysis Flame retardant mechanism

Rapid accessibility evaluation for ballistic lunar capture via manifolds: A Gaussian process regression application

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Astrodynamics 2022年第4期6卷 375-397页

作者： Sandeep K.Singh John L.Junkins Manoranjan Majji Ehsan Taheri Department of Aerospace Engineering Texas A&M UniversityCollege StationTX 77843USA Department of Aerospace Engineering Auburn UniversityAuburnAL 36849USA

In this study,a supervised machine learning approach called Gaussian process regression(GPR)was applied to approximate optimal bi-impulse rendezvous maneuvers in the cis-lunar *** demonstrate the use of the GPR approximation of the optimal bi-impulse transfer to patch points associated with various invariant manifolds in the cis-lunar *** proposed method advances preliminary mission design operations by avoiding the computational costs associated with repeated solutions of the optimal bi-impulsive Lambert transfer because the learned map is computationally *** approach promises to be useful for aiding in preliminary mission *** use of invariant manifolds as part of the transfer trajectory design offers unique features for reducing propellant consumption while facilitating the solution of trajectory optimization *** ballistic capture coasts are also very attractive for mission guidance,navigation,and control robustness.A multi-input single-output GPR model is presented to represent the fuel costs(in terms of theΔV magnitude)associated with the class of orbital transfers of interest *** developed model is also proven to provide efficient *** multi-resolution use of local GPRs over smaller sub-domains and their use for constructing a global GPR model are also *** of the unique features of GPRs is that they provide an estimate of the quality of approximations in the form of covariance,which is proven to provide statistical consistency with the optimal trajectories generated through the approximation *** numerical results demonstrate our basis for optimism for the utility of the proposed method.

关键词： Gaussian process regression supervised learning invariant manifolds ballistic transfers Bayesian inference

Elimination of antibiotic resistance genes and control of horizontal transfer risk by UV-based treatment of drinking water: A mini review

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Frontiers of Environmental Science & Engineering 2019年第3期13卷 3-11页

作者： Virender K.Sharma Xin Yu Thomas J.McDonald Chetan Jinadatha Dionysios D.Dionysiou Mingbao Feng Department of Environmental and Occupational Health School of Public Health Texas A&M University College Station TX 77843 USA Institute of Urban Environment Chinese Academy of Sciences Xiamen 361021 China Central Texas Veterans Health Care System Temple TX 76504 USA College of Medicine Texas A&M Health Science Center Bryan TX 77807 USA Environmental Engineering and Science Program Department of Chemical and Environmental Engineering (DChEE) 705 Engineering Research Center University of Cincinnati Cincinnati OH 45221 USA

Antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) have been recognized as one of the biggest public health issues of the 21 st century. Both ARB and ARGs have been determined in water after treatment with conventional disinfectants. Ultraviolet (UV) technology has been seen growth in application to disinfect the water. However, UV method alone is not adequate to degrade ARGs in water. Researchers are investigating the combination of UV with other oxidants (chlorine, hydrogen peroxide (H2O2), peroxymonosulfate (PMS), and photocatalysts) to harness the high reactivity of produced reactive species (C1-, C1O -, Cl2-,-OH, and SO4-_) in such processes with constituents of cell (e.g., deoxyribonucleic acid (DNA) and its components) in order to increase the degradation efficiency of ARGs. This paper briefly reviews the current status of different UV-based treatments (UV/chlorination, UV/H2O2, UV/PMS, and UV-photocatalysis) to degrade ARGs and to control horizontal gene transfer (HGT) in water. The review also provides discussion on the mechanism of degradation of ARGs and application of q-PCR and gel electrophoresis to obtain insights of the fate of ARGs during UV-based treatment processes.

关键词： Antibiotic resistance bacteria Advanced oxidation processes Disinfection Reactive chlorine species Sulfate radicals Reactive oxygen species

速度-压力岩石物理模型及其在页岩孔隙压力预测中的应用

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石油勘探与开发 2023年第2期50卷 360-372页

作者：郭静怡李敏庄明伟孙跃峰德克萨斯A&M大学地质与地球物理系大学城77843美国中国石油集团东方地球物理勘探有限责任公司西南物探研究院成都610213 厦门大学电磁声学研究院福建厦门361005

针对现有基于声波速度的经验公式进行地层压力预测时影响因素复杂的问题,应用弹性岩石物理模型来定量分析研究速度-压力关系的各种控制因素,提出孔构参数(γ)与压差之间的解析关系,并揭示压力对岩石体积模量和纵波速度等弹性性质的主控... 详细信息

针对现有基于声波速度的经验公式进行地层压力预测时影响因素复杂的问题,应用弹性岩石物理模型来定量分析研究速度-压力关系的各种控制因素,提出孔构参数(γ)与压差之间的解析关系,并揭示压力对岩石体积模量和纵波速度等弹性性质的主控作用,进而准确预测孔隙压力。含气页岩中微裂缝及断裂发育时,异常高压下(高γ值)细小裂缝及扁平孔隙张开,岩石体积模量远低于其在静水压力下(低γ值)平均孔隙结构偏圆时的状态。结合岩心、测井及地震数据,利用此岩石物理压力关系刻画四川盆地丁山地区上奥陶统五峰组—下志留统龙马溪组页岩的孔隙压力三维空间分布变化,压力系数与含气量呈正相关,该预测结果与现场实测数据吻合较好。岩石物理压力关系的分析和方法的提出对非常规和常规油气田的勘探、生产和钻井安全都具有重要借鉴价值。

关键词：孔隙压力压力系数声波速度体积模量孔隙结构页岩气上奥陶统五峰组下志留统龙马溪组四川盆地

CRISPR-Cas9 mediated phage therapy as an alternative to antibiotics

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Animal Diseases 2023年第4期3卷 231-241页

作者： Fikre Birhanu Balcha Sultan Abda Neja Faculty of Veterinary Medicine Hawassa UniversityP.O.Box 05HawassaEthiopia Institute of Bioscience and Technology Texas A&M University2121 West Holcombe BlvdHoustonTX77030USA

Inappropriate use of antibiotics is globally creating public health hazards associated with antibiotic *** often acquire antibiotic resistance by altering their genes through mutation or acquisition of plasmid-encoding resistance *** treat drug-resistant strains of bacteria,the recently developed CRISPR-Cas9 system might be an alternative molecular tool to conventional *** disables antibiotic-resistance genes(plasmids)or deactivates bacterial virulence factors and sensitizes drug-resistant bacteria through site-specific cleavage of crucial domains of their *** molecular tool uses phages as vehicles for CRISPR-cas9 delivery into *** phages are species-specific and natural predators of bacteria,they are capable of easily injecting their DNA to target *** CRISPR system is packaged into phagemid vectors,in such a way that the bacteria containing the antibiotic-resistance plasmid sequence or that containing specific DNA sequences were made to be *** CRISPR delivery,Cas9 is programmed to recognize target sequences through the guide RNA thereby causing double-strand cleavage of targeted bacterial DNA or loss of drug resistance plasmid,which results in cell ***,the safety and efficacy of this newly developed biotechnology tool and the biocontrol product need to be further refined for its usage in clinical translation.

关键词： CRISPR-Cas9 Bacteriophage Phagemid Antibiotic-resistant

Predicting muscular strength using demographics,skeletal dimensions,and body composition measures

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Sports Medicine and Health Science 2021年第1期3卷 34-39页

作者： Sean T.Stanelle Stephen F.Crouse Tyler R.Heimdal Steven E.Riechman Alexandra L.Remy Bradley S.Lambert Department of Health and Kinesiology Texas A&M University400 Bizzell StCollege StationTXUSA Department of Orthopedics Baylor University Medical Center3500 Gaston AveDallasTXUSA Department of Orthopedics and Sports Medicine Houston Methodist Hospital6565 Fannin StHoustonTXUSA

The purpose of this study was to develop an equation to predict strength for seven common resistance training exercises using anthropometric and demographic ***-hundred forty-seven healthy adults(74 males,73 females,3512 yr,17410 cm,8819 kg)volunteered to *** composition values(regional/total)and body dimensions were assessed using dual-energy x-ray absorptiometry(DEXA).Subjects underwent the following maximal strength assessments:Leg Press,Chest Press,Leg Curl,Lat Pulldown,Leg Extension,Tri-ceps Pushdown,and Biceps *** linear regression with stepwise removal was used to determine the best model to predict maximal strength for each *** predictor variables identified(p<0.05)were height(cm);weight(kg);BMI;age;sex(0=F,1=M);regional lean masses(LM,kg);fat mass(FM,kg);fat free mass(FFM,kg);percent fat(%BF);arm,leg,and trunk lengths(AL,LL,TL;cm);and shoulder width(SW,cm).Analyses were performed with and without regional measures to accommodate scenarios where DEXA is *** models presented were significant(p<0.05,R^(2)=0.68-0.83),with regional models producing the greatest *** indicate that maximal strength for individual resistance exercises can be reasonably estimated in adults.

关键词： Strength training Exercise testing Regression equation DEXA

Altered Carbon Partitioning Enhances CO_(2)to Terpene Conversion in Cyanobacteria

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BioDesign Research 2022年第1期2022卷 369-380页

作者： Man Li Bin Long Susie Y.Dai James W.Golden Xin Wang Joshua S.Yuan Synthetic and Systems Biology Innovation Hub Texas A&M UniversityCollege StationTexas 77843USA Department of Plant Pathology and Microbiology Texas A&M UniversityCollege StationTexas 77843USA Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application State Key Laboratory of Applied Microbiology Southern ChinaInstitute of MicrobiologyGuangdong Academy of ScienceChina Section of Molecular Biology University of California San DiegoLa JollaCA 92093USA Department of Microbiology Miami UniversityOxfordOhio 45056USA

Photosynthetic terpene production represents one of the most carbon and energy-efficient routes for converting CO_(2)into *** photosynthetic organisms,metabolic engineering has led to limited success in enhancing terpene productivity,partially due to the low carbon *** this study,we employed systems biology analysis to reveal the strong competition for carbon substrates between primary metabolism(e.g.,sucrose,glycogen,and protein synthesis)and terpene biosynthesis in Synechococcus elongatus PCC *** then engineered key“source”and“sink”***“source”limitation was overcome by knocking out either sucrose or glycogen biosynthesis to significantly enhance limonene production via altered carbon ***,a fusion enzyme complex with geranyl diphosphate synthase(GPPS)and limonene synthase(LS)was designed to further improve pathway kinetics and substrate *** synergy between“source”and“sink”achieved a limonene titer of 21.0 mg/***,the study demonstrates that balancing carbon flux between primary and secondary metabolism can be an effective approach to enhance terpene bioproduction in *** design of“source”and“sink”synergy has significant potential in improving natural product yield in photosynthetic species.

关键词： metabolism overcome kinetics

Rock physics model for velocity–pressure relations and its application to shale pore pressure estimation

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Petroleum Exploration and Development 2023年第2期50卷 404-418页

作者： GUO Jingyi LI Min ZHUANG Mingwei SUN Yuefeng Department of Geology&Geophysics Texas A&M UniversityCollege Station77843United States Southwest Geophysical Research Institute BGPCNPCChengdu 610213China Institute of Electromagnetics and Acoustics Xiamen UniversityXiamen 361005China

Acoustic wave velocity has been commonly utilized to predict subsurface geopressure using empirical *** wave velocity is, however, affected by many factors. To estimate pore pressure accurately, we here propose to use elastic rock physics models to understand and analyze quantitatively the various contributions from these different factors affecting wave velocity. We report a closed-form relationship between the frame flexibility factor(γ) in a rock physics model and differential pressure, which presents the major control of pressure on elastic properties such as bulk modulus and compressional wave velocity. For a gas-bearing shale with abundant micro-cracks and fractures, its bulk modulus is much lower at abnormally high pore pressure(high γ values) where thin cracks and flat pores are open than that at normal hydrostatic pressure(low γ values) where pores are more rounded on average. The developed relations between bulk modulus and differential pressure have been successfully applied to the Upper Ordovician Wufeng and Lower Silurian Longmaxi formations in the Dingshan area of the Sichuan Basin to map the three-dimensional spatial distribution of pore pressure in the shale, integrating core, log and seismic data. The estimated results agree well with field measurements. Pressure coefficient is positively correlated to gas content. The relations and methods reported here could be useful for hydrocarbon exploration, production, and drilling safety in both unconventional and conventional fields.

关键词： pore pressure pressure coefficient acoustic velocity bulk modulus pore structure shale gas Upper Ordovician Wufeng Formation Lower Silurian Longmaxi Formation Sichuan Basin