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BGP in Nigeria--25 Years of Staying True to Our Original Aspirations Through Thick and Thin

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China Oil & Gas 2024年第1期31卷 52-56页

作者： Yang Tao Bureau of Geophysical Prospecting inc

Aspan of twenty-five years,for a company,constitutes a engthy and eventful ***-five years ago,a group of oil professionals from the Bureau of Geophysical Prospecting inc (hereinafter referred to as BGP),set foot on the land of Nigeria and embarked on a legendary *** is a narrative of resilience,commitment,and heartfelt passion,an inspiring saga that touches the soul.

关键词： constitute True Geophysical

Hydrogen embrittlement of retrogression-reaged 7xxx-series aluminum alloys——a comprehensive review

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Science China Materials 2024年第11期67卷 3468-3490页

作者： Mohamed Qassem Amir Ershad Fanaei Mousa Javidani Department of Applied Science University of Québec at Chicoutimi Canadian Materials Testing Bureau inc.

Hydrogen embrittlement remains a crucial concern in industries that rely on high-strength *** to hydrogen poses a significant threat to the mechanical integrity of such *** review article briefly discusses the fundamentals of hydrogen embrittlement,including its mechanisms and the effects of various factors,such as chemical composition and environmental *** heat treatments have been developed to eliminate the risk of hydrogen *** various suggested heat treatments,the retrogression-reaging(RRA) treatment has proven effective in optimizing the balance between mechanical properties and resistance to hydrogen *** review highlights the role of RRA treatment in modifying the microstructure of Al-Zn-Mg alloys to enhance their ability to resist hydrogen embrittlement,building on existing *** interesting aspect explored in this article is the intricate relationship between pre-deformation and subsequent RRA ***,the review discusses the use of RRA as a post-weld heat treatment to mitigate the susceptibility of weldments to hydrogen embrittlement.A comprehensive exploration of these topics is beneficial for a thorough understanding of the multifaceted functions of RRA ***,despite its advantages,the widespread adoption of RRA treatment in the industry is hindered by certain *** review addresses these challenges,offering insights into the latest strategies to overcome them.

关键词： retrogression-reaging treatment hydrogen embrittlement pre-deformation weldments

State of the art of lightweight aggregates used in lightweight refractories for working lining of high-temperature furnaces

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Journal of Iron and Steel Research International 2024年第6期31卷 1320-1343页

作者： Wei Zhang Wen-yong Dai Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016LiaoningChina Research and Development Department AGC Plibrico(Dalian)Industries Inc.Dalian 116600LiaoningChina

Lightweight refractories for the working lining of high-temperature furnaces play an important role in the smelting of advanced steels and *** prepare lightweight refractories for the working lining of high-temperature furnaces,the synthesis of lightweight aggregates is the ***,the research on the synthesis of lightweight aggregates with high service temperature,low thermal conductivity,high strength,and good slag resistance has received widespread *** available literature on the synthesis of lightweight aggregates was summarized,including corundum,mullite,mullite-corundum,spinel,corundum-spinel,cordierite,cordierite-mullite,calcium hexaluminate,corundum-calcium hexaluminate,bauxite,magnesia,magnesia-based,and forsterite-based ***,the future development trend of lightweight aggregates was proposed.

关键词： Lightweight aggregate Lightweight refractory Working lining Apparent porosity Closed porosity Thermal conductivity Pore-forming approach

Advanced Electrical Motors and Control Strategies for High-quality Servo Systems-A Comprehensive Review

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Chinese Journal of Electrical Engineering 2024年第1期10卷 63-85页

作者： Ming Cheng Jiawei Zhou Wei Qian Bo Wang Chenchen Zhao Peng Han School of Electrical Engineering Southeast UniversityNanjing 210096China ESTUN Automation Co. Ltd.Nanjing 211106China Ansys Inc.San JoseCA 95134USA

Recent technological advancements have propelled remarkable progress in servo systems,resulting in their extensive utilization across various high-end applications.A comprehensive review of high-quality servo system technologies,focusing specifically on electrical motor topologies and control strategies is *** terms of motor topology,this study outlines the mainstream servo motors used across different periods,as well as the latest theories and technologies surrounding contemporary servo *** terms of control strategies,two well-established approaches are presented:field-oriented control and direct torque ***,it discusses advanced control strategies employed in servo systems,such as model predictive control(MPC)and fault tolerance control,among others.

关键词： Servo system servo motor control strategy magnetic field modulation

TextFormer: A Query-based End-to-end Text Spotter with Mixed Supervision

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Machine Intelligence Research 2024年第4期21卷 704-717页

作者： Yukun Zhai Xiaoqiang Zhang Xiameng Qin Sanyuan Zhao Xingping Dong Jianbing Shen School of Computer Science Beijing Institute of TechnologyBeijing 100081China Department of Computer Vision Technology Baidu Inc.Beijing 100193China

End-to-end text spotting is a vital computer vision task that aims to integrate scene text detection and recognition into a unified *** methods heavily rely on region-of-interest(Rol)operations to extract local features and complex post-processing steps to produce final *** address these limitations,we propose TextFormer,a query-based end-to-end text spotter with a transformer ***,using query embedding per text instance,TextFormer builds upon an image encoder and a text decoder to learn a joint semantic understanding for multitask *** allows for mutual training and optimization of classification,segmentation and recognition branches,resulting in deeper feature sharing without sacrificing flexibility or ***,we design an adaptive global aggregation(AGG)module to transfer global features into sequential features for reading arbitrarilyshaped texts,which overcomes the suboptimization problem of Rol ***,potential corpus information is utilized from weak annotations to full labels through mixed supervision,further improving text detection and end-to-end text spotting *** experiments on various bilingual(i.e.,English and Chinese)benchmarks demonstrate the superiority of our *** on the TDA-ReCTS dataset,TextFormer surpasses the state-of-the-art method in terms of 1-NED by 13.2%.

关键词： End-to-end text spotting arbitrarily-shaped texts transformer mixed supervision multitask modeling.

DEM analysis of the influence of stirrer design on die filling with forced powder feeding

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Particuology 2024年第5期88卷 107-115页

作者： Chao Zheng Edward Yost Ariel R.Muliadi Nicolin Govender Ling Zhang Chuan-Yu Wu School of Chemistry and Chemical Engineering University of SurreyGuildfordGU2 7XHUnited Kingdom Small Molecule Pharmaceutics GenentechInc.One DNA WaySouth San FranciscoCA94080USA

Die filling is a critical stage during powder compaction,which can significantly affect the product quality and *** this paper,a forced feeder is introduced attempting to improve the filling performance of a lab-scale die filling *** die filling process is analysed with a graphics processing units(GPU)enhanced discrete element method(DEM).Various stirrer designs are assessed for a wide range of process settings(i.e.,stirrer speed,filling speed)to explore their influence on the die filling performance of free-flowing *** results show that die filing with the novel helical-ribbon(i.e.,type D)stirrer design exhibits the highest filling ratio,implying that it is the most robust stirrer design for the feeder configuration ***,die filling performance with the type D stirrer design is a function of the stirrer speed and the filling speed.A positive variation of filling ratio(ηf>0%)can be ensured over the whole range of filling speed by adjusting the stirrer speed(i.e.,increasing the stirrer speed).The approach used in this study can not only help understand how the stirrer design affects the die filling performance but also guide the optimization of feeder system and process settings.

关键词： Discrete element method Die filling Forced feeding Stirrer design GPU computing

Jetting-based bioprinting:process,dispense physics,and applications

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Bio-Design and Manufacturing 2024年第5期7卷 771-799页

作者： Wei Long Ng Viktor Shkolnikov Singapore Centre for 3D Printing(SC3DP) School of Mechanical and Aerospace EngineeringNanyang Technological University(NTU)Singapore 639798Singapore HP inc. Palo AltoCA 94304USA

Jetting-based bioprinting facilitates contactless drop-on-demand deposition of subnanoliter droplets at well-defined positions to control the spatial arrangement of cells,growth factors,drugs,and biomaterials in a highly automated layer-by-layer fabrication *** to its immense versatility,jetting-based bioprinting has been used for various applications,including tissue engineering and regenerative medicine,wound healing,and drug development.A lack of in-depth understanding exists in the processes that occur during jetting-based *** review paper will comprehensively discuss the physical considerations for bioinks and printing conditions used in jetting-based *** first present an overview of different jetting-based bioprinting techniques such as inkjet bioprinting,laser-induced forward transfer bioprinting,electrohydrodynamic jet bioprinting,acoustic bioprinting and microvalve ***,we provide an in-depth discussion of various considerations for bioink formulation relating to cell deposition,print chamber design,droplet formation and droplet ***,we highlight recent accomplishments in jetting-based *** present the advantages and challenges of each method,discuss considerations relating to cell viability and protein stability,and conclude by providing insights into future directions of jetting-based bioprinting.

关键词： 3D bioprinting Biofabrication Jetting-based Dispense physics Machine learning

Derivation of a Revised Tsiolkovsky Rocket Equation That Predicts Combustion Oscillations

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Advances in Aerospace Science and Technology 2024年第1期9卷 10-27页

作者： Zaki Harari Novelant Scientific Research inc. Toronto Canada

Our study identifies a subtle deviation from Newton’s third law in the derivation of the ideal rocket equation, also known as the Tsiolkovsky Rocket Equation (TRE). TRE can be derived using a 1D elastic collision model of the momentum exchange between the differential propellant mass element (dm) and the rocket final mass (m1), in which dm initially travels forward to collide with m1 and rebounds to exit through the exhaust nozzle with a velocity that is known as the effective exhaust velocity ve. We observe that such a model does not explain how dm was able to acquire its initial forward velocity without the support of a reactive mass traveling in the opposite direction. We show instead that the initial kinetic energy of dm is generated from dm itself by a process of self-combustion and expansion. In our ideal rocket with a single particle dm confined inside a hollow tube with one closed end, we show that the process of self-combustion and expansion of dm will result in a pair of differential particles each with a mass dm/2, and each traveling away from one another along the tube axis, from the center of combustion. These two identical particles represent the active and reactive sub-components of dm, co-generated in compliance with Newton’s third law of equal action and reaction. Building on this model, we derive a linear momentum ODE of the system, the solution of which yields what we call the Revised Tsiolkovsky Rocket Equation (RTRE). We show that RTRE has a mathematical form that is similar to TRE, with the exception of the effective exhaust velocity (ve) term. The ve term in TRE is replaced in RTRE by the average of two distinct exhaust velocities that we refer to as fast-jet, vx1, and slow-jet, vx2. These two velocities correspond, respectively, to the velocities of the detonation pressure wave that is vectored directly towards the exhaust nozzle, and the retonation wave that is initially vectored in the direction of rocket propagation,

关键词： Tsiolkovsky Rocket Equation Ideal Rocket Equation Rocket Propulsion Newton’s Third Law Combustion Oscillations Combustion Instability

The Goldbach Conjecture Is True

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Open Journal of Discrete Mathematics 2024年第3期14卷 29-41页

作者： Jie Hou HQ Building Design inc. Oshawa Canada

Let 2m>2, m∈ℤ, be the given even number of the Strong Goldbach Conjecture Problem. Then, m can be called the median of the problem. So, all Goldbach partitions (p,q)exist a relationship, p=m−dand q=m+d, where p≤qand d is the distance from m to either p or q. Now we denote the finite feasible solutions of the problem as S(2m)={ (2,2m−2),(3,2m−3),⋅⋅⋅,(m,m) }. If we utilize the Eratosthenes sieve principle to efface those false objects from set S(2m)in pistages, where pi∈P, pi≤2m, then all optimal solutions should be found. The Strong Goldbach Conjecture is true since we proved that at least one optimal solution must exist to the problem. The Weak Goldbach Conjecture is true since it is a special case of the Strong Goldbach Conjecture. Therefore, the Goldbach Conjecture is true.

关键词： Median The Feasible Goldbach Partitions The Optimal Goldbach Partitions Congruences Effacement