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Portable System for CWA Detection Using Micro Array Gas Sensor

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稀有金属材料与工程 2006年第A03期35卷 124-128页

作者： j.H.Kwak Y.t.Lim G.H.Kim N.j.choi H.D.Park G.H.Rue j.S.Huh j.C.Kim D.D.Lee School of Electrical Engineering and Computer Science Kyungpook National UniversityDaegu 1370Korea Electronics and telecommunications Research Institute Future Technology Research Division New Functional Information Devices TeamGajeongYuseong-GuDaejeon 161 Korea Korea Electronics technology Institute Yatap-DongBundang-GuSeongnam-SiGyeonggi-Do #68Korea Department of Materials Science and Metallurgy Kyungpook National UniversityDaegu 1370Korea Department of Chemical Engineering Kyungpook National UniversityDaegu 1370Korea

Biochemistry weapon is raising new tools of war and *** research is an experiment about portable system for CWAs (chemical warfare agents) detection using micro array gas *** were divided into four types such as blood, nerve,vesicant,and choking *** detect various CWAs,semiconductor thick film sensor array based on tin oxide was fabricated and their gas responses were *** temperature was range of 250℃to 350℃and gas concentration was range of 0.1μg/g to 10μg/*** array was measured as operating temperatures,concentrations for four simulant agents of *** parameters from results were carried out classification among CWAs through the principal component analysis (PCA).Also,classification of gases is studied using adaptive resonance theory (ARt) that is one of neural network *** displayed using PDA system.

关键词： SnO2 chemical warfare agents(CWAs) portable system ARt array PCA

Recent Developments in Metallic Degradable Micromotors for Biomedical and Environmental Remediation Applications

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Nano-Micro Letters 2024年第3期16卷 1-35页

作者： Sourav Dutta Seungmin Noh Roger Sanchis Gual Xiangzhong Chen Salvador Pané Bradley j.Nelson Hongsoo choi Department of Robotics and Mechatronics Engineering Daegu Gyeongbuk Institute of Science and Technology(DGIST)Daegu 42988Republic of Korea DGISt‑EtH Microrobotics Research Center DGISTDaegu 42988Republic of Korea Multi‑Scale Robotics Lab Institute of Robotics and Intelligent SystemsETH Zurich8092 ZurichSwitzerland Institute of Optoelectronics State Key Laboratory of Photovoltaic Science and TechnologyShanghai Frontiers Science Research Base of Intelligent Optoelectronics and PerceptionFudan UniversityShanghai 200433People’s Republic of China

Synthetic micromotor has gained substantial attention in biomedicine and environmental ***-based degradable micromotor composed of magnesium(Mg),zinc(Zn),and iron(Fe)have promise due to their nontoxic fuel-free propulsion,favorable biocompatibility,and safe excretion of degradation products Recent advances in degradable metallic micromotor have shown their fast movement in complex biological media,efficient cargo delivery and favorable biocompatibility.A noteworthy number of degradable metal-based micromotors employ bubble propulsion,utilizing water as fuel to generate hydrogen *** novel feature has projected degradable metallic micromotors for active in vivo drug delivery *** addition,understanding the degradation mechanism of these micromotors is also a key parameter for their design and *** propulsion efficiency and life span govern the overall performance of a degradable metallic *** we review the design and recent advancements of metallic degradable ***,we describe the controlled degradation,efficient in vivo drug delivery,and built-in acid neutralization capabilities of degradable micromotors with versatile biomedical ***,we discuss micromotors’efficacy in detecting and destroying environmental ***,we address the limitations and future research directions of degradable metallic micromotors.

关键词： Magnesium Zinc Iron Biodegradable microrobot Biomedical Environmental

Applicability of cement-based grout for ground heat exchanger considering heating-cooling cycles

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Science China(technological Sciences) 2011年第7期54卷 1661-1667页

作者： Moonseo PARK SunhongMIN jeehee LIM jong Min choi Hangseok choi School of civil Environmental and Architectural Engineering Korea University Seoul Republic of Korea Department of Mechanical Engineering Hanbat National University Daejeon Republic of Korea

the applicability of cement grout （or cement-based grout） has been considered as an alternative to bentonite grout commonly used to backfill closed-loop vertical ground heat exchangers. In a geothermal heat pump system, repeated heating-cooling cycles may cause adverse effects on the integrity of cement grout in the ground heat exchanger. to account for the temperature cycling effect, the strength degradation of cement grout due to temperature cycling has been examined by measuring the unconfined compression strength of cured specimens in a humidity-temperature controlling chamber with applying temperature cycles between -5℃ and 50℃. there is a tendency that the unconfined compression strength decreases with an increase in the number of temperature cycles. On the other hand, an equivalent hydraulic conductivity of a pipe-embedded cement grout specimen was evaluated by carrying out a modified flexible wall permeameter test equipped with a water circulating system to control temperature inside the pipe section. the applied operating temperature range was from 5 to 35℃. After three cycles of heating-cooling circulation, the equivalent hydraulic conductivity becomes asymptotic to a constant value, which implies there is no severe detachment of the pipe from the cement grout.

关键词： cement grout bentonite grout thermal conductivity workability equivalent permeability coefficient

Small extrachromosomal circular DNA in amyotrophic lateral sclerosis matter

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Neural Regeneration Research 2025年第5期20卷 1411-1413页

作者： Marcos j.Arauzo-Bravo Daniela Gerovska Matthias Schwab Alexandra Kretz Computational Biology and Systems Biomedicine Biodonostia Health Research InstituteSan SebastianSpain Basque Foundation for Science IKERBASQUEBilbaoSpainMax Planck Institute for Molecular BiomedicineComputational Biology and Bioinformatics GroupMünsterNorth Rhine-WestphaliaGermany Department of Cell Biology and Histology Faculty of Medicine and NursingUniversity of Basque Country(UPV/EHU)LeioaSpain Department of Neurology Jena University HospitalJenaThuringiaGermany

Comprehensive studies identify motor neuron spectrum disorders including amyotrophic lateral sclerosis(ALS)as globally rising fatal disorders with the highest prevalence in aging populations,influenced by ethnicity and ancestry(GBD 2016 Motor Neuron Disease Colla borators,2018).While~10% of diagnoses involve a family history(fALS),most cases are considered sporadic(sALS).However,population-based studies suggest that even cases without a common index mutation impart heritability(Ryan et al.,2019),indicating a crucial role of rare and as yet unknown genetic denominators.

关键词： amyotrophic sclerosis

Efficient splitting schemes for magneto-hydrodynamic equations

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Science China Mathematics 2016年第8期59卷 1495-1510页

作者： choi Heejun SHEN jie Department of Mathematics Purdue University

We present in this paper several efficient numerical schemes for the magneto-hydrodynamic(MHD)equations. these semi-discretized(in time) schemes are based on the standard and rotational pressure-correction schemes for the Navier-Stokes equations and do not involve a projection step for the magnetic field. We show that these schemes are unconditionally energy stable, present an effective algorithm for their fully discrete versions and carry out demonstrative numerical experiments.

关键词： magneto-hydrodynamic (MHD) incompressible stability error analysis spectral method

Self-Driving Algorithm and Location Estimation Method forSmall Environmental Monitoring Robot in Underground Mines

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Computer Modeling in Engineering & Sciences 2021年第6期127卷 943-964页

作者： Heonmoo Kim Yosoon choi Department of Energy Resources Engineering Pukyong National UniversityBusan48513Korea

In underground mine environments where various hazards exist,such as tunnel collapse,toxic gases,the application of autonomous robots can improve the stability of exploration and efficiently perform repetitive exploratory *** this study,we developed a small autonomous driving robot for unmanned environmental monitoring in underground *** developed autonomous driving robot controls the steering according to the distance to the tunnel wall measured using the light detection and ranging sensor mounted on the robot to estimate its location by simultaneously considering the measured values of the inertial measurement unit and encoder *** addition,the robot autonomously drives through the underground mine and performs environmental monitoring using the temperature/humidity,gas,and particle sensors mounted on the *** a result of testing the performance of the developed robot at an amethyst mine in Korea,the robot was found to be able to autonomously drive through tunnel sections with∼28 m length,∼2.5 m height,and∼3 m width *** average error of location estimation was approximately 0.16 *** environmental monitoring sensors,temperature of 15–17◦C,humidity of 42%–43%,oxygen concentration of 15.6%–15.7%,and particle concentration of 0.008–0.38 mg/m3 were measured in the experimental area,and no harmful gases were *** addition,an environmental monitoring map could be created using the measured values of the robot’s location coordinates and environmental factors recorded during autonomous driving.

关键词： Underground mine environmental monitoring autonomous driving geographic information system

An optimized framework for degree distribution in Lt codes based on power law

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journal of Central South University 2013年第10期20卷 2693-2699页

作者： Asim Muhammad choi GoangSeog Department of Information and Communication Engineering Chosun University

Lt codes are practical realization of digital fountain codes, which provides the concept of rateless coding. In this scheme, encoded symbols are generated infinitely from k information symbols. Decoder uses only(1+α)k number of encoded symbols to recover the original information. the degree distribution function in the Lt codes helps to generate a random graph also referred as tanner graph. the artifact of tanner graph is responsible for computational complexity and overhead in the Lt codes. Intuitively, a well designed degree distribution can be used for an efficient implementation of Lt codes. the degree distribution function is studied as a function of power law, and Lt codes are classified into two different categories: SFLt and RLt codes. Also, two different degree distributions are proposed and analyzed for SFLt codes which guarantee optimal performance in terms of computational complexity and overhead.

关键词： fountain codes degree distribution overhead computational complexity power law

Iwasawa theory of Quadratic twists of X0（49）

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Acta Mathematica Sinica,English Series 2018年第1期34卷 19-28页

作者： junhwa choi john COAtES Department of Mathematics POSTECH Emmanuel College Cambridge University

the field K ---- Q（x/-At） is the only imaginary quadratic field with class number 1, in which the prime 2 splits, and we fix one of the primes p of K lying above 2. the modular elliptic curve X0 （49） has complex multiplication by the maximal order O of K, and we let E be the twist of Xo （49） by the quadratic extension K（v/M）/K, where M is any square free element of O with M -- i mod 4 and （M, 7） = 1. In the present note, we use surprisingly simple algebraic arguments to prove a sharp estimate for the rank of the MordeII-Weil group modulo torsion of E over the field F∞=k（Ep∞ ）, where Epic denotes the group of p∞-division points on E. Moreover, writing B for the twist of X0（49） by K（C/Et）/K, our Iwasawa-theoretic arguments also show that the weak form of the conjecture of Birch and Swinnerton-Dyer implies the non-vanishing at s =1 of the complex L-series of B over every finite layer of the unique Z2-extension of K unramified outside p. We hope to give a proof of this last non-vanishing assertion in a subsequent paper.

关键词： Birch-Swinnerton-Dyer conjecture elliptic curves Iwasawa theory

Grade-4 commercially pure titanium with ultrahigh strength achieved by twinning-induced grain refinement through cryogenic deformation

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journal of Materials Science & technology 2021年第7期66卷 193-201页

作者： Seong-Woo choi jae Sukjeong jong Woo Won jae Keun Hong Yoon Suk choi titanium Department.Korea Institute of Materials Science Changwon51508Republic of Korea School of Materials Science and Engineering Pusan National UniversityPusan.46241Republic of Korea Materials and Manufacturing Development team Doosan Heavy Industries and ConstructionChangwon51711Republic of Korea

the yield strength of commercially pure(CP) ti of AStM grade 4, the strongest among all the CP-ti grades, is too low for structural applications that require high-strength materials. Here, we demonstrate the strengthening of grade-4 CP ti by cryogenic-temperature rolling(CtR), which enables deformation twinning in grade-4 CP ti to achieve twinning-induced grain refinement. CtR activated {11.22} twinning and {10.12} twinning, which are the most common twinning systems in pure ti, whereas room-temperature rolling(RtR) did not activate any twinning system. CtR with imposing an area reduction of just 30% significantly increased the yield strength of the CP ti to 946 MPa, which is not achievable through typical processes performed at or above room temperature and is comparable to that of commercial ti-6 Al-4 V. the significant increase in strength was due to microstructural strengthening caused by twinning-induced grain refinement, combined with dislocation accumulation. In contrast to RtR, CtR greatly increased the stress concentration at grain boundaries(GBs), which caused the unusual activation of twinning in the grade-4 CP ti by facilitating twin nucleation at GBs. the stress concentration increased because CtR activated the slip to a lesser extent compared to RtR, thereby reducing the strain compatibility between neighboring grains. these results will contribute to development of ultrahigh-strength CP ti and may thereby extend its use to structural applications that require high-strength materials.

关键词： titanium twinning Cryogenic deformation Grain refinement tensile properties