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Effect of Microstructures on Elevated-Temperature Wear Resistance of a Hot Working Die Steel

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Journal of Iron and Steel Research International 2011年第10期18卷 47-53页

作者： WEI min-xian WANG Shu-qi WANG Lan CHEN kang-min School of Materials Science and Engineering Jiangsu University Zhenjiang 212013 Jiangsu China

Elevated-temperature wear tests under atmospheric conditions at 400 ℃ were performed for a hot working die steel H21 on a pin-on-disk wear tester. The phase and morphology of worn surfaces were examined using XRD and SEM, and the relation of wear resistance to tempered microstructures was studied for H21 steel. XRD patterns exhibit that oxidative wear is a predominated wear mechanism with Fe3O4 and Fe2O3 on worn surfaces. It is found that with increasing normal load, obvious plastic deformation of substrate appears on worn surfaces. Microstructures start to affect apparently wear resistance of the steel with an increase of load. Under loads of 50--100 N, wear losses of steel retain low values and relatively approach for steels with various microstructures. As loads are increased to 150--200 N, wear losses of steel start to increase obviously and present apparent difference for steel with various microstructures. Wear resistance is found to increase in the sequence as follows., tempered sorbite, tempered martensite, tempered troostite without secondary hardening and tempered troostite with secondary hardening or upcoming one. Higher strength and microstructural stability are required for steels with excellent wear resistance.

关键词： steel heat treatment microstructure wear wear resistance

Complexity Effective Frequency and Sidelink Synchronization Algorithm for LTE Device-to-Device Communication Systems

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Computers, Materials & Continua 2020年第1期62卷 443-458页

作者： Yong-An Jung min-Goo kang Young-Hwan You Department of Computer Engineering Sejong UniversitySeoulKorea Department of IT Contents Hanshin UniversityGyeonggi-doKorea

Device-to-device(D2D)communication is considered as a major challenge in the long term evolution(LTE)network wherein devices directly communicate with each *** of the key challenges in D2D sidelink is reliable and reduced-complexity *** address this issue,a computationally efficient sequential detection scheme for integer carrier frequency offset and sidelink identity is proposed in the LTE-D2D *** perform the frequency offset detection without retrieving the sidelink identity,the conjugate relation between two primary sidelink synchronization sequences is exploited,which facilitates the detection tasks of frequency offset and sidelink identity to be *** is demonstrated from simulation results that the inherent property of the sidelink synchronization sequences is effectively used for joint detection of frequency offset and sidelink identity with significantly reduced complexity,compared to existing estimation schemes.

关键词： Long term evolution device-to-device communication carrier frequency offset sidelink identity sidelink synchronization

Stable metal-organic frameworks with high catalytic performance in the cycloaddition of CO_2 with aziridines

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Science China Chemistry 2019年第5期62卷 622-628页

作者： Xiao-min kang Ying Shi Chun-Shuai Cao Bin Zhao College of Chemistry and Key Laboratory of Advanced Energy Material Chemistry Nankai University

Based on the mixed ligands XN(4′-(4-pyridine)4,2′:2′,4′′-terpyridine) and isophthalic acid(IPA), three new metal-organic frameworks(MOFs) {[M_2(XN)_2(IPA)_2]·2 H_2O}_n(M=Co(1), Mn(2), Ni(3)) were assembled and structurally characterized,presenting 3 D pillar-chain feature structures. Stability measurements demonstrate that these compounds possess high thermostability and can endure different organic solvents as well as various acid/base solutions with pH range of 1 to 14. Importantly,compounds 1–3 can serve as high-efficiency catalysts for the transformation of CO_2 and aziridines to form high-value oxazolidinones under mild conditions, exhibiting excellent cyclicity at least five times.

关键词： MOFs stability catalysis oxazolidinones CO2 conversion

Textural and compositional variation of mica from the Dexing porphyry Cu deposit:constraints on the behavior of halogens in porphyry systems

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Acta Geochimica 2023年第2期42卷 221-240页

作者： Yan Liu Jian-Feng Gao Liang Qi kang min State Key Laboratory of Ore Deposit Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China University of Chinese Academy of Sciences Beijing 100049China

The Dexing porphyry deposit is the largest porphyry Cu–Mo–Au deposit in South *** composition can record the physicochemical conditions and evolution history of magmatic-hydrothermal *** from the Dexing porphyry deposit could be divided to three types:primary magmatic biotite(Bi-M),hydrothermal altered magmatic biotite(Bi-A)and hydrothermal biotite(Bi-H).The temperature of Bi-M and Bi-H range from 719 to 767℃ and 690 to 727℃,*** magmatic and hydrothermal biotite have high Fe^(3+)/Fe^(2+)ratios(from 0.18 to 0.24)and XMgvalues(from 0.57 to 0.66),indicating a high oxygen *** has F lower than Bi-A and Bi-H(up to 0.26 wt%),but has Cl(Cl=0.18–0.30 wt%)similar to Bi-A and Bi-H(Cl=0.21–0.35 wt%),suggesting that high Cl/F ratios of early hydrothermal fluid may result from the exsolution from high Cl *** potassic alteration zone to phyllic and propylitic alteration zones,Cl decreases with increasing Cu,whereas F increases ***,Cl mostly originate from magma,but enrichment of F possibly results from reaction of fluids and Neoproterozoic *** correlation between Cl and Cu indicates that Cl might act as an important catalyst during Cu mineralization *** from Dexing has similar halogen compositions to other porphyry Cu-/Mo deposits in the *** contents of hydrothermal fluid may be critical for Cu transportation and enrichment,while consumption of Cl would promote Cu deposition.

关键词： Halogen Dexing porphyry deposit Biotite Geochemistry Porphyry Cu deposit

Genomic organization and transcriptional modulation in response to endocrine disrupting chemicals of three vitellogenin genes in the self-fertilizing fish Kryptolebias marmoratus

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Journal of Environmental Sciences 2016年第4期28卷 187-195页

作者： Bo-Mi Kim min Chul Lee Hye-min kang Jae-Sung Rhee Jae-Seong Lee Department of Biological Science College of ScienceSungkyunkwan University Department of Marine Science College of Natural SciencesIncheon National University

Vitellogenin（Vtg）is the precursor of egg yolk proteins,and its expression has been used as a reliable biomarker for estrogenic contamination in the aquatic *** examine the biomarker potential of the self-fertilizing killifish Kryptolebias marmoratus Vtgs（Km-Vtgs）,full genomic DNAs of Km-Vtgs-Aa,Km-Vtgs-Ab,and Km-Vtgs-C were cloned,sequenced,and *** Vtg genes in *** are tandemly placed in a550 kb section of the same *** silico analysis of promoter regions revealed that both the Km-Vtgs-Aa and Km-Vtgs-Ab genes had an estrogen response element（ERE）,but the Km-Vtgs-C gene did ***,all three Km-Vtgs genes had several ERE-half sites in their promoter *** analysis demonstrated that the three deduced amino acid residues were highly conserved with conventional Vtgs protein,forming distinctive clades within teleost *** tissue showed the highest expression of Km-Vtg transcripts in all tested tissues（brain/pituitary,eye,gonad,intestine,skin,and muscle）in response to endocrine disrupting chemical（EDC）-exposed ***-Vtg transcripts were significantly increased in response to 17β-estradiol（E2）,tamoxifen（TMX）,4-n-nonylphenol（NP）,bisphenol A（BPA）,and octylphenol（OP）over 24 hr *** Km-Vtg-A gene was highly expressed compared to the control in response to NP and ***-induced modulatory patterns of Km-Vtg gene expression were different depending on tissue,gender,and isoforms.

关键词： Kryptolebias marmoratus Vitellogenin Endocrine disrupting chemical

Moth-eye Structured Polydimethylsiloxane Films for High-Efficiency Perovskite Solar Cells

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Nano-Micro Letters 2019年第3期11卷 271-280页

作者： mincheol Kim Segeun Jang Jiwoo Choi Seong min kang Mansoo Choi Global Frontier Center for Multiscale Energy Systems Seoul National UniversitySeoul151.744Republic of Korea Department of Mechanical and Aerospace Engineering Seoul National UniversitySeoul151.744Republic of Korea Department of Mechanical Engineering Hanbat National UniversityDaejeon34158Republic of Korea Department of Mechanical Engineering Chungnam National UniversityDaejeon34134Republic of Korea

Large-area polydimethylsiloxane(PDMS)films with variably sized moth-eye structures were fabricated to improve the efficiency of perovskite solar *** approach that incorporated photolithography,bilayer PDMS deposition and replication was used in the fabrication *** simply attaching the moth-eye PDMS films to the transparent substrates of perovskite solar cells,the optical properties of the devices could be tuned by changing the size of the moth-eye *** device with 300-nm moth-eye PDMS films greatly enhanced power conversion efficiency of ~21 % due to the antireflective effect of the moth-eye ***,beautiful coloration was observed on the 1000-nm moth-eye PDMS films through optical interference caused by the diffraction grating *** results imply that moth-eye PDMS films can greatly enhance the efficiency of perovskite solar cells and building-integrated photovoltaics.

关键词： Polydimethylsiloxane films Moth-eye Photolithography Perovskite solar cells Photovoltaic

Ultrasensitive and Highly Stretchable Multiple‑Crosslinked Ionic Hydrogel Sensors with Long‑Term Stability

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Nano-Micro Letters 2023年第4期15卷 85-96页

作者： Jin‑Young Yu Seung Eon Moon Jeong Hun Kim Seong min kang Department of Mechanical Engineering Chungnam National UniversityDaejeon 34134Korea Emerging Nano‑Materials Research Section Electronics and Telecommunications Research InstituteDaejeon 305‑700Republic of Korea

Flexible hydrogels are receiving significant attention for their application in wearable ***,most hydrogel materials exhibit weak and one-time adhesion,low sensitivity,ice crystallization,water evaporation,and poor self-recovery,thereby limiting their application as *** issues are only partly addressed in previous ***,a multiplecrosslinked poly(2-(methacryloyloxy)ethyl)dimethyl-(3-sulfopropyl)ammonium hydroxide-co-acrylamide)(P(SBMA-co-AAm))multifunctional hydrogel is prepared via a one-pot synthesis method to overcome the aforementioned ***,ions,glycerol,and 2-(methacryloyloxy)ethyl)dimethyl-(3-sulfopropyl)ammonium hydroxide are incorporated to reduce the freezing point and improve the moisture retention *** proposed hydrogel is superior to existing hydrogels because it exhibits good stretchability(a strain of 2900%),self-healing properties,and transparency through effective energy dissipation in its dynamic crosslinked ***,2-(methacryloyloxy)ethyl)dimethyl-(3-sulfopropyl)ammonium hydroxide as a zwitterion monomer results in an excellent gauge factor of 43.4 at strains of 1300-1600%by improving the ion transportability and achieving a strong adhesion of 20.9 kPa owing to the dipole-dipole *** proposed hydrogel is promising for next-generation biomedical applications,such as soft robots,and health monitoring.

关键词： Hydrogel sensors Biocompatibility Multifunction High-sensitivity sensors Multiple-crosslink association

Selection of Heat Treatment Process and Wear Mechanism of High Wear Resistant Cast Hot-Forging Die Steel

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Journal of Iron and Steel Research International 2012年第5期19卷 50-57页

作者： WEI min-xian WANG Shu-qi WANG Lan CUI Xiang-hong CHEN kang-min School of Materials Science and Engineering Jiangsu UniversityZhenjiang 212013JiangsuChina

Dry sliding wear tests of a Cr-Mo-V cast hot-forging die steel was carried out within a load range of 50--300 N at 400℃ by a pin-on-disc high temperature wear machine. The effect of heat treatment process on wear resistance was systematically studied in order to select heat treatment processes of the steel with high wear resistance. The morphology, structure and composition were analyzed using scanning electron microscopy （SEM）, X-ray diffraction （XRD） and energy dispersive spectroscopy （EDS） ; wear mechanism was also discussed. Tribo-oxide layer was found to form on worn surfaces to reduce wear under low loads, but appear inside the matrix to increase wear under high loads. The tribo-oxides were mainly consisted of Fe3O4 and Fe2O3, FeO only appeared under a high load. Oxidative mild wear, transition of mild-severe wear in oxidative wear and extrusive wear took turns to operate with increasing the load. The wear resistance strongly depended on the selection of heat treatment processes or microstructures. It was found that bainite presented a better wear resistance than martensite plus bainite duplex structure, martensite structure was of the poorest wear resistance. The wear resistance increased with increasing austenizing temperature in the range of 920 to 1 120 ℃, then decreased at up to 1 220 ℃. As for tempering temperature and microstructure, the wear resistance increased in following order： 700℃ （tempered sorbite）, 200 ℃ （tempered martensite）, 440 to 650 ℃ （tempered troostite）. An appropriate combination of hardness, toughness, microstructural thermal stability was re- quired for a good wear resistance in high-temperature wear. The optimized heat treatment process was suggested for the cast hot-forging steel to be austenized at 1020 to 1 120 ℃, quenched in oil, then tempered at 440 to 650℃ for 2 h.

关键词： cast hot-forging die steel heat treatment process high-temperature wear mechanism wear behavior microstructure

TXV Technology:The cornerstone of 3D system-in-packaging

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Science China(Technological Sciences) 2022年第9期65卷 2031-2050页

作者： ZHAO HeRan CHEN mingXiang PENG Yang WANG Qing kang min CAO LiHua School of Mechanical Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China The 47th Institute of China Electronics Technology Group Corporation Shenyang 110000China State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China School of Aerospace Engineering Huazhong University of Science and TechnologyWuhan 430074China Institute of Metal Research Chinese Academy of SciencesShenyang 110016China Shenyang National Laboratory for Materials Science Shenyang 110016China

System-in-packaging(Si P) can realize the integration and miniaturization of electronic devices and it is significant to continue Moore’s ***-X-via(TXV) technology is the cornerstone of 3 D-SiP,which enables the vertical stacking and electrical interconnection of electronic *** originated from through-hole(TH) in PCB substrates and evolved in different substrate materials,such as silicon,glass,ceramic,and *** work provides a comprehensive review of four distinguishing TXV technologies(through silicon via(TSV),through glass via(TGV),through ceramic via(TCV),and through mold via(TMV)),including the fabrication mechanisms,processes,and *** TXV technology has unique characteristics and owns particular processes and *** process methods,key technologies,application fields,and advantages and disadvantages of each TXV technology were *** cutting-edge through-hole process and development direction were reviewed.

关键词： through silicon via(TSV) through ceramic via(TCV) through glass via(TGV) through mold via(TMV) 3D packaging chip stacking interposer