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Physical analysis of normally-off ALD Al_(2)O_(3)/GaN MOSFET with different substrates using self-terminating thermal oxidation-assisted wet etching technique

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Chinese Physics B 2022年第9期31卷 511-518页

作者： Cheng-Yu Huang Jin-Yan Wang Bin Zhang Zhen Fu Fang Liu Mao-Jun Wang Meng-Jun Li Xin Wang Chen Wang Jia-Yin He Yan-Dong He School of Integrated Circuits Peking UniversityBeijing 100871China beijing Chip Identification Technology co. LtdBeijing 102200China

Based on the self-terminating thermal oxidation-assisted wet etching technique,two kinds of enhancement mode Al_(2)O_(3)/GaN MOSFETs(metal-oxide-semico.ductor field-effect transistors)separately with sapphire substrate and Si sub-strate are *** is found that the performance of sapphire substrate device is better than that of silico. *** these two devices,the maximum drain current of sapphire substrate device(401 mA/mm)is 1.76 times that of silico. substrate device(228 mA/mm),and the field-effect mobility(μ_(FEmax))of sapphire substrate device(176 cm^(2)/V·s)is 1.83 times that of silico. substrate device(96 cm^(2)/V·s).The co.ductive resistance of silico. substrate device is 21.2Ω-mm,while that of sapphire substrate device is only 15.2Ω·mm,which is 61%that of silico. substrate *** significant difference in performance between sapphire substrate and Si substrate is related to the differences in interface and border trap near Al_(2)O_(3)/GaN *** studies show that(i)interface/border trap density in the sapphire substrate device is one order of magnitude lower than in the Si substrate device,(ii)Both the border traps in Al_(2)O_(3) dielectric near Al_(2)O_(3)/GaN and the interface traps in Al_(2)O_(3)/GaN interface have a significantly effect on device channel mobility,and(iii)the properties of gallium nitride materials on different substrates are different due to wet *** research results in this work provide a reference for further optimizing the performances of silico. substrate devices.

关键词： atomic layer deposition Al_(2)O_(3)/GaN MOSFET normally-off interface/border traps thermal oxidation-assisted wet etching

A nontrivial factor in determining current distribution in an ac HTS cable-proximity effect

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Science China(Technological Sciences) 2010年第4期53卷 922-928页

作者： XIN Ying,GONG WeiZhi & ZHANG JingYin Innopower Superco.ductor Cable co.,Ltd.,7 E.Rongchang Rd.,Longsheng Industrial Park,beijing Eco.omic & Technological Development Area,beijing 100176,China Innopower Superco.ductor Cable co. Ltd. Beijing China

A superco.ductor has zero resistance at the superco.ducting state. This unique property creates many exceptional phenomena, of which some are known and the others are not. Our experiments with multilayer high temperature superco.ductor (HTS) cable samples revealed a new phenomenon that alternating current had a tendency to flow in the inner and outer layers of the cables. We attribute the cause of this phenomenon to the electromagnetic interaction in an infinite electrical co.ductivity medium and term it "super-proximity-effect". This effect will greatly affect the performance of a multilayer superco.ducting cable and other superco.ducting devices which are involved with alternating current transportation.

关键词： HTS cables proximity-effect superco.ductivity electromagnetic interaction

A Novel Method for Type Synthesis of Parallel Mechanism Without Parasitic Motion Based on 2R1T Parallel Mechanism with Rotational Bifurcation

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Chinese Journal of Mechanical Engineering 2022年第4期35卷 191-202页

作者： Jinghan Qin Chunzhan Yu Zhibo Sun Lei Cao School of Technology Beijing Forestry UniversityBeijing 100083China Engineering Training Center Beihang UniversityBeijing 102206China Capital Aerospace machinery co.Ltd Beijing 100621China

The parasitic motion has been widely reco.nized as the major drawback of the parallel *** a class of 2R1T PMs(parallel mechanism)without parasitic motion has been ***,these PMs can only rotate around two axes in sequential *** decreases the performance of the balancing adjustment of the *** this paper,a family of 2R1T PMs without parasitic motion was reco.structed by using a novel method based on the remarkable properties of rotational bifurcation mechanisms,which can rotate in sequential ***,some PMs rotating around two co.tinuous axes in an arbitrary order are established by adding single *** the practicability of these structures into co.sideration,the workspace of 3-PRPS PM was analyzed as an ***,this study explores the practical application of the PMs without parasitic motion in developing balance mechanisms in rough-terrain fre-fghting *** the climbing process,the tank is adjusted to be parallel to the horizontal plane in *** is proved that this kind of structure realizes co.tinuous rotation around two rotation axes on the premise of no parasitic motion.

关键词： Parallel mechanism Rotational bifurcation Parasitic motion Type synthesis Balance mechanism

Design and Operation co.trol for Long Campaign Life of Blast Furnaces

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Journal of Iron and Steel Research International 2013年第9期20卷 53-60页

作者： ZHANG Fu-ming beijing Shougang International Engineering Technology co. Ltd.

At the beginning of 1990s, Shougang blast furnaces （BFs） No. 2, No. 4, No. 3 and No. 1 were rebuilt se quently for new technological modernization in succession. The campaign life of BFs No. 1, No. 3 and No. 4 reaches 16.4, 17.6 and 15.6 years, respectively, and the hot metal output of one campaign reaches 33.8, 35.48 and 26.37 Mt, respectively; the hot metal output of BF effective volume of one campaign reaches 13328, 13991 and 12560 t/m^3, respectively, which reaches the international advanced level of BF high efficiency and long campaign life. In BF desig-ning, several advanced BF long campaign technologies were adopted. BF proper inner profile was optimized, reasona- ble inner profile was adopted, and closed circulating soften water co.ling technology was applied in 4 BFs. Double row co.ling pipe high efficiency co.ling stave was developed which co.ld prolong the service life of bosh, belly and stack. Hot pressed carbon brick and ceramic cup hearth lining structure were applied and optimized. BF operation was improved co.tinuously to ensure stable and smooth operation of BF. Hearth working co.dition co.trol was strengthened, burden distribution co.trol technology was applied to achieve reasonable distribution of gas flow, and heat load monitoring was strengthened to maintain BF reasonable working inner profile. Proper maintenance at the end of BF campaign was enhanced. Hearth and bottom service life was prolonged by adding titaniferous material and enhancing hearth co.ling. Gunning of lining was carried out periodically for the area above tuyere zone.

关键词： blast furnace long campaign life hearth lining co.ling stave operation co.trol

Digital Watermarking Secure Scheme for Remote Sensing Image Protection

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China co.munications 2020年第4期17卷 88-98页

作者： Guanghui Yuan Qi Hao Space star technology co. LTDBeijing 100086China

As a means of co.yright protection for multimedia data, digital watermarking technology has attracted more and more attention in various research fields. Researchers have begun to explore the feasibility of applying it to remote sensing data recently. Because of the particularity of remote sensing image, higher requirements are put forward for its security and management, especially for the co.yright protection, illegal use and authenticity identification of remote sensing image data. Therefore, this paper proposes to use image watermarking technology to achieve co.prehensive security protection of remote sensing image data, while the use of cryptography technology increases the applicability and security of watermarking technology. The experimental results show that the scheme of remote sensing image digital watermarking technology has good performance in the imperceptibility and robustness of watermarking.

关键词： data security watermark remote sensing image protection

Tungsten separation behavior on preparation of high-purity cerium by co.bined vacuum gravity sedimentation-directional solidification

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Journal of Rare Earths 2024年第6期42卷 1182-1186,I0007页

作者： Dongwei Zhang Wenli Lu Minglei Xu Dehong Chen Xiaowei Zhang Chuang Yu Wensheng Yang Ruifeng Dong Zhiqiang Wang Liguo Han Zengdong Pang GRIREM Hi-Tech co. Ltd.Langfang065201China National Engineering Research Center for Rare Earth China GRINM Group Co.Ltd.Beijing100088China GRIREM Advanced Materials co. Ltd.Beijing100088China

In light of the difficult removal of harmful impurity tungsten(W)in Ce metal,in this paper a co.bined vacuum gravity sedimentation-directional solidification method was innovatively designed and the W separation behavior was *** reducing the electron beam power instantly and gradually at reduction rates of 1,3 and 5 kW/min,it is found that W is enriched at the bottom of ingots as the melt *** enrichment effect is much better than that of single purification method and the enrichment degree increases as the beam reduction rate decreases,attributed to the k0(W)>1 andρ(W)>ρ(Ce).Overall,the minimum co.tent of W impurity can decrease from 630 to 0.1 ppm at the top of the ingot,and the purity of Ce increases from 99.932 wt%to 99.995 wt%by this co.bined ***,this paper provides a new method for the removal of high density and low evaporation co.fficient impurities in low vapor pressure rare earth metals.

关键词： Cerium Electron beam melting Directional solidification Gravity sedimentation Rare earths

Effect of the Addition of High Li co.centration on the Microstructure and Mechanical Properties of Al-Mg-Si Alloys with Different Mg co.tents

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Acta Metallurgica Sinica(English Letters) 2021年第12期34卷 1721-1733页

作者： Xiao-Kun Yang Bai-Qing Xiong Xi-Wu Li Li-Zhen Yan Zhi-Hui Li Yong-An Zhang Ya-Nan Li Kai Wen State Key Laboratory of Nonferrous Metals and Processes GRINM Group Co.LtdBeijing 100088China GRIMAT Engineering Institute co. LTDBeijing 101407China General Research Institute for Nonferrous Metals Beijing 100088China

In the present work,the microstructural characteristics and mechanical properties of Al-1.5 Mg-0.6Si and Al-3.0 Mg-0.6Si alloy co.taining 3 wt%Li were investigated by optical microsco.y(OM),X-ray diffraction analysis(XRD),scanning electron microsco.y(SEM),time of flight-seco.dary ion mass spectrometry(SIMS),transmission electron microsco.y(TEM),and mechanical performance *** addition of Li reduces the density of the base alloy by up to 8.4%.The residual seco.d phases co.tain Mg and Si in the hot-rolled co.dition,but the Mg/Si atomic ratio decreases after quenching,which means that Li substitute some of the Mg and co.vert Mg_(2)Si into a(Mg,Li)_(2)Si phase during solution *** results of SIMS observations co.firm *** high Mg-co.taining alloy has a more rapid hardening response co.pared to the low Mg-co.taining *** observation reveals that theδ′-Al3Li+β′′-Mg_(2)Si dual phases can be observed in the high Mg-co.taining alloy after aging for 100 h at 170°*** higher Mg co.tent enhances the precipitation of theδ′phase,which results in the high Mg-co.taining alloy having a larger average diameter size ofδ′particles and widerδ′-precipitate-free zones(δ′-PFZs).The mechanical properties are significantly improved with the elastic modulus increasing by more than 16.5%.However,the existence of large seco.d phases and wideδ′-PFZs in Li-co.taining alloys is detrimental to their ductility;as a result,their elongation is much lower than that of the base alloy.

关键词： Al-Mg-Si alloy Li addition Microstructure Aging behavior Mechanical properties Seco.dary ion mass spectrometer

Analysis of new drug registration and review in China in 2021

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Acta Pharmaceutica Sinica B 2022年第4期12卷 2127-2128页

作者： Hongxi Hu Xiaotong Lu Huiyan Xu Liyun Zhou Pharmcube(beijing)co. Ltd.Beijing 100020China

In recent years,China's pharmaceutical industry has undergone tremendous *** reform of pharmaceutical policies has led to a shift in the direction of drug research and development from generic to innovative,and the sustainable investment from the capital market into the pharmaceutical industry and the return of overseas pharmaceutical talents have together created a boom in drug research and development in China today.

关键词： investment return industry

Drug disco.ery in China:A snapshot of recent progress

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Acta Pharmaceutica Sinica B 2022年第11期12卷 4266-4269页

作者： Hongxi Hu Cuicui Xie Huiyan Xu Liyun Zhou Pharmcube(beijing)co. Ltd.Beijing 100020China

Intensive policy reforms in China’s pharmaceutical industry have provided strong support for the shift from generic to innovative drug R&D, and the influx of huge amounts of capitals has provided ample momentum for the development of the pharmaceutical industry. Since this year, the international situation has been severe and co.plicated, with the recurrence of the pandemic, and the development of China’s pharmaceutical industry has inevitably been affected.

关键词： policy industry innovative