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Analytical modeling for colloid-facilitated transport of N-member radionuclides chains in the fractured rock

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Nuclear Science and Techniques 2007年第6期18卷 336-343页

作者： TIEN Neng-Chuan JEN Chun-Ping Energy and Environment research laboratories Industrial Technology Research Institute Hsinchu 310 Taiwan Department of Mechanical Engineering National Chung Cheng University Chia Yi 62102 Taiwan

A precious analytical model for N-member radionuclide decay chains has been extended to include the ef- fect of radionuclide sorption with groundwater *** distribution coefficients were employed in the nu- clide decay chain to illustrate the present *** colloid concentration was assumed constant in time and space owing to equilibrium between colloid generation and sedimentation by chemical and/or physical ***- thermore,the diffusion of colloids into the rock matrix was ignored because the diameter of colloid is relatively large and colloids and fracture surfaces are *** results indicated that colloids could facilitate the transport of radionuclides and the large adsorbability of nuclides with colloids enlarged the effect of acceleration by *** influence of colloids on the radionuclide transport was expected to be crucial to the actinides with large adsorbability; however,the present results revealed that the low-adsorbing nuclides whose parent nuclides have large capability of sorption could be also facilitated significantly by colloids ***,the role of colloids played in the transport of the radionuclides decay chain should be assessed carefully in the radioactive waste *** analyti- cal method presented herein is helpful to verify/validate further complex far-field models.

关键词：分析模型放射性核素氮元素同位素

A first-principles microkinetic study on the hydrogenation of carbon dioxide over Cu(211) in the presence of water

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Science China Chemistry 2019年第12期62卷 1686-1697页

作者： Xitong Sun Peng Wang Zhengjiang Shao Xiaoming Cao P.Hu Key laboratories for advanced Materials Centre for Computational Chemistry and Research Institute of Industrial CatalysisSchool of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai 200237China School of Chemistry and Chemical Engineering Queen's University of BelfastBelfast BT95AGUK

The hydrogenation of carbon dioxide(CO2)is one of important processes to effectively convert and utilize CO2,which is also regarded as the key step at the industrial methanol *** is likely to play an important role in this process,but it still remains *** systematically understand its influence,here we computationally compare the reaction mechanisms of CO2 hydrogenation over the stepped Cu(211)surface between in the absence and presence of water based on microkinetic simulations upon density functional theory(DFT)*** effects of water on each hydrogenation step and the whole activity and selectivity are checked and its physical origin is *** is found that the water could kinetically accelerate the hydrogenation on CO2 to COOH,promoting the reverse water gas shift reaction to produce carbon monoxide(CO).It hardly influences the CO2 hydrogenation to methanol *** addition,the too high initial partial pressure of water will thermodynamically inhibit the CO2 conversion.

关键词： CO2 activation microkinetic modeling DFT CH3OH selectivity

Optical-terahertz-optical seamless integration system for dual-λ 400 GbE real-time transmission at 290 GHz and 340 GHz

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Science China(Information Sciences) 2023年第11期66卷 302-304页

作者： Jiao ZHANG Mingzheng LEI Min ZHU Bingchang HUA Yuancheng CAI Yucong ZOU Liang TIAN Yunwu WANG Jinbiao XIAO Yongming HUANG Jianjun YU Xiaohu YOU Purple Mountain laboratories National Mobile Communications research Laboratory Southeast University School of Information Science and technology Fudan University Peng Cheng Laboratory

Terahertz band(THz-band, 0.3 to 10 THz) communications are envisioned as a promising candidate for 6G and beyond technology, which can provide data capacity tens or even hundreds of Gbps per physical layer link [1–3]. Over the past several years, a series of THz communication systems at record-high data rates have undergone significant development, accelerated by electronic and hybrid electronicphotonic techniques [4–9].

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Identification of green tea origins by near-infrared (NIR) spectroscopy and different regression tools

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Science China(Technological Sciences) 2017年第1期60卷 84-90页

作者： ZHUANG XinGang WANG LiLi CHEN Qi WU XueYuan FANG JiaXiong advanced research Center for Optics Shandong University Jinan 250100 China School of Information Science and Engineering Shandong University Jinan 250100 China State Key laboratories of Transducer technology Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences Shanghai 200050 China State Key Laboratory of Tea and Agricultural Products Detection (Huangshan) Huangshan 245000 China

In this study,near-infrared(NIR) spectroscopy was applied to efficiently and non-destructively identify Shandong green tea origins coupled with three different regression *** results indicated that partial least squares(PLS) had better performance than back propagation artificial neural network(BP-ANN) and support vector machine(SVM).For PLS,the accuracies of identification were up to 100% for both training and *** results sufficiently demonstrate that NIR spectroscopy can be efficiently utilized for the non-destructive identification of green tea origins.

关键词： near-infrared spectroscopy (NIRS) green tea origin regression tool

Effects of Craddition on Charpy impact energy in austenitic 0.45C-24Mn-(0,3,6)Cr steels

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Journal of Materials Science & technology 2020年第15期47卷 21-30页

作者： Seok Gyu Lee Bohee Kim Min Cheol Jo Kyeong-Min Kim Junghoon Lee Jinho Bae Byeong-Joo Lee Seok Su Sohn Sunghak Lee Center for advanced Aerospace Materials Pohang University of Science and TechnologyPohang37673South Korea Steel Products Design Team Hyundai SteelDangjin31779South Korea Steel Products research Group 1 Technical Research LaboratoriesPOSCOGwangyang57807South Korea Department of Materials Science and Engineering Korea UniversitySeoul02841South Korea

Effects of Cr addition(0,3,and 6 wt%) on Charpy impact properties of Fe-C-Mn-Cr-based steels were studied by conducting dynamic compression tests at room and cryogenic *** room temperature,deformation mechanisms of Charpy impacted specimens were observed as twinning induced plasticity(TWIP) without any transfo rmation induced plasticity(TRIP) in all the *** cryogenic temperature,many twins were populated in the Cr-added steels,but,interestingly,fine ε-martensite was found in the OCr steel,satisfying the Shoji-Nishiyama(S-N) orientation relationship,{111}γ//{0002}ε and γ//ε.Even though the cryogenic-temperature staking fault energies(SFEs) of the three steel were situated in the TWIP regime,the martensitic transformation was induced by Mn-and Cr-segregated *** the OCr steel,SFEs of low-(Mn,Cr) bands lay between the TWIP and TRIP regimes which were sensitively affected by a small change of *** dynamic compressive test results well showed the relation between segregation bands and the *** of Cr were known as not only increasing the SFE but also promoting the carbide *** order to identify the possibility of carbide formation,a precipitation kinetics simulation was conducted,and the predicted fractions of precipitated M23C6 were negligible,0.4-1.1×10-5,even at the low cooling rate of 10℃/s.

关键词： Austenitic high-Mn steels Charpy impact energy Split Hopkinson pressure bar Twinning induced plasticity(TWIP) Transformation induced plasticity(TRIP) Stacking fault energy(SFE)

A low-floor bit-mapping scheme for LDPC coded BICM for 5G and beyond systems

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Science China(Information Sciences) 2023年第10期66卷 263-277页

作者： Mingyang ZHU Ming JIANG Chunming ZHAO Lijie HU Xiaodong XU National Mobile Communications research Laboratory Southeast University Purple Mountain laboratories China Mobile research Institute

This paper proposes a low-floor bit-mapping(LFBM) scheme for bit-interleaved coded modulation(BICM) systems to meet more stringent quality of service requirements of 5G and beyond. For highefficiency transmissions, we consider the 5G low-density parity-check codes with high-order 2m-quadrature amplitude modulations(QAMs). The proposed LFBM scheme overcomes plenty of trapping sets induced by the bit interleaver, which focuses on the waterfall performance too aggressively. When the high-order QAM is used, the row-column interleaver specified by the 5G standard is such a bit interleaver. The LFBM scheme only optimizes the rule of mapping an m-bit tuple output by the row-column interleaver to a modulation symbol, rather than the entire bit interleaver. Therefore, the optimized bit mapper is actually an m-bit permutation module concatenated with the original bit interleaver employed in the current 5G BICM *** simulation results confirm that the LFBM scheme can lower the error floor of the 5G BICM system by approximately two orders of magnitude, while with negligible performance loss in the waterfall region.

关键词： bit-interleaved coded modulation low-density parity-check codes error floors bit mapping high-order modulation

Wafer level hermetic packaging based on Cu-Sn isothermal solidification technology

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Journal of Semiconductors 2009年第8期30卷 164-168页

作者：曹毓涵罗乐 State Key laboratories of Transducer technology Shanghai Institute of Microsystem and Information TechnologyChinese Academy of Sciences

A novel wafer level bonding method based on Cu-Sn isothermal solidification technology is established. A multi-layer sealing ring and the bonding processing are designed, and the amount of solder and the bonding parameters are optimized based on both theoretical and experimental results. Verification shows that oxidation of the solder layer, voids and the scalloped-edge appearance of the Cu6Sn5 phase are successfully avoided. An average shear strength of 19.5 MPa and an excellent leak rate of around 1.9 × 10-9 atm cc/s are possible, meeting the demands of MIL-STD-883E.

关键词： wafer level package Cu-Sn isothermal solidification technology hermeticity

Volumetric Virtual Environments

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Journal of Computer Science & technology 2000年第1期15卷 37-46页

作者： HE Taosong(Software Production research Department, Bell laboratoriesLucent Technologies, Naperville, IL 60566, USA)E-mail: taosong@*** Software Production research Department Bell Laboratories Lucent Technologies Naperville USA

Driven by fast development of both virtual reality and volume visualization, we discuss some critical techniques towards building a volumetric VRsystem, specifically the modeling, rendering, and manipulations of a volumetric *** such as voxel-based object simplification, accelerated volume rendering,fast stereo volume rendering, and volumetric 'collision detection' are introduced andimproved, with the idea of demonstrating the possibilities and potential benefits ofincorporating volumetric models into VR systems.

关键词： volume visualization volume rendering virtual reality volumegraphics object simplification level of detail wavelets theory volumetric collisiondetection

Joint optimization of spectral efficiency and energy efficiency with low-precision ADCs in cell-free massive MIMO systems

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Science China(Information Sciences) 2022年第5期65卷 169-183页

作者： Han WANG Chang SUN Jiamin LI Pengcheng ZHU Dongming WANG Xiaohu YOU National Mobile Communications research Laboratory Southeast University Purple Mountain laboratories

In cell-free massive multiple-input multiple-output(MIMO) systems, it is beneficial to apply low-precision analog-to-digital converters(ADCs) to reduce power consumption, hardware cost, and the load on backhaul link. However, low-precision ADCs will result in serious degradation in spectral efficiency(SE). It is important to achieve a good tradeoff between SE and energy efficiency(EE) for cell-free massive MIMO systems with low-precision ADCs. In this paper, we first derive the closed-form expressions of uplink achievable rates with maximal ratio combining(MRC) receiver and zero-forcing(ZF) receiver in cell-free massive MIMO systems. Then we analyze the EE model of cell-free massive MIMO systems. Based on the above analysis, the tradeoff between SE and EE is studied. Moreover, we propose two quantization bit allocation algorithms to optimize the SE and EE jointly from the perspective of multi-objective *** algorithm is based on the deep Q-network(DQN) and the other one is based on the non-dominated sorting genetic algorithm Ⅱ(NSGA-Ⅱ). The proposed algorithms provide more feasible solutions and achieve better system performance than equal quantization bit allocation algorithm. Numerical results verify the accuracy of the derived closed-form expressions and the effectiveness of the proposed optimization algorithms.

关键词： cell-free massive MIMO low-precision ADC spectral efficiency energy efficiency multi-objective optimization