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Activation redistribution Based Hybrid Asymmetric Quantization Method of Neural Networks

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工程与科学中的计算机建模(英文) 2024年第1期138卷 981-1000页

作者： Lu Wei Zhong Ma Chaojie Yang r&d Innovation Center Xi’an Microelectronics Technology InstituteXi’an710065China

The demand for adopting neural networks in resource-constrained embedded devices is continuously *** is one of the most promising solutions to reduce computational cost and memory storage on embedded *** order to reduce the complexity and overhead of deploying neural networks on Integeronly hardware,most current quantization methods use a symmetric quantization mapping strategy to quantize a floating-point neural network into an integer ***,although symmetric quantization has the advantage of easier implementation,it is sub-optimal for cases where the range could be skewed and not *** often comes at the cost of lower *** paper proposed an activation redistribution-based hybrid asymmetric quantizationmethod for neural *** proposedmethod takes data distribution into consideration and can resolve the contradiction between the quantization accuracy and the ease of implementation,balance the trade-off between clipping range and quantization resolution,and thus improve the accuracy of the quantized neural *** experimental results indicate that the accuracy of the proposed method is 2.02%and 5.52%higher than the traditional symmetric quantization method for classification and detection tasks,*** proposed method paves the way for computationally intensive neural network models to be deployed on devices with limited computing *** will be available on https://***/ycjcy/Hybrid-Asymmetric-Quantization.

关键词： Quantization neural network hybrid asymmetric accuracy

Three-channel CMOS transimpedance amplifier for LidAr sensor receiver

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Journal of Systems Engineering and Electronics 2024年第1期35卷 74-80页

作者： LIU ruqing ZHU Jingguo JIANG Yan LI Feng JIANG Chenghao MENG Zhe Photoelectric r&d Center Academy of Opto-ElectronicsChinese Academy of SciencesBeijing 100094China

For time-of-flight(TOF)light detection and ranging(LidAr),a three-channel high-performance transimpedance amplifier(TIA)with high immunity to input load capacitance is presented.A regulated cascade(rGC)as the input stage is at the core of the complementary metal oxide semiconductor(CMOS)circuit chip,giving it more immunity to input photodiode detectors.A simple smart output interface acting as a feedback structure,which is rarely found in other designs,reduces the chip size and power consumption *** circuit is designed using a 0.5μm CMOS process technology to achieve low *** device delivers a 33.87 dB?transimpedance gain at 350 *** a higher input load capacitance,it shows a-3 dB bandwidth of 461 MHz,indicating a better detector tolerance at the front end of the *** a 3.3 V supply voltage,the device consumes 5.2 mW,and the total chip area with three channels is 402.8×597.0μm2(including the test pads).

关键词： transimpedance amplifier(TIA) three-channel regulated cascade(rGC) light detection and ranging(LidAr)

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Thickening progression mechanism of silica fume-oil well cement composite system at high temperatures

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Petroleum Science 2024年第4期21卷 2793-2805页

作者： Hang Zhang Miao-Miao Hu Peng-Peng Li Guo-Qing Liu Qing-Lu Chang Jie Cao Ming Liu Wen-Hua Xu Xiu-Jian Xia Jin-Tang Guo School of Chemical Engineering and Technology Tianjin University Zhejiang institute of Tianjin University Haihe Laboratory of Sustainable Chemical Transformations CNPC Engineering Technology r&d Company Limited

This work studied the thickening progression mechanism of the silica fume-oil well cement composite system at high temperatures(110-180.C) in order to provide a theoretical guidance for the rational application of silica fume in the cementing engineering. results showed that silica fume seldom affected the thickening progression of oil well cement slurry at 110-120.C, but when temperature reached above130.C, it would aggravate the bulging degree of thickening curves and significantly extend the thickening time, meanwhile causing the abnormal “temperature-based thickening time reversal” and“dosage-based thickening time reversal” phenomena in the range of 130-160.C and 170-180.C respectively. At 130-160.C, the thickening time of oil well cement slurry was mainly associated with the generation rate of calcium hydroxide(CH) crystal. The introduced silica fume would be attracted to the cement minerals' surface that were hydrating to produce CH and agglomerate together to form an“adsorptive barrier” to hinder further hydration of the inner cement minerals. This “adsorptive barrier”effect strengthened with the rising temperature which extended the thickening time and caused the occurrence of the “temperature-based thickening time reversal” phenomenon. At 170-180.C, the pozzolanic activity of silica fume significantly enhanced and considerable amount of C-S-H was generated, thus the “temperature-based thickening time reversal” vanished and the “dosage-based thickening time reversal” was presented.

关键词： Silica fume Oil well cement Thickening time reversal Pozzolanic reaction Adsorptive barrier CH and C−S−H

development and performance evaluation of high temperature resistant strong adsorption rigid blocking agent

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Petroleum Science 2024年第4期21卷 2650-2662页

作者： Zhe Xu Jin-Sheng Sun Jing-Ping Liu Kai-He Lv Xiao-dong dong Zong-Lun Wang Tai-Feng Zhang Yuan-Wei Sun Zhi-Wen dai School of Petroleum Engineering China University of Petroleum (East China) CNPC Engineering Technology r&d Company Limited

As drilling wells continue to move into deep ultra-deep layers, the requirements for temperature resistance of drilling fluid treatments are getting higher and higher. Among them, blocking agent, as one of the key treatment agents, has also become a hot spot of research. In this study, a high temperature resistant strong adsorption rigid blocking agent(QW-1) was prepared using KH570 modified silica,acrylamide(AM) and allyltrimethylammonium chloride(TMAAC). QW-1 has good thermal stability,average particle size of 1.46 μm, water contact angle of 10.5., has a strong hydrophilicity, can be well dispersed in water. The experimental results showed that when 2 wt% QW-1 was added to recipe A(4 wt% bentonite slurry+0.5 wt% dSP-1(filtration loss depressant)), the API filtration loss decreased from 7.8to 6.4 m L. After aging at 240.C, the API loss of filtration was reduced from 21 to 14 m L, which has certain performance of high temperature loss of filtration. At the same time, it is effective in sealing 80-100mesh and 100-120 mesh sand beds as well as 3 and 5 μm ceramic sand discs. Under the same conditions,the blocking performance was superior to silica(5 μm) and calcium carbonate(2.6 μm). In addition, the mechanism of action of QW-1 was further investigated. The results show that QW-1 with amide and quaternary ammonium groups on the molecular chain can be adsorbed onto the surface of clay particles through hydrogen bonding and electrostatic interaction to form a dense blocking layer, thus preventing further intrusion of drilling fluid into the formation.

关键词： High adsorption rigid microsphere High temperature resistance Blocking performance

Combined Promoting Effects of Specific Organic Functional Groups and Alumina Surface Characteristics for the design of a Highly Efficient NiMo/Al_(2)O_(3) Hydrodesulfurization Catalyst

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China Petroleum Processing & Petrochemical Technology 2024年第1期26卷 1-11页

作者： Li Huifeng Li Mingfeng Zhang Le Wang Wei Nie Hong National Energy r&d Center of Petroleum refining Technology SINOPEC Research Institute of Petroleum Processing Co.Ltd.Beijing 100083China

To prepare a highly efficient NiMo/Al_(2)O_(3) hydrodesulfurization catalyst,the combined effects of specific organic functional groups and alumina surface characteristics were ***,the correlation between the surface characteristics of four different alumina and the existing Mo species states was *** was found that the Mo equilibrium adsorption capacity can be used as a specific descriptor to quantitatively evaluate the changes in surface characteristics of different alumina.A lower Mo equilibrium adsorption capacity for alumina means weaker metal-support interaction and the loaded Mo species are easier to transform into ***,the Mo-O-Al bonds still exist at the metal-support *** introduction of cationic surfactant hecadecyl trimethyl ammonium bromide(CTAB)can further improve Mo species dispersion through electrostatic attraction with Mo anions and interaction of its alkyl chain with the alumina surface;meanwhile,the introduction of ethylenediamine tetraacetic acid(EdTA)can complex with Ni ions to enhance the Ni-promoting effect on ***,the NiMo catalyst designed using alumina with lower Mo equilibrium adsorption capacity and the simultaneous addition of EdTA and CTAB exhibits the highest hydrodesulfurization activity for 4,6-dimethyl dibenzothiophene because of its proper metal-support interaction and more well-dispersed Ni-Mo-S active phases.

关键词： alumina Mo equilibrium adsorption capacity organic functional groups metal-support interaction hydrodesulfurization

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Improvement of mechanical properties and investigation of strengthening mechanisms on the Ti_(3)AlC_(2) ceramic with nanosized WC addition

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Journal of Advanced Ceramics 2024年第6期13卷 861-876页

作者： Yi Zhong Ying Liu Qinkai Jiang Na Jin Zifeng Lin Jinwen Ye School of Materials Science&Engineering Sichuan UniversityChengdu 610065China Yibin r&d Park Yibin Industrial Technology Research InstituteSichuan UniversityYibin 644005China

Ti_(3)AlC_(2) (TAC) has great potential for use as an ablation material in aerospace applications due to its great oxidation/ablation resistance, but its high-temperature strength and thermal shock resistance still have much room for simultaneous improvement under fast temperature variation conditions. Herein, we used Ti_(3)AlC_(2) and WC powders as raw materials and successfully fabricated textured (Ti,W)_(3)AlC_(2) ceramic with small amounts of TiC and Al_(2)O_(3), and room temperature mechanical properties such as flexural strength (1146±46.9 MPa), fracture toughness (11.78±0.44 MPa·m^(1/2)), and hardness (5.81±0.11 GPa) at 5 wt% WC addition were achieved. The high-temperature strength of the ceramic was significantly improved, and better thermal shock resistance from 298 to 1173 K was simultaneously acquired together with the regulation of the elastic modulus, thermal conductivity, and thermal expansion coefficient, providing (Ti,W)_(3)AlC_(2) with more possibilities for fast-temperature variation applications. Strengthening and toughening mechanisms were proposed. Scanning transmission electron microscopy high-angle annular dark-field imaging (STEM-HAddF) showed that W randomly replaced the Ti1 and Ti2 sites of Ti_(3)AlC_(2), providing a good reference for establishing crystal models, and further density functional theory (dFT) calculations based on these models indicated a higher fracture energy of (Ti,W)_(3)AlC_(2) along different crystal planes, providing superior resistance to transgranular fracture;a lower mismatch degree of (Ti,W)_(3)AlC_(2)/Al_(2)O_(3) resulted in stronger interface bonding, resulting in greater resistance to intergranular fracture as well as more balanced stress distributions at different interfaces.

关键词： mechanical properties solid solution MAX phase transmission electron microscopy(TEM) ceramic atomic structure

Fabricating functionally graded Fe-Cr-Co permanent magnetic alloys via laser powder bed fusion

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Journal of Iron and Steel research International 2024年第3期31卷 729-737页

作者： Ya-zhou He Ya-qing Hou Peng Shen Hao Zhang dong Zhou Hang Su Central Iron and Steel research institute Co. Ltd.Beijing 100081China Material digital r&d Center China Iron and Steel Research Institute Group Co.Ltd.Beijing 100081China

Laser powder bed fusion(LPBF)in-situ alloying technology offers the possibility to construct gradient materials with varied structures and *** graded Fe-Cr-Co permanent magnetic alloys were fabricated by LPBF and in-situ alloying mixed powders of Fe,Cr,and Co *** effects of different Fe,Cr and Co contents on the microstructure,magnetic properties and hardness of Fe-Cr-Co alloys prepared by LPBF were *** as-built Fe-Cr-Co alloys present a single body-centered-cubic phase and have a homogeneous distribution of *** mechanical properties and magnetic properties of the compositionally graded sample show a gradient *** the increase in Cr content,the Vickers hardness of the sample increases,and the saturation magnetization of the sample *** optimal magnetic properties in an isotropic state are given as coercivity HcB=21.65 kA/m,remanence Br=0.70 T and energy product(BH)_(max)=5.35 kJ/m^(3),which are comparable to or higher than the reported magnetic properties in an isotropic state prepared by traditional powder *** in-situ alloying technology has the potential to further explore Fe-Cr-Co magnetic materials,such as those consisting of multiple or more constituent elements,and to maximize the compositional flexibility of magnetic materials.

关键词： Fe-Cr-Co alloy Laser powder bed fusion In-situ alloying Functional material Magnetic property

Microstructure evolution and phase transformation of the mushy zone in a quenchedβ-solidifying TiAl alloy

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Journal of Materials Science & Technology 2024年第2期169卷 28-41页

作者： Fuqiang Zhang Xianfei ding Leming Xu Xin Feng Hai Nan Jianping He Yongfeng Liang Junpin Lin State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China Cast Titanium Alloy r&d Center Beijing Institute of Aeronautical MaterialsBeijing 100095China

This study investigates the phase constitutions and transformations that occur in the mushy zone and in the adjacent phase fields of a directionally solidified Ti-44Al-8Nb-1Cr alloy via quenching *** results indicate that the mushy zone consists of unmeltedβdendrites and interdendritic liquid,whose formation can be attributed to the difference in melting point aroused by local heterogeneity in ***βdendrite is composed of numerous subgrains with various *** quenching,theβdendrite transforms into Widmanstättenαvia a precipitation reaction,owing to the decreasing cooling rate caused by heat transfer from the surrounding ***,after quenching,the interdendritic liquid is transformed intoγ*** the singleβphase field and the lower part of the mushy zone,a massive transformation ofβtoγ***,in theβ+αphase field,bothβandαphases are retained to ambient *** the heating process,the transformation ofα→βgives rise to the formation ofβvariants,which affects the orientation ofβdendrites in the mushy *** growth kinematics of theα→βtransformation was elucidated,revealing the preferential growth directions of111and112forβ***,this study presents an illustration of the formation process of the mushy zone and the microstructural evolution during the heating and quenching process.

关键词： Titanium aluminides Mushy zone Quenching Electron backscattering diffraction Phase transformation

A new type of lipophilic hydrophobic self-repairing cellulose insulating paper developed with ST-110/FAS/PTFE ternary system as coating substrate

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High Voltage 2024年第2期9卷 474-483页

作者： Zhenglin Zeng Jinshan Qin Zuhao Wang Weimin Tan Chao Tang College of Engineering and Technology Southwest UniversityChongqingChina International r&d Center for New Technologies of Smart Grid and Equipment ChongqingChina

The moisture generated by the ageing of the oil-paper insulating system can easily lead to the deterioration of the performance of the insulating *** order to alleviate the impact of moisture on the performance of the insulating paper,we developed a kind of lipophilic hydrophobic self-repairing cellulose insulating paper(new insulating paper)based on the ternary system of polytetrafluoroethylene,fluorocarbon surfactant and fluorinated alkyl silane,and accelerated thermal ageing test for 45 days at 130°C was carried *** experimental results show that the new insulating paper with excellent lipophilic property can realise hydrophobic self-repairing through heat treatment after physical *** tensile strength and elongation at break of the new insulating paper increased by 5%–8%and 6.25%–27%respectively compared with the original cellulose insulating *** the end of ageing,the relative dielectric constant and dielectric loss factor of new insulating paper are 10.4%and 9.9%lower than that of the original cel-lulose insulating paper,while the breakdown voltage is 6.8%*** acid and moisture content produced during the ageing process of the insulating oil impregnated with new insulating paper are also less,indicating that the coating can delay the ageing of the insulating paper.

关键词： coating moisture cellulose