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European Conference on Wireless technology

作者： Junghwan Moon Jangheon Kim Ildu Kim Young Yun Woo Sungchul Hong Han Seok Kim Jong Sung Lee Bumman Kim Department of Electrical Engineering Pohang University of Science and Technology Pohang Gyeongbuk Republic of Korea Telecommunication Research & Development Center Samsung Electronics Company Limited Suwon Gyeonggi South Korea Telecommunication R&D Center Samsung Electronics Co. LTD Suwon Gyeonggi Republic of Korea

We have implemented a doherty amplifier for 3.5-GHz World Interoperability for Microwave Access (WiMAX) applications using Eudyna 90-W (P 3dB ) Gallium-Nitride (GaN) High Electron Mobility Transistor (HEMT) because of the poor efficiency of a standard class AB amplifier when the linearity performance is good. The load modulation performance of the GaN HEMT device for the doherty operation is rather moderate but workable. The linearity is improved using the in-band error cancellation technique of the doherty amplifier. The implemented doherty amplifier has been designed at an average output power of 43 dBm, backed-off about 8 dB from the 51 dBm (P 3dB ). For WiMAX signal with 28 MHz signal bandwidth, the measured drain efficiency of the amplifier is 27.8%, and the measured relative Constellation Error (rCE) is -33.17 dB, while those of the comparable class AB amplifier are 19.42% and -24.26 dB, respectively, at the same average output power level.

关键词： Gallium nitride HEMTs WiMAX Power amplifiers Microwave amplifiers Linearity Power generation Power measurement Microwave devices MOdFETs

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Fabrication of a direct-type silicon pixel detector for a large area hybrid x-ray imaging device

Fabrication of a direct-type silicon pixel detector for a la...

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IEEE Symposium on Nuclear Science (NSS/MIC)

作者： Kun-Sik Park Tae-Woo Kim Yong-Sun Yoon Jong-Moon Park Jin-Yeong Kang Jin-Gun Koo Bo-Woo Kim J. Kosonen Kwang-Soo No Electronics and Telecommunications Research Institute Semiconductor Process Team Daejeon South Korea Department of Materials Science and Engineering Korea Advanced Institute of Science and Technology Daejeon South Korea X-ray Sensor R&D Center Value Added Technologies Company Limited Hwaseong South Korea

We demonstrated the design and the fabrication processes of a direct-type silicon pixel detector for a digital dental radiography made using a high-resistive n-type silicon substrate. The structure of the detector is based on a fully-depleted p-i-n diode. The detector is composed of 644,328 pixels with a pitch of 35 mum. The size of the detector is 2.58 cm x 3.47 cm and it is composed of a 4-block assembly with four read-out CMOS ICs. We focused on experimentally evaluating the process conditions for the silicon pixel detector to reduce the leakage current and improve the breakdown voltage. From the experimental results, we found that the high temperature drive-in after p + ion implantation deteriorates the leakage current and p + passivation by thermal oxidation improves the breakdown voltage. The leakage current of a pixel was 0.07 pA/pixel and the breakdown voltage was more than 1700 V. The read-out IC consists of a current-integrating pixel readout CMOS chip and PbSn bumps. After bump-bonding four read-out ICs to a pixel detector and wire-bonding to a PCB, X-ray image tests showed a resolution of 11 lp/mm and provided a good image of human teeth.

关键词： Fabrication Silicon Pixel X-ray detection X-ray detectors X-ray imaging Leakage current dentistry radiography P-i-n diodes

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Pore-Scale Understandings for Steady-State Two-Phase Flow in Natural Porous Media from Pore Connectivity Quantification

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SSrN 2023年

作者： Qiao, Juncheng Zeng, Jianhui An, Ting Jiang, Shu Ma, Yong Liu, Yazhou Chen, dongxia Cai, Jianchao Zhang, Yongchao Feng, Xiao Cao, Zhe Sun, Chenhao State Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum Beijing102249 China College of Geosciences China University of Petroleum Beijing102249 China Fengcheng Oilfield operation District Xinjiang Oilfield Company CNPC Karamay834000 China Energy & Geosciences Institute Department of Chemical Engineering University of Utah UT84108 United States Key Laboratory of Tectonics and Petroleum Resources of Ministry of Education School of Earth Resources China University of Geosciences Wuhan430074 China The Key Laboratory of Gas Hydrate Ministry of Natural Resources Institute of Marine Geology Qingdao266071 China CNPC Engineering Technology R&D Company Limited Beijing102206 China Sinopec Petroleum Exploration and Production Research Institute Beijing102206 China

Fluid and chemical transport in the connected pore system of various natural porous sandstone governs numerous energetic and industrial activities. A nanometer-millimeter pore connectivity quantification is compiled,on the basis of which steady-state two-phase flow physics are explored. Connectivity evaluation indicates that high permeable sandstone shares a reticular connection network with scale-invariant connected ratio stays at around 0.60, low-permeability sandstone exhibits branch-like pattern with the ratio ranging from 0.53 to 0.60, while tight sandstone is characterized by local chain-like pattern with an average ratio of 0.31. With decreasing connectivity degree, differed deviated linear and power-law flows present in the fractional non-wetting phase flow of steady-state two-phase flow. A coupled phase’s mobility, dynamic phase’s interactions, and dynamic non-wetting phase flow paths evaluations based on the connectivity quantification, incorporating dLVO theory, augmented Young-Laplace equation, and effective hydraulic radius model, explain the reasons for flow regime distinctions. It indicates that the full-range connected pore size distribution determines multiphase mobility potential and dynamic multiphase interaction force, which successively control the dynamic expansion of non-wetting phase pathway. differences in preferential non-wetting phase flow path expansions and accompanying non-wetting phase flow resistances in the connected pores © 2023, The Authors. All rights reserved.

关键词： Two phase flow

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An On-Line Inductance Identification Method for Permanent Magnet Synchronous Motors Under Sensorless Control in The Full Speed domain

An On-Line Inductance Identification Method for Permanent Ma...

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International Conference on Power Electronics and Motion Control (IPEMC)

作者： Yue Liu Liguo Wang Qiang Gao Yong Li Fei E Department of Electrical Engineering Shanghai Jiao Tong University Shanghai China State Grid Suzhou Power Supply Company Substation Maintenance Center Suzhou China Department of R&D Contemporary Amperex Electric Vessel Technology Co. Limited Ningde China Department of Technology Contemporary Amperex Electric Vessel Technology Co. Limited Ningde China

ISBN: (数字)9798350351330

ISBN: (纸本)9798350351347

This work presents an online inductance identification method for permanent magnet synchronous motors in the full speed domain. Online inductance estimation is realized by injecting two modified high-frequency square wave voltage signals into the d-q axis simultaneously. This method can achieve high-precision identification of inductance in the full sensorless speed domain. The simulation results show that the inductance identification accuracy of this method can reach ±4% whether under constant loading, sudden addition and subtraction loading or dynamic loading.

关键词： Inductance Accuracy Simulation Loading Asia Estimation Sensorless control

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Synthesis and study of polystyrene/montmorillonite nanocomposite emulsion drilling fluid lubricant

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IOP Conference Series: Earth and Environmental Science 2019年第1期384卷

作者： Zhengrong Zhang Huiting Liu Yongjin Yu Yangchuan Ke Chengcheng Yu CNPC Engineering Technology R&D Company Limited Building 1 yard 5 huanghe street changping district Beijing China CNPC Nanochemistry Key Laboratory College of Science China University of Petroleum Beijing 102249 China

Conventional drilling fluid lubricants could effectively improve the lubricity of the system, but the temperature and salt resistance was poor. In this paper, a new type of emulsion drilling fluid lubricant was prepared by mixing a polystyrene/modified montmorillonite (MMT) nanocomposite emulsion with vegetable base oil. The nanocomposite emulsion was prepared by emulsion polymerization of organic MMT, modified with the tributyltetradecylphosphonium chloride and sodium lauryl sulfonate, and styrene. The work revealed effects of the amount of modified MMT and lubricant on the performance of the drilling fluid. It was shown that lubricants have less effect on the rheology and density changes of the drilling fluid. The lubricity, temperature resistance and salt resistance of the drilling fluid were enhanced, while the fluid loss was significantly reduced due to the addition of the lubricant. Our results provide the basic method needed to guide design of the lubricant.

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Investigation of the Effects of Various Operating and design Parameters of a Biodiesel-Fueled Pcci Combustion Engine by Kiva-Chemkin Coupling

SSRN

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SSrN 2023年

作者： Zehni, Alborz Khoshbakhti Saray, rahim Poorghasemi, Kamran Mousavi, Seyed Mohammad Mashhadi, Khashayar Imani, Amin Engineering Department Krengel Manufacturing ClevelandOH United States Department of Mechanical Engineering Sahand University of Technology Sahand New Town Tabriz Iran Department of Mechanical Engineering Islamic Azad University Shabestar Branch Shabestar Iran Department of Mechanical Engineering University of Manitoba WinnipegMBR3T 5V6 Canada R&D Department of Mega Motor Company Engine Division Iran Malek-Ashtar University of Technology Iran Sharif University of Technology Iran

In the current work, a parametric investigation is conducted by KIVA-CHEMKIN code to evaluate the impacts of the temperature and pressure of intake charge, injection timing and pressure, and EGr rate parameters on the combustion and emission characteristics of neat biodiesel (B100) within a PCCI engine. In this simulation, multi-chemical surrogate mechanism using methyl decanoate (Md) and methyl-9-decenoate (Md9d) is utilized for the biodiesel reaction mechanism. The analyses are conducted under conditions of 2000 rpm engine speed and 5.5 bar indicated mean effective pressure (IMEP). The numerical results show that higher EGr rate retards the first and second peaks of heat release rate. Also, increasing intake temperature decrease the first peak, and increase the second peak of heat release rate. Increasing the injection pressure does not always lead to improved combustion. The phasing of the peak of low temperature heat release is shifted with the timing of the injection event, but, this sensitivity is lower for the peak of high temperature heat release. Each design parameter has its own influence on exhaust emissions. For different various operating and design parameters, range of combustion efficiency varies between 48% and 51.84%. The presented numerical 2-d and 3-d results of this investigation can be construed to offer an in-depth insight into the qualities of the biodiesel PCCI combustion. © 2023, The Authors. All rights reserved.

关键词： Biodiesel

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research on the method of dynamic PdC cutters distribution

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IOP Conference Series: Earth and Environmental Science 2021年第1期675卷

作者： Qi Peng Yingcao Zhou Xiongwen Yang Yu Liu Chris Cheng CNPC Engineering Technology R & D Company Limited Beijing China Research Institute of Petroleum Exploration & Development Beijing China CNPC USA Corporation (Houston TX USA)

PdC bit design, especially the design of the crown and cutters of PdC bit, is a relatively complex analysis process, which involves many factors such as the back-dip angle, cutting depth, cutting force, cutting power and other factors of PdC cutters. At present, the traditional design methods of PdC cutters distribution are mostly based on analysis of rock breaking efficiency of single cutter, which can only reflect the working state of the single cutter under the set parameters, and cannot fully reflect the differences of different positional cutters during the cutting process. In order to solve this problem, this article proposes a dynamic method through target formation lithology characteristics. The working parameters of all the PdC cutters are analyzed in detail basing on equal wear theory and bottom hole covering theory. The working parameters include static parameters (cutting position, back dip angle, cutting depth, effective cutting area.) and dynamic parameters (cutting force, cutting power, cutting torque and cutting energy etc.). The energy required by all the PdC cutters to break rock of per volume during drilling process is taken as the target constraint condition for iterative analysis. This design method can intuitively and effectively analyse the working parameters of cutters which located bit core, nose, shoulder and gauge area, and it provides a good reference for dynamic balance design of PdC bit.

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High Throughput Grain Mapping with Sub-Nanometer resolution by 4d-STEM

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Microscopy and Microanalysis 2019年第S2期25卷 1960-1961页

作者： Frances I. Allen Thomas C. Pekin Arun Persaud Steven J. rozeveld Gregory F. Meyers Jim Ciston Colin Ophus Andrew M. Minor Department of Materials Science and Engineering UC Berkeley Berkeley CA USA. National Center for Electron Microscopy Molecular Foundry LBNL Berkeley CA USA. Accelerator Technology and Applied Physics Division LBNL Berkeley CA USA. Core R&D – Analytical Sciences The Dow Chemical Company Midland MI USA.

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Effect of the combination of hydrophilic nano-SiO2 and gaffix VC-713 polymer on CH4 hydrate formation: Insight from the experimental study

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IOP Conference Series: Materials Science and engineering 2019年第1期634卷

作者： r Wang X G Xu X M Shi Y Y Li J Zhang Z Yang CNPC Engineering Technology R & D Company Limited Beijing 102206 China National Engineering Laboratory for Oil & Gas Drilling Technology Beijing 102206 China

In this paper, the effect of the combination of hydrophilic nano-SiO2 with a particle size of 80 nm and gaffix VC-713 polymer (VC-713) on their hydrate inhibition was investigated at 4.0°C and 6.0 MPa, and the underlying influence mechanism was analysed by a multiple scales of the meso-structural observation experiments. Experimental results indicated that the combination doesn't exhibit any synergistic inhibition effect on the formation of CH4 hydrate, but it weakens the hydrate inhibition abilities of both components. Moreover, with the increase of the VC-713 content to 0.75 wt% and 1.00 wt%, the inhibition of hydrophilic nano-SiO2 completely disappears.

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An Integrated Method for Evaluating Lost Circulation risk for Shale Gas drilling in Sichuan Basin

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IOP Conference Series: Earth and Environmental Science 2021年第6期861卷

作者： rong-Chao Cheng Ming-Ming Chu Jie Zhang Hui-Jiun Hao Hai Lin Qiang Tan Yong-Cun Feng CNPC Engineering Technology R&D Company Limited Beijing 102206 Tianjin Branch China National Offshore Oil Corporation Tianjin 300452 China College of Petroleum Engineering China University of Petroleum Beijing

Accurate prediction of lost circulation fracture width and lost circulation pressure is the basis for preventing lost circulation and curing the losses. They are controlled by many factors, such as in-situ stress, wellbore fluctuating pressure, rock properties, natural fractures, and so on. researchers have put forward a variety of calculation models of lost circulation pressure for fractured formations; however, in the field practice, it is still mainly based on the minimum horizontal principal stress. The lost circulation of fractured formation seriously jeopardizes the safety and progress of drilling and production. At present, the success rate of curing the losses is low, one of the important reasons is that the fracture width cannot be accurately predicted. It is difficult to determine the wellbore strengthening method and particle size of the lost circulation materials due to unknown fracture width. Various prediction models of fracture width are used to calculate the fracture width of the loss layer, and the influence of the factors such as the loss time, drilling fluid properties (viscosity and yield value), and the angle between the fracture and the wellbore on the calculated fracture width is studied. For the lost circulation pressure, the acceptable loss rate in the drilling process is given. On the premise of the calculated fracture width, the lost circulation pressure under the acceptable loss rate is determined. The results show that the values of fracture width and lost circulation pressure predicted by the three methods are close to each other, and the prediction results of the three methods can be averaged in the field application to provide reference for the following work. The fracture width is sensitive to drilling fluid viscosity, bottom hole pressure, and other parameters, so the value of these parameters should be accurately measured in the field to reduce the uncertainty. The results also show that the larger the angle between fracture and we

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