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Gaussian process hydrodynamics
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作者 H.OWHADI 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2023年第7期1175-1198,共24页
We present a Gaussian process(GP)approach,called Gaussian process hydrodynamics(GPH)for approximating the solution to the Euler and Navier-Stokes(NS)equations.Similar to smoothed particle hydrodynamics(SPH),GPH is a L... We present a Gaussian process(GP)approach,called Gaussian process hydrodynamics(GPH)for approximating the solution to the Euler and Navier-Stokes(NS)equations.Similar to smoothed particle hydrodynamics(SPH),GPH is a Lagrangian particle-based approach that involves the tracking of a finite number of particles transported by a flow.However,these particles do not represent mollified particles of matter but carry discrete/partial information about the continuous flow.Closure is achieved by placing a divergence-free GP priorξon the velocity field and conditioning it on the vorticity at the particle locations.Known physics(e.g.,the Richardson cascade and velocityincrement power laws)is incorporated into the GP prior by using physics-informed additive kernels.This is equivalent to expressingξas a sum of independent GPsξl,which we call modes,acting at different scales(each modeξlself-activates to represent the formation of eddies at the corresponding scales).This approach enables a quantitative analysis of the Richardson cascade through the analysis of the activation of these modes,and enables us to analyze coarse-grain turbulence statistically rather than deterministically.Because GPH is formulated by using the vorticity equations,it does not require solving a pressure equation.By enforcing incompressibility and fluid-structure boundary conditions through the selection of a kernel,GPH requires significantly fewer particles than SPH.Because GPH has a natural probabilistic interpretation,the numerical results come with uncertainty estimates,enabling their incorporation into an uncertainty quantification(UQ)pipeline and adding/removing particles(quanta of information)in an adapted manner.The proposed approach is suitable for analysis because it inherits the complexity of state-of-the-art solvers for dense kernel matrices and results in a natural definition of turbulence as information loss.Numerical experiments support the importance of selecting physics-informed kernels and illustrate the major impact of such kernels on the accuracy and stability.Because the proposed approach uses a Bayesian interpretation,it naturally enables data assimilation and predictions and estimations by mixing simulation data and experimental data. 展开更多
关键词 I Navier-Stokes(NS)equation EULER LAGRANGIAN VORTICITY Gaussian pro-cess(GP) physics-informed kernel
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Investigation of magnetization reversal and domain structures in perpendicular synthetic antiferromagnets by first-order reversal curves and magneto-optical Kerr effect
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作者 王向谦 李佳楠 +2 位作者 何开宙 谢明玲 朱旭鹏 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第11期580-584,共5页
Perpendicular synthetic-antiferromagnet(p-SAF) has broad applications in spin-transfer-torque magnetic random access memory and magnetic sensors. In this study, the p-SAF films consisting of (Co/Ni)3]/Ir(tIr)/[(Ni/Co)... Perpendicular synthetic-antiferromagnet(p-SAF) has broad applications in spin-transfer-torque magnetic random access memory and magnetic sensors. In this study, the p-SAF films consisting of (Co/Ni)3]/Ir(tIr)/[(Ni/Co)3are fabricated by magnetron sputtering technology. We study the domain structure and switching field distribution in p-SAF by changing the thickness of the infrared space layer. The strongest exchange coupling field(Hex) is observed when the thickness of Ir layer(tIr) is 0.7 nm and becoming weak according to the Ruderman–Kittel–Kasuya–Yosida-type coupling at 1.05 nm,2.1 nm, 4.55 nm, and 4.9 nm in sequence. Furthermore, the domain switching process between the upper Co/Ni stack and the bottom Co/Ni stack is different because of the antiferromagnet coupling. Compared with ferromagnet coupling films, the antiferromagnet samples possess three irreversible reversal regions in the first-order reversal curve distribution.With tIrincreasing, these irreversible reversal regions become denser and smaller. The results from this study will help us understand the details of the magnetization reversal process in the p-SAF. 展开更多
关键词 perpendicular synthetic antiferromagnet first-order reversal curves magnetization reversal pro-cess DOMAIN
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Evaluation of a gate-first process for AlGaN/GaN metal-oxide-semiconductor heterostructure field-effect transistors with low ohmic annealing temperature 被引量:1
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作者 李柳暗 张家琦 +1 位作者 刘扬 敖金平 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第3期445-447,共3页
In this paper, TiN/A1Ox gated A1GaN/GaN metal-oxide-semiconductor heterostructure field-effect transistors (MOS- HFETs) were fabricated for gate-first process evaluation. By employing a low temperature ohmic process... In this paper, TiN/A1Ox gated A1GaN/GaN metal-oxide-semiconductor heterostructure field-effect transistors (MOS- HFETs) were fabricated for gate-first process evaluation. By employing a low temperature ohmic process, ohmic contact can be obtained by annealing at 600 ℃ with the contact resistance approximately 1.6 Ω.mm. The ohmic annealing process also acts as a post-deposition annealing on the oxide film, resulting in good device performance. Those results demonstrated that the TiN/A1Ox gated MOS-HFETs with low temperature ohmic process can be applied for self-aligned gate AIGaN/GaN MOS-HFETs. 展开更多
关键词 metal-oxide-semiconductor heterostructure field-effect transistors low temperature ohmic pro-cess inductively coupled plasma
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A dual channel perturbation particle filter algorithm based on GPU acceleration 被引量:1
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作者 LI Fan BI Hongkui +2 位作者 XIONG Jiajun YU Chenlong LAN Xuhui 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2018年第4期854-863,共10页
The particle filter(PF) algorithm is one of the most commonly used algorithms for maneuvering target tracking. The traditional PF maps from multi-dimensional information to onedimensional information during particle... The particle filter(PF) algorithm is one of the most commonly used algorithms for maneuvering target tracking. The traditional PF maps from multi-dimensional information to onedimensional information during particle weight calculation, and the incorrect transmission of information leads to the fact that the particle prediction information does not match the weight information, and its essence is the reduction of the information entropy of the useful information. To solve this problem, a dual channel independent filtering method is proposed based on the idea of equalization mapping. Firstly, the particle prediction performance is described by particle manipulations of different dimensions, and the accuracy of particle prediction is improved. The improvement of particle degradation of this algorithm is analyzed in the aspects of particle weight and effective particle number. Secondly, according to the problem of lack of particle samples, the new particles are generated based on the filtering results, and the particle diversity is increased. Finally, the introduction of the graphics processing unit(GPU) parallel computing the platform, the “channel-level” and “particlelevel” parallel computing the program are designed to accelerate the algorithm. The simulation results show that the algorithm has the advantages of better filtering precision, higher particle efficiency and faster calculation speed compared with the traditional algorithm of the CPU platform. 展开更多
关键词 particle filter (PF) dual channel filtering graphic pro-cessing unit (GPU) parallel operation.
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In-Line Inspection of Pipeline Defects Detection Using Ring-Type Laser 被引量:2
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作者 Mathivanan Durai Yang-Min Hsu Ho Chang 《World Journal of Engineering and Technology》 2021年第3期589-603,共15页
Pipeline plays a vital role in transporting fluids like oils, water, and petrochemical substances for longer distances. Based on the materials they carry</span><span style="white-space:normal;font-size:1... Pipeline plays a vital role in transporting fluids like oils, water, and petrochemical substances for longer distances. Based on the materials they carry</span><span style="white-space:normal;font-size:10pt;font-family:"">,</span><span style="white-space:normal;font-size:10pt;font-family:""> prolonged usage may cause the initiation of defects in the pipeline. These defects occur due to the formed salt deposits, chemical reaction happens between the inner surface and the transferring substance, prevailing environmental conditions, etc. These defects, if not identified earlier may lead to significant losses to the industry. In this work, an in-line inspection system utilizes the nondestructive way for analyzing the internal defects in the petrochemical pipeline. This system consists of a pipeline inspection robot having two major units namely the visual inspection unit and the power carrier unit. The visual inspection unit makes use of a ring-type laser diode and the camera. The laser diode serves as a light source for capturing good quality images of inspection. This unit is controlled by the Arduino in the power carrier unit which provides the necessary movement throughout the pipe. The inspected images captured by the camera are further processed with the aid of NI vision assistant software. After applying the processing function parameters provided by this software, the defect location can be clearly visualized with high precision. Three sets of defects are introduced in a Polylactide (PLA) pipe based on its position and angle along the circumference of the pipe. Further, this robot system serves as a real-time interactive image synchronization system for acquiring the inspected images. By comparing the actual and calculated defect size, the error percentage obtained was less than 5%. 展开更多
关键词 Pipeline Robotic System Ring-Type Laser Vision Assistant Image pro-cessing Leak Holes Detection Nondestructive Testing
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Fabrication and characterization of the normally-off N-channel lateral 4H–SiC metal–oxide–semiconductor field-effect transistors
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作者 宋庆文 汤晓燕 +8 位作者 何艳静 唐冠男 王悦湖 张艺蒙 郭辉 贾仁需 吕红亮 张义门 张玉明 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第3期362-365,共4页
In this paper, the normally-off N-channel lateral 4H-SiC metal-oxide-semiconductor field-effect transistors (MOSF- FETs) have been fabricated and characterized. A sandwich- (nitridation-oxidation-nitridation) type... In this paper, the normally-off N-channel lateral 4H-SiC metal-oxide-semiconductor field-effect transistors (MOSF- FETs) have been fabricated and characterized. A sandwich- (nitridation-oxidation-nitridation) type process was used to grow the gate dielectric film to obtain high channel mobility. The interface properties of 4H-SiC/SiO2 were examined by the measurement of HF l-V, G-V, and C-V over a range of frequencies. The ideal C-V curve with little hysteresis and the frequency dispersion were observed. As a result, the interface state density near the conduction band edge of 4H-SiC was reduced to 2 x 1011 eV-l.cm-2, the breakdown field of the grown oxides was about 9.8 MV/cm, the median peak field- effect mobility is about 32.5 cm2.V-1 .s-1, and the maximum peak field-effect mobility of 38 cm2-V-1 .s-1 was achieved in fabricated lateral 4H-SiC MOSFFETs. 展开更多
关键词 metal-oxide-semiconductor field-effect transistors 4H-SIC field-effect mobility oxidation pro-cess
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Spectroscopic Measurement of Shock Waves in an Arcjet Plasma Expanding Through a Conical Nozzle
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作者 K.KOZUE G.KUMAKAWA +4 位作者 S.NAMBA T.ENDO K.TAKIYAMA K.SATO N.TAMURA 《Plasma Science and Technology》 SCIE EI CAS CSCD 2013年第2期89-92,共4页
A diamond-shaped shock wave was created in a helium arcjet plasma. Visi- ble/ultraviolet emission spectroscopy was used to investigate the condition for the formation of stable shocks and to determine characteristics ... A diamond-shaped shock wave was created in a helium arcjet plasma. Visi- ble/ultraviolet emission spectroscopy was used to investigate the condition for the formation of stable shocks and to determine characteristics of the plasma. Dependence of the position of the shock front on the gas pressure in the expansion region was investigated. It was found that the shock wave arises from the collision of plasma particles and residual neutral atoms in that region. Continuum and line spectra of neutral helium were measured, from which the electron temper- atures were derived. The electron density was deduced from the Inglis-Teller limit of the He I 2p3p-3d3D series. The temperature and density were found to have almost constant values of 0.2 eV and 8.5x 1013 cm-3, respectively, across the shock front. 展开更多
关键词 arcjet plasma shock wave plasma spectroscopy atomic and molecular pro-cesses
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Design and Implementation a Distributed Complex-Event Processing Engine
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作者 Ping Lu Yuming Qian Kezhi Zhu 《ZTE Communications》 2014年第1期52-56,共5页
A high-performance, distributed, complex-event processing en- gine with improved scalability is proposed. In this new engine, the stateless proeessing node is combined with distributed stor- age so that scale and perf... A high-performance, distributed, complex-event processing en- gine with improved scalability is proposed. In this new engine, the stateless proeessing node is combined with distributed stor- age so that scale and performance can be linearly expanded. This design prevents single node failure and makes the system highly reliable. 展开更多
关键词 CEP stream processing M2M sliding window real-time pro-cessing
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Synthesis of Branched Silicon-Containing Arylethyleneacetylene Resin and the Performance of Casting
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作者 Yusheng Chen Xintong You Shifeng Deng 《Journal of Materials Science and Chemical Engineering》 2018年第7期1-7,共7页
With good thermal properties, dielectric property and high-temperature ceramics performance, silicon-containing arylacetylene resin (PSA) has opened an attractive alternative to high performance thermosetting resins i... With good thermal properties, dielectric property and high-temperature ceramics performance, silicon-containing arylacetylene resin (PSA) has opened an attractive alternative to high performance thermosetting resins in application in the area of aircraft and missile. However, it is difficult to introduce silicon into the main chain of organic arylacetylene. In this paper, branched silicon-containing arylethyleneacetylene (BSA) resin was synthesized by methyltrichlorosilane and diethynylbenzene with zinc powder as catalyst. The advantages lie in simple operation, short reaction period and mild heat release. BSA resin exhibits excellent processability with the processing temperature of 20?C - 150?C and processing window of 130?C. The glass transition temperature of the resin casting is over 500?C. The temperature of 5% weight loss (Td5) is up to 575?C and char yield of thermoset at 800?C (Y800) reaches 91% under nitrogen. Also, the dielectric constant and dielectric loss of casting has no change within 10 - 106 Hz. 展开更多
关键词 BRANCHED Silicon-Containing Arylethyleneacetylene (BSA) Zinc Powder pro-cessability HEAT-RESISTANT Material
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Impact of Degrees of Freedom of Polyatomic Ideal Gas on Efficiency of Three-Stroke-Cycle Heat Engines
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作者 Haiduke Sarafian 《Journal of Modern Physics》 2018年第9期1807-1813,共7页
It is customary to evaluate the efficiency of four-stroke-cycle heat engines such as Carnot, Otto and Diesel with a working ideal gas [1] [2] [3]. Here we consider various three-stroke-cycle heat engines that are comp... It is customary to evaluate the efficiency of four-stroke-cycle heat engines such as Carnot, Otto and Diesel with a working ideal gas [1] [2] [3]. Here we consider various three-stroke-cycle heat engines that are composed of three out of four special processes: adiabatic, isothermal, isobaric and isochoric. We deviate from the customary norm considering the working material to be a polyatomic ideal gas with various degrees of freedom. We develop analytic expressions for the efficiency of each design as a function of degrees of freedom. For suitable practical values of relevant (V, P, T), we evaluate the corresponding efficiencies. 展开更多
关键词 EFFICIENCY of Heat Engine Three-Stroke-Cycle ADIABATIC ISOTHERMAL pro-cesses
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Distinct Assembly Mechanisms for Prokaryotic and Microeukaryotic Communities in the Water of Qinghai Lake 被引量:1
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作者 Mingxian Han Jianrong Huang +3 位作者 Jian Yang Beichen Wang Xiaoxi Sun Hongchen Jiang 《Journal of Earth Science》 SCIE CAS CSCD 2023年第4期1189-1200,共12页
Assembly processes of prokaryotic and microeukaryotic community is an important issue in microbial ecology.However,unclear remains about the relative contribution of deterministic and stochastic processes to the shapi... Assembly processes of prokaryotic and microeukaryotic community is an important issue in microbial ecology.However,unclear remains about the relative contribution of deterministic and stochastic processes to the shaping of prokaryotic and microeukaryotic communities in saline lake water.Here,we systematically investigated the assembly processes governing the prokaryotic and microeukaryotic communities in Qinghai Lake with the use of Illumina sequencing and a null model.The results showed that both deterministic and stochastic processes play vital roles in shaping the assemblies of prokaryotic and microeukaryotic communities,in which stochastic processes appeared to dominate(> 70%).Prokaryotic communities were mainly governed by non-dominant processes(60.4%),followed by homogeneous selection(15.8%),variable selection(13.6%) and dispersal limitation(10.2%),whereas microeukaryotes were strongly driven by non-dominant processes(68.9%),followed by variable selection(23.6%) and homogenizing dispersal(6.3%).In terms of variable selection,nutrients(e.g.,ammonium,dissolved inorganic carbon,dissolved organic carbon and total nitrogen) were the major factors influencing prokaryotic and microeukaryotic community structures.In summary,prokaryotes and microeukaryotes can be predominantly structured by different assembly mechanisms,in which stochasticity is stronger than deterministic processes.This finding helps to better comprehend the assembly of prokaryotic and eukaryotic communities in saline lakes. 展开更多
关键词 microbial community composition saline water deterministic processes stochastic pro-cesses QinghaiLake.
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Organic geochemical studies of sinking particulate material in China sea area Ⅱ——Geochemical significance of compositional features of ketone, aldehyde and alcohol compounds 被引量:1
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作者 DUAN Yi,CUl Mingzhong, MA Lanhua, SONG Jinming, ZHOU Shixin and LUO Binjie1. Lanzhou Institute of Geology, Chinese Academy of Sciences, Lanzhou 730000, China 2. Earthquake Research Institute of Lanzhou, SSB, Lanzhou 730000, China 3. Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China 《Chinese Science Bulletin》 SCIE EI CAS 1997年第22期1894-1898,共5页
SINKING particulate organic matter of the sea plays an important role in marine environment. Itnot only provides food for marine organisms and takes part in chemical cycling, but also pro-vides sedimentary organic mat... SINKING particulate organic matter of the sea plays an important role in marine environment. Itnot only provides food for marine organisms and takes part in chemical cycling, but also pro-vides sedimentary organic matter for marine sediments. Therefore, researchers always payclose attention to the source and processes of transport and transformation of marine sinkingparticulate organic matter. Its transport process can be understood by measuring the 展开更多
关键词 marine SINKING paniculate material composition of lipid COMPOUNDS ORGANIC matter source and biochemical pro-cesses.
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Use of Xinfeng capsule to treat abarticular pathologic changes in patients with rheumatoid arthritis 被引量:10
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作者 Jian Liu Yunxiang Cao +12 位作者 Chuanbing Huang Yuan Wang Xi Chen Wandong Zhang Guizhen Wang Haixia Fan Yao Ge Ruilian Chen Ruikai Zong Yajun Qi Yue Sun Yifei Liu Fang Wang 《Journal of Traditional Chinese Medicine》 SCIE CAS CSCD 2014年第5期532-538,共7页
OBJECTIVE: To observe the influence of Xinfengcapsule(XFC) on abarticular pathologic changes(APCs) and other indices of patients with rheumatoid arthritis(RA) and explore the mechanism of action of XFC in improving su... OBJECTIVE: To observe the influence of Xinfengcapsule(XFC) on abarticular pathologic changes(APCs) and other indices of patients with rheumatoid arthritis(RA) and explore the mechanism of action of XFC in improving such changes.METHODS: Three-hundred RA patients were divided randomly into a treatment group(n=150) and control group(n=150). A normal control(NC)group(n=90) was also created. Changes in cardiac function, pulmonary function, anemia indices and platelet parameters of RA patients were measured.Curative effects of the two groups were compared,and comparison carried out with the NC group.RESULTS: In 300 RA patients, late diastolic peak flow velocity(A peak) was much higher(P<0.01)and early diastolic peak flow velocity(E peak), E/A,and left ventricular fraction shortening much lower(P<0.01) than those in the NC group. Vital capacity(VC), forced vital capacity in one second, forced vital capacity(FVC), maximal voluntary ventilation(MVV), maximal expiratory flow in 50% of VC(FEF50) and FEF75 were lowered remarkably(P<0.05 or P<0.01). Platelet count(PLT), plateletcrit(PCT) and mean platelet volume(MPV) increased markedly(P<0.05 or P<0.01), and hemoglobin(Hb)level decreased significantly(P<0.05). After XFC treatment, the A peak and PLT and PCT were much lower(P<0.05), and E/A and the number of red blood cells as well as Hb level were much higher(P<0.05), as were FVC, MVV and FEF50(P<0.05 or P<0.01), in the treatment group than those in the NC group. Total score of pain and swelling in joints,uric-acid level and high-sensitivity C-reactive protein level were much lower, and superoxide dismutase level as well as the number of CD4 +CD25+ regulation T cells(Treg) and CD4+CD25+CD127- Treg were much higher(P<0.05 or P<0.01)in the treatment group than those in the NC group.CONCLUSION: RA patients with pathologic changes in joints also suffer from lower cardiac and pulmonary functions and from parameters of anemia and platelet factors. XFC can improve the symptoms of RA patients, ameliorate their cardiac and pulmonary functions and reduce the parameters of anemia and platelet factors. XFC lowers the immune inflammatory reaction to improve APCs in RA patients. 展开更多
关键词 Arthritis rheumatoid Pathologic pro-cesses Xinfeng capsule
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Recent advances in the catalytic pyrolysis of biomass 被引量:1
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作者 Changwei HU Yu YANG +3 位作者 Jia LUO Pan PAN Dongmei TONG Guiying LI 《Frontiers of Chemical Science and Engineering》 SCIE EI CSCD 2011年第2期188-193,共6页
Biomass is considered as a renewable and alternative resource for the production of fuels and chemicals,since it is the only carbon and hydrogen containing resource that we canfind in the world except for fossil resour... Biomass is considered as a renewable and alternative resource for the production of fuels and chemicals,since it is the only carbon and hydrogen containing resource that we canfind in the world except for fossil resources,capable of being converted to hydro-carbons.The pyrolytic liquefaction of biomass is a promising way to convert biomass to useful products.This paper briefly surveys the present status of the direct catalytic pyrolysis for the liquefaction of biomass.The direct use of catalysts could decrease the pyrolysis temperature,increase the conversion of biomass and the yield of bio-oil,and change the distribution of the pyrolytic liquid products then improve the quality of the bio-oil obtained.The fact that biomass is in solid state present great challenges for its conversion and for the effective use of catalysts due to the bad heat transfer characteristics and bad mass transfer properties.These barriers appeal for the development of a new catalyst and new catalytic process as well as the integration of both.Process design and process intensification are of significant importance in the catalytic conversion of biomass. 展开更多
关键词 BIOMASS LIQUEFACTION CATALYSIS BIO-OIL pro-cess intensification
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Process simulation and economic analysis of reactor systems for perfluorinated compounds abatement without HF effluent 被引量:1
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作者 Boreum Lee Sunggeun Lee +2 位作者 Ho Young Jung Shin-Kun Ryi Hankwon Lim 《Frontiers of Chemical Science and Engineering》 SCIE EI CAS CSCD 2016年第4期526-533,共8页
New and efficient proposed to treat perfluorinated reactor systems were compounds via catalytic decomposition. One system has a single reactor (S-1), and another has a series of reactors (S-2). Both systems are c... New and efficient proposed to treat perfluorinated reactor systems were compounds via catalytic decomposition. One system has a single reactor (S-1), and another has a series of reactors (S-2). Both systems are capable of producing a valuable CaF2 and eliminating toxic HF effluent and their feasibility was studied at various temperatures with a commercial process simulator, Aspen HYSYS. They are better than the conventional system, and S-2 is better than S-1 in terms of CaF2 production, a required heat for the system, natural gas usage and CO2 emissions in a boiler, and energy consumption. Based on process simulation results, preliminary economic analysis shows that cost savings of 12.37% and 13.55% were obtained in S-2 at 589.6 and 621.4℃compared to S-1 at 700 and 750 ℃, respectively, for the same amount of CaF2 production. 展开更多
关键词 perfluorinated compounds (PFCs) CF4 pro-cess simulation economic analysis
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Fast changing processes in radiotelemetry systems of space vehicles
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作者 Yesmagambetov Bulat-Batyr Sauhymovich Inkov Alexander Mikhailovich 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2015年第5期941-945,共5页
The method of processing of the non-stationary casual processes with the use of nonparametric methods of the theory of decisions is considered. The use of such methods is admissible in telemetry systems in need of pro... The method of processing of the non-stationary casual processes with the use of nonparametric methods of the theory of decisions is considered. The use of such methods is admissible in telemetry systems in need of processing at real rate of time of fast-changing casual processes in the conditions of aprioristic uncertainty about probabilistic properties of measured process. 展开更多
关键词 radiotelemetry information non-stationary casual pro-cesses irreversible compression of data nonparametric statistics intervals of a stationarity.
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Process evaluation of an alternating aerobic-anoxic process applied in a sequencing batch reactor for nitrogen removal
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作者 ZENG Wei PENG Yongzhen WANG Shuying 《Frontiers of Environmental Science & Engineering》 SCIE EI CSCD 2007年第1期28-32,共5页
In order to improve the nitrogen removal efficiency and save operational cost,the feasibility of the alternating aerobic-anoxic process(AAA process)applied in a sequencing batch reactor(SBR)system for nitrogen removal... In order to improve the nitrogen removal efficiency and save operational cost,the feasibility of the alternating aerobic-anoxic process(AAA process)applied in a sequencing batch reactor(SBR)system for nitrogen removal was investigated.Under sufficient influent alkalinity,the AAA process did not have an advantage over one aerobic-anoxic(OAA)cycle on treatment efficiency because microorganisms had an adaptive stage at the alternating aerobic-anoxic transition,which would prolong the total cycling time.On the contrary,the AAA process made the system control more complicated.Under deficient influent alkalinity,when compared to OAA,the AAA process improved treatment efficiency and effluent quality with NH4+-N in the effluent below the detection limit.In the nitrification,the average stoichiometric ratio between alka-linity consumption and ammonia oxidation is calculated to be 7.07 mg CaCO_(3)/mg NH4+-N.In the denitrification,the aver-age stoichiometric ratio between alkalinity production and N_(3)^(−)-N reduction is about 3.57 mg CaCO(3)/mg NO_(3)^(−)-N.As a result,half of the alkalinity previously consumed during the aerobic nitrification was recovered during the subsequent anoxic denitrification period.That was why the higher treat-ment efficiency in the AAA process was achieved without the supplement of bicarbonate alkalinity.If the lack of alkalinity in the influent was less than 1/3 of that needed,there is no need for external alkalinity addition and treatment efficiency was the same as that under sufficient influent alkalinity.Even if the lack of alkalinity in the influent was more than 1/3 of that needed,the AAA process was an optimal strategy because it reduced the external alkalinity addition and saved on operational cost. 展开更多
关键词 alternating aerobic-anoxic process(AAA pro-cess) one aerobic-anoxic process(OAA process) sequencing batch reactor(SBR) alkalinity
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