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Characterization of Ultra Fine Solids(BS) in Athabasca Bitumen

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Chinese Journal of Structural Chemistry 2004年第7期23卷 751-754页

作者：李再峰 judy KUNG 涂云 Luba S.Kotlyar Keng h.Chung College of Chemistry and Molecular Engineering Qingdao University of Science and TechnologyShandong 266042China National Research Council of Canada Institute for Chemical Process andEnvironmental TechnologyMontreal Road CampusOttawaOntarioCanada K1A 0R6 Syncrude Canada Ltd.Edmonton Research Centre9421-17th Avenue EdmontonAlberta Canada T6N 1H4

The ultra fine (<200 nm) inorganic solids (BS) were separated from bitumen which was washed by toluene and centrifugated at 2000 rpm. The result of PAS FTIR and image of TEM showed that the structure of BS particles w... 详细信息

The ultra fine (hich was washed by toluene and centrifugated at 2000 rpm. The result of PAS FTIR and image of TEM showed that the structure of BS particles was smiliar to that of kaolinite clay. On the surface of BS, both toluene insoluble organic matter and structural Oh group are detected at the same time. The surface characteristics imparted a bi-wettable nature to the BS. As a result, the BS is able to stabilize fine water emulsion in the bitumen phase. The organic matter associated with BS is a possible factor of the fouling on catalyst and equipment.

关键词： ultra fine solids characterization bitumen

Dynamic modeling of twin roll casting AZ41 magnesium alloy during hot compression processing

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Transactions of Nonferrous Metals Society of China 2010年第B7期20卷 513-518页

作者：王敏王守仁 S.BKANG J.h.cho 王砚军 School of Materials Science and Engineering Shandong University School of Mechanical Engineering University of Jinan Korea Institute of Materials Science 66 Sangnam-dong

A dynamic material model of Mg-4.51Al-1.19Zn-0.5Mn-0.5Ca(AZ41,mass fraction,%)magnesium alloy was put *** results show that the dynamic material model can characterize the deformation behavior and microstructure evolution and describe the relations among flow stress,strain,strain rates and deformation *** analysis shows the validity of the proposed *** model predicts that lower deformation temperature and higher strain rate cause the sharp strain hardening. Meanwhile,the flow stress curve turns into a steady state at high temperature and lower strain *** moderate temperature of 350 ℃and strain rate of 0.01 s-1 are appropriate to this alloy.

关键词： AZ41 alloy flow stress deformation behavior dynamic model twin-roll casting hot compression

Recent advances towards single biomolecule level understanding of protein adsorption phenomena unique to nanoscale polymer surfaces with chemical variations

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Nano Research 2020年第5期13卷 1295-1317页

作者： David h.cho Tian Xie Johnson Truong Andrew C.Stoner Jong-in hahm Department of Chemistry Georgetown University37th&O Sts.NW.WashingtonDC 20057USA

Protein adsorption onto polymer surfaces is a very complex and ubiquitous phenomenon whose integrated process impacts essential applications in our daily lives such as food packaging materials,health devices,diagnostic tools,and medical ***,novel polymer materials with greater chemical intricacy and reduced dimensionality are used for various applications involving adsorbed proteins on their ***,the nature of protein-surface interactions to consider is becoming much more complicated than before.A large body of literature exists for protein ***,most of these investigations have focused on collectively measured,ensemble-averaged protein behaviors that occur on macroscale and chemically unvarying polymer surfaces instead of direct measurements at the single protein or sub-protein *** addition,interrogations of protein-polymer adsorption boundaries in these studies were typically carried out by indirect methods,whose insights may not be suitably applied for explaining individual protein adsorption processes occurring onto nanostructured,chemically varying polymer ***,an important gap in our knowledge still exists that needs to be systematically addressed via direct measurement means at the single protein and sub-protein *** efforts will require multifaceted experimental and theoretical approaches that can probe multilength scales of protein adsorption,while encompassing both single proteins and their collective ensemble behaviors at the length scale spanning from the nanoscopic all the way to the macroscopic *** this review,key research achievements in nanoscale protein adsorption to date will be ***,protein adsorption studies involving polymer surfaces with their defining feature dimensions and associated chemical partitions comparable to the size of individual proteins will be discussed in *** this regard,recent works bridging the crucial knowledge gap in protein adso

关键词： nanoscale protein adsorption nanoscale protein assembly protein self-assembly on polymer protein nanopatterning protein-nanosurface interaction

Single-pilot operations in commercial flight:Effects on neural activity and visual behaviour under abnormalities and emergencies

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Chinese Journal of Aeronautics 2024年第8期37卷 277-292页

作者： Qinbiao LI Chun-hsien ChEN Kam K.h.NG Xin YUAN cho Yin YIU human Factors and Ergonomics Laboratory Department of Aeronautical and Aviation EngineeringThe Hong Kong Polytechnic UniversityHong Kong Special Administrative Region 100872China School of Mechanical&Aerospace Engineering Nanyang Technological UniversitySingapore 639798Singapore

With cutting-edge technologies and considering airline human-resource-saving,a single pilot in commercial jets could be technically *** changes in captains’natural behaviours are initially required to comprehend the specific safe human performance envelope for safeguarding single-pilot flight,particularly in high-risk *** paper investigates how captains’performance transforms for fixing emergencies when operating from Dual-Pilot Operations(DPO)to Single-Pilot Operations(SPO)through a physiological-based *** pilots flew an emergency-included flight with/without first officers’*** neural activities and scanning behaviours were recorded using a 32-channel Electroencephalogram(EEG)and glasses-based eye tracker,with the observation and post-experiment questionnaires to evaluate the flight operations and pilots’*** alone,there was a significantly increased cortical activity in h and b waves over the frontal,parietal,and temporal lobes during the more complicated emergencies,and pilots focused less on the primary flight display while spending significantly more time scanning the other *** physiological fluctuating patterns associated with risky operations in SPO were highlighted by cross-correlating multimodal *** experimental-based noteworthy insights may wish to inform commercial SPO measures to lessen the persistent physiological fluctuation,assisting airlines in creating SPO-oriented intelligent flight systems to give captains adequate support for assuring safer air transportation.

关键词： Aviation engineering Single pilot operations Behaviour changes Eye tracker Electroencephalogram

Effect of Applied Pressure on the Joining of Combustion Synthesized Ni_3Al Intermetallics with Al Alloy

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Journal of Materials Science & Technology 2008年第1期24卷 123-126页

作者： G.S.cho J.h.Yang K.h.choe K.W.Lee A.Ikenaga Advanced Material Processing Team Korea Institute of Industrial Technology 7-47 Songdo-Dong Yeonsu-Ku Incheon 406-840 Korea Department of Metallurgy and Materials Science Graduate School of Engineering Osaka Prefecture University 1-1 Gakuen-Cho Sakai Osaka 599-8531 Japan

We focused on the surface reinforcement of ligth weight casting alloys with Ni-AI intermetallic compounds by in-situ combustion reaction to improve the surface properties of non-ferrous casting *** our previous works,green compact of elemental Ni and Al powders were reacted to form Ni-3Al intermetallic compound by ShS （Self-propagating high temperature synthesis） reaction with the heat of molten Al alloy and simultaneously bonded with Al casting *** some defects such as tiny cracks and porosities were remained in the reacted *** we applied pressure to prevent thermal cracks and fill up the pores with liquid Al alloy by squeeze casting *** compressed Al alloy bonded with the Ni-3Al intermetallic compound was sectioned and observed by optical microscopy and scanning electron microscopy （SEM）.The stoichiometric compositions of the intermetallics formed around the bonded interface and in the reacted compact were identified by energy dispersive spectroscopy （EDS） and electron probe micro analysis （EPMA）. Si rich layer was formed on the Al alloy side near the bonded interface by the sequential solidification of Al *** porosities observed in the reacted Ni-3Al compact were filled up with the liquid AI *** Si particles from the molten Al alloy were detected in the pores of reacted Ni-3Al intermetallic *** Al casting alloy and Ni-3Al intermetallic compound were joined very soundly by applying pressure to the liquid Al alloy.

关键词： Joining Combustion synthesis Ni3AI Intermetallic compound Squeeze casting

Some Radius Problems Related to a Certain Subclass of Analytic Functions

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Acta Mathematica Sinica,English Series 2014年第7期30卷 1133-1144页

作者： Oh Sang KWON Young Jae SIM Nak Eun cho h.M.SRIVASTAVA Department of Mathematics Kyungsung University Department of Applied Mathematics Pukyung National University Department of Mathematics and Statistics University of Victoria

For real parameters αand β such that 0≤α 〈 1 〈β, we denote by S（α,β） the class of normalized analytic functions which satisfy the following two-sided inequality：where U denotes the open unit disk. We find a sufficient condition for functions to be in the class S（α,β） and solve several radius problems related to other well-known function classes.

关键词： Analytic functions univalent functions starlike functions functions of bounded real pos-itive real part radius problems

Effects of Alloying Elements on the Microstructures and Mechanical Properties of heavy Section Ductile Cast Iron

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Journal of Materials Science & Technology 2007年第1期23卷 97-101页

作者： G.S.cho K.h.choe K.W.Lee A.Ikenaga Advanced Material Processing Team Korea Institute of Industrial Technology994-32Dongchun-DongYeonsu-KuIncheon 406-130South Korea Department of Metallurgy and Materials Science Graduate School of EngineeringOsaka Prefecture University1-1Gakuen-ChoSakaiOsaka 599-8531Japan

The effects of alloying elements on the as-cast microstructures and mechanical properties of heavy section ductile cast iron were investigated to develop press die material having high strength and high ductility. Measurements of ultimate tensile strength, 0.2% proof strength, elongation and unnotched Charpy impact energy are presented as a function of alloy amounts within 0.25 to 0.75 wt pct range. hardness is measured on the broken tensile specimens. The small additions of Mo, Cu, Ni and Cr changed the as-cast mechanical properties owing to the different as-cast matrix microstructures. The ferrite matrix of Mo and Ni alloyed cast iron exhibits low strength and hardness as well as high elongation and impact energy. The increase in Mo and Ni contents developed some fractions of pearlite structures near the austenite eutectic cell boundaries, which caused the elongation and impact energy to drop in a small range. Adding Cu and Cr elements rapidly changed the ferrite matrix into pearlite matrix, so strength and hardness were significantly increased. As more Mo and Cr were added, the size and fraction of primary carbides in the eutectic cell boundaries increased through the segregation of these elements into the intercellular boundaries.

关键词： heavy section ductile cast iron Alloying elements As-cast microstructures As-cast mechanical properties

Effect of Vibrational Modes on Sand Pressure and Pattern Deformation in the EPC Process

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Journal of Materials Science & Technology 2004年第3期20卷 326-329页

作者： A.Ikenaga G.S.cho K.h.choe K.W.Lee Department of Metallurgy and Materials Science Graduate School of EngineeringOsaka Prefecture University1-1 Gakuen-ChoSakaiOsaka 599-8531JapanAdvanced Material Processing TeamKorea Institute of Industrial Technology472KaJwa4-DongSeo-KuIncheon 404-264Advanced Material Processing TeamKorea Institute of Industrial Technology472KaJwa4-DongSeo-KuIncheon 404-264Advanced Material Processing TeamKorea Institute of Industrial Technology472KaJwa4-DongSeo-KuIncheon 404-264

During the EPC (expendable pattern casting) process, one of the essential requirements is to prevent pattern distortion duringsand filling and compaction. A new method which vibrates the system in a two-dimensional circular mode has been appliedto the EPC process. The molding properties of unbonded sand obtained by this new vibration mode are investigated andcompared with those in the one-dimensional vertical mode. For adequate compaction of sand. the circular vibration mode ismore effective than the vertical mode. Sand became more fluidized by the circular vibration and the particle pressure coefficientwas close to unity The particle pressure coefficient, which is defined as the ratio of horizontal to vertical sand pressure, isresponsible for the effectiveness of sand filling.

关键词： EPC process Sand compaction Vibration mode Pattern deformation Sand pressure

Thermal stress analysis method considering geometric effect of risers in sand mold casting process

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China Foundry 2014年第6期11卷 531-536页

作者： S.Y.Kwak h.Y.hwang C.cho e-Design R&D Group Korea Institute of Industrial Technology (KITECH) Department of Virtual Engineering Korea University of Science and Technology(UST) Department of Mechanical Engineering Inha University

Solidif ication and f luid f low analysis using computer simulation is a current common practice. There is also a high demand for thermal stress analysis in the casting process because casting engineers want to control the defects related to thermal stresses, such as large deformation and crack generation during casting. The riser system is an essential part of preventing the shrinkage defects in the casting process, and it has a great inf luence on thermal phenomena. The analysis domain is dramatically expanded by attaching the riser system to a casting product due to its large volume, and it makes FEM mesh generation diff icult. however, it is diff icult to study and solve the above proposed problem caused by riser system using traditional analysis methods which use single numerical method such as FEM or FDM. In this paper, some research information is presented on the effects of the riser system on thermal stress analysis using a FDM/FEM hybrid method in the casting process simulation. The results show the optimal conditions for stress analysis of the riser model in order to save computation time and memory resources.

关键词： thermal stress sand mold casting riser numerical analysis hybrid method simulation