http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
금형면 자동 다듬질 전문가 시스템 개발에 관한 연구-Ⅱ : 통합 연마 파라미터를 사용한 최적 가공 구현 및 전문가 시스템 구축
민헌식,이성환,안유민,조남규,한창수 한국공작기계학회 2002 한국생산제조학회지 Vol.11 No.1
To reduce the cost and increase reliability of die and mold products, automation of the finishing (polishing) process is essential. A major element of automation is a reliable database and a knowledge base for polishing status. This paper presents a polishing expert system which can determine optimal polishing sequences and conditions by using an empirical formula and an experimental database. The simplex method was used for the cure fittings of the experimental results. Also a graphical user interface, which visualizes the optimized results, was developed.
민헌식,이성환,안선응 한국공작기계학회 2002 한국생산제조학회지 Vol.11 No.3
As laser cutting process is widely used in industry, an automated on-line process control system has become very important. In this paper, development of a laser cutting monitoring system, which is regarded as the fundamental step toward automation of the process, is presented. Acoustic emission and an artificial neural network were used for the monitoring system. With given process parameters including laser power and scanning speed, the system can predict the suitability of laser beam for the cutting of a stainless steel (STS304) plate.
민헌식,이성환 한국공작기계학회 2002 한국생산제조학회지 Vol.11 No.3
Though the laser cutting process is increasingly used in industry, a process automation and systematic database is still yet to be developed. In this study, as the fundamental step toward the construction of a reliable process expert system, a laser cutting quality monitoring/analysis system is developed based on simulation and experimental results. The relations between laser process parameters and laser cutting surface quality parameters such as kerf geometry, striation, surface roughness and dross formation are characterized and analyzed. A graphical user interface is used to visualize the results.
금형면 자동 다듬질 전문가 시스템 개발에 관한 연구-Ⅰ : DB 구축을 위한 회전 및 진동 연마 가공의 실험적 연구
민헌식,이성환,안유민,조남규,한창수 한국공작기계학회 2002 한국생산제조학회지 Vol.11 No.1
In manufacturing die and mold, polishing is important as it takes as mush as 50% of the production cost. In this research, an attachable type polishing device to a CNC machining center was developed. Experiments were done with a specially designed rotation type polishing device. Also an ultra-sonic (Vibration type) waving device was introduced to acquire finer surface finishes. From the constructed data base based on the experimental results, it is shown that optimal polishing conditions are generated by the combined use of the rotation type tool and the vibration type tool.
Lee, Seungmin,Lee, Yohan,Lee, Jaehyoung,Lee, Huen,Seo, Yongwon American Chemical Society 2013 Environmental science & technology Vol.47 No.22
<P>The methane (CH<SUB>4</SUB>) – carbon dioxide (CO<SUB>2</SUB>) swapping phenomenon in naturally occurring gas hydrates is regarded as an attractive method of CO<SUB>2</SUB> sequestration and CH<SUB>4</SUB> recovery. In this study, a high pressure microdifferential scanning calorimeter (HP μ-DSC) was used to monitor and quantify the CH<SUB>4</SUB> – CO<SUB>2</SUB> replacement in the gas hydrate structure. The HP μ-DSC provided reliable measurements of the hydrate dissociation equilibrium and hydrate heat of dissociation for the pure and mixed gas hydrates. The hydrate dissociation equilibrium data obtained from the endothermic thermograms of the replaced gas hydrates indicate that at least 60% of CH<SUB>4</SUB> is recoverable after reaction with CO<SUB>2</SUB>, which is consistent with the result obtained via direct dissociation of the replaced gas hydrates. The heat of dissociation values of the CH<SUB>4</SUB> + CO<SUB>2</SUB> hydrates were between that of the pure CH<SUB>4</SUB> hydrate and that of the pure CO<SUB>2</SUB> hydrate, and the values increased as the CO<SUB>2</SUB> compositions in the hydrate phase increased. By monitoring the heat flows from the HP μ-DSC, it was found that the noticeable dissociation or formation of a gas hydrate was not detected during the CH<SUB>4</SUB> – CO<SUB>2</SUB> replacement process, which indicates that a substantial portion of CH<SUB>4</SUB> hydrate does not dissociate into liquid water or ice and then forms the CH<SUB>4</SUB> + CO<SUB>2</SUB> hydrate. This study provides the first experimental evidence using a DSC to reveal that the conversion of the CH<SUB>4</SUB> hydrate to the CH<SUB>4</SUB> + CO<SUB>2</SUB> hydrate occurs without significant hydrate dissociation.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/esthag/2013/esthag.2013.47.issue-22/es403542z/production/images/medium/es-2013-03542z_0012.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/es403542z'>ACS Electronic Supporting Info</A></P>
Lee, Huen,Kang, Seong Pil,Lee, Yoon Young,Lee, Hoon Wu 한국화학공학회 1996 NICE Vol.14 No.1
The vapor-liquid equilibrium data of the binary CFC, HCFC, and FC mixtures were correlated with the Soave-Redlich-Kwong equation of state incorporated with some types of mixing rules the conventional one fluid, Panagiotopoulos-Reid and modified Huron-Vidal second order mixing rules. the Panagiohtpoulos-Reid mixing rule showed the superiority to the other models in predicting the VLE of freon mixtures with low errors. the modified Huron-Vidal second order model showed good convergence ability, which was due W is robustness to parameter variation.
Phase behavior of gas hydrates in nanoporous materials: Review
Huen Lee,Daeok Kim 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.7
−A precise understanding of phase behavior for a variety of both artificial and natural processes is essential to achieving scientific and technological goals. There has been growing research interest in gas hydrates confined in nanoporous media aiming to simulate and analyze the unique behavior of natural gas hydrates in sediments. Moreover, the appearance of peculiar properties due to the confinement effect stimulates research on gas hydrate technology for gas separation, such as CO2 capture from versatile pre/post combustion emissions. In spite of their importance, reliable phase equilibrium data on gas hydrates confined at a nanoscale are scattered throughout the literature, while those in bulk state are abundant. Accordingly, we surveyed the previous studies on the phase behavior of gas hydrates in various nanoporous materials to include and provide valuable information and knowledge for start-up researchers in various gas hydrate fields.
Thermodynamic and spectroscopic identification of aldehyde hydrates
Huen Lee,Hyery Kang,안윤호,Dong-Yeun Koh 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.6
It has been reported that some aldehyde compounds have formed simple sII clathrate hydrates without help-gas molecules, showing a self-forming effect. However, the structure of aldehyde hydrates is quite unstable due to the “gem-diol reaction”. According to the previous studies, the aldehyde hydrate slowly decomposes at atmospheric condition with the conversion of aldehyde to gem-diol. We investigated binary aldehyde (acetaldehyde, propionaldehyde, and isobutyraldehyde)+methane clathrate hydrate with spectroscopic and thermodynamic analyses. Similar to the simple aldehyde hydrate, the binary hydrates also formed a sII hydrate. During the hydrate formation process, we found that most of the aldehydes converted to gem-diols and were then incorporated into the large cages of the sII hydrate. Depending on the equilibrium constant of the gem-diol reaction caused by the molecular structures of the three aldehydes, different phase equilibrium curves of aldehyde+methane hydrates were obtained.
Huen, Wai Yeong,Lee, Hyuk,Vimonsatit, Vanissorn,Mendis, Priyan,Lee, Han-Seung Elsevier 2019 Surface & coatings technology Vol.366 No.-
<P><B>Abstract</B></P> <P>Instrumented indentation continuous stiffness measurement (CSM) method is applied to investigate the nanomechanical properties of the aluminum and zinc arc thermal spray aluminum coating. This study shows that individual component within a multi-phase material can be differentiated through the stiffness characteristic transition in a single indentation. Using this approach, the nanomechanical properties of the individual phases can be isolated and quantified using statistical deconvolution method. This paper further demonstrates that through the use of computational simulation and artificial neural network, the nanomechanical properties can be predicted based on experimental nanoindentation loading and unloading, where the load-unload responses of an individual material phase can be replicated once the nanomechanical properties are made known. This study shows that CSM method is able to predict the material's elasticity and plasticity properties, including elastic modulus, hardness, yield strength and work hardening, of individual aluminum and zinc components of the thermal arc spray coating.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Nanoindentation measured elastic modulus and hardness are presented </LI> <LI> CSM stiffness-displacement gradient is unique for each phase </LI> <LI> Stiffness-displacement feature can identify phase change with depth </LI> <LI> ANN can accurately predict elastic and plastic parameters </LI> </UL> </P>