排序方式: 共有45条查询结果,搜索用时 15 毫秒
1.
Jae-Ou CHAE Young-Jun JEONG V. M. SHMELEV A. A. DENICAEV V.M. POUTCHKOV V. RAVI 《等离子体科学和技术》2006,8(4):443-446
A plasma discharge initiation system for the explosive volumetric combustion charge was designed, investigated and developed for practical application. Laboratory scale experiments were carried out before conducting the large scale field tests. The resultant explosions gave rise to less noise, insignificant seismic vibrations and good specific explosive consumption for rock blasting. Importantly, the technique was found to be safe and environmentally friendly. 相似文献
2.
Young-Hun Lim Myung-Eui Song Won-Hee Lee Hui-Je Cho Dae-Sung Bae 《Multibody System Dynamics》2009,22(2):145-162
The paper proposes a multibody dynamic simulation to numerically evaluate the generated axial force (GAF) and plunging resistant
force (PRF) practically related to the shudder and idling vibration of an automobile. A numerical analysis of the drive shaft
coupling of a ball joint (BJ) and two plunging type joints, a tripod joint (TJ), and a very low axial force tripod joint (VTJ),
are conducted using the commercial program DAFUL. User-defined subroutines of a friction model illustrating the contacted
parts of the outboard and inboard joint are subsequently developed to overcome the numerical instability and improve the solution
performance. The Coulomb friction effect is applied to describe the contact models of the lubricated parts in the rolling
and sliding mechanisms. The numerical results, in accordance with the joint articulation angle variation, are validated with
experimentation. The offset between spider and housing is demonstrated to be the critical role in producing the third order
component of the axial force that potentially causes the noise and vibration in the vehicle. The VTJ shows an excellent behavior
for the shudder when compared with the TJ. In addition, a flexible nonlinear contact analysis coupled with multibody dynamics
is also performed to show the dynamic strength characteristics of the rollers, housing, and spider. 相似文献
3.
Daily meat consumption produces a lot of bone waste, and dumped bone waste without treatment would result in environmental hazards. Conventional treatment methods of waste bones have some disadvantages. Herein, an investigation of bone waste treated using thermal plasma technology is presented. A high-temperature plasma torch operated at 25.2 kW was used to treat bone waste for seven minutes. The bone waste was finally changed into vitric matter and lost 2/3 of its weight after the treatment. The process was highly efficient, economical, convenient, and fuel-free. This method could be used as an alternative for disposal of bone waste, small infectious animals, hazardous hospital waste, etc. 相似文献
4.
Won So Young-Hun Kim Chang Jun Lee Dongil Shin En Sup Yoon 《Korean Journal of Chemical Engineering》2011,28(3):656-666
Accidents involving domino effects are more serious than other type of accidents. Although there have been studies on such
accidents, it is still difficult to examine the actual factors and causes since the domino effect is influenced nonlinearly
by factors involving flame, overpressure, and flying objects. We considered the case of adding new facilities to an existing
system in a given site. The layout of new facilities suggests positions that minimize the domino effects, based on nonlinear
optimization taking domino factors into account. We quantitatively calculated the domino risk of each facility through the
concept of combined domino factors (flame, overpressure, and missile). Also, we identified variations of domino damage extent
of the target system through comparison of the impacts of domino effect when additional facilities were installed. Simulated
annealing was adopted for searching optimal positions. As a case study, we applied the proposed method to the case of adding
DME storage tanks in the existing LPG charging facilities. The presented framework of the quantitative assessment of domino
risk and safety standard for the layout of additional facilities would be useful for proper layout design for improved accident
prevention. 相似文献
5.
Jamin Koo Seunghyok Kim Hyosuk Kim Young-Hun Kim En Sup Yoon 《Korean Journal of Chemical Engineering》2009,26(6):1476-1483
A systematic approach towards accident analysis and prevention has been developed. It relies on system theory as an incident
causation model, and adopts a hybrid model for identifying elements of the safety management system. PDCA (Plan-Do-Check-Act)
process, commonly practiced in business for quality control, has been applied to defining components of the system. Using
the experts’ judgment, accident data and their reported causes are correlated to the defined components, with RBI (risk-based
inspection) defined consequence scores as weighting factors. The application of this approach allows users such as governments
and companies to identify and prioritize among causes of accidents and near-misses in the petrochemical industry. A case study
using the accident data of Yeosu petrochemical complex from 1990 to 2004 has been applied to illustrate insights readily obtainable
by using the developed analysis technique. The results suggest comprehensive identification and ranking of accident causes
for effective prevention of accidents in the future. 相似文献
6.
Seo-Yeong Yeo Tae-Hyeong Kwon Chang-Sun Park Chang-Il Kim Ji-Sun Yun Young-Hun Jeong Youn-Woo Hong Jeong-Ho Cho Jong-Hoo Paik 《Journal of Electroceramics》2018,41(1-4):1-8
The main objective of our work is to increase transmittance in the mid infrared region by removing impurities through the pre-heating treatment of zinc sulfide (ZnS) produced by hydrothermal synthesis. The pre-heating treatment proceeded at 450 to 600 °C for 2 h under vacuum atmosphere (10?2 Torr). It was confirmed that the particle size increased as the pre-heating temperature increased. Additionally, all ZnS nano powders had a sphalerite (cubic) structure unaffected by pre-heating treatment. The ZnS nano powders were sintered by hot-press sintering method. As the pre-heating temperature increased, transmittance was improved due to the decreasing of porosity, increase of particle size, and the removal of impurities (carbon and sulfate). However, when the pre-heating treatment temperature was 600 °C, the transmittance slightly decreased due to the formation of a hexagonal phase. The ZnS ceramic with pre-heating treatment at 550 °C showed the highest transmittance (71.6%) and density (99.9%). 相似文献
7.
Young-Hun Jeong Dong-Woo Cho 《The International Journal of Advanced Manufacturing Technology》2003,22(7-8):553-561
The cross-feed directional cutting force acts normal to the machined surface of a workpiece. It is important to estimate and control this force, since it directly affects the machined surface. However, using the current supplied to a stationary motor to predict the cutting state poses difficulties, because of the current's somewhat undesired behaviour. In this paper, a largely empirical approach was used to help resolve this problem. We show that the current's undesired behaviour is related to infinitesimal rotations of the motor. Subsequently, the relationship between the current and the cutting force was identified with an error of less than 15%. The predictions obtained using two machine tools with different characteristics were compared to confirm the validity of the method when investigating the characteristics of the stationary feed motor current. 相似文献
8.
Ju Dong Lee Man Sig Lee Won Sik Shin Young-Hun Kim Sang June Choi 《Korean Journal of Chemical Engineering》2005,22(5):682-686
Pilot studies were conducted for the removal of two freshwater diatoms (Synedra acus andStephanodiscus sp.). Poly aluminum chloride (PAC), one of the coagulants commonly used in conventional potable water treatment, was found
to be not effective in removing diatoms, especially forSynedra. In this work, preozonation and polyamine coagulant-aid in the presence of PAC were compared with each other and combined
to investigate their performances on removing diatoms. It was found that the preozonation and polyamine coagulant-aid increased
the removal rate significantly for both diatoms, better performance than PAC alone. When polyamine coagulant-aid and preozonation
were combined with PAC, approximately 90% ofSynedra and 100% ofStephanodiscus were eliminated. It can be concluded that the combination of preozonation and polyamine coagulant-aid in the presence of
PAC could be a promising solution for removing resistant diatoms in water treatment. 相似文献
9.
采用销-盘摩擦副接触方式在常温常压及液体润滑下,对不同密度的50μm和110μm大小的微小凹痕图案表面进行摩擦试验,探讨接触压力及滑动速度对不同大小以及密度的微小凹痕图案的摩擦性能影响,并利用Stribeck曲线分析在不同试验条件下不同密度的50μm和110μm大小的微小凹痕图案表面的摩擦特性.结果表明:降低摩擦中,不同的微小凹痕图案表面具有最佳的密度含量.即大小为50μm的微小凹痕图案中,密度为32.4%的微小凹痕图案表面的摩擦系数最低;大小为110μm的微小凹痕图案中,密度为19.8%的微小凹痕图案表面的摩擦系数最低. 相似文献
10.
The tribological performance of Al2O3/NiCr coating deposited on steel (SM45C) was investigated under lubrication. The parameters of sliding wear consist of normal
load and coating thickness. Test result showed that there was no evidence of an improved bonding strength in the coating.
However, the wear resistance of the Al2O3/NiCr coating was significantly greater than that of the Al2O3 coating. It was evident that the residual stress for the AI2O3 coating was higher than that of the Al2O3/NiCr coating from the scratch test failure of coating. The bond coating played an important role in decreasing the residual
stress. Also, it was found that the residual stress had a notable influence on the wear mechanism. 相似文献