• Korean Chemical Engineering Research
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• v.44 no.2
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• pp.114-120
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• 2006

Bismuth vanadate is one of the environmentally benign substitutes for conventional inorganic pigments composed of heavy metals. The effect of process parameters on the physical properties of bismuth vanadate pigment prepared from aqueous solutions of potassium vanadate and bismuth nitrate were experimentally examined. Two aqueous solutions were fed into precipitation chamber at the same flow rate, and precipitates were formed at primary pH of 4.5 and secondary pH of 7.0~7.5. After aging for 3 hours in reaction mixture, 3 hours' calcination at $400^{\circ}C$ gave bismuth vanadate pigment with a good color and hiding power. Increase in molybdenum concentration in reaction mixture increased the hiding power of the pigment, but the other minor constituents had minor effect on the physical properties of the pigment.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.12
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• pp.1035-1042
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• 2010

The thermal stratification effect has been thought as one of the way to avoid dramatically generating the heat from HCCI combustion. We investigate the effect of thermal stratification on HCCI combustion fueled by DME and n-Butane. The thermal stratification occurs in a combustion chamber of a rapid compression machine with premixture by buoyancy effect that is made of fuel and air. The premixture is then adiabatically compressed, and during the process, the in-cylinder gas pressure is measured and two-dimensional chemiluminescence images are prepared and analyzed. Under the thermal stratification, the LTR starting time and the HTR starting time are advanced than that of homogeneous case. Further, the LTR period and the luminosity duration under homogeneous conditions are shorter than the corresponding quantities under stratified conditions. Additionally, under stratified conditions, the brightest luminosity intensity is delayed longer than that of homogeneous condition.

• Journal of Arbitration Studies
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• v.23 no.4
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• pp.97-122
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• 2013

Vietnam has become an attractive destination for foreign investors, but confidence in the country's legal system to resolve commercial disputes remains low. Reasons include the lack of an independent judiciary, the lack of published court decisions, and a tendency to criminalize civil disputes, among others. As such, arbitration has become a preferred alternative to litigation. On June 17, 2010, the National Assembly of Vietnam passed a new act on commercial arbitration replacing the July 1, 2003 ordinance on commercial arbitration. The new act will take effect on January 1, 2011, and it is widely expected by the Vietnamese legal profession and lawmakers will create a favorable legal framework for the expansion of the arbitration service market in Vietnam. The new act is inspired by the UNCITRAL Model Arbitration Law of 1985 as are most new arbitration laws throughout the world. As opposed to the 2003 ordinance, the 2010 Act allows parties to request interim relief from the arbitrators. Also the new act eliminates the mandate that arbitrators be Vietnamese. The law has addressed the ordinance's shortcomings and reflects international standards. Commercial arbitration law is an important milestone in the improvement process of the laws on commercial arbitration in Vietnam. However, it is still too soon to affirm anything definitely because there remain many obstacles to the activation of arbitration. Rule of law and business cultural factors are important. The leading arbitral institution, VIAC, which is attached to the Vietnam Chamber of Commerce and Industry, is expected to play an important role for boosting the competitiveness of Vietnamese arbitration as an avenue to dispute settlement.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.5
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• pp.564-571
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• 2016

As the amount of rice straw collected increases, green manure crops are used to provide the needed organic matter. However, as green manure crops generate methane in the process of decomposition, we tested with different tillage depths in order to reduce the emission. The atmosphere temperature of the chamber was $25{\sim}40^{\circ}C$ during the examination of methane and soil temperature was $2{\sim}10^{\circ}C$ lower than air temperature. The redox potential (Eh) of the soil drastically fell right before irrigated transplanting and showed -300~-400 mV during the cultivating period of rice (7~106 days after transplant). When hairy vetch was incorporated to soil and the field was not irrigated, the generation of methane did not occur from 12 to 4 days before transplanting rice and started after irrigation. Regarding the pattern of methane generation during the cultivation of rice, methane was generated 7 days after transplanting, reached the pinnacle at by 63~74 days after transplanting, rapidly decreased after 86~94 days past transplanting and stopped after 106 days past transplanting. When tested by different soil types, methane emission gradually increased in loam and clay loam during early transplant, whereas it sharply increased in sandy loam. The total amount of methane emitted was highest in sandy loam, followed by loam and clay loam. In all three soil types, methane emission significantly reduced when tillage depth was 20 cm compared to 10 cm. The rice growths and yield were not affected by tillage depth. Therefore, reduction of methane emission could be achieved when application hairy vetch to the soil with tillage depth of 20 cm in paddy soil.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.1
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• pp.1-8
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• 2020

In this study, a configuration design of a CH₄/LOx small rocket engine was made and test system was established for the performance evaluation. A coaxial swirl injector was chosen because of its remarkable atomization performance and low combustion instability. Three aspect ratios for the combustion chamber configuration, i.e., 1.5, 1.8, and 2.1 were also set for the comparison of the combustion efficiency. The reliability of the thrust measurement rig was enhanced by pre-and post-calibration process. From the preliminary ground hot-firing test, the measured thrust and specific impulse values were 89.2 N and 181.8 s, respectively, which were 21.6% lower than the ideal values. In addition, the efficiency of characteristic velocity was measured as 84.2%.

• Journal of the Semiconductor & Display Technology
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• v.15 no.1
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• pp.65-69
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• 2016

We have investigated the possibility of recycling of an organic material that is wasted during thermal evaporation. To this end, we have collected a wasted organic material (N,N'-diphenly-N,N'-bis(1,1'-biphenyl)-4,4'-diamine(NPB)) from a vacuum chamber, purified it by recrystallization, and fabricated bilayer organic light-emitting diodes (OLEDs) with the recycled NPB. It is found that the surface roughness of thin films coated with the purified NPB is much enhanced. OLEDs fabricated by thermal evaporation of the purified NPB show lower device efficiency than OLEDs with the original NPB. However, the power efficiency of OLED fabricated by spin coating of the purified NPB is comparable with that of OLED with the original NPB. Therefore, such a recycling method by recrystallization would be more suitable for solution-processed OLEDs.

• Journal of the Korea Convergence Society
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• v.9 no.3
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• pp.217-222
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• 2018

In this paper, a new micro polymer chip platform and protocol were developed for rare cell sample preparation. The proposed platform and protocol overcome the current limitation of the dilution method which is based on statistics and the FACS method which expensive and requires fluorescence staining. It allows collecting exact number of target cells simply and selectively because the cells are visually confirmed during the collecting process. The collected cells can be transported or spiked into a desired locations, such as a microchamber, without cell loss. This research may applicable not only to a rare cell sample preparation for Lab on a Chip cancer diagnosis, but also to a single/double/multiple cell sample preparation for a cell analysis field. To verify this platform and protocol, five human breast cancer cells (MCF-7) were collected and transported into a hemocytometer chamber.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.41-43
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• 1999

Among the feffoelectric thin films that have been widely investigated for ferroelectric random access memory (FRAM) applications, SrBi$_2$Ta$_2$$O_{9}$ thin film is appropriate to memory capacitor materials for its excellent fatigue endurance. However, very few studies on etch properties of SBT thin film have been reported although dry etching is an area that demands a great deal of attention in the very large scale integrations. In this study, the a SrBi$_2$Ta$_2$$O_{9}$ thin films were etched by using magnetically enhanced inductively coupled Ar/CHF$_3$ plasma. Etch properties, such as etch rate, selectivity, and etched profile, were measured according to gas mixing ratio of CHF$_3$(Ar$_{7}$+CHF$_3$) and the other process conditions were fixed at RF power of 600 W, dc bias voltage of 150 V, chamber pressure of 10 mTorr. Maximum etch rate of SBT thin films was 1750 A77in, under CHF$_3$(Ar+CHF$_3$) of 0.1. The selectivities of SBT to Pt and PR were 1.35 and 0.94 respectively. The chemical reaction of etched surface were investigated by X-ray photoelectron spectroscopy (XPS) analysis. The Sr and Ta atoms of SBT film react with fluorine and then Sr-F and Ta-F were removed by the physical sputtering of Ar ion. The surface of etched SBT film with CHF$_3$(Ar+CHF$_3$) of 0.1 was analyzed by secondary ion mass spectrometer (SIMS). Scanning electron microscopy (SEM) was used for examination of etched profile of SBT film under CHF$_3$(Ar+CHF$_3$) of 0.1 was about 85˚.85˚.˚.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.6
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• pp.1882-1888
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• 2008

Effects of 1-MCP(1-methylcyclopropene) on the postharvest life and fruit quality of cucumber 'Baekdadaki' were investigated. Cucumber were held at room and cold chamber($10^{\circ}C$) treated with several concentrations of 1-MCP. Physico-chemical characteristics such as fresh weight and firmness were greatly varied during storage, and the treatment with I-MCP(500ppb) showed the minimal loss of the values at harvest. The peel b value representing a senescence process was higher investigated in 1-MCP(250 and 1,000ppb treatment, and led to the apparent yellowing and softening after cold storage for 15 days. 1-MCP(500ppb) showed lower decay rate and better marketability of cucumber than other treatments after cold storage for 15 days. The respiration rate was higher found in cucumber treated with 1-MCP(250ppb) than in other treatment. Ethylene evolution was most detected in cucumber treated with 1-MCP(1000ppb) after room storage for 6 days. 1-MCP did not affect the production of ethylene in cucumber during room and cold storage.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1621-1622
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• 2006

This paper presents the effect of driving waveform for piezoelectric bend mode inkjet printhead with optimized mechanical design. Experimental and theoretical studies on the applied driving waveform versus jetting characteristic s were performed. The inkjet head has been designed to maximize the droplet velocity, minimize voltage response of the actuator and optimize the firing frequency to eject ink droplet. The head design was carried out by using mechanical simulation. The printhead has been fabricated with Si(100) and SOI wafers by MEMS process and silicon direct bonding method. To investigate how performance of the piezoelectric ceramic actuator influences on droplet diameter and droplet velocity, the method of stroboscopy was used. Also we observed the movement characteristics of PZT actuator with LDV(Laser Doppler Vibrometer) system, oscilloscope and dynamic signal analyzer. Missing nozzles caused by bubbles in chamber were monitored by their resonance frequency. Using the water based ink of viscosity of 4.8 cps and surface tension of 0.025N/m, it is possible to eject stable droplets up to 20kHz, 4.4m/s and above 8pL at the different applied driving waveforms.