• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.9 no.4
• /
• pp.204-211
• /
• 2004

Autonomous profiling CTD floats are a useful tool for observing the oceans. We, however, cannot perform post-deployment calibration of the CTD's attached to the floats, and the assessment of the accuracy and stability of the profile data from the floats is one of the important issues in the delayed mode quality control of the profiles. Variations in salinity in the intermediate level of East Sea is comparable to the accuracy of salinity data required by the international Argo Program, which is 0.01. Therefore, we can assess the credibility of salinity data from the floats deployed in the East Sea using three independent methods while considering the East Sea as a salinity calibration bath. The methods utilized here are 1) comparison of high quality CTD data and float data obtained at similar locations at similar time, 2) comparison of float data obtained at similar locations at similar time, and 3) investigation of long term stability and accuracy of salinity data from parking depths. All three methods show that without any calibration, the salinity data satisfy the accuracy criterion by the Argo Program. While assuming that the intermediate level temperature in the East Sea is as homogeneous as the salinity, we have applied the three methods to temperature data. We found that the accuracy of temperature reading is 0.01$^{\circ}C$, which is about twice larger than the requirement by the Argo Program, 0.005$^{\circ}C$. This does not mean that the temperature readings are inaccurate, because the intermediate level temperature does vary spacially and temporally more than the accuracy interval required by the Argo Program. If we take into account the variation in the intermediate level temperature, the accuracy of temperature data from the floats is not significantly different from that proposed by the Argo Program. Therefore, one could use both temperature and salinity profiles from the floats assessed in this study without calibration.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.28 no.5
• /
• pp.115-121
• /
• 2014

The intrinsic simplicity, ruggedness, and simple power electronic drive requirement of a Switched Reluctance Motor(SRM) make it possible to use in many commercial adjustable speed application. The simple magnetic circuit results in a high efficiency drive and low temperature rise, and the drive system provides a good drive characteristics. This paper is provides two phase 4/3 SRM that is similar to two phase 6/3 SRM as aspect to magnetic structure. Although 6/3 SRM does not experience any flux reversal as the flux is in the same direction whether phase A or B is excited, but two phase 4/3 SRM experiences a flux reversal in small part of stator yoke. The flux reversal in two phase 4/3 SRM could be relieved by an adjustment of stator yoke structure. The magnetic analysis and design considerations of the two phase 4/3 SRM have been obtained by the finite element method analysis (FEM).

• Journal of Sensor Science and Technology
• /
• v.30 no.5
• /
• pp.320-325
• /
• 2021

Biochemical oxygen demand (BOD) and chemical oxygen demand (COD) methods are conventional analytical methods to analyze water quality. Both of these methods are technically indirect measurement methods, require complicated preconditions, and are time-consuming. On the other hand, the total organic carbon (TOC) method is a direct and fast measurement method which is more intuitive and accurate than the BOD and COD methods. However, general TOC analysis methods involve complicated processes and high power consumption owing to the process of phase transition from liquid to gas by a high-temperature heater. Furthermore, periodic consumables are also required for the removal of inorganic carbon (IC). Titanium dioxide (TiO₂) is one of the most suitable photocatalysts for simple processes. Its usage involves low power consumption because it only reacts with the organic carbon (OC) without the requirement of any other reagents and extra processes. We investigated a TiO₂ photocatalyst-based TOC analysis for simple and affordable products. TiO₂-coated fiber substrate maintained under carbon included water was exposed to ultraviolet (UV) radiation of wavelength 365 nm. This method is suitable for the real-time monitoring of water pollution because of its fast reaction time. Its linear property is also sufficient to match the real value.

• Nuclear Engineering and Technology
• /
• v.56 no.4
• /
• pp.1213-1224
• /
• 2024

The liquid lead-bismuth cooled fast reactor has been in a single-phase, low-pressure, and high-temperature state for a long time during operation. Considering the requirement of calculation efficiency for long-term transient accident calculation, based on a homogeneous hydrodynamic model, one-dimensional heat conduction model, coolant flow and heat transfer model, neutron kinetics model, coolant and material properties model, this study used the fully implicit difference scheme algorithm of the convection-diffusion term to solve the basic conservation equation, to develop the transient analysis program NUSOL-LMR 2.0 for the lead-bismuth fast reactor system. The steady-state and typical design basis accidents (including reactivity introduction, loss of flow caused by main pump idling, excessive cooling, and plant power outage accidents) for the ABR have been analyzed. The results are compared with the international system analysis software ATHENA. The results indicate that the developed program can stably, accurately, and efficiently predict the transient accident response and safety characteristics of the lead-bismuth fast reactor system.

• Journal of the Korean Solar Energy Society
• /
• v.21 no.4
• /
• pp.29-35
• /
• 2001

The chemical heat storage as the one way of utilization for high temperature solar energy was considered. The stram reforming reaction of methane was chosen for endothermic reaction. The reactor was made of stainless steel tube and it's dimension was 0.635 cm I.D. and 30 cm long, coiled tube because of the geometry requirement of solar receiver The effects of space velocity and reactants mole ratio on the methane conversion and CO selectivity were examined. From the experimental results, the optimum steam/methane mole ratio was determined.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.51 no.2
• /
• pp.69-76
• /
• 2002

To obtain a high performance in a vector controlled induction motor, it is essential to know the instantaneous position of the rotor flux which depends on the rotor time constant. But the rotor time constant mainly varies due to the temperature rise in the motor winding, so real time compensating algorithm is necessary. This paper proposes that it uses short duration pulses added to the constant flux command current and then resultant torque command current produced by speed controller is utilized for the rotor resistance estimation. This method has advantage with a low computational requirement and does not require voltage sensors. The proposed method is proved by simulations and experimentals.

• Interdisciplinary Bio Central
• /
• v.4 no.3
• /
• pp.8.1-8.7
• /
• 2012

The motor neuron degeneration 2 (mnd2) mice carry a point mutation of A to T nucleotide transversion at the serine 276 residue of high temperature requirement A2 (HtrA2), resulting in losses of an AluI restriction enzyme site (5'AGCT3') and the HtrA2 serine protease activity. Moreover, dysfunctions of HtrA2 are known to be intimately associated with the pathogenesis of neurodegenerative diseases, including Parkinson's disease. Thus, this mnd2 mouse is an invaluable model for understanding the physiological role of HtrA2 and its pathological role in neurodegenerative diseases. Nevertheless, many molecular and cellular biologists in this field have limited experience in working with mutant mouse models due to the necessity of acquired years of the special techniques and knowledges. Herein, using the mnd2 mouse model as an example, we describe easy-to-use standard protocols for web-based analyses of target genes, such as HtrA2, and a novel approach for simple and accurate PCR-AluI-RFLP-based genotype analysis of mnd2 mice. In addition, band resolution of AluI-RFLP fragments was improved in 12% polyacrylamide gel running in 1X Tris-Glycine SDS buffer. Our study indicates that this PCR-AluI-RFLP genotype analysis method can be easily applied by the molecular and cellular biologist to conduct biomedical science studies using the other mutant mouse models.

• Textile Coloration and Finishing
• /
• v.17 no.6 s.85
• /
• pp.11-19
• /
• 2005

Textile dyeing with vat dyes has the highest color fastness although one and the same dye of all vat dyes cannot always satisfy every color fastness requirement. So we examined cotton, nylon 6, and polyester fabrics dyed with vat dyes. Cotton, nylon 6 and polyester fabrics were dyed with vat dyes such as C. I. Vat Blue 1, Blue 19, Black 9, Green 1, Orange 2, and Violet 1 containing sodium hydrosulfite and NaOH. Oxidation were carried out by a sodium peroxoborate after dyeing. The dyed materials were soaped at the boil after oxidation. Especially hydrolysis and overreduction for dyed polyester with vats dyes containing -NHCO- and -NH- groups such as C. I. Vat Blue 6, Black 25, Black 27, Red 10, and Green 3 occurred. It seems that these phenomena are due to a high dyeing temperature. Wash and rubbing fastness of nylon are higher than that of cotton and polyester. Light fastness of cotton is higher than that of polyester and nylon.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.341-341
• /
• 2016

The discovery of light emission in nanostructured silicon has opened up new avenues of research in nano-silicon based devices. One such pathway is the application of silicon quantum dots in advanced photovoltaic and light emitting devices. Recently, there is increasing interest on the silicon quantum dots (c-Si QDs) films embedded in amorphous hydrogenated silicon-nitride dielectric matrix (a-SiNx: H), which are familiar as c-Si/a-SiNx:H QDs thin films. However, due to the limitation of the requirement of a very high deposition temperature along with post annealing and a low growth rate, extensive research are being undertaken to elevate these issues, for the point of view of applications, using plasma assisted deposition methods by using different plasma concepts. This work addresses about rapid growth and single step development of c-Si/a-SiNx:H QDs thin films deposited by RF (13.56 MHz) and ultra-high frequency (UHF ~ 320 MHz) low-pressure plasma processing of a mixture of silane (SiH4) and ammonia (NH3) gases diluted in hydrogen (H2) at a low growth temperature ($230^{\circ}C$). In the films the c-Si QDs of varying size, with an overall crystallinity of 60-80 %, are embedded in an a-SiNx: H matrix. The important result includes the formation of the tunable QD size of ~ 5-20 nm, having a thermodynamically favorable <220> crystallographic orientation, along with distinct signatures of the growth of ${\alpha}$-Si3N4 and ${\beta}$-Si3N4 components. Also, the roles of different plasma characteristics on the film properties are investigated using various plasma diagnostics and film analysis tools.

• Nuclear Engineering and Technology
• /
• v.52 no.2
• /
• pp.279-286
• /
• 2020

In this article, we develop a reactive distillation (RD) column configuration for the production of hydrogen. This RD column is in the HI decomposition section of the sulphur - iodine (SI) thermochemical cycle, in which HI decomposition and H₂ separation take place simultaneously. The section plays a major role in high hydrogen production efficiency (that depends on reaction conversion and separation efficiency) of the SI cycle. In the column simulation, the rigorous thermodynamic phase equilibrium and reaction kinetic model are used. The tuning parameters involved in phase equilibrium model are dependent on interactive components and system temperature. For kinetic model, parameter values are adopted from the Aspen flowsheet simulator. Interestingly, there is no side reaction (e.g., solvation reaction, electrolyte decomposition and polyiodide formation) considered aiming to make the proposed model simple that leads to a challenging prediction. The process parameters are determined on the basis of optimal hydrogen production as reflux ratio = 0.87, total number of stages = 19 and feeding point at 8th stage. With this, the column operates at a reasonably low pressure (i.e., 8 bar) and produces hydrogen in the distillate with a desired composition (H₂ = 9.18 mol%, H₂O = 88.27 mol% and HI = 2.54 mol%). Finally, the results are compared with other model simulations. It is observed that the proposed scheme leads to consume a reasonably low energy requirement of 327 MJ/kmol of H₂.