• The Journal of the Acoustical Society of Korea
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• v.34 no.1
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• pp.1-11
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• 2015

Salinity affects sound speed in the low salinity environment, in the seas where freshwater from large rivers and flows into the marginal sea area near the Yangtze River and the Niger River. In this paper, SSC (Surface Sound Channel) formed by low salinity water was investigated in the East China Sea and the Gulf of Guinea of rainy season. The data from KODC (Korea Oceanographic Data Center) in the East China Sea and from ARGO (Array for Real-time Geostrophic Oceanography) in the Gulf of Guinea of the tropical area were used for analysis. SSC haline channel was formed 14 times among 32 SSC occurrences when the 90 data from 9 points were analyzed during a decade (2000 ~ 2009) in the East China Sea. In the Gulf of Guinea, haline channel was formed 18 times among 20 SSC occurrences during 3 years (2006 ~ 2009). When the sound speed gradient was analyzed from temperature-salinity gradient diagram, the gradients of both salinity and temperature affect SSC formation in the East China Sea. In contrast, the salinity gradient mostly affects SSC formation due to the least change of temperature in the well-developed mixed layer in the Gulf of Guinea. Their acoustic characteristics show that channel depth is 6.5 m, critical angle is $1.5^{\circ}$ and difference of transmission loss between surface and thermocline is 11.5 dB in the East China Sea, while channel depth is 18 ~ 24 m, critical angle is $4.0{\sim}5.4^{\circ}$ and difference of transmission loss is 21.5 ~ 27.9 dB in the Gulf of Guinea. These results are expected to be used as a basic understanding of the acoustic transmission changes due to low salinity water at the estuaries and the ocean with heavy precipitation.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.429-429
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• 2016

Organolead halide perovskite have attracted much attention over the past three years as the third generation photovoltaic due to simple fabrication process via solution process and their great photovoltaic properties. Many structures such as mesoporous scaffold, planar heterojunction or 1-D TiO2 or ZnO nanorod array structures have been studied to enhance performances. And the photovoltaic performances and carrier transport properties were studied depending on the cell structures and shape of perovskite film. For example, the perovskite cell based on TiO2/ZnO nanorod electron transport materials showed higher electron mobility than the mesoporous structured semiconductor layer due to 1-D direct pathway for electron transport. However, the reason for enhanced performance was not fully understood whether either the shape of perovskite or the structure of TiO2/ZnO nanorod scaffold play a dominant role. In this regard, for a clear understanding of the shape/structure of perovskite layer, we applied anodized aluminum oxide material which is good candidate as the inactive scaffold that does not influence the charge transport. We fabricated vertical one dimensional (1-D) nanostructured methylammonium lead mixed halide perovskite (CH3NH3PbI3-xClx) solar cell by infiltrating perovskite in the pore of anodized aluminum oxide (AAO). AAO template, one of the common nanostructured materials with one dimensional pore and controllable pore diameters, was successfully fabricated by anodizing and widening of the thermally evaporated Al film on the compact TiO2 layer. Using AAO as a scaffold for perovskite, we obtained 1-D shaped perovskite absorber, and over 15% photo conversion efficiency was obtained. I-V measurement, photoluminescence, impedance, and time-limited current collection were performed to determine vertically arrayed 1-D perovskite solar cells shaped in comparison with planar heterojunction and mesoporous alumina structured solar cells. Our findings lead to reveal the influence of the shape of perovskite layer on photoelectrical properties.

• Journal of Broadcast Engineering
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• v.21 no.1
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• pp.76-86
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• 2016

This study was investigated whether the perceived depth was changed depending on the measurement methods. In the method of direct comparison, virtual object with one of the various binocular disparities was presented in the frontal space with LEDs which were used for depth estimation for a binocular stimulus, while in the method of indirect comparison, visual object was presented in the frontal space but the LEDs were placed rightward at the angle of 45 degree from the mid-sagittal line. In these experimental setup, the depth of binocular stimulus was directly matched that of LED in direct comparison condition. In indirect comparison condition, however, observer estimated the depth of binocular stimulus, turned one's head rightward to the array of LEDs and turned on the LED which was supposed to be the same depth as binocular stimulus. Additionally, it was investigated whether the perceived depth was different depending on observer's stereo acuity. The results showed that perceived depths measured in the direct comparison were more similar to the depth predicted from geometry than those in the indirect comparison, and that the perceived depths from observers with high stereo acuity were similar to the predicted depth from geometry those from observers with low stereo acuity. These results indicated that stereoscopic depths of the binocular stimuli would vivid and compelling when binocular stimuli was simultaneously presented with real objects in the same visual space, like a mixed reality.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1062-1062
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• 2001

The concept of “precision agriculture” or “site-specific farming” is usually confined to the fields of soil science, crop science and agronomy. However, because plants grow in soil, animals eat plants, and humans eat animal products, it could be argued (perhaps with some poetic licence) that the fields of feed quality, animal nutrition and animal production should also be considered in this context. NIR spectroscopy has proved over the last 20 years that it can provide a firm foundation for quality measurement across all of these fields, and with the continuing developments in instrumentation, computer capacity and software, is now a major cog in the wheel of precision agriculture. There have been a few giant leaps and a lot of small steps in the impact of NIR on the animal world. These have not been confined to the amazing advances in hardware and software, although would not have occurred without them. Rapid testing of forages, grains and mixed feeds by NIR for nutritional value to livestock is now commonplace in commercial laboratories world-wide. This would never have been possible without the pioneering work done by the USDA NIR Forage Research Network in the 1980's, following the landmark paper of Norris et al. in 1976. The advent of calibration transfer between instruments, algorithms which utilize huge databases for calibration and prediction, and the ability to directly scan whole grains and fresh forages can also be considered as major steps, if not leaps. More adventurous NIR applications have emerged in animal nutrition, with emphasis on estimating the functional properties of feeds, such as in vivo digestibility, voluntary intake, protein degradability and in vitro assays to simulate starch digestion. The potential to monitor the diets of grazing animals by using faecal NIR spectra is also now being realized. NIR measurements on animal carcasses and even live animals have also been attempted, with varying degrees of success, The use of discriminant analysis in these fields is proving a useful tool. The latest giant leap is likely to be the advent of relatively low-cost, portable and ultra-fast diode array NIR instruments, which can be used “on-site” and also be fitted to forage or grain harvesters. The fodder and livestock industries are no longer satisfied with what we once thought was revolutionary: a 2-3 day laboratory turnaround for fred quality testing. This means that the instrument needs to be taken to the samples rather than vice versa. Considerable research is underway in this area, but the challenge of calibration transfer and maintenance of instrument networks of this type remains. The animal world is currently facing its biggest challenges ever; animal welfare, alleged effects of animal products on human health, environmental and economic issues are difficult enough, but the current calamities of BSE and foot and mouth disease are “the last straw” NIR will not of course solve all these problems, but is already proving useful in some of these areas and will continue to do so.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.1
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• pp.9-18
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• 2013

Two-phase vapor-liquid flows exist in many shell and tube heat exchangers such as condensers, evaporators, and nuclear steam generators. To understand the fluid dynamic forces acting on a structure subjected to a two-phase flow, it is essential to obtain detailed information about the characteristics of a two-phase flow. The characteristics of a two-phase flow and the flow parameters were introduced, and then, an experiment was performed to evaluate the pressure loss in the tube bundles and the fluid-dynamic force acting on the cylinder owing to the pressure distribution. A two-phase flow was pre-mixed at the entrance of the test section, and the experiments were undertaken using a normal triangular array of cylinders subjected to a two-phase cross-flow. The pressure loss along the flow direction in the tube bundles was measured to calculate the two-phase friction multiplier, and the multiplier was compared with the analytical value. Furthermore, the circular distributions of the pressure on the cylinders were measured. Based on the distribution and the fundamental theory of two-phase flow, the effects of the void fraction and mass flux per unit area on the pressure coefficient and the drag coefficient were evaluated. The drag coefficient was calculated by integrating the measured pressure on the tube by a numerical method. It was found that for low mass fluxes, the measured two-phase friction multipliers agree well with the analytical results, and good agreement for the effect of the void fraction on the drag coefficients, as calculated by the measured pressure distributions, is shown qualitatively, as compared to the existing experimental results.

• Journal of Acupuncture Research
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• v.32 no.2
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• pp.1-9
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• 2015

Objectives : The present study was an evaluation and standardization of herbal components in order to establish the efficacy and safety of Shinbaro pharmacopuncture. Methods : Among the raw materials of Shinbaro pharmacopuncture, the components Cibotii Rhizoma, Eucommiae Cortex, and Ledebouriellae Radix were assessed through ingredient verification experiments using thin-layer chromatography(TLC) and ultraviolet rays(UV) lamps. In addition, we standardized Acanthopanacis Cortex and Achyranthis Radix through validation using high performance liquid chromatograph-diode array detector(HPLC-DAD). Results : As result appeared a blue-white fluorescence under ultraviolet rays; changed to dark green after adding 1 % ferric chloride solution(due to Cibotii Rhizoma), and presented a yellow-green fluorescence when mixed with an ethyl ether under UV lamps by way of the ethyl ether layer, confirming Eucommiae Cortex. Ledebouriellae Radix was confirmed as dark brown spots at Rf values of 0.56 and 0.71 using TLC. Additionally, Acanthopanacis Cortex and Achyranthis Radix HPLC test results showed that linearity was $R^2{\geq}0.99$, and detection limit and quantitation limit were 0.23 to $1.29{\mu}g/mL$, and 0.71 to $3.90{\mu}g/mL$, respectively. Furthermore, precision and accuracy were confirmed to have relative standard deviation(RSD) values of 0.10 to 1.89 % and 96.19 to 103.72 %, respectively. Shinbaro pharmacopuncture did not have any overlapping or interference from other peaks in detection under the abovementioned analysis conditions. Conclusions : In conclusion, we confirmed that maintenance of Shinbaro pharmacopuncture validity was possible by means of quality control of Cibotii Rhizoma, Eucommiae Cortex, and Ledebouriellae Radix through ingredient identification and Acanthopanacis Cortex and Achyranthis Radix through high performance liquid chromatograph(HPLC) analysis. Further, we hope to contribute to the development strategy of herbal industry acupuncture.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.12 no.2
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• pp.21-34
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• 2002

In this paper we propos a new hardware architecture of modular exponentiation using a division chain method which has been proposed in (2). Modular exponentiation using the division chain is performed by receding an exponent E as a mixed form of multiplication and addition with divisors d=2 or $d=2^I +1$ and respective remainders r. This calculates the modular exponentiation in about $1.4log_2$E multiplications on average which is much less iterations than $2log_2$E of conventional Binary Method. We designed a linear systolic array multiplier with pipelining and used a horizontal projection on its data dependence graph. So, for k-bit key, two k-bit data frames can be inputted simultaneously and two modular multipliers, each consisting of k/2+3 PE(Processing Element)s, can operate in parallel to accomplish 100% throughput. We propose a new encoding scheme to represent divisors and remainders of the division chain to keep regularity of the data path. When it is synthesized to ASIC using Samsung 0.5 um CMOS standard cell library, the critical path delay is 4.24ns, and resulting performance is estimated to be abort 140 Kbps for a 1024-bit data frame at 200Mhz clock In decryption process, the speed can be enhanced to 560kbps by using CRT(Chinese Remainder Theorem). Futhermore, to satisfy real time requirements we can choose small public exponent E, such as 3,17 or $2^{16} +1$, in encryption and verification process. in which case the performance can reach 7.3Mbps.

• Korean Journal of Poultry Science
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• v.49 no.4
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• pp.221-228
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• 2022

Major egg white proteins and their hydrolysates serve as functional food ingredients that have certain metal-chelating properties. Employing egg white proteins and their hydrolysates to scavenge dietary oxalates is anticipated to have beneficial effect in the prevention of kidney stones. The objective of this study was to determine the biogenic oxalate-chelating activity of ovalbumin, ovomucin, and ovotransferrin and their hydrolysates. To prepare oxalate extracts, 30 mL of 0.25 N HCl was added to separately to 0.5 g of dried spinach and starfruit powders followed by boiling for 15 min, and after cooling, the addition of a further 20 mL of 0.25 N HCl. Having prepared these extracts, ovalbumin, ovomucin, and ovotransferrin and their hydrolysates were separately mixed with oxalate extracts and incubated at 3℃ for 24 h. Following centrifugation, supernatants were analyzed by HPLC using a reverse-phase C18 column coupled with a diode array detector. We found that all assessed proteins and their hydrolysates showed biogenic oxalate-chelating activity against the oxalates of spinach. In contrast, however, only ovalbumin, ovalbumin-hydrolysate, and ovomucin showed chelating activity (57.10%±8.84%, 85.44%±5.30%, 73.20%±4.13%, respectively) against the oxalates of starfruit (P<0.05). Overall, hydrolyzed ovalbumin was identified as the most effective chelator of the oxalates both spinach and starfruit. In this study, we thus established that the assessed egg white proteins and their hydrolysates have oxalate-chelating activity in vitro, thereby indicating that these compounds have potential utility as nutraceuticals for the chelation of dietary oxalate. However, further research will be necessary to verify their oxalate-chelating activities against different fruits and vegetables and under specific in vivo conditions and against purified oxalate.

• Korean Journal of Animal Reproduction
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• v.21 no.2
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• pp.147-156
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• 1997

Ultrasound-guided follicular aspiration was performed in Holstein heifers once weekly with or without pretreatment of single or multiple decreasing doses using a total of 400 mg FSH. Oocytes were aspirated with a 6.5 MHz convex-array ultrasound trasducer designed for intravaginal use. All the visible follicles larger than 4 mm in diameter were punctured with a 17 gauge, 55 cm needle at each aspiration session and the follicular fluids containing oocytes were obtained by vacuum suction. The results obtained were as follows: As a preliminary experiment, the recovery rates of folicular oocytes by ultrasound-guided aspiration from the isolated ovaries of Korean native cows were compared between suction methods using manual syringe or vacuum pump. The recovery rate of oocytes using vacuum pump (80.7%) was significantly (P<0.05) higher than that using manual syringe (47.1%). The follicles were counted by their size in diameter with ultrasound image, and recovery rates and grades of follicular oocytes collected by ultrasound-guided aspiration were investigated in Holstein heifers pretreated with or without FSH. A group of heifiers were injected with multiple decreasing doses (twice a day for 3 days) of a total of 400 mg FSH. The other 2 groups were injected with a single dose of 400 mg FSH mixed with 25% PVP. Ultrasound observation of follicle population and/or ultrasound-guided transvaginal oocyte aspiration were performed 12 hrs following the last FSH injection in the multiple dose group, and 48 or 60 hrs after FSH injection in the single dose groups. Most of the visible follicles had small size of less than 3 mm in diameter in unstimulated heifers (71.0%), but medium size in all the heifers treated with FSH. (70.5 to 92.8%). The number of OPU follicles per session (4.6$\pm$1.9) were much less, compared to the vilsible follicle counts (9.7$\pm$2.2), in the nustimulated heifers due to the small dominant follicles. Among 4 goups of heifers the most visible as well as OPU follicles were observed in the heifers at 60 hrs following treatment of a single dose of 400 mg FSH (21.2$\pm$2.3 and 21.0$\pm$2.0), and the differences in both the follicle counts between the groups was found significant (P<0.05) The rates of oocyte recovery from the follicles by ultrasound-guilded aspiration were varied 46.3 to 75.0% in the heifers unstimulated and treated with a single dose of 400 mg FSH, but the group difference was not significant. The number of recovered oocytes per session a, pp.ared to be highest at aspiration at 60 hrs following single FSH (10.6$\pm$2.2) than at aspiration at 48 hrs after single FSH (7.8$\pm$2.7) or in the unstimulated heifers (3.4$\pm$3.0). The proportion of grade I and II oocytes to all oocytes collected was varied 31.8 to 64.0% between the groups. However, there was found no significant difference in both the number of oocytes recovered per session and the percentage and the percentage of grade I and II oocytes. From the above results it was concluded that the more oocytes of superior quality might be recovered economically by ultrasound-guided aspiration at 60 hrs following the pretreatment of a single dose of 400 mg FSH and by suction using a vacuum pump system of about negative pressure of 75 to 85 mmHg.

• Korean Journal of Food Science and Technology
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• v.33 no.1
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• pp.33-39
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• 2001

To develop a method for separation process using Sep-pak $C_18$, simultaneous and systematic analysis of 8 permitted and 11 non-permitted synthetic food colors in Korea, optimization of analysis conditions for reverse phase ion-pair high performance liquid chromatography was carried out. For the best result of Sep-pak $C_18$ separation the pH of color standard mixture solution was $5{\sim}6$ and 0.1% HCl-methanol solution were set as eluent. The colors eluated from Sep-pak $C_18$ cartridge were determined and confirmed by high performance liquid chromatography with a photodiode array detector at 420 nm for yellow colors type, at 520 nm for red colors type, at 600 nm for blue and green colors type and at 254 nm for mixed colors. Conditions for HPLC analysis were as follows: column, Symmetry $C_18$ (5 m, 3.9 mm $i.d.{\times}150\;mm$); mobile phase, 0.025 M ammonium acetate (containing 0.01 M tetrabutylammonium bromide) : acetonitrile : methanol (65 : 25 : 10) and 0.025 M ammonium acetate(containing 0.01 M tetrabutylammonium bromide) : acetonitrile : methanol (40 : 50 : 10); flow rate, 1 mL/min. It takes 35 minutes for simultaneaus analysis and 18 minutes for systematic analysis. The detection limits range of each colors were $0.01{\sim}0.05\;{\mu}g/g$.