• The Korean Journal of Nuclear Medicine
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• v.22 no.2
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• pp.193-197
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• 1988

Measurement of gastric emptying rate has been performed by a variety of techniques. Nuclear medicine method is a major advance in the quantitative evaluation of gastric function and also of pharmacologic intervention. Normal gastric emptying rate was measured in 48 healthy volunteers using live chicken liver labeled with $^{99m}Tc-Tin$ Colloid as a solid phase marker. In vitro studies were performed to evaluate the labeling efficiency and stability in hydrochloric acid and in human gastric juice of intracellularly labeled chicken liver. Anterior image counts only were compared with the geometric mean of anterior and posterior counts in 12 healthy volunteers who were studied by both anterior count and posterior count. The results were as follows: 1) The labeling efficiency in gastric juice and hydrochloric acid were $95.5{\pm}1.23%,\;95.7{\pm}1.15%$, respectively. 2) Half gastric emptying time by anterior count only was $126{\pm}21$ minutes 3) Although standard deviation of geometric mean method was smaller than anterior count method, gastric emptying curves from both method were similar. In daily practice, anterior count method may be useful alternative to geometric mean method in evaluation of gastric emptying rate.

• Journal of Chest Surgery
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• v.25 no.12
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• pp.1570-1577
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• 1992

The vascular surgery is the field that has developed in early 20 century and is progressing nowadays. Recent advance in surgical technique accompanying with excellent medical diagnosis and treatment, prompt angiographic usage, development of variable prosthetic material, and concomitant use of anti-coagulant have made remarkable results of vascular surgery. 83 cases of vascular surgery have been performed at Thoracic and Cardiovascular Surgery Department of Pusan National Unversity Hosaital since 1971 till 1990, for 20 years and their results are followed. Patient ductus arteriosus and Buerger`s disease were omited in this study. 1. The age distribution shows that the fifth and sixth decades are most frequently affected and mean age was 56.1 years old. Male to female ratio is 1: 2.32. 2. Among the 83 cases of all, number of occlusive vascular disease is 46 and that of aneurysmal disease is 33. 3. In clinical manifestation, most common symptom of occlusive disease is pulselessness and pain was next. Mass sensation is most commonly complained by patients of aneurysmal disease. 4. CT scan was more important in diagnosis of aneurysmal diseases and angiogram was more commonly used in occlusive diseases. 5. The common site of arterial occlusion was common iliac artery, femoral artery, aortic bifurcation, and external iliac artery, as its frequency rate. The most commonly affecting portion of aortic aneurysm was abdminal aorta, and descending thoracic aorta and femoral artery were next 6. Preoperative associated diseases were atherosclerosis[41 cases], hypertension[21 cases], valvular heart disease[11 cases], and diabetes mellitus[9 cases], etc, 7. Operative methods in ocllusive diseases were thrombectomy[36.9%], endarterectomy [10.9%], and bypass graft insertion[52.7%]. Among the bypass graft, Y-graft was used in 7 case, straight graft was used in 17 cases, and saphenous venous graft was used in 2 cases. 8. Postoperative complications were developed in 17 cases, and morbidity rate was 36. 9. Eleven patient were died within 1 month after operation, so operative mortality rate was 13.3%. 10. Duration of patency was beteween 7 and 58 months[average 27.5 months] in occlusive diseases and their 5-year patency rate was 56.3%. Duration of patency of aneurysmal disease was 20 months in aveage and their 5-year patency rate was 51.3%. 11. Patients of eleven cases of occlusive disease and two cases of aneurysmal disease required reoperation for variable reason. 12. 35 cases of patient have used anticoagulants: coumadin, ticlid, and persanthin-ASA combination.

• Journal of the Institute of Convergence Signal Processing
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• v.22 no.4
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• pp.171-178
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• 2021

Caravans are easily affected by external physical factors and often cause dangerous situations for passengers. Therefore, in order to secure the stability of the passenger, there is a need to develop a sway reduction device capable of preventing the sway phenomenon in advance. This paper aims to minimize the hitch angle between the tow vehicle and the caravan. Specifically, the initial instability of the caravan is detected through an IMU sensor mounted on each of the tow vehicle and the caravan, and a control value is calculated to reduce errors from the Hitch angle and Hitch yaw rate using a PID controller. Different braking torques are generated, distributed, and controlled on the left and right brakes of the caravan according to the calculated control value. It could be verified through the driving experiment that the hitch angle was decreased compared to the case where the performance of the sway reduction device was not controlled, and the transverse stability improvement rate was improved by 94.49% compared to before control.

• Bulletin of the Korean Space Science Society
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• 2009.10a
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• pp.36.3-37
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• 2009

This is an attempt to improve a formula to predict variations of geomagnetic storm indices (Dst) from solar wind parameters. A formula which is most widely accepted was given by Burton et al. (1975) over 30 years ago. Their formula is: dDst*/dt = Q(t) - Dst*(t)/$\tau$, where Q(t) is the Dst injection rate given by the convolution of dawn-to-dusk electric field generated by southward solar wind magnetic field and some response function. However, they did not clearly specify the response function. As a result, misunderstanding seems to be prevailing that the injection rate is proportional to the dawn-to-dusk electric field. In this study we tried to determine the response function by examining 12 intense geomagnetic storms with minimum Dst < -200 nT for which solar wind data are available. The method is as follows. First we assume the form of response function that is specified by several time constants, so that we can calculate the injection rate Q1(t) from the solar wind data. On the other hand, Burton et al. expression provide the observed injection rate Q2(t) = dDst*/dt + Dst*(t)/$\tau$. Thus, it is possible to determine the time constants of response function by a least-squares method to minimize the difference between Q1(t) and Q2(t). We have found this simple method successful enough to reproduce the observed Dst variations from the corresponding solar wind data. The present result provides a scheme to predict the development of Dst 30 minutes to 1 hour in advance by using the real time solar wind data from the ACE spacecraft.

• Journal of the Korean institute of surface engineering
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• v.34 no.5
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• pp.395-402
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• 2001

An induction thermal plasma system have been newly designed for advanced operation with a pulse modulated mode to control the plasma power in time domain and to create non-equilibrium effects such as fast quenching of the plasma to produce new functional materials in high rate. The system consists of MOSFET power supply with a maximum power of 50 kW with a frequency of 460 kHz, an induction plasma torch with a 10-turns coil of 80 mm diameter and 150 mm length and a vacuum chamber. The pulse modulated plasma was successfully generated at a plasma power of 30 kW and a high pressure of 100 kPa, with taking the on and off time as 10 ms, respectively. Measurements were carried out on the time-dependent spectral lines emitted from Ar species. The dynamic behavior of plasma temperature in a pulse cycle was estimated by the Boltzmann plot and the excitation temperature of Ar atom was found to be changed periodically from around 0.5 to 1.7 eV during the cycle. Two application regions of the induction thermal plasma newly generated were introduced to material processing with high rate synthesis based on non equilibrium effects, and to the finding of new arc quenching gases coming necessary for power circuit breaker, which is friendly with earth circumstance alternative to SF6 gas.

• Journal of the Korean Society of Industry Convergence
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• v.18 no.2
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• pp.110-118
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• 2015

In this study, it is designed and used the test engine bed which is installed with turbocharger, and in addition to equipped using by oxygen adder. It has been controlled the oxygen volumetric fraction of intake air chrge, and supercharged flow rate into the cylinder of SI 4-stroke engine, and then, has been analyzed engine performance, combustion characteristics, and exhaust emission as analysis parameters. The tested parameters were the oxygen fraction and the variation of engine speed and air-fuel ratio.

• Korean Journal of Veterinary Service
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• v.15 no.2
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• pp.109-120
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• 1992

330 Samples of the slaughtered cattle heart muscle were collected from the abattoirs of five regions in Kangwon - do to reveal the frequency of sarcocystis infections during January through December in 1991. The samples were inspected for bradyzoites by the trypsin digestion technique and the possitive samples were fed to dogs and cats for the detection of sporocysts shed in the feces. The results obtained were summarized as follows : 1. The infection rate of bovine Sarcocystis investigated from 330 samples was 43.6%. 2. It revealed that the infection rate of Sarrocystis increased gradully with the advance in the age, 14.5% in below two years, 26.1% in the three years, 30% in four years, 54.7% in five years, 74.4% in six years, 90% in seven years and 100% in older than eight years. 3. The cyst walls detected out from the heart muscles were less than l${\mu}{\textrm}{m}$ in thickness and the size of bradyzoites were $11.8{\times}2.8{\mu}m$ in average. 4. The size of sporocysts shed in the feces of dogs were $15.8{\times}9.8{\mu}m$ in average and the prepatent periods ranged from 12 to 16days. 5. Sarcorystis found in the bovine heart muscles were identified as Sascocystis cruzi ( Hasselman, 1923) , wenyon, 1926.

• Structural Engineering and Mechanics
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• v.16 no.2
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• pp.219-240
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• 2003

One of the most versatile approaches for analyzing the dynamic behavior of structural systems is direct time integration of semi-discrete equations of motion. However responses computed by time integration are generally inexact and hence the corresponding errors would rather be studied in advance. In spite of the various error estimation formulations that exist in the literature, it is accepted practice to repeat the analyses with smaller time steps, followed by a comparison between the results. In this paper, after a review of this simple method and disregarding the round-off errors, a more efficient, reliable and yet simple method for estimating errors and enhancing the accuracy is proposed. The main objectives of this research are more realistic error estimation based on the concept of convergence, approximately controlling the reliability by comparing the actual rate of convergence with the integration method's order of accuracy, and enhancement of reliability by applying Richardson's extrapolation. Starting from the errors at specific time instants, the study is then generalized to cases in which the errors should be estimated and decreased at specific events e.g. peak responses. Numerical study illustrates the efficacy of the proposed method.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.2
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• pp.178-186
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• 2003

Seasonal variation of phytoplankton was investigated with surface mixed layer ecosystem model in the East Sea. The model consisted of four compartments (phytoplankton, zooplankton, nutrient, detritus) forced by mixed layer depths, photosynthetically available radiation and nutrient concentrations. From model results we estimated entrainment rate $2.5-4.0\;m{\cdot}day^{-1}$ to reproduce the two annual blooms, and reproduced seasonal variation of phytoplankton at southern and northern regions by the difference of surface winter mixed layer depth (MLD) using the entrainment rate value $3.0\;m{\cdot}day^{-1}$. The spring blooms in the southern and northern regions closely related to deepening of a winter surface MLD. In the southern region where MLD was shallow and phytoplankton spring bloom occurs one month in advance to the northern region where MLD was deep. The amount of light increases within the MLD during the onset of stratification and water temperature increases faster in spring in the southern region than the northern region. Decrease of phytoplankton was mainly affected by zooplankton grazing in the southern region and by nutrient exhaustion in the northern region. The fall bloom in the two regions was caused by the nutrient availability and entrainment on the phytoplankton.

• Journal of Power System Engineering
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• v.11 no.4
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• pp.32-37
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• 2007

Regarding the need of energy in advance and the depletion of fossil fuel energy, all researches around the world now are trying to extract energy from many alternative sources especially the renewable one. Solar, ocean tidal, wind and geothermal energy are renewable energy fields which many researches are focused on. This paper explains about effort to replace electric pump used in solar water heating system by bubble pump. The utilization of bubble pump in this system is very efficient since it needs heat energy for its operation that can be obtained easily. In addition, it can also simplify the construction of the system. Bubble pump also functions as a controller to circulate water inside the system. Before the installation of bubble pump, the special quality and performance of bubble pump should be analyzed. The result got from the analysis could show the fluctuation of water flow rate occurred because it sensitively reacts to the heat quantity. Here the heat quantity is taken from the solar that, as we know, is not stable in a whole day. Problems often occurred are the flow rate in this system is very low moreover it could be stop if the pressure exceeds the limit.