• 한국자동차공학회논문집
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• 제15권1호
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• pp.154-161
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• 2007

Hot spot phenomenon that occurs, during judder vibration, is locally concentrated heat due to friction between brake disk and pad. It is important to understand the reason behind hot spot phenomenon, for reduction of judder vibration. In this experimental study, experiments were performed in accordance with rotation speed of brake disk, pressure of master cylinder and pad length for achieving different aspects of hot spot phenomenon. Temperature distribution of hot spot was obtained by using the infrared camera. As the hot spot occurred, vibration was measured and frequency analysis was performed. Finite element analysis of thermal deformation of disk was performed by using temperature distribution that was achieved by experimental results. And mode shapes of disk was analyzed by finite element analysis and compared with experimental results. It was observed that the excitation frequency band of frictional contact and frictional force mainly affects the hot spot phenomenon.

• Food Science and Biotechnology
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• 제17권6호
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• pp.1185-1190
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• 2008

When 10 kinds of herbal medicines were fractionated into hexane, MeOH, cold-water, and hot-water extracts, hot-water extracts from Acanthopanax senticosus (AS), Glycyrrhiza uralensis (GU), Cichorium intybus (CI), and Polygonatum odoratum (PO) showed the potent intestinal immune system modulating activity (1.72-, 1.62-, 1.60-, and 1.53-fold of control at $100{\mu}g/mL$, respectively). Especially, hot-water extracts from AS (215% compared with the control) and GU (187%) also had macrophages stimulating activity and mitogenic activity of splenocytes (7.1- and 6.5-fold) at $100{\mu}g/mL$. In addition, the effects of hot-water extracts from herbal medicines on anticancer activities were studied in mice. Hot-water extracts from AS and GU enhanced cytotoxicity of natural killer cell against cancer cell, Yac-1 (37 and 34% cytotoxicity) at E/T ratio 100:1, and colon 26-M3.1 cancer cell lines had significantly inhibited (82.1 and 75.2%) in experimental lung metastasis. These results suggest that hot-water extracts from A. senticosus and G. uralensis can be used as biological response modifiers to stimulate immune system and inhibit tumor.

• Structural Engineering and Mechanics
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• 제19권3호
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• pp.261-279
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• 2005

The hot spot stress approach is usually adopted in the fatigue design and analysis of tubular welded joints. To apply the hot spot stress approach for fatigue evaluation of long span suspension bridges, the FEM is used to determine the hot spot stress of critical fatigue location. Using the local finite element models of the Tsing Ma Bridge, typical joints are developed and the stress concentration factors are determined. As a case for study, the calculated stress concentration factor is combined with the nominal representative stress block cycle to obtain the representative hot spot stress range cycle block under traffic loading from online health monitoring system. A comparison is made between the nominal stress approach and the hot spot stress approach for fatigue life evaluation of the Tsing Ma Bridge. The comparison result shows that the nominal stress approach cannot consider the most critical stress of the fatigue damage location and the hot spot stress approach is more appropriate for fatigue evaluation.

• 대한한방내과학회지
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• 제40권1호
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• pp.154-163
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• 2019

Objective: We report on the administration progression and adverse event of Er-Xian decoction for menopausal hot flushes. A hot flush is a rapid and intense heat-dissipation reaction that involves considerable sweating, enlargement of the peripheral blood vessels, and internal body heat. Er-Xian decoction is a prescription for treating menopausal hot flush symptoms in postmenopausal women. We report administration progression and adverse event of Er-Xian decoction for menopausal hot flush. Methods: We used the Menopause Rating Scale and Menopause-Specific Quality of Life questionnaire to evaluate the progression of hot flushes, and we conducted a literature review to determine the effective dosage of Er-Xian decoction. Result: In all cases, Facial hot flushes and evaluation variables were improved by the administration of EXD. However, in Case 1, a rise of liver function indexes which may be related to EXD administration was observed. Conclusion: Considering that menopausal flushing usually lasts for several years, The resluts are meaningful that the short-term administration of EXD led to improvement of symptoms. In order to further use EXD in the future, it will be necessary to conduct follow-up studies on the subject of safety verification, such as repeated dose toxicity studies.

• 대한금속재료학회지
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• 제47권4호
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• pp.217-222
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• 2009

Cu as a tramp element has been reported to encourage transverse cracking upon straightening operation during continuous casting or mini-mill processing. Therefore, the hot workability of steels containing Cu should be investigated. The purpose of the present study was to examine the effect of Cu contents on the hot ductility of low carbon steels by using hot compression test. Hot compression test was carried out using a Gleeble. The specimens were heated to $1300^{\circ}C$ for solution treatment and then held for 300s before cooling at a rate of $1^{\circ}C/s$ to test temperatures in the range of $650{\sim}1150^{\circ}C$ ($50^{\circ}C$ intervals) with strain rate of $5{\times}10^{-3}/s$. In Cu containing steels, the hot ductility was decreased with increasing Cu content at high temperature region which is to be attributed to copper enriched phase formed at scale/steel interface, and low hot ductility with increasing Cu content at low temperature region is attributable to the strengthening of matrix by the formation of ${\varepsilon}-Cu$. The width of ductility trough region was decreased with increasing Cu content.

• Nuclear Engineering and Technology
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• 제54권8호
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• pp.2840-2851
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• 2022

Electric boilers (EBs) are the backup steam source for the auxiliary steam system of high-temperature gas-cooled reactor nuclear power plants. When the plant is in normal operations, the EB is always in hot standby status. However, the current hot standby operation strategy has problems of slow response, high power consumption, and long operation time. To solve these problems, this study focuses on the optimization of hot standby operations for the EB system. First, mathematical models of an electrode immersion EB and its accompanying deaerator were established. Then, a control simulation platform of the EB system was developed in MATLAB/Simulink implementing the established mathematical models and corresponding control systems. Finally, two optimization strategies for the EB hot standby operation were proposed, followed by dynamic simulations of the EB system transient from hot standby to normal operations. The results indicate that the proposed optimization strategies can significantly speed up the transient response of the EB system from hot standby to normal operations and reduce the power consumption in hot standby operations, improving the dynamic performance and economy of the system.

• 대한한의진단학회지
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• 제19권3호
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• pp.141-149
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• 2015

Objectives Recently the fuzzy logic is widely used in the decision making, identification, pattern recognition, optimization in various fields. In this study, we propose the fuzzy logic as the objective method of distinguishing hot and cold, the basis of diagnosis in Korean medicine. Methods We developed fuzzy inference system to distinguish whether the subjects had hot or cold. The cold and hot questionnaire of Korean traditional university textbook, the pulse rate and the DITI value of face used in the system. These three kinds of information were defined as 'fuzzy sets,' and 54 fuzzy rules were established on the basis of clinical practitioners' knowledge. The fuzzy inference was performed by using the Mamdani's method. To evaluate the usefulness of the fuzzy inference system, 200 cases of data measured in the Woosuk university hospital of oriental medicine were used to compare the determining hot, normal, cold results obtained from the experts and from the proposed system. Results As a result, 100 cases of "cold", 54 cases of "normal", and 34 cases of "hot" were matched between the experts and the proposed system. This fuzzy system showed the conformity degree of 94%(${\kappa}=0.853$). Conclusions In this study, we could express the process of distinguishing hot-cold using the fuzzy logic for objectification and quantification of hot-cold identification. This is the first study that introduce a fuzzy logic for distinguish pattern identification. The degree of the heat characteristic of the patients inferred by this system could provide a more objective basis for diagnosing the hot-cold of patients.

• 동의생리병리학회지
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• 제22권6호
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• pp.1354-1358
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• 2008

In Traditional Korean Medicine it is one of basic principle that personality reflects physical conditions. In both of personality and ordinary symptoms, there are some criteria used for diagnosis whether the patient is in cold or hot condition. We studied the relationship between the criteria of cold-hot shown in personality pattern and ordinary symptom pattern. And also analyzed the relativeness in four constitution type. 877 patients who had visited oriental medical hospital and had been confirmed their constitution by drug response were included in this study. Patients filled out the questionnaire composed of personality and ordinary symptom questions. We selected questions related to cold-hot patterns. Next we made personality cold-hot index(PCHI) and ordinary symptom cold-hot index(OSCHI). The two indices were compared and analyzed totally and from the viewpoint of 4 constitution types. The coefficient of correlation between two indices was not high. In Soemin the coefficient was 0.257, in three other constitution it was lower than 0.200 or negative. In Soemin both indices were lower (cold-biased), but in three other constitution no significant results were found. In Tae-emin OSCHI was higher (hot-biased) than PCHI, in Tae-yangin PCHI was higher than OSCHI significantly. Personality is not affected by cold-hot less than expected. The criteria used for diagnosis of cold-hot seems to be biased on Soemin's.

• 대한한방부인과학회지
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• 제19권4호
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• pp.205-215
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• 2006

Purpose : To identify factors related to the severity and frequency of hot flush of postmenopausal women who participated in a clinical trial. Methods : A cross-section study of 34 postmenopausal women between 40 and 60 years of age was done. VAS(visual analog scale) was used to evaluate the hot flush degree. Statistical analysis was performed with multiple linear regression analysis. Results : Hot flush VAS was proportional to the percent body fat with 1.467 regression coefficient (p-value= 0.010). It implies that the symptom of hot flush becomes worse as the percent body fat increases. Some hormones also have effects on hot flush. We found that LH might cause increment of hot flush VAS(i.e., the corresponding regression coefficient is 0.912). Sasang constitution was not relevant to the hot flush degree. Hot flush VAS seemed to increase as the vascular aging degree by SA-2000 getting worse, but it was not statistically significant (p-value= 0.594). Conclusion : This study is a part of a prospective clinical trial. For more accurate result, larger-scale cross-section study or clinical trial are necessary.

• Journal of Biosystems Engineering
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• 제34권5호
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• pp.363-370
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• 2009

Hot air heater with light oil combustion is used as the most common heater for greenhouse heating in the winter season. Hot air heaters of 256,246 units have been supplied as main greenhouse heating equipment until 2008 and greenhouse heating cost has reached to 620 billions won in Korea. In order to improve the thermal efficiency of the hot air heater and to reduce the expenses for greenhouse heating, prototype hot air heater was manufactured and tested in this experiment. The heat exchanger of tested prototype hot air heater was circular and hexagonal pipe type and inline and stagger arrangement type. Capacity of the heating was 43,062 kJ/h and total heat transfer area of the heat exchanger was $10.728\;m^2$. According to the performance test, it could supply heat of 38,240 to 35,100 kJ/h depending on the fan motor speed of 1,740~1,220 rpm, respectively. Thermal efficiency of hot air heater was 87.0% to 80.8% in the same conditions. As a result, thermal efficiency of hot air heater with hexagonal pipe-stagger arrangement heat exchanger developed in this study was higher 10.2% than that of conventional hot air heater and heating energy saving rate of 14.3% increased.