• 소성∙가공
• /
• 제7권6호
• /
• pp.530-538
• /
• 1998

Elimination of the heat treatment process is very important in automation of metal forming since controlling heat treatment by computer has many difficulties and it has bottle neck problem. non-heat-treated steels materials which are not in need of heat treatment have been developed for cold forging. However to apply non-heat-treated steel to structural parts. it is necessary to prove reliability of mechanical properties. In order to define the reliability of mechanical properties we have investigated microstructure, hardness, the tensile strength compressive strength and tensile fatigue strength for both steels. Considering the results of high cycle fatigue test for both specimen the characteristics of non-heat-treated steel are decided on the yield strength, It has same tendency for heat-treated steel. Therefore non-heat-treated steel which has the appropriate yield strength may be applied in cold forging.

• 소성∙가공
• /
• 제29권1호
• /
• pp.5-10
• /
• 2020

Heat treatment conditions of 88.5% asymmetrically cold rolled oxygen free copper (OFC) sheets have been studied to obtain an equiaxed fine microstructure with a grain size of less than 10 ㎛. The commercial OFC sheets with the thickness of 10 mm were asymmetrically cold rolled by using equal speed asymmetric rolling (ESAR) processes and total rolling reduction. The thickness of the rolled sheets were 88.5% and 1.15 mm, respectively. An equiaxed fine microstructure of OFC sheets with a grain size of 6.0 ㎛ were obtained when the asymmetrically cold rolled OFC sheets were heat treated at 180℃ for 40 minutes. The tensile strength of the asymmetrically cold rolled specimen increased from 217.6 MPa to 396.1 MPa, while the elongation of the specimen asymmetrically cold rolled and heat treated increased from 29.0% to 66.9% along with an 8% increase of the tensile strength.

• 소성∙가공
• /
• 제23권7호
• /
• pp.419-424
• /
• 2014

In order to improve efficiency, an outdoor unit using a refrigerant cooling method is designed into many air conditioner systems. The heat exchanger is composed of a Cu tube and an plate. The optimal design for the cold plate is very important because the efficiency of the heat transfer depends on the contact area between the Cu tube and the cold plate. The current study focused on the design of the cold plate to obtain a uniform contact between the Cu tube and the cold plate. Both FE(finite element) analysis and optimization were used in the design. The contact area between the tube and plate was predicted and improved by 16% through the press forming simulations. The springback after press forming was also reduced when the optimized design parameters were used. To verify the validity of the optimal cold plate design, a verification test was conducted. As a result, the performance of the heat exchanger improved by 34% when compared to benchmarked products.

• 한국의류학회지
• /
• 제21권4호
• /
• pp.669-676
• /
• 1997

The purpose of this study is to examine the effect of the improved cold tolerance resulting from cool clothing in winter on heat tolerance in summer. Ten healthy women were divided into two groups, cold group(C group) (n=5) and warm group(W group) (n=5) . In the previous study, C group was proved that their cold acclimatization was achieved through wearing cool clothing from September to February of the following year, while Wgroup was not proved because of wearing warm clothing during same period. After February, no more clothing training was continued in two groups. To determine the heat tolerance, both groups were exposed from a thermoneutral environment(25$\pm$1$^{\circ}C$, 50$\pm$5% R.H.) to a hot environment (35$\pm$1$^{\circ}C$, 50$\pm$5% R.H.) before and after clothing training, respectively September in 1994 and truly in 1995. Rectal temperature, skin temperatures, thermal sensation and comfort were measured every 10 min., and Os uptake was measured at 10, 45, 85 min. after entering the chamber for 5 min. Body weight was measured before and after the experiment and amount of local sweat was measured during the 90 min long experiment. The results are as follows: Rectal temperatures in 35'c environment of C group were increased after training when compared with before clothing, while those of W group were not changed. But the changes of rectal temperature and heat production during 90 min in hot environment were almost the same in two groups after training. And mean skin temperatures, the changes of mean skin temperatures during 90 min in hot environment, total sweat amount and local sweat amount after training were also the same in two groups. From these results, it might be supposed that the heat loss of two groups were the same but the heat production, especially heat production during rest in C group was higher than in Wgroup. This fact suggests that the increase of rest heat production from cold acclimatization in winter is maintained to summer of the following year. And mild cold acclimatization coming from westing cool clothing does not have a negative effect on heat tolerance.

• 동의생리병리학회지
• /
• 제23권1호
• /
• pp.180-185
• /
• 2009

We are developing the methods for the objective and systematic diagnosis, but in actuality the relativity between a diagnosis of Korean medical doctor to a symptom of patients and the conformity to the expression of the Korean medical diagnostic mechanism is short of the statistical data. so, the questionnaire of Cold-Heat & Deficiency-Excess and a diagnosis of Korean medical doctor and a result of the Korean medical diagnostic mechanism, through the relationship of those, we have offered the objective data for diagnostic validity. The study group was 750 volunteers who diagnosed by Cold-Heat & Deficiency-Excess, out of 1475 volunteers who participated in Korean-Western medical examination. We compared the results of the questionnaires for Cold-Heat & Deficiency-Excess patternization through the questionnaire with a diagnosis of Korean medical doctor. we also studied the diagnostic validity for the item of the questionnaire by statistics analysis. It is proper that 9 questions of 16 questions for the Cold, 6 questions of 14 questions for the Heat, 13 questions of 14 questions for the Deficiency, 6 questions of 9 questions for the Excess, and there is close correlation between the questionnaire to the diagnosis. The difference between the questionnaire score is meaningful(p=0.000), this conforms to the diagnosis of the Korean medical doctor, so the questionnaire have the validity. The result of the questionnaire of Cold-Heat & Deficiency-Excess conform to a diagnosis of Korean medical doctor, it carries an important meaning by the measure of diagnosis, and it is necessary for further study for the significance of the medical diagnostic mechanism.

• 대한한방내과학회지
• /
• 제35권1호
• /
• pp.50-58
• /
• 2014

Objectives : The aim of this study was to analyze relationship between post-stroke depression (PSD) and cold, heat, deficiency and excess patterns. Methods : Twenty-eight PSD patients were recruited from STROKE center and measured with questionnaires for cold, heat, deficiency and excess patternvalues and saliva for cortisol awakening response (CAR). Saliva samples were collected immediately, 15, 30 and 45 min after awakening. In addition, Beck Depression Inventory (BDI) and Hamilton Depression Rating Scale (HDRS) were conducted for PSD severity. We conducted correlation analysis to find the relationship between cold, heat, deficiency and excess patterns and CAR or BDI and HDRS. Results : Deficiency and excess patterns werepositively correlated with area under the curve with respect to the increase (AUCi), but not with area under the curve with respect to the global (AUCg), in CAR. Furthermore, it was negatively correlated with BDI and HDRS, while cold and heat patterns were not correlated with CAR, BDI and HDRS. Conclusions : In terms of deficiency and excess patterns, the higher the PSD severity, the higher the deficiency and the lower the PSD severity, the higher the excess. However, there was not a significant relationship between PSD and cold and heat patterns.

• 대한예방한의학회지
• /
• 제20권2호
• /
• pp.17-26
• /
• 2016

Objectives : We presented the results of reliability study in advance, and analyzed agreement between Korean medicine doctors(KMDs)' diagnosis and cold-heat pattern identification questionnaire(CHPI)'s diagnosis. Methods : This survey was conducted from May 16 to 17, 2015. The subjects were 93 adults living in rural society. Diagnosis of CHPI was performed by 2 KMDs who have clinical experience more than 5 years. The KMDs' diagnosis was set as a reference index, and then we compare 23 items(cold pattern 11 items and heat pattern 12 items) of CHPI questionnaire and 15 items(cold pattern 8 items and heat pattern 7 items) that were brief form of it. We had cut-off value by standard of KMDs' diagnosis using receiver operating characteristic-curve(ROC-curve), with which we calculated agreement including kappa value. Correlation analysis between CHPI evaluation score by KMDs and by the questionnaire was fulfilled as well. Results : Agreement about 11 and 8 cold pattern items showed 87.1% together, and the value of kappa each recorded 0.742 and 0.741. Agreement about 12 and 7 heat pattern items suggested 81.7% and 78.5%, and the value of kappa showed 0.634 and 0.570. Correlation coefficients were 0.803 of 11 items and 0.761 of 8 items about cold pattern. In addition, correlation coefficients were 0.789 of 12 items and 0.767 of 7 items about heat pattern. The significant probability (p-value) was under 0.001. Conclusions : We have developed CHPI questionnaire involving reliability and agreement based on usual symptoms, and hope additional complements so that Korean medicine diagnostics and Korean preventive medicine would be improved.

• 한국분말재료학회지
• /
• 제18권6호
• /
• pp.552-561
• /
• 2011

This study attempted to manufacture a Cu-15 at.%Ga coating layer via the cold spray process and investigated the effect of heat treatment environment on the properties of cold sprayed coating material. Three kinds of heat treatment environments, $5%H_2$+argon, pure argon, and vacuum were used in this study. Annealing treatments were conducted at $200{\sim}800^{\circ}C$/1 hr. With the cold sprayed coating layer, pure ${\alpha}$-Cu and small amounts of $Ga_2O_3$ were detected in the XRD, EDS, EPMA analyses. Porosity significantly decreased and hardness also decreased with increasing annealing temperature. The inhomogeneous dendritic microstructure of cold sprayed coating material changed to the homogeneous and dense one (microstructural evolution) with annealing heat treatment. Oxides near the interface of particles could be reduced by heat treatment especially in vacuum and argon environments. Vacuum environment during heat treatment was suggested to be most effective one to improve the densification and purification properties of cold sprayed Cu-15 at.%Ga coating material.

• 대한한의진단학회지
• /
• 제19권2호
• /
• pp.91-100
• /
• 2015

Objectives The aim of this study is to develop a structured clinical protocol related with acquisition of radial pulse wave in the randomized, $2{\times}2$ cross-over design, and cold-heat intervention trial for a pilot and preliminary study. Methods The protocol was contrived based on wide ranging literature searches for cold-heat intervention experiments and radial pulse diagnoses. Results Sample size of 60 subjects was calculated based on an effect size derived from the previous study designed to detect the pre-post cold-heat differences in the radial pulse. Each subjects will be randomly assigned to the cold (first) to heat (last) group (n=30) or heat (first) to cold (last) group (n=30). All subjects will fill out a case report form and questionnaires related with pattern identification, dietary patterns, sleep quality, and physical activity will be surveyed and used as a secondary outcomes. Safety assessment will be reported at the final stage. Conclusions This protocol will provide an additional reference to future studies related with observation of radial pulse during any interventions and also expect to be used as a guideline for acquisition of reliable radial pulse wave data.

• 동의생리병리학회지
• /
• 제26권6호
• /
• pp.934-939
• /
• 2012

To investigate and characterize basic patterns of prehypertension. Participants were divided into three groups; ideal blood pressure(n=40), prehypertension(n=62), and stage 1 hypertension groups(n=68) according to the JNC 7 standards. They answered questionnaire asking various symptoms and received clinical examination. Data were collected and analyzed in the focus of three Zheng patterns, cold-heat, deficiency-excess and four major hypertension types. Analysis of variance was used to find differences among groups. In addition, relationship between the cold-heat trends and risk factors of hypertension were analyzed using Pearson's correlation analysis. Three risk factors; age, body mass index (BMI), and fasting blood sugar (FBS) showed intergroup differences. Statistical significances were revealed in the cold-heat pattern and two hypertension subtypes. The cold scores decreased from $4.8{\pm}1.84$ to $3.9{\pm}1.88$ and $3.7{\pm}1.27$ (p=0.022), while the heat increased from $1.9{\pm}1.32$ to $2.8{\pm}1.72$ and $2.8{\pm}1.48$ (p=0.009). Additionally two hypertension subtypes, the excessive liver fire, and the yin-yang deficiency showed significant differences. Cold had negative correlations with blood pressure (both systolic and diastolic), BMI, triglyceride, and FBS. Heat had positive correlations with systolic blood pressure, BMI, triglyceride, and FBS. Prehypertension could be characterized by using the cold-heat patterns. The cold-heat are correlated with Blood pressure, BMI, blood lipids and sugar.