• Journal of the Korea Concrete Institute
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• v.21 no.6
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• pp.763-771
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• 2009

As the demand on long span structures increases more in recent years, the excessive deflection, in addition to the ultimate strength, in horizontal members becomes a very important issue. For this reason, as an alternative method to effectively solve the deflection problems, the application of post-tensioned structural system with unbonded tendon increases gradually. However, most of the existing researches on post-tensioned members with unbonded tendons (UPT) focused on the ultimate flexural strength, which would be impossible or improper to check serviceability such as deflections. Therefore, this study aims at proposing a stress prediction model for unbonded tendons that is applicable to the behavior of UPT members from the very initial loading stages, post-cracking states, and service to ultimate conditions. The applicability and accuracy of the proposed model were also evaluated comparing to the existing test results from literature. Based on such comparison results, it was verified that the proposed model provided very good predictions on tendon stresses of UPT members at various loading stages regardless their different characteristics; wide range of reinforcement index, different loading patterns, and etc. The proposed model especially well considered the effect of various loading types on stress increases of unbonded tendons, and it was also very suitable to apply on the over-reinforced members that easily happened during strengthening/repairing work.

• Geotechnical Engineering
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• v.14 no.4
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• pp.47-60
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• 1998

A series of conventional tests and CRS consolidation tests with different rates of strain were performed to investigate the consolidation characteristics of marine clay. Preconsolidation pressures were evaluated by applying previously proposed methods for both the conventional tests and CRS tests results in order to check the legitimacy of those methods. The effects of strain rate on effective consolidation stress strain relationship, porewater pressure, and preconsolidation pressure were also discussed It was found that the effective stress strain relationship and the preconsolidation pressure are a function of strain rate imposed during consolidation test, but compression index isn't. The preconsolidation pressure ratio ($a_2=\sigma'_{pCRS}/\sigma'_{pConv}$)of marine clay appears proportional to the logarithm of strain rate, with average values ranging from 1.11 to 1.30 for strain rates between $1\timesx10^{-4} %/sec\; and\; 4\times10 %/sec$. The porewater pressure ratio during CRS teats does not exceed 6.0% except when the strain rate is $6.67\times10^{-4} %/sec$. Coefficient of consolidation or coefficient of permeability at normally consolidated range was not affected by the type of consolidation tests and the strain rate. Typical values of compression index (C.), coefficient of consolidation(c.), and coefficient of permeability (k.) at normally consolidated range were 0.56-0.95, $0.56\times10^{-4}~3.0\times10^{-4}cm2/sec,\; and\; 2.0\times10^{-8}~7.0\time10^{-4}cm/sec,$ respectively.

• Journal of the Korean Geotechnical Society
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• v.19 no.6
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• pp.273-283
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• 2003

Fissured rock and soft ground always suggest, problems in the construction of the underground space. The stress release of the weak underground material by opening the underground space with a soft ground, fissures and joints can lead to the failure of the opening. Grouting of the weak rock and the soft ground, which is a process of injecting some bonding agents into the soft ground, is one of the measures to reinforce the soft ground and to prohibit the failure of the underground construction due to the stress release. The proper installation of the grouting is essential to ensuring the safety of the tunneling operation, so that the evaluation of the grouting performance is very significant. The general procedure of evaluating the grouting is coring the grouted section and measuring the compression strength of the core. However, sometimes when the grouted section is at the crown of the tunnel and the grouting is installed at a wide section, the coring is not good enough. This study is oriented to propose a new and a non-destructive procedure of evaluating the grouting performance. The proposed method is based on the wave propagation of elastic waves, and evaluates the shear stiffness of the ground and investigates the anomalies such as voids and cracks. The SASW ( Spectral-Analysis-of-Surface-Waves) method is one of the candidate s to make the inspection of the pouting performance, and is adopted in this study. The practical grouting activity was monitored by SASW method, and the proposed method was applied to the inspection of the grouting performance to check the verification of the proposed method.

• The Korean Journal of Food And Nutrition
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• v.26 no.4
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• pp.895-908
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• 2013

The purpose of this study is to examine female baby boomers' dietary habits and their attitudes together with their needs for future perspectives of dietary life. Our aim is to use these findings as a basic data when forecasting for food-related industries or policy making. A survey is being carried out for a total of 358 female baby boomers and analyzed by SPSS 12.0. The following is a summary of this study. The average age is 52.6 years old, most of them graduated from highschool (63.1%) and had a nuclear type of family (76.1%). Only 39.0% is composed of housewives, others had either full-time or part-time jobs. Self-assessment of stress is not so high and only 8.1% are dissatisfied with their lives. 38.2% are either overweight or obese in terms of BMI, and most of them are non-smokers (97.2%) or non-drinkers (63.0%). Their mean dietary habit scores are $70.6{\pm}11.8$, and the scores show significant relations with their education levels (p<0.01), monthly income (p<0.01), life satisfaction rates (p<0.001), stress levels (p<0.001), smoking habits (p<0.05), drinking habits (p<0.05), regular exercises (p<0.001) and regular health check-ups (p<0.05). The rate of skipping breakfast, lunch and dinner are 18.2%, 1.1%, 5.2% respectively. The main reason for skipping breakfast is the 'lack of time'. With regards to the frequency of grocery shopping, almost half of the subjects (55.7%) said '1~2 times per week' and bought mainly raw food sources such as vegetables, fruits, and meats. The majority of the subjects (91.3%) report that they cooked meals at homes, and took about 1 hour of time. The subjects also point out that cooking was a bothering task, and only 46.4% would prepare meals at home, while others would rather eat out or eat convenience foods. The main reasons for not wanting meal services in the elderly welfare facility are because they didn't want to live such places (48.4%) and the meals are tasteless (31.3%). As for delivery meal services, 60.1% are aware of it, and 39.9% would consider using it in the future. Factors to be considered when using the delivery meal service are sanitation (43.7%), nutrition (28.7%), taste (18.4%), price (6.3%), and brand name (2.9%). This study is expected to be used as useful information when developing food-related strategies for baby boomers in the future.

• The Journal of Engineering Geology
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• v.25 no.3
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• pp.377-385
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• 2015

We constructed a model test apparatus to evaluate the dependence of the saturation velocity (V_s) in soils on rainfall intensity (I_R). The apparatus comprises a soil box, a rainfall simulator, and measuring sensors. The model grounds (60 cm × 50 cm × 15 cm) were formed by Joomunjin standard sand with a relative density of 75%. The rainfall simulator can control the rainfall intensity to reenact the actual rainfall in a soil box. Time Domain Reflectometer (TDR) sensors and tensiometers were installed in the soils to measure changes in the volumetric water content and matric suction due to rainfall infiltration. During the tests, the soil saturation was determined by raising the groundwater table, which was formed at the bottom of the soil box. [Please check that the correct meaning has been maintained.] The wetting front did not form at the ground surface during rainfall because the soil particles were uniform and the coefficient of permeability was relatively high. Our results show that the suction stress of the soils decreased with increasing volumetric water content, and this effect was most pronounced for volumetric water contents of 20%-30%. Based on a regression analysis of the relationship between rainfall intensity and the average saturation velocity, we suggest the following equation for estimating the saturation velocity in soils: V_savg (cm/sec) = 0.068I_R (mm/hr).

• Journal of Korean Medicine Rehabilitation
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• v.15 no.2
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• pp.141-154
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• 2005

Objectives : This study was planned to evaluate clinical status of the alopecia patients who had visited oriental medicine clinic. Methods : 80 patients with alopecia, who had visited oriental medicine clinic from January 2004 to August 2004, were examined. Results & Conclusions : 1. The kinds and incidences of Alopecia : androgenetic alopecia 57.5%(46/80), alopecia areatea 20.0%(16/80), telogen effluvium 16.3%(13/80), seborrheic alopecia 6.3%(5/80). 2. In distribution of sex, the rate of male to female was 1:1 and most patients belonged to 20-30 year old group. 3. The most common onset of age was adolescence(63.8%) and the most common duration of hair loss was 1 to 3 years. 4. Among the 30 male androgenetic alopecia patients, Hamilton's type 4 was most common and among the 16 female androgenetic alopecia patients, Ludwig's type II and III were most common. 5. Family history of baldness in Androgenetic alopecia and alopecia areata were 56.5% and 25.0%, respectively. 6. Self-conscious causes of hair loss : stress(48.8%), irregular eating habits(21.3%), and lack of sleep(20.0%). 7. Associated diseases with alopecia patients : chronic neck pain(58.8%), temporomandibular disorders(55.0%) and seborrheic dermatitis(20.0%). 8. Associated symptoms with alopecia Patients : stress(78.8%), sleep disorders(68.8%), irregular eating habits(55.0%), Hot flush(43.8%), Stool disorders(43.8%), cold hands and feet(37.5%) and menstruation disorders(31.3%). 9. The most common scalp type was oily scalp(70.0%) and the symptoms of scalp were iching, dandruff, pain, inflammation. 10. $Bi{\grave{a}}n$ $zh{\grave{e}}ng$(辨證) of alopecia patients : $xu{\grave{e}}-r{\grave{e}}-f{\bar{e}}ng-z{\grave{a}}u$(血熱風燥) (25.0%), $g{\bar{a}}n-sh{\grave{e}}n-b{\grave{u}}-z{\acute{u}}$(肝腎不足) (23.8%), $shi-r{\grave{e}}-sh{\grave{a}}ng-zh{\bar{e}}ng$(濕熱上蒸) (16.3%), $xu{\grave{e}}-r{\grave{e}}-sh{\bar{e}}ng-f{\bar{e}}ng$(血熱生風) (13.8%), $xu{\grave{e}}-x{\bar{u}}-f{\bar{e}}ng-z{\grave{a}}u$(血熱風燥) (13.8%), $y{\bar{u}}-xu{\grave{e}}-z{\check{u}}-lu{\grave{o}}$(瘀血阻絡) (7.5%).

• Korean Journal of Health Education and Promotion
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• v.15 no.1
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• pp.115-131
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• 1998

Understanding average abnormal obese high school students' health awareness and attitude, We analyzed problems affect on this to provide basic data for the school health education in the near future. From March, 1997, covering a month period, We investigated 300 average obese students from each 3 school, both boys and girls, around Taegu area. Followings are the summary. 1) Grouping obesity, 86.6% of boys were abdominal type and 54.0% of girls were lump types. 2) IN physical check-up and serum lipid lab., there were a lot of abnormal students for blood pressure, serum glucose, total cholesterol, high density lipoprotein(HDL), low density lipoprotein(LDL), neutral lipid, the rate of lipid in the body, atherosclerosis index and electrocardiogram (ECG).; Especially, for the rate of Lipid in the body, 100.0% were in the abnormal range. 3) The main reasons of stress were on the physique and grade. Over 50.0% of students get rid of their stress by singing and dancing. 4) 46.7% of boys and 56.0% of girls were satisfied with their desks and 51.3% of boys and 48.0% of girls were satisfied with their chairs.; 70.0% of boys and 78.7% of girls usually felt uncomfortable for their desks and chairs. 5) 100.0% of boys and 98.0% of girls have been educated for obesity.; 53.3% of boys and 50.7% of girls were not interested in whether joining in or not, if ‘Obese school’ is open. 60.7% of boys get information about weight loss from television, while 41.3% of girls get it from all sorts of publications.; Both sexes said eating convenience food is the main reason to be obese. Most frequent disease is high blood pressure.; 30.0% of boys and 31.3% of girls were hypertensives. 6) 84.7% of boys and 78.0% of girls are awake to the seriousness of obesity from their families. 58.7% of boys and 66.0% of girls sometimes have meals with their families. For the boys, 30.0% of them eat fruit and 29.3% eat cookies while 37.3% of girls eat cookies for their snacks. Both 57.3% of boys and 40.0% of girls have a snack once a day and they drink soft drinks frequently. Both 32.0% of boys and 46.7% of girls have midnight meals 1-2times a week. 7) Both 45.3% of boys and 50.0% of girls suddenly gained their weight in the elementary school times. 30.0% of boys exercise 1 hour for a week, while 48.0% of girls don't exercise. For the exercise hour, both 53.3% of boys and 42.0% of girls exercise for 10-30 minutes a time. 59.7% of boys and 82.0% of girls strongly don't trust in the informations on weight loss. Both 74.0% of boys and 75.3% of girls think physical therapy is the most suitable way for obesity care.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.593-601
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• 2021

The axial fan is an element of a blower used for ventilation in various industrial fields. Many studies on aerodynamic performance have been conducted to assess axial fans using fluid dynamics. The subject was a large axial fan size, 1800 mm in diameter with 100 horsepower. The blower's axial fan consisted of blades, hubs, hub caps, and bosses are important components. The blade design has a great influence on the aerodynamic performance. 3D point data is extracted using an aerodynamic performance prediction program, and a 3D modeling shape is generated. The blades and hubs, which are important components, can be easily modified if processed by cutting owing to the environment in which blades and hubs are manufactured through die casting or gravity casting. In this study, the structural safety of components and the analysis results of weak areas at the rated operating speed of the axial fan were verified using the maximum stress and safety factor. The tip clearance reflected in the design was the rotation of the blade. To check whether there is interference with other components, the displacement result was derived to verify the structural safety of the axial fan.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.6
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• pp.1125-1146
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• 2018

Segment lining applied to the TBM tunnel is mainly made of concrete, and it requires sufficient structural capacity to resist loads received during the construction and also after the completion. When segment lining is design to the Limit State Design, both Ultimate Limit State (ULS) and Service Limit State (SLS) should be met for the possible load cases that covers both permanent and temporary load cases - such as load applied by TBM. When design segment lining, it is important to check structural capacity at the joints as both temporary and permanent loads are always transferred through the segment joints, and sometimes the load applied to the joint is high enough to damage the segment - so called bursting failure. According to the various design guides from UK (PAS 8810, 2016), compression stress at the joint surface can generate bursting failure of the segment. This is normally from the TBM's jacking force applied at the circumferential joint, and the lining's hoop thrust generated from the permanent loads applied at the radial joint. Therefore, precast concrete segment lining's joints shall be designed to have sufficient structural capacity to resist bursting stresses generated by the TBM's jacking force and by the hoop thrust. In this study, bursting stress at the segment joints are calculated, and the joint's structural capacity was assessed using Leonhardt (1964) and FEM analysis for three different design cases. For those three analysis cases, hoop thrust at the radial joint was calculated with the application of the most widely used limit state design codes Eurocode and AASHTO LRFD (2017). For the circumferential joints bursting design, an assumed TBM jack force was used with considering of the construction tolerance of the segments and the eccentricity of the jack's position. The analysis results show reinforcement is needed as joint bursting stresses exceeds the allowable tensile strength of concrete. This highlights that joint bursting check shall be considered as a mandatory design item in the limit state design of the segment lining.

• Korean Journal of Plant Resources
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• v.10 no.1
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• pp.100-104
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• 1997

A new baekji(Angelica dahurica Bentham et Hooker) variety, Baekji l, was developed through a pure line selection at the Gyeongbug Provincial RDA during the period of 1990 to 1995. The variety was characterized to have high plant height. Long root length and large root diameter as compared with a check varicty of Bonghwa baekji but emergence date, flowering date and leaf number of Baekji l was similar to that of the check variety, and it was also more tolerant to nematode and heat stress. Peeled root color of Backji l was yellowbrown but number of the lateral root of the variety was greater. The dried-root yield of Baekji l in yield trial, regional adaptation trial and farmer's field trial was always $21\sim31%$ higher than that of the check variety.