• Title/Summary/Keyword: Pressure Relaxation

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An Experimental Study on Time Dependency of Strain for Saturated Clay (포화점토(飽和粘土)의 변형(變形)에 있어서 시간의존성(時間依存性)에 관한 실험적(實驗的) 연구(研究))

  • Park, Byong Kee;Lee, Jin Soo
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.4 no.3
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    • pp.43-52
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    • 1984
  • This paper is concerned with the strain characteristics of the time effect on the remoulded saturated day sampled from the downstream of the Yeongsan river, and the constitutive equation that can generally explain time-dependent behaviors of norma1ly consolidated clay. This paper examines whether or not the afore-said constitutive equation can be applied to the remoulded Mooan-clay. Throughout this study, the conclusions obtained are as follows. 1. Throughout the isotropic consolidation test for 7 days and the isotropic relaxation test, the existence of the static and dynamic yielding surfaces is confirmed respectively. 2. The characteristics of time effect of the deformation, namely, the existence of a unique stress-strain-time relation, is conformed from the experimental result on the Mooan-clay. 3. The prodictions of the stress path and the strain on the Cam-clay theory is not consistent with those observed during the experiments. 4. Constitutive equation(2-3-12) obtained by applying Cam-clay theory to Perzyna's elastic-viscoplasticity theory can explain the behavior of pore water pressure during isotropic stress relaxation, concerned with time dependency under undrained condition. The equation can also explain the results of the undrained triaxial compression test for the clay with different strain rate under the same or different consolidation history. 5. This constitutive equation has eight material parameters which can be determined from triaxial compression tests.

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Anorectal Manometry in Idiopathic Constipation in Children (특발성변비 환아에서의 직장항문압측정검사)

  • Beck, Nam-Seon;Seo, Jeong-Kee
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.2 no.1
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    • pp.30-39
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    • 1999
  • Purpose: Anorectal manometry is a way of investigation for ano-rectal sphincters. In this paper we evaluated the usefulness of anorectal manometry in constipation patients and compared the anal spnincter function in control, constipation and encopresis patients Methods: We analysed the data of anorectal function studies in normal children (control, n=11), children with constipation (constipation group, n=20) and children with encopresis (encopresis group, n=16). Results: The specific manometric parameters in normal children were like as follows; external anal sphinter pressure $21.0{\pm}8.00$ mmHg, internal anal sphicter pressure $30.0{\pm}14.57$ mmHg, conscious rectal sensitivity threshold $11.4{\pm}4.52$ mmHg. The above results were not different from that of previous studies except conscious rectal sensitivity threshold, which was slightly lower than that of others. Internal and external anal sphincter pressure were elevated significanlty in constipation and encopresis groups than in control, which results was the same in conscious rectal sensitivity threshold. But the values of rectoanal inhibitory threshold and percent relaxation of rectoanal inhibitory reflex were not different among control group, constipation group and encopresis group. External sphincter activity was increased during the act of bearing down for defecation in none of the child in control group, in 6 of 17 children in constipation group and 5 of 12 children in encopresis group. Conclusion: With the results of above we could say that complete history taking and physical examination are important in diagnosis of constipation, and we could say also that the anorectal manometry was a valuable tool to understand the physiology of normal defecation and the pathophysiology of constipation and encopresis.

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A study on Palpation of the back-shu points (배유혈(背兪穴) 안진(按診)에 관(關)한 고찰(考察))

  • Hong, Mun-Yeup;Park, Won-Hwan
    • The Journal of Dong Guk Oriental Medicine
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    • v.8 no.2
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    • pp.155-173
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    • 2000
  • The diagnosis in Oriental medicine is done by inspection, auscultation and olfaction, interrogation, four diagnostics of pulse feeling and palpation, and various system of identification like identification according to Qi(vital energy), Xue and body fluids, identification according to fair principles, identification according to principles of Wei, Qi, Ying and Xue, identification according to Sanjiao(the triple heater), identification according to four type physical constitution. Sometimes, symptoms and diagnosis techniques according to symptoms is selectively applied for the diagnosis. Among them the pulse feeling and palpation diagnosis technique using the sense of finger and palm of the hand is divided into feeling of pulse and palpation and pressing maneuver. Pressing maneuver is a diagnosis technique pressing and rubbing the affected part in order to attain data of identification including inside and outside condition of the body with regard to the nature, condition and relative seriousness of disease. There are palpation of the skin, palpation the hand and foot, palpation the chest and the abdomen, palpation shu points in pressing maneuver. The diagnosis of the Back Shu points is a technique to examine the change of disease condition from pressure ache, spontaneous ache, tension, relaxation, solidification revealed through channels and collaterals. I investigates starting disease and an attack of disease of twelve pulse and pulse condition through the study relative to the substance and technique of pressing maneuver, and adjusts diagnosis techniques of a region for acupuncture and matters to be attended. The conclusions are as follows. 1. The Shu or stream points in which pathogenic factors go are important to medical treatment of dormant diseases like bowels disease, cold symptom complex and insufficiency symptom complex. 2. Disease classified by system is diagnosed by the condition of process part like pro-trusion, cave-in, tension, relaxation, pressure ache through palpating the Shu or stream points, that is pressing upward or downward left and right sides of the backbone process by hands. 3. In real clinic pressing maneuver of one's back side is very important to patient's diagnosis treatment. Thus, pressing maneuver of one's back side have to be done without omission. 4. Diagnosis must be accomplished through the perception about the diversity of diagnosis technique of bowels disease, the exact knowledge about pressing maneuver of one's back side for enlargement of treatment range and rising of treatment rate, and pressing maneuver of the Shu or the stream points.

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An Analysis of the Healing Effects of Forest Therapy and Horticultural Therapy (숲치유와 원예치료의 치유효과 분석)

  • Park, Sun-A;Jeong, Moon-Sun;Lee, Myungwoo
    • Journal of the Korean Institute of Landscape Architecture
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    • v.43 no.3
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    • pp.43-51
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    • 2015
  • Stresses from desolate urban environments cause illnesses and worsen health conditions of urban residents, while natural environments have a positive influence on human. Natural healing programs such as forest therapy and horticultural therapy can be differentiated by the characteristic of activity space. However, previous studies of healing programs have focused on either forest therapy or horticulture therapy and there is a limit to comprehending the effects of adopting and connecting various healing programs. This study compares and analyzes the physiological and psychological effects of forest therapy and horticultural therapy to identify the effects and differences by types of healing programs. The before and after effects of horticultural therapy and forest therapy are measured by experiment and survey for 5 days with 5 subjects in each program. For physiological reaction, blood pressure, pulse, and cortisol levels are measured and the profile of moods states(POMS) is used to measure psychological reaction. Collected data are analyzed with the analysis of variance(ANOVA) and Paired-Sample T-test in SPSS 18.0. The results of this study are as follows: 1) forest therapy and horticultural therapy show positive effects in physiological and physiological aspects, 2) forest therapy is more effective than horticultural therapy in physiological relaxation and stress mitigation, 3) horticultural therapy has a tendency to alleviate depression more effectively than forest therapy. In conclusion, this study contributes to providing fundamental information for the development of healing programs and design guidelines for healing spaces through identifying the characteristics of each healing program.

A study on Crack Healing of Various Glassy Polymers (part I) -theoretical modeling- (유리질 중합체의 균열 Healing에 관한 연구 (제1보) -이론 모델링-)

  • Lee, Ouk-Sub
    • Journal of the Korean Society for Precision Engineering
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    • v.3 no.1
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    • pp.40-49
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    • 1986
  • Crack, craze and void are common defects which may be found in the bulk of polymeric materials such as either themoplastics or thermosets. The healing phenomena, autohesion, of these defects are known to be a intrinsic material property of various polymeric materials. However, only a few experimental and theoretical investigations on crack, void and craze healing phenomena for various polymeric materials have been reported up to date [1, 2, 3]. This may be partly due to the complications of healing processes and lacking of appropriate theoretical developments. Recently, some investigators have been urged to study the healing phenomena of various polymenic materials since the significance of the use of polymer based alloys or composites has been raised in terms of specific strength and energy saving. In the earlier published reports [1, 2, 3, 4], the crack and void healing velocity, healing toughness and some other healing mechanical and physical properties were measured experimentally and compared with predicted values by utilizing a simple model such as the reptation model under some resonable assumptions. It seems, however, that the general acceptance of the proposed modeling analyses is yet open question. The crack healing processes seem to be complicate and highly dependent on the state of virgin material in terms of mechanical and physical properties. Furthermore, it is also strongly dependent on the histories of crack, craze and void development including fracture suface morphology, the shape of void and the degree of disentanglement of fibril in the craze. The rate of crack healing may be a function of environmental factors such as healing temperature, time and pressure which gives different contact configurations between two separated surfaces. It seems to be reasonable to assume that the crack healing processes may be divided in several distinguished steps like stress relaxation with molecular chain arrangement, surface contact (wetting), inter- diffusion process and com;oete healing (to obtain the original strength). In this context, it is likely that we no longer have to accept the limitation of cumulative damage theories and fatigue life if it is probable to remove the defects such as crack, craze and void and to restore the original strength of polymers or polymer based compowites by suitable choice of healing histories and methods. In this paper, we wish to present a very simple and intuitive theoretical model for the prediction of healed fracture toughness of cracked or defective polymeric components. The central idea of this investigation, thus, may be the modeling of behavior of chain molecules under healing conditions including the effects of chain scission on the healing processes. The validity of this proposed model will be studied by making comparisons between theoretically predicted values and experimentally determined results in near future and will be reported elsewhere.

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A study on the development and field application of SP-Rockbolt with high-strength steel pipe (고강도 강관을 적용한 SP-록볼트 개발 및 현장 적용을 위한 연구)

  • Shin, Hyunkang;Jung, Hyuksang;Ahn, DongWook
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.19 no.4
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    • pp.651-668
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    • 2017
  • For initial stability of the tunnel, the primary support, Shotcrete and rockbolt shall be placed in the most appropriate time. This is because the role of such support plays a vital role in long-term and short-term tunnel stability. In this study, the rock bolt is an important supporting system that receives the external pressure generated by the stress relaxation during tunnel excavation as axial force and transmits it to the shotcrete on the tunnel excavation surface. Until now, most of the materials of rock bolts have been used in the field, but there have been many problems such as uncertain quality of Chinese materials entering the market, poor packing due to falling down of rock bolts when filled with mortar, and corrosion due to water. Therefore, in this study, we have developed a high strength steel pipe rock bolt using Autobeam material to solve and improve various problems of existing rock bolts. In order to evaluate the performance of the developed bolt, field tests were carried out and the existing mortar filler in order to improve the performance of the rock bolt, the design and construction criteria were studied and the results were included in this paper.

General Pharmacology of G009, a Polysaccharide Isolated from Ganoderma lucidum IY 009

  • Kim, Su-Ung;Lee, Seung-Yong;Lee, Seung-Mok;Jeong, Hoon;Hyun, Ik-Sang;Lee, June-Woo;Han, Man-Deuk;Lee, Eun-Bang;Cheon, Seon-Ah;Kim, Sang-Mee;Kim, Kyung-Ran
    • Proceedings of the Korean Society of Applied Pharmacology
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    • 1995.04a
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    • pp.106-106
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    • 1995
  • A polysaccharide, G009, isolated from Ganoderma lucidum IY009 subjected to investigating on general pharmacology. This material at the large oral doses of 1000 and 2000mg/kg in mice did neither exhibit any abnormal behaviors nor effects on central nervous system. It also had no influences on hexobarbital-induced sleeping time, rotarod test and spontaneous activity test at each oral dose of 1000mg/kg in mice. No effects on the body temperature and on acetic acid induced writhing syndrome in mice were observed with its oral administration at 1000mg/kg, and the convulsions induced by strychnine and pentetrazole were not inhibited at its oral doses of 1000mg/kg in mice. The solution of G009 as given intravenously at the doses of 30 and 60mg/kg in rabbit had no influences on blood pressure and respiration rates and depth. In isolated organs of rat uterus and fundus muscles and guinea-pig ileum and trachea, it did not show any contraction or relaxation at the concentration of 2$\times$10$^{-3}$g/ml, and the contractive actions produced by oxytocin, acetylcholine, serotonin and histamine did not inhibited by the same doses. This material showed no effect on intestinal propulsion test in mice and gastric secretion in rats at the oral doses of 1000mg/kg. However, it is interesting that the material exhibited potent inhibition of acidified aspirin induced gastric damage at the doses of 500 and 1000mg/kg in rats.

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Comparison of Accommodative Function of Young Adults in their Twenties Wearing Monovision, Modified Monovision and Multifocal Soft Contact Lenses (모노비전, 변형된 모노비전, 멀티포컬 콘택트렌즈로 교정 시 20대 성인의 조절기능 비교)

  • Lee, A-Young;Kim, Jeong-Mee;Lee, Koon-Ja
    • Journal of Korean Ophthalmic Optics Society
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    • v.20 no.2
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    • pp.117-124
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    • 2015
  • Purpose: The purpose of this study was to compare the accommodative function of young adult in their 20s wearing monovision, modified monovision, and aspheric multifocal contact lenses at near task. Methods: Thirty young adults ($23.53{\pm}2.37years$) were fitted with monovision, modified monovision (the application of single vision contact lenses and center-near low addition aspheric multifocal contact lenses), and aspheric center-near multifocal contact lenses. After wearing these modalities during a week for adaption, and after watching visual display at computer for inducing accommodative pressure for 1 hour. The following assessments of accommodative function were made: contrast visual acuity (VA) at distance and near; accommodative response; near accommodative facility; and negative relative accommodation (NRA)/positive relative accommodation (PRA). All measurements were carried out binocularly. Results: In binocular distance VA with contrast of 10%, monovision was the worst among the four modalities (p=0.005). In accommodative response at 1 m (1.00 D), monovision was the lowest (p<0.05) and accommodative response at 40 cm (2.50 D) with monovision was lower than that of modified monovision and multifocal contact lens (p<0.05). We also found that there were no significant differences in accommodative facility and NRA/PRA among the four modalities. Conclusions: In young adult (20s), monovision with low add reduced the accommodative response at near task, however, modified monovision and multifocal lens with center-near type did not affect accommodative relaxation.

Vasorelaxing Mechanism of Crude Saponin of Korea Red Ginseng in the Resistance-sized Mesenteric Artery of Rat

  • Kim, Shin-Hye;Park, Hyung-Seo;Lee, Mee-Young;Oh, Young-Sun;Kim, Se-Hoon
    • Journal of Ginseng Research
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    • v.26 no.1
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    • pp.1-5
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    • 2002
  • It has been well known that Korea red ginseng has an antihypertensive effect. The antihypertensive effect may be due to its ability to change the peripheral resistance. Change of vascular tone in the resistance-sized artery contribute to the peripheral resistance, thereby regulate the blood pressure. Therefore, we investigated to clarify the vasorelaxing mechanism induced by crude saponin of Korea red ginseng in the resistance-sized mesenteric artery of rats. The resistance-sized mesenteric artery was isolated and cut into a ring. The ring segment was immersed in HEPES-buffered solution and its isometric tension was measured using myograph force-displacement transducer. Crude saponin of ginseng relaxed the mesenmetric arterial rings precontracted with norepinephrine (3$\mu$M) in dose-dependent manner (0.01 mg/㎖ -1 mg/㎖. The relaxation by crude saponin was smaller in endothelium-intact preparation than that in endothelium-denuded preparation. The contraction induced by A23187 or phorbol 12,13-dibutyrate was not affected by crude saponin of ginseng. The vasorelaxing effect of crude saponin of ginseng was significantly attenuated by the increase of the extracellular K$\^$+/ concentration. Crude saponin-induced vasorelaxation was not affected by tetraethylammonium (1 mM), glybenclamide (10$\mu$M), and 4-aminopyridine (0.1 mM) in these preparations. Ba$\^$2+/(10$\mu$M ∼100$\mu$M) markedly reduced the crude saponin-induced vasorelakation dose-dependently. From the above results, we suggest that crude saponin of ginseng may stimulate K$\^$+/ efflux and hyperpolarize the membrane, thereby cause the vasorelaxation in the resistance-sized mesenteric artery of rats.

Effects of Dental Fear on Depression Symptom and Stress in Adults (일부 성인의 치과공포가 우울 증상과 스트레스에 미치는 영향)

  • Park, Eun-Seon
    • The Journal of the Korea Contents Association
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    • v.17 no.9
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    • pp.203-211
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    • 2017
  • The purpose of this study was to determine the association of some adult dental fear and depression, and stress. Among the patients who came to the dental clinic for periodontal treatment, 68 patients who agreed to participate in the study and who met the selection criteria were included. Dental fear, depression symptom questionnaire, salivary cortisol, which can objectively evaluate blood pressure, pulse, and stress. The results of the analysis showed that depressive symptom was related to 'delayed treatment promise', 'cancellation of treatment appointment', 'increased muscle tension', 'rapid breathing when entering dentistry', 'fear when waiting in the waiting room', 'fear when you smell the hospital', 'fear when looking at the dental clinic', 'fear when seeing the anesthetic needle', 'fear when tooth whistle was heard', 'fear when teeth were removed', and 'total fear of dentistry'(p<0.05). Stress symptoms were higher in 'having sweated in the dentist', 'faster pulse', 'fear of entering the dentist' and 'total fear of the dentist'(p<0.05). Based on these results, it is necessary to study the effective methods to control the depressive symptoms and stress of patients who visit dental clinics, and it seems that continuous management is needed to prepare methods such as relaxation therapy for dental fear patients.