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Heat transfer characteristics of an internal cooling channel with pin-fins and ribbed endwalls in gas turbine blade

  • Vu T.A. Co;Hung C. Hoang;Duy C.K. Do;Son H. Truong;Diem G. Pham;Nhung T.T. Le;Truong C. Dinh;Linh T. Nha
    • Advances in aircraft and spacecraft science
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    • v.11 no.2
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    • pp.153-175
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    • 2024
  • In jet engines, turbine blade cooling has an extremely important role. The pin-fin array, which is situated close to the trailing edge of the blade, aids in internal cooling of the gas turbine blades and preserves the structural integrity of the blade. Previous studies often focused on pin-fin configurations, but the current research focuses on improving the geometry at the endwalls to reduce wake vortices behind the pin-fins and enhance heat transfer at the endwalls location. Using the k-ω turbulence model, a numerical study was conducted on a ribbed shape situated on the walls between pin-fin arrays, spanning a Reynolds number range of 7400 to 36000, in order to determine the heat transport characteristics. The heat transfer efficiency coefficient and Nusselt number increase dramatically with the revised wall configuration, according to the numerical data. The channel's heat transfer efficiency is increased by enlarging the heat transfer areas near the pin-fins and by the interaction of the flow with the endwalls. The addition of ribs causes the Nusselt number of the new model to climb from 78% to 96% at the previously given Reynolds numbers, and the heat transfer efficiency index to rise from 60% to 73%. The height (Hr), position (Lr), forward width (Wf), and backward width (Wb) of the ribs are among the geometric elements that were looked at in order to determine how they affected the performance of heat transmission. In comparison to the reference design, the parametric study results demonstrate that the best forward width (Wf/R=18.75%) and backward width (Wb/R=31.25%) increase the heat transfer efficiency index by 0.4% and 1.3%, respectively.

The Acceptance Testing of 5 Mega Pixels Primary Electronic Display Devices and the Study of Quality Control Guideline Suitable for Domestic Circumstance (5 Mega 화소 진단용 전자표시장치 인수검사 및 국내 실정에 적합한 정도관리 가이드라인 연구)

  • Jung, Hai-Jo;Kim, Hee-Joung;Kim, Sung-Kyu
    • Progress in Medical Physics
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    • v.18 no.2
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    • pp.98-106
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    • 2007
  • In June 2005, Yonsei University Medical Center, Severance Hospital upgraded a full-PACS system by adding twenty (5 mega pixels) Totoku ME511L flat panel LCD display devices for diagnostic interpretation purposes. Here we report upon the quantitative (or visual) acceptance testing of the twenty Totoku ME511L display devices for reflection, luminance response, luminance spatial dependency, resolution, noise, veiling glare, and display chromaticity based on AAPM TG 18 report. The tools used in the tests included a telescopic photometer, which was used as a colorimeter, illuminance meter, light sources for reflection assessment, light-blocking devices, and digital TG18 test patterns. For selected 8 flat panel displays, mean diffuse reflection coefficient ($R_d$) was $0.019{\pm}0.02sr^{-1}$. In the luminance response test, luminance ratio (LR), maximum luminance difference ($L_{max}$), and deviation of contrast response were $550{\pm}100,\;2.0{\pm}1.9%\;and\;5.8{\pm}1.8%$, respectively. In the luminance uniformity test, maximum luminance deviation was $14.3{\pm}5.5%$ for the 10% luminance of the TG18-UNL10 test pattern. In the resolution test with luminance measurement method, percent luminance (${\Dalta}L$) at the center was $0.94{\pm}0.64%$. In all cases of noise testing, rectangular target In every square in the three quadrants was visible and all 15 targets except the smallest one in the every corner pattern and the center pattern. The glare ratio (GR) was $12,346{\pm}1,995$. The color uniformity, (u',v'), was $0.0025{\pm}0.0008$. Also, the research results of qualify control guideline of primary disply devices suitable for domestic circumstance are presented All test results are in-line with the criteria recommended by AAPM TG18 report and are thus fully acceptable for diagnostic image interpretation. As a result, the acceptance testing schedule described provides not only an acceptance standard but also guidelines for quality control, optimized viewing conditions, and a means for determining the upgrading time of LCD display devices for diagnostic interpretation.

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A Review of the Domestic Study Trends on Obstetrics & Gynecological Diseases by Using Digital Infrared Thermal Imaging as a Diagnosis Instrument (한방여성의학 영역에서 진단 도구로 적외선 체열 검사(Digital Infrared Thermal Imaging, DITI)를 활용한 국내 연구 동향 분석)

  • Im, Ji-Yeong;Hwang, Deok-Sang;Lee, Jin-Moo;Lee, Chang-Hoon;Jang, Jun-Bock
    • The Journal of Korean Obstetrics and Gynecology
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    • v.33 no.3
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    • pp.80-94
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    • 2020
  • Objectives: The purpose of this review is to analyze the domestic study trends of clinical use of Digital Infrared Thermal Imaging (DITI) as a diagnosis instrument on obstetrics and gynecological diseases in Korean literature. Methods: We searched for clinical studies using DITI in the journal of Korean obstetrics & gynecology, National Digital Science Library, Research Information Sharing Service, Korean Medical Database up to May 2020. After searching studies, we selected studies and analyzed according to disease. Results: 18 clinical studies were published in two kinds of academic journals. There were 4 studies about dysmenorrhea and menopausal symptoms, 2 studies about postpartum disease and hypercryalgesia, 1 study about amenorrhea, premenstrual syndrome, leukorrhea, infertility, polycystic ovary syndrome and hot flush. Conception vessel was frequently used for DITI measurement, followed by stomach meridian. The temperatures of abdomen (CV4, CV12), face (HN3), upper and lower limb (PC8, LU4, LR3, ST32) were commonly measured. Conclusions: This study shows that DITI could be one of effective diagnosis instrument for obstetrics and gynecological diseases. More well-designed clinical studies using DITI will be needed.

OCCLUSAL ANALYSIS OF PATIENTS WITH TEMPOROMANDIBULAR DYSFUNCTION BY USE OF T-SCAN SYSTEM (T-Scan system을 이용한 측두하악 장애 환자의 교합 분석에 관한 연구)

  • Park Seon-Joo;Chung Chae-Heon
    • The Journal of Korean Academy of Prosthodontics
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    • v.29 no.3
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    • pp.121-140
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    • 1991
  • Fifteen dental college students of Chosun University without the abnormal occlusion, the history and symptom of temporomandibular dysfunction(TMD), and who had all permanent teeth except third molar and the fifteen moderate group and the fifteen severe group classified according to Helkimo's dysfunction index among patients on the basis of the symptom of TMD were selected. The occlusal contact, occlusal force and occlusal interference in eccentric movement was studied and analyzed using T-Scan system. The result were as follows : 1. The TLR centering around midsagittal axis was located at $1.42{\pm}0.82mm$ in control group, $3.36{\pm}1.45mm$ in severe group, and as TMD was heavier, occlusal contact was located at the farther point from midsagittal axis. 2. The PLR from the first contact to the fifth contact centering around midsagittal axis was located at $1.73{\pm}1.78mm$ in control group, $3.36{\pm}1.41mm$ in moderate group, and $5.39{\pm}4.32mm$ in severe group, and as TMD was heavier, occlusal contact was located at the farther point from midsgittal axis. 3. The TFB, PFB, RFB and LFB of occlusal contact centering around incisal axis had no significant difference statistically among control group, moderate group, and severe group, and it was located at first molar. 4.The LF and RF was smaller in TMD group than in control group. 5. The LR moment of occlusal force centering around midsagittal axis was located at $178.51{\pm}139.81N.mm$ in control group, $466.25{\pm}296.47N.mm$ in moderate group, and $749.18{\pm}588.18N.mm$ in severe group. And as TMD was heavier, it was located at the farther point from midsagittal axis. 6. The RL and LL of occlusal force centering around incisal axis had not-significance statistically among control group, moderate group, and severe group, and it was at the first molar. 7. The number of occlusal interference of the eccentric movement was increased in the patients of TMD.

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The Effect of Lotus Root Powder on the Quality of Dasik (연근가루 첨가가 다식의 품질특성에 미치는 영향)

  • Yoon, Sook-Ja;Noh, Kwang-Seok;Jung, Sang-Eun
    • Korean journal of food and cookery science
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    • v.25 no.2
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    • pp.143-149
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    • 2009
  • The objective of this study was to evaluate the quality characteristics of lotus root Dasik prepared by different additions of lotus root powder (0%, 20%, 40%, 60%, 80%). As the level of lotus root powder in the formulation increased, the moisture contents of samples increased. Also, the L-, a-, and b-values of samples significantly decreased as the amount of lotus root powder increased. According to the results for mechanical characteristics, hardness, gumminess, springiness, cohesiveness, and chewiness decreased, whereas adhesiveness increased, as the amount of lotus root powder increased. The sensory evaluation results showed that the 40% lotus root sample received the highest preference scores; therefore, the 40% lotus root Dasik prepared with 60 g of flour, 40 g of lotus root powder, and 80 g of honey was chosen as the superior product.

Common Peroneal Neuropathy Treated with Acupuncture plus Electro-acupuncture: Case Report (총비골신경병증 환자에 대한 침 및 침전기 자극술 병용 치험 1례)

  • Lee, Sang Young;Shin, Hyun Kwon;Kim, Ki Yuk;Hwang, Choon Ho;Jung, Pil Sun;Kim, Hee Young;Go, Yong Jun;Jo, Hyun Jung;Park, Jae Suk;Sul, Jae Uk;Jo, Hee Guen
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.27 no.5
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    • pp.672-676
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    • 2013
  • The purpose of this study is to report that a patient suffered from Common Peroneal Neuropathy (CPN) caused by ankle sprain was improved by acupuncture plus electro-acupuncture. In this study, the patient was diagnosed with magnetic resonance image(MRI) and electomyography(EMG). We treated at acupoints ST36, ST41, SP9, GB34, GB39 and LR3 by acupuncture plus electro-acupuncture twice a day for 16 days; a total of 30 times. We used evaluation scale including muscle manual testing(MMT) and visual analogue scale (VAS). MMT changed from Grade 0 to Grade 5 and VAS changed from 10 to 2 after treatment for 16days with hospitalization. Though it is a case report, these results suggest that acupuncture and electrical acupuncture might have valid effect on CPN in controlled environment.

Negative noxiousness of aldosterone analogue-induced hypertension and inhibition of aldosterone by silver spike point electrical stimulation (Aldosterone 유도체-고혈압의 음성적 유해와 은침점전기자극의 aldosterone 억제)

  • Chon, Ki-Young;Kim, Jung-Hwan;Kim, Soon-Hee;Min, Kyung-Ok
    • Journal of Korean Physical Therapy Science
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    • v.10 no.2
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    • pp.199-207
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    • 2003
  • The present study examined that in vivo/vitro test is investigated in normotensive sham-operated rats(NSR) and aldosterone-analogue deoxycorticosterone acetate (DOCA)-salt hypertensive rats(ADHR) and that the antiliypertensive effect was induced by silver spike point(SSP) electrical stimulation at meridian points(CV-3, -4, Ki-12, SP-6, LR-3, BL-25, -28, -32, -52), specifically, such as aldosterone in 24 hour urine analysis from normal volunteer. The heart weight, the tickness of vascular wall, collagen fiber and the systolic blood pressure were significantly increased in ADHR than that in NSR. The required time of PSS-induced resting tone and the phosphorylation of stress-activated protein kinase/c-Jun N-terminal protein kinase(SAPK/JNK) were significantly increased in ADHR than that in NSR. However, the Kv currents were significantly decreased in ADHR than that in NSR. The current of 1 Hz continue type of SSP electrical stimulation significantly decreased in excretion of urine aldosterone from normal volunteer. These results suggest that the development of aldosterone analogue-induced hypertension is associated with changed heart weight, content of collagen fiber, tickness of vascular wall, blood pressure, resting tone, voltage-dependent K+ current(Kv) and phosphorylation of SAPK/JNK, which directly affects blood pressure. Therefore the hypertension is a risk factor on cerebrovascular disease. Moreover, These results suggest that the SSP electrical stimulation, especially current of 1 Hz continue type, significantly regulates excretion of urine aldosterone from volunteer.

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A Study on Osteoarthritis of the Knee (슬관절(膝關節)의 퇴행성 관절염에 대한 고찰)

  • Jang Jun-Huk;Kim Kyeng-Ho
    • Journal of Acupuncture Research
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    • v.15 no.2
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    • pp.493-509
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    • 1998
  • Osteoarthritis(degenerative joint disease), the most common arthropathy affecting the aged people, is characterized by degeneration of articular cartilage with proliferation and remodeling of subchondral bone. Osteoarthritis of the knee, which probably has greater social cost and more associated disability than osteoarthritis of any other joint, prevalence is known to increase with age, and females have higher rates than males; radiographic abnormalities are present in more than 30% of persons more than 65 years old, with approximately 40% of these persons symptomatic. Though the etiology of osteoarthritis is not entirely understood, much information is available regarding risk factors for the development of knee osteoarthritis that permit some reasonable guideline for preventive strategies. Traumatic damage or occupational or recreational overuse of knee joint may result in osteoarthritis, and obesity also is related to osteoarthritis of the knee. A variety of other possible risk factors for the development of knee osteoarthritis have been proposed, including increased bone mass, smoking, diseases such as diabetes or elevated serum uric acid, and some metabolic factors, but the contribustions of these and other factors such as smoking or race and diseases such as diabetes are as yet undetermined. The usual clinical manifestations include pain, stiffnesss, crepitus and loss of function. In oriental medicine, osteoarthritis of the knee is very similar to diseases such as Bijung(痺症), Haksulpung(鶴膝風), Youkjeolpung(歷節風) in symptoms. The diseases such as Bijung(痺症), Haksuipung(鶴膝風), Youkjeolpung(歷節風) is related to the of function liver(肝) and kidney(腎) and risk factors are regarded as Pung(風), Han(寒), sub(濕). The diagnosis of osteoarthritis of the knee has often been based on radiographic appearance and clinical manifestations. The acupuncture therapy of osteoarthritis of the knee has often been based on Stomach meridian(ST), Spleen meridian(SP), Kidney meridian(KI), Liver meridian(LR).

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Two Cases of Dystonia and Chorea in Basal Ganglia (기저핵병변(基底核病變)에 의(依)한 불수의운동(不隨意運動) 환자(患者) 2례(例)에 대(對)한 임상보고(臨床報告))

  • Kim, Gi-Yeol;Kim, Jong-Dae;Jeong, Ji-Cheon
    • Korean Journal of Oriental Medicine
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    • v.3 no.1
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    • pp.215-228
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    • 1997
  • Extrapyramidal movement disorders are divided descriptively into hypokinesias(such as parkinsonism), characterized by poverty and slowness of movement : hyperkinesias(such as chorea, athetosis, dystonia, ballism, etc.), manifested by abnormal involuntary movement. Chorea refers to widespread arrythythmic movements of a forcible, rapid, jerky, restless type Choreic movements are noted for their irregularity and variability. They are generally continuous, may be simple or quite elaborate, and affect any part of the body. Dystonla refers to abnormally increased muscular tone that causes fixed abnormal postures. Some patients with dystonia also have shifting postures, resulting from irregular, forceful twisting movement that affect trunk and produce bizarre, grotesque movements and positions of the body. The most frequent and familiar type of focal dystonia is spasmodic torticollis. It consists of an involuntary turning of the head to one side - intermittent at first, then gradually worsening to the point of being more or loss continuous. The combination of blepharospasm and oromandibular dystonia is sometimes refered to as Meige's syndrome. We report two patients with dystonia and chorea in cerebral infarction at basal ganglia. We have experienced good improvement by the oriental medicine and acupuncture treatment.'rho acupuncture points of LI 4, ST 36, TE 3, GB 34, GB 41, LR 3, GB 39 were used. The therapies of herb-medicine were treated by Zibu-Ganshen(滋補肝腎), Huoxue-Xifeng-Tongluo(活血息風通絡).

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The Prevalence and Genotype of Human Papillomavirus from Patients with Genital Warts in Eastern Guangdong Province

  • Luo, Zhao-Yun;Chen, Qiang;Yang, Hui;Lin, Min;Chen, Chan-Yu;Yang, Chun;Yang, Li-Ye
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.14
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    • pp.5675-5679
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    • 2015
  • Background: Low-risk human papillomavirus (LR-HPV) infection is the main cause of genital warts. LRHPV genotypes 6 and 11 are associated with genital warts, but there have only been a few published studies about the genotype-specific prevalence of HPV in genital warts in China. The objective of our study was to assess the prevalence of HPV genotypes for clinical cases involving both men and women and to evaluate the potential benefit of a quadrivalent (genotypes 6, 11, 16, and 18) HPV vaccine in eastern Guangdong province of China. Materials and Methods: A total of 696 eligible patients with genital warts were enrolled during the period Aug 2009 through Oct 2014. Specimens were collected from genital warts, the HPV GenoArray test was used for HPV detection and genotyping, which could detect 21 HPV genotypes, including genotypes 6, 11, 16, and 18. Results: Among the 696 cases, 675 samples were successfully genotyped. The median age of patients was 32.1 years (range, 16-67 years). The most prevalent genotypes were HPV-6 (285/675, 42.2%), HPV-11 (265/675, 39.3%), HPV-52 (52/675, 7.7%), HPV-16 (51/675, 7.56%), HPV-81 (50/675, 7.40%) and HPV-58 (37/675, 5.48%). Low-risk genotypes predominated, with a prevalence of 96.59%. The cumulative prevalence of genotypes 6 and 11 was 78.7% (531/675), the cumulative prevalence of genotypes 16 and 18 was 11.6% (78/675), and the cumulative prevalence of genotypes 6, 11, 16, and 18 was 82.5% (557/675). Conclusions: Our results provide strong evidence that, in eastern Guangdong, different from Western countries, the most prevalent low risk HPV genotypes in patients with genital warts are 6, 11 and 81. The quadrivalent HPV vaccine could prevent 82.5% of genital warts in eastern Guangdong.