• Title/Summary/Keyword: Loss factor

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Design of a Microwave Bias-Tee Using Lumped Elements with a Wideband Characteristic for a High Power Amplifier (광대역 특성을 갖는 집중 소자를 이용한 고출력 증폭기용 마이크로파 바이어스-티의 설계)

  • Oh, Hyun-Seok;Jeong, Hae-Chang;Yeom, Kyung-Whan
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.22 no.7
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    • pp.683-693
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    • 2011
  • In this paper, a design of high current and broad-band microwave bias-tee was presented for a stable bias of a high power amplifier. An input impedance of bias-tee should be shown to 50 ohm with the wideband in order to be stably-biased the amplifier. For this design of the bias-tee, a capacitor of bias-tee for a DC block was designed with a high wide-band admittance by a parallel sum of capacitors, and a inductor for a RF choke and a DC feeding was designed with a high wide-band impedance by a series sum of inductors. As this inductor and capacitor for the sum has each SRF, band-limitation of lumped element was driven from SRF. This limitation was overcome by control of a resonance's quality factor with adding a resistor. 1608 SMD chips for design's element was mounted on the this pattern for the designed bias-tee. The fabricated bias-tee presented 10 dB of return loss and wide-band about 50 ohm input impedance at 10 MHz~10 GHz.

Piezoelectric Properties of 0.94(Na0.5K0.5)NbO3-0.06(Sr0.5Ca0.5)TiO3 with 0.1 MnO2 Addition at Varying Sintering Temperatures (소결 온도에 따른 0.94(Na0.5K0.5)NbO3-0.06(Sr0.5Ca0.5)TiO3-0.1 MnO2의 압전 특성)

  • Jung, Hye-Rin;Lee, Sung-Gap;Lee, Tae-Ho;Kim, Min-Ho;Jo, Ye-Won
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.27 no.1
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    • pp.14-17
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    • 2014
  • In this study, lead-free Piezoelectric $(Na_{0.47}K_{0.47}Sr_{0.03}Ca_{0.03})(Nb_{0.94}Ti_{0.06})O_3$-0.1 $MnO_2$ ceramics were fabricated using mixed oxide method and the effects of various sintering temperature on the structural and electrical properties were investigated. For the $(Na_{0.47}K_{0.47}Sr_{0.03}Ca_{0.03})(Nb_{0.94}Ti_{0.06})O_3$-0.1 $MnO_2$ (NKN-SCT-$MnO_2$) ceramics sintered at temperatures of $1,025{\sim}1,100^{\circ}C$. The results indicated that all specimens were perovskite single phase formation without any second phase. It has been shown that relative density is increased to increasing sintering temperature. When the sintered temperature at $1,075^{\circ}C$, highest sintered density and maximum value of $4.45g/cm^3$. Average grain size is increased to increasing sintering temperature. The electromechanical coupling factor, dielectric constant, dielectric loss, d33 and curie temperature at the sintering temperature $1,075^{\circ}C$ of NKN-SCT-$MnO_2$ specimens were 0.22, 511, 0.033, 103 and $380^{\circ}C$, respectively.

Periodontal wound healing following reciprocal autologous root transplantation in class III furcation defects

  • Takeuchi, Naoshi;Shirakata, Yoshinori;Shinohara, Yukiya;Sena, Kotaro;Noguchi, Kazuyuki
    • Journal of Periodontal and Implant Science
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    • v.47 no.6
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    • pp.352-362
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    • 2017
  • Purpose: Furcation involvement in the molars is difficult to treat, and has been recognized as a risk factor for tooth loss. Although periodontal regenerative therapies, including guided tissue regeneration and various types of bone grafts, have been applied to furcation defects, the effects of these treatments are limited, especially in large class III furcation defects. The purpose of this pilot study was to investigate the effect of reciprocal autologous root transplantation on periodontal wound healing and regeneration in class III furcation defects in dogs. Methods: Furcation defects (7 mm wide and 6 mm high) were surgically created after root separation of the unilateral third and fourth premolars in 4 dogs. Eight furcation defects were randomized to receive either reciprocal autologous root transplantation (test) or no further treatment (control). In the test group, the mesial and distal roots were transplanted into the distal and mesial extraction sockets, respectively. The animals were sacrificed 10 weeks after surgery for histologic evaluation. Results: The healing pattern in the control group was characterized by extensive collapse of the flap and limited periodontal regeneration. New bone formation in the test group ($3.56{\pm}0.57mm$) was significantly greater than in the control group ($0.62{\pm}0.21mm$). Dense collagen fibers inserting into the residual cementum on the transplanted root surfaces were observed in the test group. Slight ankylosis was observed in 2 of the 4 specimens in the test group on the mesiodistal sides where the root-planed surfaces faced the existing bone. Root resorption (RR) was detected in both the control and test groups. Conclusions: Within the limits of this study, it can be concluded that reciprocal autologous root transplantation was effective for bone regeneration in class III furcation defects in dogs. However, further studies are required to standardize the approach in order to prevent unwanted RR prior to clinical application.

Retreatment of fractured implant overdenture due to long-term maintenance failure (장기간의 유지관리 실패로 인해 파절된 임플란트 피개의치 재수복 증례)

  • Kim, Minjee;Hong, Seoungjin;Paek, Janghyun;Noh, Kwantae;Pae, Ahran;Kim, Hyeong-Seob;Kwon, Kung-Rock
    • The Journal of Korean Academy of Prosthodontics
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    • v.56 no.3
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    • pp.235-242
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    • 2018
  • Periodontal and prosthodontic maintenance of implant overdenture is a very important factor for the long term success of the prosthesis and implants. Failure of maintenance can lead to prosthetic failure due to peri-implant bone loss and fracture and wear of the prosthesis or components. In this case, the existing gold milled bars were reconstructed with cobalt chrome milled bar in a manner that does not interfere with the external shape for the retreatment of fractured implant overdenture by maintenance failure. Two implants of mandible were selected strategically and the CM LOC attachments were connected to the two implants, and implant overdentures were fabricated. As a result, prosthesis with a functional and esthetic design that facilitates good hygiene management of the patient was delivered, which is advantageous for long term maintenance, and regular check-ups were scheduled for proper maintenance.

Response of Muscle Protein Synthesis to the Infusion of Insulin-like Growth Factor-I and Fasting in Young Chickens

  • Kita, K.;Shibata, T.;Aman Yaman, M.;Nagao, K.;Okumura, J.
    • Asian-Australasian Journal of Animal Sciences
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    • v.15 no.12
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    • pp.1760-1764
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    • 2002
  • In order to elucidate the physiological function of circulating IGF-I on muscle protein synthesis in the chicken under malnutritional conditions, we administrated recombinant chicken IGF-I using a osmotic mini pump to fasted young chickens and measured the rate of muscle protein synthesis and plasma metabolite. The pumps delivered IGF-I at the rate of $22{\mu}g/d\{300{\mu}g{\cdot}(kg\;body\;weight{\cdot}d)^{-1}\}$. Fractional rate of protein synthesis in the muscle was measured using a large dose injection of L-[$2,6-^3H$]phenylalanine. Constant infusion of chicken IGF-I did not affect plasma glucose level. Significant interaction between dietary treatment and IGF-I infusion was observed in plasma NEFA and total cholesterol concentrations. When chicks were fasted, IGF-I infusion decreased plasma NEFA and total cholesterol concentrations. On the other hand, IGF-I administration did not affect plasma levels of both metabolites. Fasting reduced plasma triglyceride concentration significantly. IGF-I infusion also decreased the level of plasma triglyceride. Plasma IGF-I concentration of young chickens was halved by fasting for 1 d. IGF-I infusion using an osmotic minipump for 1 d increased plasma IGF-I concentration in fasted chicks to the level of fed chicks. Fasting decreased body weight and the loss of body weight was significantly ameliorated by IGF-I infusion. There was a significant interaction between dietary treatment and IGF-I infusion in the fractional rate of breast muscle protein synthesis. There was no effect of IGF-I infusion on muscle protein synthesis in fed chicks. Muscle protein synthesis reduced by fasting was ameliorated by IGF-I infusion, but did not reach to the level of fed control. Muscle weight of fasted chicks infused with IGF-I was similar to fasted birds without IGF-I infusion, which suggests that muscle protein degradation would be increased by IGF-I infusion as well as protein synthesis in fasted chicks.

Evaluation of available energy and total tract digestibility of acid-hydrolyzed ether extract of cottonseed oil for growing pigs by the difference and regression methods

  • Zhao, Jinbiao;Li, Zhongchao;Lyu, Mingbin;Liu, Ling;Piao, Xiangshu;Li, Defa
    • Asian-Australasian Journal of Animal Sciences
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    • v.30 no.5
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    • pp.712-719
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    • 2017
  • Objective: The objective of this study was to determine the effect of inclusion level on the digestible energy (DE), metabolizable energy (ME), and total tract digestibility of acid-hydrolyzed ether extract (AEE) of cottonseed oil when fed to growing pigs. Methods: Forty-two barrows (initial body weight = $35.51{\pm}2.01kg$) were randomly allotted to a completely randomized design with a corn-soybean meal basal diet, five levels of cottonseed oil (2%, 4%, 6%, 8%, and 10%) and a 10% soybean oil diet. Each diet was replicated six times with one pig per replicate. The experiment lasted 19 days, 7 d for cage adaptation, 7 d for diets adaptation and last 5 d for feces and urine collection. The energy values and apparent total tract digestibility (ATTD) of cottonseed oil and soybean oil were calculated by the difference method, and regression equations were established to predict the energy values of cottonseed oil. The apparent digested fat of the entire intestinal tract was also regressed against dietary fat intake to determine the true total tract digestibility (TTTD) and endogenous loss of fat for cottonseed oil. Results: The results showed that the DE and ME contents of cottonseed oil were not different as the inclusion level increased. The DE and ME values determined by the regression equation were 36.28 MJ/kg and 34.96 MJ/kg, respectively, and the values were similar to the mean DE and ME values calculated by the difference method (36.18 and 35.56 MJ/kg, respectively). The ATTD of cottonseed oil was also not affected by the inclusion level of cottonseed oil, and the TTTD and EFL determined by the regression method were 92.40% and 13.83 g/kg of dry matter intake for corn-soybean basal diet. The DE, ME, and ATTD of AEE in soybean oil determined by the difference method were 35.70 MJ/kg, 35.20 MJ/kg and 92.31%, respectively. There were no differences in the DE, ME, and ATTD between cottonseed oil and soybean oil, although the ratio of unsaturated to saturated fatty acids for soybean oil was higher than for cottonseed oil. Conclusion: The DE, ME, and ATTD values of cottonseed oil were not affected by its dietary inclusion level. The energy values of cottonseed oil determined by the difference and regression methods were similar. Furthermore, the ratio of unsaturated to saturated fatty acid for oils was not the decisive factor to influence the energy values and ATTD of oils.

Clinical Characteristics and Helicobacter pylori Status of Gastric Cancer in Thailand

  • Vilaichone, Ratha-Korn;Panarat, Wirat;Aekpongpaisit, Surasak;Mahachai, Voracha
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.20
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    • pp.9005-9008
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    • 2014
  • Background: Gastric cancer is the second leading course of cancer death worldwide and H. pylori infection is an important risk factor for gastric cancer development. This study was design to evaluate the clinical, pathological features, survival rate and prevalence of H. pylori infection in gastric cancer in Thailand. Materials and Methods: Clinical information, histological features, endoscopic findings and H. pylori status were collected from gastric cancer patients from Thammasat university hospital during June 1996-December 2011. H. pylori infection was assessed by histological evaluation, rapid urease test and serological test. Clinical information, endoscopic findings and histopathology of all patients were recorded and compared between patients with active or non-active H. pylori infection. Results: A total of 100 gastric cancer patients (55 men and 45 women with mean age of $55{\pm}16.8years$) were enrolled in this study. Common presenting symptoms were dyspepsia (74%), weight loss (66%), anemia (63%) and anorexia (38%). Mean duration of symptoms prior to diagnosis was 98 days. Overall prevalence of H. pylori infection was 83% and active H. pylori infection was 40%. 1-year and 5-year survival rates were 43% and 0%. There was no significant difference between active H. pylori infection in different locations (proximal vs non-proximal: 47.1% vs 48.5%; P-value = 0.9, OR=0.9; 95%CI=0.3-3.1) and histology of gastric cancer (diffuse type vs intestinal type: 47.4% vs 50%; P-value = 0.8, OR=0.9, 95%CI=0.3-2.7). However, linitis plastica was significantly more common in non-active than active H. pylori infection (27.9% vs 0%; P-value<0.0001, OR=13.3, 95%CI=3.2-64.5). Moreover, gastric cancer stage 4 was higher in non-active than active H. pylori infection (93% vs 50%, P-value<0.001). Conclusions: Prevalence of H. pylori infection in Thai gastric cancer patients was high but active infection was low. Most gastric cancer patients presented in advance stage and had a grave prognosis. Screening for gastric cancer in high risk individuals might be an appropriate tool for early detection and improve the treatment outcome for this particular disease in Thailand.

A study on the efficiency advancement for evacuation of the crews by ship structural improvement (선박 구조 개선을 통한 승무원의 피난 효율 향상을 위한 연구)

  • Kim, Wonouk;Lee, Myoungho;Kim, Jongsu
    • Journal of Advanced Marine Engineering and Technology
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    • v.38 no.3
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    • pp.342-348
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    • 2014
  • Onshore great fires can normally be extinguished by firefighters using special firefighting equipment and its suitable method. However, offshore fires on the ships are to be extinguished by the crew without any supports from the onshore. Also, crews working on board are exposed to high risk of emergency evacuation due to the complicated structure arrangement of the ships and different accident types such as fire and ship collisions. As most of damage and loss of life in fire are associated with suffocation, shortening of evacuation time is an important factor to improve a survival rate. In this study, visibility in the accommodation area is analyzed by using the temperature and smoke flow which are obtained by the Fire Dynamic Simulator(FDS) as a Three-Dimensional Fire Analysis program to understand the survival rate of the crew upon the fire. The fire doors for most of ships are designed to close automatically when the fire alarm is activated. These automatic closing of the fire doors is a very effective system to delay the spread of flame and smoke flow for the unmanned spaces of the fire protected area. However, if the crew cannot escape within the estimated time, the crew inside the fire protected area will be damaged a lot. In this paper, the comparative analysis between the evacuations by using the fire door from the fire protected area and the suggested fire shielding structure in this study is carried out by the smoke flow rate and the temperature rise rate.

Impact of Tumor Length on Survival for Patients with Resected Esophageal Cancer

  • Mirinezhad, Seyed Kazem;Jangjoo, Amir Ghasemi;Seyednejad, Farshad;Naseri, Ali Reza;Mohammadzadeh, Mohammad;Nasiri, Behnam;Eftekharsadat, Amir Taher;Farhang, Sara;Somi, Mohammad Hossein
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.2
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    • pp.691-694
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    • 2014
  • Background: Tumor length in patients with esophageal cancer (EC) has recently received great attention. However, its prognostic role for EC is controversial. The purpose of our study was to characterize the prognostic value of tumor length in EC patients and offer the optimum cut-off point of tumor length by reliable statistical methods. Materials and Methods: A retrospective analysis was conducted on 71 consecutive patients with EC who underwent surgery. ROC curve analysis was used to determine the optimal cut-off point for tumor length, measured with a handheld ruler after formalin fixation. Correlations between tumor length and other factors were surveyed, and overall survival (OS) rates were compared between the two groups. Potential prognostic factors were evaluated by univariate Kaplan-Meier survival analysis. A P value less than 0.05 was considered significant. Results: There were a total of 71 patients, with a male/female divide of 43/28 and a median age of 59. Characteristics were as follows: squamous/adenocarcinoma, 65/6; median tumor length, 4 (0.9-10); cut-off point for tumor length, 4cm. Univariate analysis prognostic factors were tumor length and modality of therapy. One, three and five year OS rates were 84, 43 and 43% for tumors with ${\leq}4cm$ length, whereas the rates were 75, 9 and 0% for tumors >4 cm. There was a significant association between tumor length and age, sex, weight loss, tumor site, histology, T and N scores, differentiation, stage, modality of therapy and longitudinal margin involvement. Conclusions: Future studies for modification of the EC staging system might consider tumor length too as it is an important prognostic factor. Further assessment with larger prospective datasets and practical methods (such as endoscopy) is needed to establish an optimal cut-off point for tumor length.

An Analysis of Tendencies of Studies on Herbal Acupuncture - Focusing on domestic theses since 2001 about anti-inflammation, pain relief and anti-obesity effects, including safety- (약침(藥鍼)의 연구 동향에 대한 분석 - 항염(抗炎) ${\cdot}$ 진통(鎭痛) ${\cdot}$ 비만(肥滿) 및 안전성(安全性)에 관한 연구를 중심으로 -)

  • Kang, Jun-Hyuk;Heo, Dong-Seok;Yoon, Il-Ji;Oh, Min-Seok
    • The Journal of Korean Medicine
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    • v.28 no.2 s.70
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    • pp.93-113
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    • 2007
  • Objective : To research Trends of studies about anti-inflammation and pain relief, obesity, and safety of herbal acupuncture therapy by analyzing domestic theses, published since 2001, about herbal acupuncture therapy. Methods : Domestic theses, published since 2001, mentioning anti-inflammation or pain relief, obesity, or safety of herbal acupuncture therapy were reviewed and analyzed. These theses were then classified by university, year, and subject. Results : The following results were obtained in this study. 1. Among published theses related to anti-inflammation effects of herbal-acupuncture, studies about arthritis comprised the most part, 52. In theses relating to causes of arthritis, 16 were about adjuvant, which was the most, followed by Type II collagen, LPS and carrageenan. Blood test, reactions of inflammation and revelation of cytokine and immune cellswere methods for evaluating anti-inflammation effect. The tendency of experimental methods was to focus on molecular biologic method. 2. In theses related to pain relief, many clinical attempts with herbal injection were carried out, and Carthami Flos and Scolopendrawere used most. Observing reduction of pain inducing factor and checking behavioral change were methods for evaluating pain relief. 3. In theses related to obesity, research focused on effects in association with spots on the body suitable for acupuncture. There were also attempts comparing effectiveness between single injections and complex injections. Astraball Radix, Angelica Gigantis Radix, Coicis Semen and Taeumjowetang were used. Evaluation of anti-obesity effects were by weight loss, food efficiency, blood lipid profile and evaluation of liver function. 4. In theses related to safety of herbal-acupuncture, Herba Chelidonii Chaenonelis Fructus, Clematis Florida Thunb, Corydalidis Tuber, Paeoniae Radix, and Carthami Flos which marked 2 theses each were most studied. Methods of evaluating safety were mostly by observing liver and kidney functions based on blood test, and by applying herbal injections to clinical treatment. Conclusion : Herbal acupuncture is being used in various ways associating with its anti-inflammation, pain relief and anti-obesity effect. Studies on efficacy and mechanism of herbal acupuncture are being conducted even at the molecular biology level.

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