• Title/Summary/Keyword: Silent

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Shape Optimization of a Switched Reluctance Motor Having 6/4 Pole Structure for the Reduction of Torque Ripple Using Response Surface Methodology (반응표면법을 이용한 6/4극 구조를 갖는 스위치드 릴럭턴스 모터의 토크 리플 저감을 위한 형상 최적설계)

  • Choi, Yong-Kwon;Yoon, Hee-Sung;Koh, Chang-Seop
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.55 no.12
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    • pp.608-616
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    • 2006
  • Recently, a switched reluctance motor is widely used in various industries because it has many advantages such as a simple structure, robustness, less maintenance, high torque/weight ratio, and easy speed control over other types of motors. However, a switched reluctance motor inherently produces acoustic noise and vibration caused by torque ripple. Applications of these motors where silent operation is desirable have thus been limited. In this paper, a new stator pole face having a non-uniform air-gap and a pole shoe attached to the lateral face of the rotor pole are suggested in order to minimize torque ripple. The effects of each design parameter are validated using a time-stepping finite element method. The parameters are optimized by utilizing response surface method (RSM) combined with (1+1) evolution strategy. The result shows that the optimized shape gives higher average torque and drastically reduced torque ripple.

Development of a Low Noise and High Efficiency Rotary Compressor with a New Muffler (신규 저소음 및 고효율 머플러 적용 회전식 압축기 개발)

  • Jarng, In-Sun;Kim, Bong-Jun;Youn, Young;Sung, Choon-Mo;Lee, Seung-Kap
    • The KSFM Journal of Fluid Machinery
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    • v.8 no.2 s.29
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    • pp.23-30
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    • 2005
  • The rotary compressor is widely used in the air conditioner because it is efficient and compact. Recently, the need for silent and efficient compressors is much stronger than the past. The new type muffler was invented to reduce the noise level and to improve the efficiency. The new type muffler that has two side discharge holes and dome shape resulted in much lower overall noise level, especially noise levels around 1kHz than the old type one of one center discharge hole in the acoustic spectra. Also it showed a higher efficiency of air conditioner by lowering oil discharging amount of a compressor than old type one of a rectangular shape and two side discharge holes. The noise reduction and efficiency improvement by the new type muffler were verified by tests for votary compressors and air conditioners.

Liver abscess and septic complications associated with advanced gastric cancer (간농양에 의한 패혈성 합병증과 동반된 진행성 위암)

  • Youn, Gun Jung;Choi, Young;Kim, Min Jae;Lee, Jae Sin;Ko, Ui Won;Joo, Yeon Ho
    • Journal of Yeungnam Medical Science
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    • v.32 no.1
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    • pp.38-41
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    • 2015
  • Pyogenic liver abscess with metastatic septic complications is a rare and serious infectious disease if not treated properly. Pyogenic liver abscesses are caused by bacterial, fungal, or parasitic organisms. Escherichia coli used to be the predominant causative agent, but Klebsiella pneumoniae emerged as a major cause in the 1990s. Liver abscesses are caused by hepatic invasion via many routes, such as, the biliary tree, portal vein, hepatic artery, direct extension, or penetrating trauma. Furthermore, diabetes mellitus and malignant conditions are established important risk factors of K. pneumoniae liver abscesses and of septic metastasis, and several recent studies have asserted that K. pneumoniae liver abscess might be a presentation of occult or silent colon cancer. We report a case of K. pneumoniae liver abscess, metastatic septic pulmonary embolism, and endophthalmitis associated with diabetes and advanced gastric cancer.

The Effects of Avoidance of the Contacts under the CISG - Focusing on Duty of Restoring to the Original State - (CISG상 계약해제의 효과 - 원상회복의무를 중심으로 -)

  • Sur, Ji Min
    • THE INTERNATIONAL COMMERCE & LAW REVIEW
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    • v.63
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    • pp.25-62
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    • 2014
  • Avoidance refers to the process of terminating a contract because of a non-performance. It implies the right of the aggrieved party to refuse to accept further performance by the other side and to refuse to perform one's own counter-obligations, on a permanent basis. The 1980 U.N. Convention on the International Sale of Goods, hereinafter 'CISG', regulates in Arts. 81-84 the effects of avoidance. The primary effect is that prescribed in Art. 81.1 CISG: both parties are released from their obligations under the contract, subject to any damages which may be due. As seen, the CISG deals with the legal consequences of avoidance, including restitutionary claims. However, a closer look to CISG provisions on restitution reveals that certain matters are left open. For instance, the CISG leaves open questions such as the costs, place and time where restitution is to be made. In this particular, the Convention remains silent as to the consequences of a delayed or refused restitution or the buyer's liability when the goods are damaged or destroyed after the avoidance. In light of the above, the present article attempts to determine the extent to which the modes of restitution are regulated in the CISG and how possible gaps are to be filled.

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Polyamines and Their Metabolites as Diagnostic Markers of Human Diseases

  • Park, Myung Hee;Igarashi, Kazuei
    • Biomolecules & Therapeutics
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    • v.21 no.1
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    • pp.1-9
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    • 2013
  • Polyamines, putrescine, spermidine and spermine, are ubiquitous in living cells and are essential for eukaryotic cell growth. These polycations interact with negatively charged molecules such as DNA, RNA, acidic proteins and phospholipids and modulate various cellular functions including macromolecular synthesis. Dysregulation of the polyamine pathway leads to pathological conditions including cancer, inflammation, stroke, renal failure and diabetes. Increase in polyamines and polyamine synthesis enzymes is often associated with tumor growth, and urinary and plasma contents of polyamines and their metabolites have been investigated as diagnostic markers for cancers. Of these, diacetylated derivatives of spermidine and spermine are elevated in the urine of cancer patients and present potential markers for early detection. Enhanced catabolism of cellular polyamines by polyamine oxidases (PAO), spermine oxidase (SMO) or acetylpolyamine oxidase (AcPAO), increases cellular oxidative stress and generates hydrogen peroxide and a reactive toxic metabolite, acrolein, which covalently incorporates into lysine residues of cellular proteins. Levels of protein-conjuagated acrolein (PC-Acro) and polyamine oxidizing enzymes were increased in the locus of brain infarction and in plasma in a mouse model of stroke and also in the plasma of stroke patients. When the combined measurements of PC-Acro, interleukin 6 (IL-6), and C-reactive protein (CRP) were evaluated, even silent brain infarction (SBI) was detected with high sensitivity and specificity. Considering that there are no reliable biochemical markers for early stage of stroke, PC-Acro and PAOs present promising markers. Thus the polyamine metabolites in plasma or urine provide useful tools in early diagnosis of cancer and stroke.

Identification of functional SNPs in genes and their effects on plant phenotypes

  • Huq, Md. Amdadul;Akter, Shahina;Nou, Ill Sup;Kim, Hoy Taek;Jung, Yu Jin;Kang, Kwon Kyoo
    • Journal of Plant Biotechnology
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    • v.43 no.1
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    • pp.1-11
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    • 2016
  • Single nucleotide polymorphism (SNP) is an abundant form of genetic variation within individuals of species. DNA polymorphism can arise throughout the whole genome at different frequencies in different species. SNP may cause phenotypic diversity among individuals, such as individuals with different color of plants or fruits, fruit size, ripening, flowering time adaptation, quality of crops, grain yields, or tolerance to various abiotic and biotic factors. SNP may result in changes in amino acids in the exon of a gene (asynonymous). SNP can also be silent (present in coding region but synonymous). It may simply occur in the noncoding regions without having any effect. SNP may influence the promoter activity for gene expression and finally produce functional protein through transcription. Therefore, the identification of functional SNP in genes and analysis of their effects on phenotype may lead to better understanding of their impact on gene function for varietal improvement. In this mini-review, we focused on evidences revealing the role of functional SNPs in genes and their phenotypic effects for the purpose of crop improvements.

A study on the Noise Reduction of Vane-type Vacuum pump Mounted on Alternator using Design of Experiments (실험계획법을 이용한 교류발전기 부착형 진공펌프의 소음저감에 관한 연구)

  • Park, Soon-Sik;Kim, Yong-Chan;Kim, Byoung-Duk
    • Tribology and Lubricants
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    • v.23 no.5
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    • pp.234-239
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    • 2007
  • Recently one of the automobile customer's greatest concerns is quietness in a vehicle along with various functional requirements such as comfort, stability, mobility etc. Therefore car makers place more weight on vehicle noise. Especially, in the case of diesel engine, as the noise level of engine becomes more silent by the development of engineering technology. The noise of alternator with vacuum pump has been able to be noticed enough becoming an issue on vehicles. In this study vacuum pump noise on alternator was identified andclassified into five types. DOE was applied to induce the statistical analysis result to reduce the vacuum pump noise. It was done by subjective listening. Design and statistical analysis are done with Minitab software. This work provides dominant elements of vacuum pump noise on alternator and can be the basis of furture studies.

A STUDY ON MUTATIONS OF P53 TUMOR SUPPRESSOR GENE IN ORAL TUMORS (구강종양에서 p53 종양억제 유전자의 돌연변이에 관한 연구)

  • Joo, Seong-Chai;Pyo, Sung-Woon
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.26 no.1
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    • pp.45-52
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    • 2000
  • Nowadays, there are a lot of evidence that mutation of the p53 tumor suppressor gene is one of the most common genetic abnormalities in neoplastic progression. In this study, we analyzed 20 specimens of oral tumors(squamous cell carcinoma 14 cases, ameloblastoma 3 cases, adenoid cystic carcinoma 2 cases, malignant schwannoma 1 case)using polymerase chain reaction and direct sequencing which used an automated DNA sequencer and software for detection of mutations. Polymerase chain reactions were performed with 4 sets of primers encompassing exon 5, 6, 7, 8, and direct sequencing method was employed. The results were as followings. 1. We detected 10 point mutations out of 20 specimens (50%). 2. The genetic alterations included 7 mis-sense mutations resulting in single amino acid subtitutions, 2 silent mutations, 1 non-sense mutations encoding a stop codon. 3. Mutations were mostly in exon 7(7 out of 10 mutations, 70%) and involved codons 225, 234, 235, 236, 238, 247. 4. Therse were 4 cases of $T{\rightarrow}A$ transversion, 2 cases of $C{\rightarrow}A$ transversion, $A{\rightarrow}G$ transition, 1 case of $C{\rightarrow}G$, $T{\rightarrow}G$ transversion respectively. 5. We could find out point mutations more conveniently using PCR - Automated Direct Sequencing method.

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Ozone Generation Synergy Effects of Three-Phase Voltage Apply Type Superposed Discharge Ozonizer (3상 전압인가형 중첩방전 오존발생기의 오존생성 상승효과)

  • Lee, Byeong-Jun;Lee, Sang-Geun;Song, Hyeon-Jik;Kim, Yeong-Hun;Park, Won-Ju;Lee, Gwang-Sik
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.49 no.8
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    • pp.468-476
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    • 2000
  • Nowadays, ozone is mainly utilized for water treatment and home equipments. Although the demand for ozone is increasing, the ozone yield of silent discharge type ozonizer is low. Therefore, it is expected to improve the energy efficiency and ozone yield of an ozonizer. In this paper, a new ozone generation system is proposed. The 60[Hz] three-phase voltage is applied to three-phase superposed discharge type ozonizer(3PSDO) which has three electrodes(central, internal and external electrodes). There is no discharge pause time when three-phase voltage is applied due to 120-degree phase difference of applied voltage. The synergy effect of the three-phase superposed discharge type ozonizer is investigated by comparing with the three sort of single-phase discharge type ozonizer(1PDO). So, three-phase superposed discharge type ozonizer is able to obtain high ozone yield, and optimize discharge space, because this can increase the discharge power at low applied voltage.

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The Charecteristics of Superposed Discharge Type Ozonizing System Considering the Change of Temperature of. the Supplied Gas (원료가스의 온도변화를 고려한 중첩방전형 오존발생장치의 특성)

  • Lee, Sang-Keun;Song, Hyun-Jig;Chun, Byung-Joon;Kim, Yeong-Hun;Kim, Sang-Gu;Park, Won-Zoo;Lee, Kwang-Sik
    • Proceedings of the KIEE Conference
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    • 1998.07e
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    • pp.1705-1707
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    • 1998
  • In this paper, a superposed discharge type ozonizer was designed and manufactured. The ozonizer is equipped with three electrodes : central electrode, internal electrode and external electrode, and it consists of two gaps. The ozone is generated by superposing silent discharge, which are respectively generated betweens two gaps. This paper describes the following two characteristics : (1) 'the characteristics of discharge with variation with output voltage of AC High Voltage source, quantity of the supplied gas and discharge voltage (2) the characteristics of ozone discharge power, temperature of the supplied gas.

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