• Journal of Mechanical Science and Technology
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• v.15 no.2
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• pp.225-231
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• 2001

A mathematical model for the analysis of roll gap phenomena in the strip temper rolling process is described. A new approach to solve the roll indentation and diverging problem in modeling of severe temper rolling cases is obtained by adopting the preliminary displacement principle of two contacted rough bodies to describe the friction behavior in the roll gap. The mechanical peculiarities of the temper rolling process, such as a high friction value with high roughness rolls and a non-circular contact arc, low reduction and non-negligible entry and exit elastic zones as well as central preliminary displacement zone etc., are all taken into account. The deformation of work rolls is calculated with the influence function method and an arbitrary contact are shape is permitted. The strip deformation is modeled by the slab method and the entry and exit elastic deformation zones are included. The preliminary displacement principle is used to determine the boundaries and to calculate the friction of the central preliminary displacement zone. The model is calibrated against the production mill data and installed in the setup computer of a temper rolling mill in POSCO. The validity and precision of the model have been proven through a comparison of the measured roll forces and the predicted ones.

• Advances in aircraft and spacecraft science
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• v.2 no.4
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• pp.445-467
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• 2015

The paper presents some details of the CFD modeling of a novel design where jet ignition devices replace the traditional spark plugs for a faster and more complete combustion. The numerical simulations show how the pre-chamber jet ignition in a Wankel engine differs from reciprocating piston engine applications. The jets issuing from the jet ignition pre-chamber have many different speeds in the different directions as the pressure build-up at the trailing edge of the rotating chamber makes extremely fast the ignition of the chamber mixture in the direction of rotation. Conversely it prevents the jet ignition in the opposite direction. Careful positioning along the periphery and design of the connecting pipes and the prechamber volume with the help of CFD simulations permits to achieve extremely fast and complete combustion as impossible with spark plugs. The paper proposes results of CFD simulations of the combustion evolution within a jet ignited Wankel engine rotor, detailing challenges and opportunities of the application, as well as a first assessment of the impact the faster and more complete combustion permitted by jet ignition may have on the performances of Wankel engines for unmanned aerial vehicles applications.

• The Plant Pathology Journal
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• v.30 no.1
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• pp.10-24
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• 2014

Genetic diversity and differentiation of 50 Colletotrichum spp. isolates from legume crops studied through multigene loci, RAPD and ISSR analysis. DNA sequence comparisons by six genes (ITS, ACT, Tub2, CHS-1, GAPDH, and HIS3) verified species identity of C. truncatum, C. dematium and C. gloeosporiodes and identity C. capsici as a synonym of C. truncatum. Based on the matrix distance analysis of multigene sequences, the Colletotrichum species showed diverse degrees of intera and interspecific divergence (0.0 to 1.4%) and (15.5-19.9), respectively. A multilocus molecular phylogenetic analysis clustered Colletotrichum spp. isolates into 3 well-defined clades, representing three distinct species; C. truncatum, C. dematium and C. gloeosporioides. The ISSR and RAPD and cluster analysis exhibited a high degree of variability among different isolates and permitted the grouping of isolates of Colletotrichum spp. into three distinct clusters. Distinct populations of Colletotrichum spp. isolates were genetically in accordance with host specificity and inconsistent with geographical origins. The large population of C. truncatum showed greater amounts of genetic diversity than smaller populations of C. dematium and C. gloeosporioides species. Results of ISSR and RAPD markers were congruent, but the effective maker ratio and the number of private alleles were greater in ISSR markers.

• Korean Journal of Food Science and Technology
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• v.4 no.1
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• pp.24-28
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• 1972

Synthetic food preservatives were analysed in foods collected in Seoul area on Aug. 10, 1971. Sorbic acid, benzoic acid, dehydroacetic acid and butyl p-hydroxybenzoate were determined by the simultaneous gas chromatography using FID at $200{\circ}C$ and a column of Chromosorb W coated with 5% $DGS{\sim}1%\;H_3PO_4$. The recovery rates of each preservative were from 76.7% to 96.3%. The calibration curves show linearity within a range from 0.3 to $2.5{\mu}g$ of standard preservatives. The results obtained were as follows: 1) Benzoic acid was used as well as butyl p-hydroxybenzoate in soy. 2) Sorbic acid was not found in soy. 3) From all breads and biscuits benzoic acid was found as trace. 4) Detected preservatives were below the range of permitted limit. 5) From 2 soy among 15 samples dehydroacetic acid was found.

• Journal of Chest Surgery
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• v.27 no.6
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• pp.489-493
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• 1994

Our patient was a 2.3 kg, male of 33 weeks gestation and spontaneous vaginal delivery. Copious salivary secretion, mild aspiration pneumonia episode due to tracheoesophageal fistula and intermittent cyanotic appearance due to hypoxia were noted shortly after birth. Head up position, frequent upper pouch suction, and adequate fluid and antibiotic therapy were done in incubator. Combined Chest and abdominal film was revealed gas in the stomach and an haziness in right chest with mediastinal shift to the right side. Esophagogram revealed markedly dilated proximal esophagus as blind pouch, and Two dimensional echocardiography showed the Ventricular Septal Defect. The conclusion was congenital esophageal atresia with tracheoesophageal fistula, Vogt-Gross type C, Waterston Risk Category B. Surgical correction with Beardmore anastomosis was performed extrapleurally through 3rd rib bed after the cannulation of umbilical vein and preliminary gastrostomy. The fistula was closed by triple ligation and the upper pouch was then brought down to the presenting surface of the lower esophageal segment that incised, and end to side anastomosis was underwent using interrupt suture placed through the full thickness of both upper pouch and lower esophageal segment. The postoperative patient was well tolerated and recovered uneventfully, permitted feeding on 7th postoperative day after esophagogram.

• Journal of Advanced Navigation Technology
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• v.6 no.4
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• pp.318-325
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• 2002

In this paper, the effects of the interference environments on the performance of the time hopping(TH) binary PPM impulse radio(IR) system are presented. Based on the monocycle pulse available within the frequency of 3.1~10.6 GHz permitted for application by FCC, a PPM-modulated TH IR system simulator was designed and followed by the analysis of the monocycle pulse characteristics as well as the system performance. Particularly for the evaluation of the system performance, the multiple access interference and the narrowband system interference signals were considered as the interference signals. Since the narrowband system interference signal has very narrow bandwidth and very large amplitude compared with those of IR system, the analysis of the IR system performance was implemented by considering the interference power and band fraction ratio of the narrowband interference signal.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.8
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• pp.438-442
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• 2013

The alternative refrigerant R436B is applied, to assess the application feasibility for a commercial cooling water system. The characteristic stability was verified by Sealed glass tube test and Autoclave test. R436B is chemically stable with the compressor material. The Oil miscibility test shows the usual compressor oil mixed well with R436B. Through the life acceleration test, the cooling performance is maintained. Though slight changes in oil and capillary tube diameter were found, they were within the permitted range. R436B should be applied to commercial cooling water systems as a simple replacement for the usual refrigerant.

• YAKHAK HOEJI
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• v.57 no.1
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• pp.43-54
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• 2013

Viral hepatitis is the inflammation of liver cells caused by viruses, and still one of the major health-care problems worldwide. A number of viruses to cause hepatitis are type A, B, C, D, E or G. Among these viruses leading to hepatitis, B and C are more troublesome being more prone to chronic illness which can cause the potentially fatal conditions of hepatocellular carcinoma (HCC) and/or liver failure. If immediate treatment is not initiated, liver transplant is the only option left. Over the past few decades there has been remarkable progress in diagnose and monitor all hepatitis virus infections for treatment and prevention. Nonetheless, important challenges remain to develop more effective and safe vaccines for prevention as well as antiviral agents to reduce viremia/viral load by inhibiting viral replication. The development and evaluation of antiviral agents through carefully designed clinical trials over the last 25 years has heralded a new dawn in the treatment of patients chronically infected with the hepatitis B and C viruses, but not so for the D virus. The introduction of Direct Acting Antivirals (DDAs) for the treatment of HBV carriers has permitted the long term use of these compounds for the continuous suppression of viral replication. This review aims to summarize the current status and development approaches of antiviral drugs for the treatment of viral hepatitis and future perspectives.

• Journal of Information Science Theory and Practice
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• v.9 no.3
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• pp.31-41
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• 2021

The growing number of threats to society through the uncontrolled distribution of information is forcing library communities in many countries to reconsider their views on free access to collections. Based on the content of numerous documents of international importance, it can be concluded that in any democratic country access to information is one of the most important human rights, along with the right to life, liberty, and security of person. However, the state has the right to restrict citizens' access to information within the framework of existing legislation. Constantly, restrictions on access to information are established in order to protect the ethical foundations of the constitutional order, morality, health, rights, and legitimate interests of others, to ensure the country's defense and state security. It goes without saying that each country has the right to independently decide where the boundaries lie between permitted and prohibited information, including printed information, contained in library collections. This article describes three levels of access restriction: foreign, state, and regional. The authors have analyzed the legal and regulatory documents that govern libraries, as well as the reasons and methods of limitation. A comparative analysis of the restriction of access to information in the countries of Europe and Asia is presented.

• Land and Housing Review
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• v.11 no.4
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• pp.67-74
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• 2020

Despite its ecological importance of wetlands in our life, wetlands around cities and villages have been steadily disappearing. It is mainly due to either natural geological changes or man-made causes such as permitted land zone changes for the purpose to convert to agriculture land. This study aims to establish a comprehensive database of wetlands using GIS in a historic conservation city Gongju City. The systemic data management would enable to identify distribution of wetlands and their ecological attributes, and to estimate the conservation value of the wetlands. The data base will be able to use in strategic way to preserve the local ecological areas for local residents and tourists and manage the quality of wetlands in the historic and conservation city. For the purpose, it is suggested organising a wider network with not only local residents but local authorities and relevant stakeholders would be beneficial. This study also recommends that long-term strategic plan to preserve the existing wetlands. This study findings as a seminal case example can be used to apply to other geographical areas of the country and can contribute to create a national ecological nature map as well as evaluate the attributes and quality of natural ecosystem service of the region.