• Journal of applied mathematics & informatics
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• 제42권1호
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• pp.65-76
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• 2024

In this paper, the I-transform of the Mellin convolution type is presented. Based on the Mellin transform theory, a general integral transform of the Mellin convolution type is introduced. The generating operators for I-transform together with the corresponding operational relations are also presented.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 춘계학술대회 논문집
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• pp.329-332
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• 2005

Cross rolling process is one of incremental forming processes to form an axi-symmetric shaped metal component. It can be classified into two types according to the shape of dies, which are a drum type (roll type) and a plate type (straight type). It can also be classified into a wedge type and a ramp type processes according to deformation characteristics of a material. The ramp type die is applied to plate type cross rolling process in cold forming process for forming of teeth of gear or bolt, while the wedge type die is generally utilized to drum type and plate type cross rolling processes in hot forming process. A shape of the ramp type die is usually same as final shape of a product at every section of a progressing direction, while the shape of the wedge type die has different shapes in a progressing direction. In this paper, a rolling of neck part in a ball stud component has been carried out using the plate type cross rolling process with a ramp shaped die. Forming characteristics have been performed using finite element analysis in order to obtain a proper preform for the ramp type plate cross rolling process.

• 한국분말재료학회지
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• 제27권1호
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• pp.58-62
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• 2020

Recently, electrochromic devices (ECDs) have gathered increasing attention owing to their high color contrast and memory effect, which make them highly applicable to smart windows, auto-dimming mirrors, sensors, etc. Traditional ECDs have a sandwich structure that contains an electrochromic layer between two ITO substrates. These sandwich-type devices are usually fabricated through the lamination of two electrodes and followed by the injection of a liquid electrolyte in the inner space. However, this process is sometimes complex and time consuming. In this study, we fabricated ECDs with a lateral electrode structure that uses only an ITO substrate and an all-in-one electrochromic gel, which is a mixture of electrolyte and electrochromic material. Furthermore, we investigated the EC properties of the lateral-type device by comparing it with a sandwich-type device. The lateral-type ECD shows strong blue absorption as the applied voltage increases and has a competitive coloration efficiency compared to the sandwich-type device.

• The Korean Journal of Physiology and Pharmacology
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• 제28권1호
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• pp.31-38
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• 2024

As in type 1 diabetes, the loss of pancreatic β-cells leads to insulin deficiency and the subsequent development of hyperglycemia. Exercise has been proposed as a viable remedy for hyperglycemia. Lithium, which has been used as a treatment for bipolar disorder, has also been shown to improve glucose homeostasis under the conditions of obesity and type 2 diabetes by enhancing the effects of exercise on the skeletal muscles. In this study, we demonstrated that unlike in obesity and type 2 diabetic conditions, under the condition of insulin-deficient type 1 diabetes, lithium administration attenuated pancreatic a-cell mass without altering insulin-secreting β-cell mass, implying a selective impact on glucagon production. Additionally, we also documented that lithium downregulated the hepatic gluconeogenic program by decreasing G6Pase protein levels and upregulating AMPK activity. These findings suggest that lithium's effect on glucose metabolism in type 1 diabetes is mediated through a different mechanism than those associated with exercise-induced metabolic changes in the muscle. Therefore, our research presents the novel therapeutic potential of lithium in the treatment of type 1 diabetes, which can be utilized along with insulin and independently of exercise.

• Nuclear Engineering and Technology
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• 제55권8호
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• pp.3080-3087
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• 2023

Thermoelectric (TE) materials working in radioisotope thermoelectric generators are irradiated by neutrons throughout its service; thus, investigating the neutron irradiation stability of TE devices is necessary. Herein, the influence of neutron irradiation with fluences of 4.56 × 10¹⁰ and 1 × 10¹³ n/cm² by pulsed neutron reactor on the electrical and thermal transport properties of n-type Bi₂Te_2.7Se_0.3 and p-type Bi_0.5Sb_1.5Te₃ thermoelectric alloys prepared by cold-pressing and molding is investigated. After neutron irradiation, the properties of thermoelectric materials fluctuate, which is related to the material type and irradiation fluence. Different from p-type thermoelectric materials, neutron irradiation has a positive effect on n-type Bi₂Te_2.7Se_0.3 materials. This result might be due to the increase of carrier mobility and the optimization of electrical conductivity. Afterward, the effects of p-type and n-type TE devices with different treatments on the output performance of TE devices are further discussed. The positive and negative effects caused by irradiation can cancel each other to a certain extent. For TE devices paired with p-type Bi_0.5Sb_1.5Te₃ and n-type Bi₂Te_2.7Se_0.3 thermoelectric legs, the generated power and conversion efficiency are stable after neutron irradiation.

• 센서학회지
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• 제27권2호
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• pp.112-117
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• 2018

In this study, a bender-type piezoelectric energy harvester was fabricated and evaluated to compensate for the disadvantages of high-power generation only in the resonance frequency range of a piezoelectric harvester using a piezoelectric cantilever. The generated power was investigated according to various changes in the vibration environment. Compared with the piezoelectric cantilever module, the bender-type piezoelectric module showed a larger number of peak voltages. The primary peak voltage shifted toward the low frequency when the spring was coupled to the bender-type piezoelectric module. The harvester of the three bender-type modules had a vibration frequency exceeding 1 mW in the 34-45 Hz range and generated 3.112 mW of power at the vibration frequency of 38 Hz. The harvester of the six bender-type modules had a vibration frequency exceeding 1 mW in the 31-45 Hz range and generated 3.081 mW of power at the vibration frequency of 35 Hz.

• Journal of applied mathematics & informatics
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• 제17권1_2_3호
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• pp.433-455
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• 2005

Fritz John, and Karush-Kuhn-Tucker type optimality conditions for a constrained variational problem involving higher order derivatives are obtained. As an application of these Karush-Kuhn-Tucker type optimality conditions, Wolfe and Mond-Weir type duals are formulated, and various duality relationships between the primal problem and each of the duals are established under invexity and generalized invexity. It is also shown that our results can be viewed as dynamic generalizations of those of the mathematical programming already reported in the literature.

• 대한음성학회:학술대회논문집
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• 대한음성학회 2002년도 11월 학술대회지
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• pp.77-80
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• 2002

This study proposes phonation type index k as a descriptor of the overall spectral tilt, which is free from the effects of fundamental frequency and vowel quality. The newly proposed phonation type index k presents a simple and single measure of the overall spectral tilt. Phonation type index k can be applied to speech technology. It can also be used in diagnosing patients voice qualities in speech pathology. The distribution of phonation type index k, which is speaker-dependent, may be useful in forensic phonetics and voice recognition as an indicator of speaker identity.

• Journal of Animal Science and Technology
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• 제66권2호
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• pp.251-265
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• 2024

Meat derived from skeletal muscles of animals is a highly nutritious type of food, and different meat types differ in nutritional, sensory, and quality properties. This study was conducted to compare the results of previous studies on the muscle fiber characteristics of major porcine skeletal muscles to the end of providing basic data for understanding differences in physicochemical and nutritional properties between different porcine muscle types (or meat cuts). Specifically, the muscle fiber characteristics between 19 major porcine skeletal muscles were compared. The muscle fibers that constitute porcine skeletal muscle can be classified into several types based on their contractile and metabolic characteristics. In addition, the muscle fiber characteristics, including size, composition, and density, of each muscle type were investigated and a technology based on these muscle fiber characteristics for improving meat quality or preventing quality deterioration was briefly discussed. This comparative review revealed that differences in muscle fiber characteristics are primarily responsible for the differences in quality between pork cuts (muscle types) and also suggested that data on muscle fiber characteristics can be used to develop optimal meat storage and packaging technologies for each meat cut (or muscle type).

• 한국문헌정보학회지
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• 제29권
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• pp.345-382
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• 1995

The type printing of first Ch'ing dynasty term in China is worthy to be studied because the type printing during that period included metal type, wood type, and clay type as well as the development phase was similar to Chosun dynasty culturally and technologically. This paper studied typography during the first Ch'ing dynasty term, including Shunzhi(1662-1722), Yongaheng(1723-1735), Qianlong(1736-1795), Jiaqing(1796­1820) period. The main results of the study is as follows. 1. The main body of type printing was bookstore, lecture-hall, and individual as well as the royal court that is the central government. 2. The content of type edition covers classics, history, philosophy, and literary works. Specifically, even though Wuyingdienjuzhenban series is excluded, the content includs study of the classics, class of the history, class of the philosophy, literature works that include collection works and novel and government official bulletin. 3. The printing technique of bronze type was very popular In Beijing. Jiangsu, and Taiwan. It's scale and production technique was more elaborate than in Ming dynasty. 4. Wood type was very popular in Beijing, Jiangsu, Zhejiang, Anhui, Sichuan, and Fujian. In addition to wood type, chinese ware type was applied to book printing in Shandong. However, most of them were wood type and they were used after Qianlong period. 5. The production technique of type was skilled enough to present the fine view of a style of type. The typesetting technique was improved as much as woodblock printing. With regard to the making technology of Chinese ink, the light and darkness of chinese ink was not even sometimes. But, the technology was improved significantly when comparing with the failure experience of printing that chinese ink was not developed in early type invention. 6. In case that the book was printed in bookstore with the intention of profit and the number of book was large, the proofreading attitude was rough. However, overally, it was made correction carefully applying the various methods of proofreading. 7. The support of government made a great contribution in the area of all printing technology, including production, typesetting, and brushing of type.