• Title/Summary/Keyword: gamma-gamma log

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LOG-SINE AND LOG-COSINE INTEGRALS

  • Choi, Junesang
    • Honam Mathematical Journal
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    • v.35 no.2
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    • pp.137-146
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    • 2013
  • Motivated essentially by their potential for applications in a wide range of mathematical and physical problems, the log-sine and log-cosine integrals have been evaluated, in the existing literature on the subject, in many different ways. The main object of this paper is to present explicit evaluations of some families of log-sine and log-cosine integrals by making use of the familiar Beta function.

Effects of Gamma Irradiation on Queso Blanco Cheese (퀘소블랑코 치즈의 감마선 조사 처리 효과)

  • Jeong, Seok-Geun;Noh, Young-Bae;Shin, Ji-Hye;Han, Gi-Sung;Chae, Hyun-Seok;Yoo, Young-Mo;Ahn, Jong-Nam;Lee, Ju-Woon;Jo, Cheor-Un;Lee, Wan-Kyu;Ham, Jun-Sang
    • Journal of Dairy Science and Biotechnology
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    • v.25 no.1
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    • pp.15-20
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    • 2007
  • Effects of gamma irradiation on chemical, microbiological, and immunological changes of Queso Blanco cheese were investigated. Although Queso Blanco cheese was made by heat pasteurization at 85$^{\circ}$C and addition of acid without lactic starter culture, total bacterial counts and lactic acid bacterial counts of control cheese were 7.65${\pm}$0.04 and 7.64${\pm}$0.02 log CFU/mL, respectively. It was thought that this microbial growth was due to the incomplete inactivation of raw milk by the heat treatment, resulting into growth during the pressing and the drying process. It demonstrated the possibility that if heat- and acid-resistant hazard microbes are present in raw milk, they can grow during the processes. Lactic acid bacterial counts of the irradiated cheese were 5.45${\pm}$0.02 log CFU/mL at 1kGy, 2.12${\pm}$0.12 log CFU/mL at 2kGy, and not detected at 3kGy or higher doses. The reduction of antigenicity by gamma irradiation was not found. It might be caused by the fact that most whey proteins of milk, a major antigen in milk, were already denaturated by heat process and removed during the draining.

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Microbiological and Sensory Qualities of Musaengchae(Radish Salad) with Gamma-irradiated Red Pepper Powder added Prior to Storage (감마선 조사된 고춧가루 첨가 무생채의 저장 중 품질 변화)

  • Kim, Sun-Im;Park, Jae-Nam;Cho, Won-Jun;Song, Beom-Seok;Kim, Jae-Hun;Byun, Myung-Woo;Sohn, Hee-Sook;Lee, Ju-Woon
    • Food Science and Preservation
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    • v.16 no.2
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    • pp.160-165
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    • 2009
  • Microbiological and sensory qualities of Musaengchae prepared with gamma-irradiated red pepper powder were investigated during storage at $4^{\circ}C$. Total aerobic bacteria in non-irradiated raw materials prior to Musangchae preparation were 6.71 log CFU/g in red pepper powder, 3.39 log CFU/g in radish, 2.21 log CFU/g in scallion, and 2.10 log CFU/g in garlic, respectively. Coliforms(2.15 log CFU/g) were detected only in red pepper powder, and not in Musangchae to which gamma-irradiated red pepper powder. None of pH, Hunter's color value, or sensory properties were significantly affected by addition of irradiated red pepper powder. These results suggest that addition of such powder, after irradiation with less then 10 kGy, could improve Musangchae microbiological safety without changing the sensory or physical qualities.

A Study of Option Pricing Using Variance Gamma Process (Variance Gamma 과정을 이용한 옵션 가격의 결정 연구)

  • Lee, Hyun-Eui;Song, Seong-Joo
    • The Korean Journal of Applied Statistics
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    • v.25 no.1
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    • pp.55-66
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    • 2012
  • Option pricing models using L$\acute{e}$evy processes are suggested as an alternative to the Black-Scholes model since empirical studies showed that the Black-Sholes model could not reflect the movement of underlying assets. In this paper, we investigate whether the Variance Gamma model can reflect the movement of underlying assets in the Korean stock market better than the Black-Scholes model. For this purpose, we estimate parameters and perform likelihood ratio tests using KOSPI 200 data based on the density for the log return and the option pricing formula proposed in Madan et al. (1998). We also calculate some statistics to compare the models and examine if the volatility smile is corrected through regression analysis. The results show that the option price estimated under the Variance Gamma process is closer to the market price than the Black-Scholes price; however, the Variance Gamma model still cannot solve the volatility smile phenomenon.

Application of Gamma Ray Irradiation to the Microbiological Safety of Dried Seafood Products (건조 수산물의 미생물학적 안전성 확보를 위한 감마선 조사 기술의 이용)

  • Choi, Jong-Il;Kim, Hyun-Joo;Kim, Jae-Hun;Ahn, Dong-Hyun;Chun, Byung-Soo;Lee, Ju-Woon
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.43 no.2
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    • pp.169-173
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    • 2010
  • This study evaluated the effects of gamma ray irradiation on the safety of dried seafood products. Dried salted squid, Engraulis japonica, Hizikia fusiformis, Mytilus coruscus, and Porphyra tenera were gamma-irradiated at doses of 0, 1, 3, and 5 kGy. The total bacterial populations were then enumerated on total plate count agar, and bacteria isolated from the samples were identified by 16S rDNA sequencing. In addition, the isolated strains were inoculated in the products to determine $D_{10}$ values. The total bacterial populations in the dried seafood products ranged from 3.40 to 6.59 log CFU/g, and those of yeasts and molds ranged from 2.21 to 4.56 log CFU/g. The sequence analysis identified Staphylococcus sp. as the most common species in the dried seafood products, except for dried P. tenera. The $D_{10}$ values of the contaminating bacteria were lower than 0.7 kGy, except for Deinococcus sp., which had a value of 1.39 kGy. This study demonstrated that gamma irradiation could be used to improve the safety of dried seafood products.

Effect of Gamma Irradiation on Microbial Populations in the Dried Raw Materials and Saengsik Powder (감마선 조사에 따른 원료분말 및 생식의 미생물 제어 효과)

  • Choi, Soo-Jeong;Park, Jae-Nam;Song, Beom-Seok;Yoon, Young-Min;Han, In-Jun;Park, Jong-Heum;Kim, Jae-Kyung;Byun, Eui-Baek;Lee, Ju-Woon;Hong, Seong-Gil;Yook, Hong-Sun;Kim, Jae-Hun
    • Journal of Radiation Industry
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    • v.7 no.2_3
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    • pp.177-182
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    • 2013
  • This study was conducted to evaluate the effect of gamma irradiation on the microbial populations of dried raw materials (9 products) and Saengsik powder. The samples were gammairradiated at doses of 2, 4, 6 and 8 kGy and the microbiological populations were evaluated. The total numbers of bacteria and Bacillus cereus in non-irradiated dried-raw materials for Saengsik powder was 1.3~3.4 and $1.7{\sim}2.4log\;CFU\;g^{-1}$. However, gamma irradiation reduced the microbiological populations in all samples, and Saengsik powder were sterilized at more than 6 kGy. Moreover, Clostridium perfringens were not observed in all samples within detection limit (<$1log\;CFU\;g^{-1}$). Therefore, the results of this study suggest that gamma irradiation at 6 kGy is sufficient to sterilize Saengsik powder, and thus, irradiated Saengsik powder at 6 kGy fulfills the microbiological requirements for sterilized food.

Microbial reduction effect of steam heating, UV irradiation, and gamma irradiation on red pepper powder (스팀 가열 및 자외선, 감마선 조사 처리에 따른 고춧가루의 미생물 저감화 효과)

  • Choi, Jun-Bong;Cheon, Hee Soon;Chung, Myong-Soo;Cho, Won-Il
    • Korean Journal of Food Science and Technology
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    • v.52 no.2
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    • pp.177-182
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    • 2020
  • This study evaluated the effect of steam heating, gamma irradiation, and ultraviolet (UV) irradiation on microorganism reduction in order to determine an effective sterilization method for red pepper powder. The effect of each treatment on the reduction of thermoduric bacteria and total aerobic bacteria in red pepper powder were as follows: 10 kGy gamma irradiation, reduction of 4 log and 6 log CFU/g, respectively; 12 mW/㎠ UV irradiation (264 nm UV-C), reduction of less than 1 log CFU/g; steam heating at 120℃ for 40 s, reduction of approximately 2 log CFU/g. High-temperature short-time processing at 110℃ for 30 s reduced the total bacterial count in Gochujang solution from 5.70 log CFU/g to 2.26 log CFU/g; at 121℃, the solution was commercially sterile. Steam heating resulted in 1, 2, and 4 log microbial inactivation in garlic, onion, and pepper powder, respectively. Steam sterilization, which consumers prefer over other methods, may be an effective method for reducing microorganisms in spice powders, including those in red pepper powder.

Effect of Gamma Irradiation on the Overall Quality of a Commercial Plain-type Yogurt Products (안전성 향상을 위해 감마선 조사한 시판 플레인 요구르트의 품질 특성)

  • Kim, Hyun-Joo;Song, Hyun-Pa;Ham, Jun-Sang;Lee, Ju-Woon;Kim, Kee-Hyuk;Jo, Cheor-Un
    • Food Science of Animal Resources
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    • v.28 no.5
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    • pp.574-579
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    • 2008
  • To develop a yogurt for sensitive consumer such as infants, children or immuno-compromised patients using gamma irradiation, the effects of gamma irradiation on the microbiological, chemical, and sensory quality in a commercial plain yogurt were investigated. No viable coliform bacteria were detected in the sample and approximately a 6 decimal reduction was achieved in the number of total aerobic bacteria by irradiation at 5 kGy. The initial population of lactic acid bacteria observed in the commercial plain yogurt was 8.95 log CFU/g. Gamma irradiation significantly reduced the initial microbial level to 6.47 and 2.85 log CFU/g after irradiation at 1 and 3 kGy, respectively (p<0.05). However, irradiation dose up to 5 kGy could not completely eliminate the lactic acid bacteria in commercial plain yogurt. pH, color, lactose and lactic acid content, and sensory quality were not affected by irradiation treatment and storage. Our results suggest that irradiation can improve the microbial quality of commercial plain yogurt without impairing the physicochemical and sensory quality.

Effect of Gamma Radiation on the Microbial Growth and Mechanical Properties of Korean Traditional Paper (방사선 조사가 한국전통한지의 미생물 생장과 기계적 물성에 미치는 영향)

  • Choi, Jong-Il;Yoon, Min-Chul;Chung, Yong-Jae;Kang, Dai-Ill;Kim, Gwang-Hoon;Lee, Ju-Woon
    • Journal of Conservation Science
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    • v.26 no.4
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    • pp.377-383
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    • 2010
  • The effect of gamma irradiation on the microbial growth inoculated in the Korean traditional paper, Hanji, was investigated. Also, the mechanical properties of Korean traditional paper were measured to verify the possible change by gamma radiation. Bacillus cereus and Aspergillus niger were cultivated and the spores were innoculated in papers at the 250,000 and 500,000 colonies, respectively. In these results, 5log spores of B. cereus could be all inactivated at the dose of 6 kGy, and 5log A. niger be inactivated at 8 kGy, respectively. There was also showed no significant change in tensile strength, bursting strength and color index of Korean traditional paper by the gamma irradiation upto the dose of 50 kGy. These results confirmed that radiation treatment of Korean traditional paper is extremely efficient and could be used to preserve ancient books and archives documents from being damaged by moulds and fungi.

Application of Gamma Irradiation on Manufacturing Changran Jeotgal (aged and seasoned intestine of Alaska pollack) : Microbiological and Sensory Characteristics (양념 창란젓갈 제조시 감마선 조사기술 적용: 미생물학적 및 관능적 품질특성)

  • Jo, Cheorun;Kim, Dong-Ho;Lee, Won-Dong;Lee, Jae-Jin;Byun, Myung-Woo
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.32 no.5
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    • pp.673-678
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    • 2003
  • Changran Jeotgal (aged and seasoned intestine of Alaska pollack) was prepared as the same method as commercial one and irradiated at 0, 2.5, 5.0 and 10 k㏉ by gamma ray for industrial application. Changran Jeotgal using 10 k㏉-irradiated red pepper powder was also prepared to compare with control (0 k㏉). Commercial red pepper powder was already contaminated at 3.8$\times$10$^{6}$ CFU/$m\ell$ level by total plate count and 10k㏉ of irradiation reduced the number about 4 log cycles. Gamma irradiated Changran Jeotgal at 2.5,5.0, and 10k㏉ showed 3 6, and 7 log cycles of reduction compared to the non-irradiated control in the total plate count after 12 weeks of storage at 1$0^{\circ}C$. Using irradiated (10k㏉) red pepper powder reduced the microbial contamination significantly by 2 log cycles compared to the control. Sensory evaluation showed that the sample irradiated at 2.5 k㏉ was the most acceptable, followed by the sample using irradiated red pepper powder and non-irradiated control. Thus, 2.5 k㏉ of irradiation of Changran Jeotgal was effective to improve safety during distribution and storage without change of sensory quality. Furthermore, using the irradiated red pepper powder is also recommended for safety enhancement of the products.