• Title/Summary/Keyword: CSA

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Effect of Carbon Dioxide-reduced Cement on Properties of Lightweight-foamed Concrete (이산화탄소 저감형 시멘트 함량에 따른 경량기포 콘크리트의 물성평가)

  • Im, Donghyeok;Lee, Won-Ki
    • Journal of Environmental Science International
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    • v.29 no.6
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    • pp.605-612
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    • 2020
  • To improve the initial strength and stability of lightweight-foamed concrete, which shows suitable sound absorption and insulation characteristics, the effect of CO2-reduced cement on the properties of the concrete was investigated. Various mixing ratios were applied by substituting a certain amount of slag and Calcium Sulfo Aluminate (CSA) in CO2-reduced Ordinary Portland Cement (OPC) and the physical properties of the samples were examined using the Korean Standard. The kiln temperatures of the CSA were 100-200℃ ; these values are lower than those of OPC and can lead to energy saving. In addition, the low limestone content reduces greenhouse gas emissions by 20 %. Adding a small amount of CSA in OPC content activates Ca-Al-H2-based hydrates, and the initial compressive strength of the concrete is improved. As the CSA content increased, the thermal conductivity of the concrete decreased by up to 8% compared to plain concrete, thus indicating an improvement in its insulation. Therefore, the settlement stability was improved as the addition of CSA shortened the setting time.

Hydrate Characteristics of Cement Mixtures with Expansion Additive According to Age and Improvement Effect on Initial Strength (팽창재를 사용한 시멘트 혼합물의 재령별 수화물의 특성과 초기강도 개선 효과)

  • Song, Tae-Hyeob;Park, Ji-Sun;Lee, Sea-Hyun
    • Korean Journal of Materials Research
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    • v.23 no.10
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    • pp.599-605
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    • 2013
  • CSA, a cement mineral compound that is mainly composed of $3CaO{\cdot}3Al_2O_3{\cdot}CaSO_4$, generates ettringite as a hydration product after a reaction with glass (lime), gypsum and water to speed up the hardening process and enhance the strength and degree of expansion. When used as a cement admixture, there is increased production of ettringite, which can improve the initial strength in the first three days and ameliorate the reduction in the initial strength caused by the use of fly ash in particular. In this study, a hydrate analysis was performed using XRD and SEM after substitution with fly ash (30%) and CSA (8%) with the goal of observing the effect of CSA on the initial strength of a cement mixture containing fly ash. The results of the analysis showed that an addition of CSA promoted the production of ettringite and improved the initial strength, resulting in the generation of hydrates, which can effectively enhance the long-term strength of these materials.

Analysis of Characteristics of Slurry and Thermal Insulation Materials Using Hauyne Cement

  • Kim, Tae Yeon;Jo, Ki Sic;Chu, Yong Sik
    • Journal of the Korean Ceramic Society
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    • v.56 no.5
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    • pp.468-473
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    • 2019
  • This study focused on manufacturing an inorganic insulation material set with various amounts of calcium-sulfoaluminate (CSA) (hauyne) content for enhancing both workability (demolding, handling) and the high thermal insulating property. To carry out the experiment, the amounts of CSA utilized were 5%, 10%, 15%, and 20%, with anhydrous gypsum added in equal proportion to produce a stable formation. As the content of CSA increased, a sinking phenomenon occurred because of the hydration reaction from the slurry, so it was difficult to utilize a retarder normally used in the cement manufacturing process. However, an RCOOM surfactant was able to solve the local clumping problem from cement and CSA and obtain a rapid retarding effect, so it was included in this process at 0.3%. Furthermore, the cement fineness was not 7000 ㎠/g but rather 3300 ~ 4000 ㎠/g to prevent a rapid temperature increase in the slurry. The specific gravity of the sample manufactured with 20% CSA was approximately 0.11 g/㎤, and its thermal conductivity was 0.041 W/m·K, providing an excellent insulating property.

Study on the effect of Post Open laser Lumbar Micro-discectomy on the Cross Section Area of Deep Muscles in Patients (요추부 미세 현미경 레이져 디스크 수술(OLM)이 환자의 심부근육 단면적 크기에 미치는 영향)

  • Kong, Bong-Jun;Kim, Jin-Sang;Min, Dong-Ki
    • PNF and Movement
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    • v.10 no.2
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    • pp.25-31
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    • 2012
  • Purpose : The purpose of this study is to figure out the effects of Open Laser Microdiscectomy(OLM) on deep muscles by comparing multifidus and longissimus muscle size (cross section area; CSA) of pre and post operation. Methods : The subjects consisted of forty patients who had OLM. The data were analyzed with paired t-test comparing left and right deep muscle CSA of pre and post-operation, and both the deep muscle CSA of pre and post-operation, using SPSS ver. 15.0 program. Results : The results of this study showed a significant difference in deep muscle size (CSA) between pre and post operation (p<.05). Although there was not a meaningful difference between right and left deep muscle size (CSA) in pre operation (p>.05), there was a significant difference between both of them in post operation (p<.05). Conclusion : Therefore we made the conclusion that the operation causes decrease of muscle tone in deep muscles and muscle imbalance by causing muscle atrophy in the lumbar deep muscle after the operation.

CT Evaluation of Age-Related Changes in Epaxial Muscle Attenuation and Cross-Sectional Area for Sarcopenia and Myosteatosis in Small Breed Dogs

  • Ji Yeong Lee;Tae Sung Hwang;Hee Chun Lee
    • Journal of Veterinary Clinics
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    • v.40 no.3
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    • pp.182-188
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    • 2023
  • Sarcopenia and myosteatosis can increase the risk of adverse effects in dogs and humans. However, such imaging study results for evaluating sarcopenia and myosteatosis in small dogs have not yet been available. The objective of this study was to assess age-related changes according to the breed in epaxial muscle cross-sectional area (CSA) and fat infiltration using CT to evaluate sarcopenia and age-related myosteatosis in small breed dogs. In 144 dogs (92 Maltese dogs, 27 Poodle dogs, and 25 Shih Tzu dogs), Hounsfield Unit (HU) values and CSA of left epaxial muscle were measured at the thirteenth thoracic vertebral level on non-contrast transverse CT images. Differences in HU values and CSA according to age and breed were analyzed. The geriatric group (≥12 years) had significantly lower HU values of epaxial muscle than mature adult group (2 to 6 years) of all breeds. The geriatric group had significantly lower CSA of epaxial muscle than mature adult and senior groups (7 to 11 years) of Maltese dogs. HU values of epaxial muscle were not significantly different among all age groups of all breeds. Maltese dogs had significantly lower CSA of epaxial muscle than Poodle and Shih Tzu dogs in all age groups. Results of this study showed that as age increased in small breed dogs, muscle mass and density decreased.

The Child Sexual Assaults by Kin -The Experience of YoungNam District Sunflower Center for Prevention of Child Sexual Assaults- (친족에 의한 아동 성폭력 실태 - 영남권역 해바라기 아동센터의 경험 -)

  • Seo, Sun-Ki;Lee, Sang-Han
    • Journal of forensic and investigative science
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    • v.2 no.2
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    • pp.21-29
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    • 2007
  • News from the media on sexual assaults to children committed by natural fathers doesn't attract social attention any more. The number of crimes related to Child Sexual Assault(CSA) is increasing every year in spite of the "Special Act on Prevention of Sexual Assault in Korea". The YoungNam District Sunflower Center for prevention of Child Sexual Assaults(SC-CSA) was established in Daegu, June 2005. The YoungNam District SC-CSA provides forensic evaluation of physical evidence, medical and psychological treatment for the victims less than 13 years of sexual assaults simultaneously. This study carried out 36 cases of CSA by kin reported to YoungNam District SC-CSA, among 180 cases in total until December 2006 since its opening. Most of the victims were girls (32 cases). 28 cases (78%) were indecent assaults (78%) and 8 cases (22%) were rapes. The assailants were overwhelmingly males (35 cases). The assailants of 21 cases (58.3%) were identified as the victims' natural fathers. The incident locations were victim's residence (31 cases, 86.1%) and the victims had been sexually assaulted regularly for many years (25 cases, 69.4%). Considering the above research, we can conclude that CSA committed by kin has specific characteristics. CSA is not a one-time incident, but consistently occurring crime. However, in 22 cases (61.1%), the victim's guardian didn't want to report about it or punish the assailants. As the assailants were natural fathers or relatives of the victims, the other family members probably thought it might be shameful to reveal their wrong doings and would lead to defamation of their family's reputation. The SC-CSA provides the counseling and medical treatment to the victims with the consent of the parents. Due to the guardians' misjudgment, the incident is sometimes not reported to the police. By not reporting the incident to the police, the assailant freely commits other crimes, which multiplies victims. The legal Act of supporting the management of the SC-CSA is still not regulated, so the stability of the SC-CSA is not guaranteed, yet. Even though it is obligatory to report incidents to the police, some cases are still not reported. Currently, there are three SC-CSA centers : in Seoul, in Daegu, and in Gwangju. More centers need to be established to diminish CSA cases in Korea.

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Design and Implementation of DVB-CSA3 Scramble System (DVB-CSA3 스크램블 시스템의 설계 및 구현)

  • Cho, Yong Seong;Jung, Joon Young;Hur, Namho;Im, Han Jae
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2016.06a
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    • pp.220-221
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    • 2016
  • 최근 UHD 방송서비스에 대한 관심이 고조됨에 따라 고품질 방송 콘텐츠 보호에 대한 요구가 증가하고 있다. 이에 따라, DVB, MPEG, ATSC 등 국제 표준단체에서는 기존 방식보다 보안 성능이 우수한 디지털 방송 보호 규격을 논의하고 있으며, 디즈니, 파라마운트, 소니 픽처스 등 세계 주요 콘텐츠 제작사들이 설립한 비영리 기관인 MovieLabs 에서도 고품질 콘텐츠 보호를 목적으로 AES-128 또는 그 이상의 강도를 갖는 콘텐츠 암호화 알고리즘을 필수적으로 사용하도록 규정하였다. 본 논문에서는 디지털 방송 보안을 위해 널리 사용되고 있는 DVB-CSA 및 AES-128 보다 보안성능이 우수한 것으로 알려진 방송 콘텐츠 암호화 규격인 DVB-CSA ver3 표준 규격 기반으로 설계 및 구현된 스크램블 시스템에 대해 소개한다.

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Flaw Sizing by ASME and CSA Code (ASME 및 CSA 코드에 의한 초음파 결함 크기 측정)

  • Park, Moon-Ho;Kang, Suk-Chul
    • Journal of the Korean Society for Nondestructive Testing
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    • v.18 no.4
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    • pp.313-320
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    • 1998
  • To record and evaluate the flaws which were found during pre-service/in-service inspection performance of nuclear power plants in Korea, the center line beam method described in ASME code and 6 dB drop method stated in CSA code were used. The measured through wall dimensions and lengths by these methods were compared and analyzed in this report. With the measured data analysis, the ekact understanding and use of these methods improves the reliability of flaw sizing and assures the integrity of nuclear power plant components.

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Properties and Field Application of Non-shrinkage High Strength Concrete (무수축 고강도 콘크리트의 특성 및 현장적용)

  • 조일호;성찬용
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.42 no.6
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    • pp.115-121
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    • 2000
  • The purpose of this research is to investigate properties and field application of non-shrinkage high strength concrete containing expansive additive. Before the field applications, several basic laboratory test are performed to evaluate the characteristics of air content, workability and strength of the concrete using calcium sulfa aluminate(CSA) expansive additive. As a result, high strength concrete using CSA expansive additive show similar workability and compressive strength to that normal concrete, and the optimum replacement ratio of them is obtained by 10% CSA expansive additive. Accordingly, it can be concluded that the use of CSA expansive additive is effective to prevent shrinkage crack and to achieve volume stability of concrete structure.

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Pharmacokinetic and Pharmacodynamic Characteristics of Cyclosporin A in Rats and Rabbits

  • Lee, Yong-Bok
    • Proceedings of the PSK Conference
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    • 2002.10a
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    • pp.214-217
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    • 2002
  • Cyclosporin A (CSA) is a poorly water-soluble cyclic peptide comprising 11 amino acids. It inhibits T-lymphocyte function that plays an important role in the induction of immune response. The potent immunosuppressive activity of CSA has been used for the prevention of rejection following transplantation of liver, kidney and bone marrow, etc. The use of CSA has been often limited by several disadvantages including low bioavailability, narrow therapeutic window, nephrotoxicity, hepatotoxicity and neurotoxicity. Moreover, CSA injection is limited to patients who are unable to take the oral preparations, because it has a risk of anaphylactic shock and nephrotoxicity due to Cremophor EL$\textregistered$, a solubilizing agent used in the commercial intravenous formulation. Owing to above mentioned disadvantages of commercial products, there is a great interest in the development of the alternative dosage forms. (omitted)

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