• 한국축산식품학회지
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• 제43권4호
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• pp.580-593
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• 2023

The purpose of this study was to analyze whether seawater has positive effects on appearance characteristics, such as CIE a^*, and to determine the gas composition concentration that is suitable for maintaining it. Pork hind meat was cured with four types of curing agent for 5 d at 4℃. The different curing agents comprised the control salt, control nitrite pickling salt (CN), treatment brine, and treatment bittern (BT). The cured hams were cooked at 65℃ for 4 h and packaged at O₂:N₂ gas ratios of 7:3, 8:2, and 9:1 for 3 wk. The physicochemical properties were assessed immediately after heating the sample, and the color properties were measured after a 3 wk storage period. Based on the correlation results of the physicochemical properties, BT had a higher curing and cooking yield than the other treatments, owing to its high salinity. Results of color properties for BT (7:3) and CN (8:2) showed similar color CIE L^*, CIE a^* chroma, and hue angle values. Therefore, BT can be said to be a sous-vide curing agent suitable for preserving the color of ham, and a high nitrogen concentration of 30% helps to maintain the appearance of seawater sous-vide ham.

• 미생물학회지
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• 제20권1호
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• pp.11-20
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• 1982

A study was undertaken to examine the effect of curing agents on the stability, curing and segregation of R plasmid pSL100. And also the stability, transfer frequency, and recombination of its segregants obtained from curing agent treatment were studied. Ethidium bromide, acridine orange, and mitomycin-C were used as curing agent. The results obtained were as follows ; 1. The curing agent ethidium bromide, acridine orange, and mitomycin-C were not effective for curing the multiple antibiotic resistant determinant of pSL100 in Salmonella typhimurium and Escherichia coli. However, they induced plasmid segregation with high frequency in S.typhimuruim LT-2strains. TcApSmCm, TcSmCmKm, TcApCm, TcAp, TcKm, Tc segregants were obtained. 2. The resistant markers of the segregents were transferred to S.typhimurium LT-2 strains with high frequencies whereas they were transferred to E.coli K-12 only with low frequencies. 3. The transconjugants obtained from conjugation between two different S.typhimurium segregants were similar to the phenotype of the original R factor pSL100 and the resistant markers were transferred to the S.typhimurium LT-2 or E.coli strain with equal frequencies, indicating that they are recombinants. 4. The transconjugants obtained from conjugation between pSL100 segrgants and pKM101, or pBR322 possessed the resistant markers of the two parental plasmids and they were transferred to both S.typhimurium and E.coli K-12 strains with the same frequencies and maintained stably, suggesting that they are also recombinants. 5. The recombinant pSL100 could be also obtained in rec A-strains of E.coli, suggesting that the gene function of rec A is required for the recombination of pSL100 segregants in E.coli.

• 한국농공학회지
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• 제24권2호
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• pp.67-75
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• 1982

A study on the effect of water reducing agent on the various characteristics of concrete has been conducted. The experimental results of the study are summarized as follows. 1. Slump test for the concrete added water reducing setretarding agent in proper quantity have been conducted. According to the test results, the decreasing rate of slump value become bigger than plain concrete with increase of the unit weight of cement and elapse of time 2. In case the proper quantity content of maximum compressive strength in Fig. 5 of water reducing set retarding agent is added, unit weight of water is decreased about 15% or so as compared with plain concrete. with the increase of water reducing set accelerating agent content unit weight of water is decreased much more, And other hand, amount of air entraining shows the increasing tendency with the increase of water reducing agent content. 3. The adding rate of water reducing agent which produce maximum strength shows that WR-CH and WR-SA which is water reducing set-starding agent is 0.2% and WR-CO is 0.5% and that WS-PO which is water reducing set accelerating agent is 0.5 4. compressive strength jof the concrete made of sulfate resistant cement shows less than the strength of normal portland cement at initial strength but the strength of both cement shows almost same at curing age of 28 days. 5. when proper quantity of water reducing set retarding agent is used, boned strength is increased about 15% at curing age of 28days. 6. According to the result of durability test, dynamic young's mudulus of elasticity at plain concrete is decreased about 50% as compared with initial step at 300 cycle of freezing and thawing after curing age of days. on the contarary the concrete used water reducing agent is decreased less than 7%.

• Composites Research
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• 제32권6호
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• pp.349-354
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• 2019

복합재료 중심인장선의 구성은 강화재로 사용되는 탄소섬유 및 유리섬유와 기지재로 사용되는 속경화 열경화성 에폭시로 되어있다. 본 연구에서는 가공송전선의 복합소재 중심인장선(ACCC)에 사용되는 에폭시 경화물에 대하여 분석하였다. 다관능성 에폭시 중 4관능성 에폭시(PA 806)을 사용하고 MNAn, HHPA 두가지 경화제 및 경화 촉진제를 사용하여 에폭시 경화물을 만들고 이를 분석하였다. 경화제의 종류 및 경화 촉진제의 함량에 따른 최적조건을 도출하였다.

• Elastomers and Composites
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• 제43권3호
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• pp.147-156
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• 2008

본 연구에서는 실란 커플링제을 변량 배합하여 습식법과 건식법으로 실리카를 전처리하여 epoxy/carboxyl-terminated butadiene acrylonitirile (EP/CTBN) 복합체를 제조하였다. EP/CTBN 복합체의 경화특성 및 표면자유에너지, 인장강도 및 충격강도의 기계적 특성과 계면 특성을 건식법과 습식법에 따라 고찰하였다. Differential scanning calorimetry(DSC)의 결과 실란커플링제의 양이 증가함에 따라 실리카의 기공을 막아 경화제의 양을 증가시켜 경화온도가 감소되었으며, 건식법보다는 습식법이 EP/CTBN 복합체의 경화온도를 감소시킴을 알 수 있었다. 또한 실란커플링제의 양이 증가함 따라 표면자유에너지와 충경강도가 증가되었으나, 인장강도는 실란커플링제의 양이 4 wt%일 때 감소되었으며, 습식법보다는 건식법이 더 물성을 향상시킴을 알 수 있었다.

• 한국초지조사료학회지
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• 제16권4호
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• pp.315-326
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• 1996

An experiment was carried out to determine effect of cultivar, drying agent concentration and preservative on the moisture content, temperature and quality changes of fall harvested oat(Avena sativa L.) hay during field curing and storage. The main plots consisted of the cultivar such as 'Foothill' and 'Swan', the subplots consisted of drying agent concentration such as 7Skg/ha(C1), lOSkglha(C2) and control(C0) and the sub-subplots consisted of preservative such as buffered acid(BA), lactic bacteria inoculant(LB) and control(C0). Moisture contents of 'Foothill' and 'Swan' oat cultivar at harvest were 635.5 and 385.4%DW(Dry weight), respectively, but the final moisture contents of the oat cultivars were 117 and 86%DW. The moisture content of cut oat was not affeded by drying agent concentration. Core temperature of baled 'Swan' oat hay was a little higher than that of 'Foothill' and no consistent preservative effect was found. Total nitrogen content of 'Swan' oat hay was 3.08% and that of 'Foothill' oat hay was 3.45%(P<0.05). Drying agent treatment increased total nitrogen content of 'Swan'(P <0.05), but preservative had no effect. Crude fiber content of oat cultivar was increased as the curing progressed(P<0.05) and the difference of crude fiber content of oat cultivar was maintained through the whole curing period. Effect of drying agent concentration on crude fiber content was not found after preservation. Crude fiber content of 'Swan' oat hay was higher than that of 'Foothill' by 1.O% in ADF and 3.1 % in NDF(P<0.05). No preservative effect was found in crude fiber content. According to RFV of oat cultivar at harvest, forage quality of 'Foothill' and 'Swan' was Prime and Grade 1, respectively, but that of both cultivm was above Grade 2 at the final curing day. RFV of the stored 'Foothill' and 'Swan' oat hay was 122 and 114(P<0.05), respectively, and the quality of oat hay was classified as Grade 1 and 2, respectively, according to the forage quality standard assigned by AFGC.

• Elastomers and Composites
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• 제55권2호
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• pp.95-102
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• 2020

Currently, peroxide cure is a widely used cure system for rubber materials. To improve its effectivity, co-agents are used to enhance the peroxide efficiency and mechanical properties of rubber materials. Co-agents are multifunctional organic compounds that are highly reactive towards free radicals. These co-agents provide higher cross-link densities for a given peroxide concentration and improve the mechanical properties of peroxide-cured rubber composites. In this study, trimethylolpropane trimethacrylate (TMPTMA) and high vinyl 1,2-polybutadiene (HVPBD) were used as co-agents. In order to obtain a concentration that achieves a favorable balance between mechanical properties and co-agent concentration, this research investigated the effects of co-agent content on the curing characteristics, chemical structures, and mechanical properties of HNBR composites. Additionally, the heat aging properties and compression sets of HNBR composites were investigated. Based on the results, we found that the HNBR composites with TMPTMA co-agents exhibited higher Shore A hardness and 10% modulus and better heat aging resistance and compression set than that of the HVPBD co-agent. The heat aging resistance and compression set deteriorated with increasing HVPBD content.

• 한국염색가공학회지
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• 제13권3호
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• pp.188-196
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• 2001

1, 1-diamino-3, 3, 5, 5-tetrachlorocyclotriphosphazene, 1, 1-diami-no3, 3, 5, 5-tetra-(p-bromophenoxy)cyclotriphosphazene, and 1, 1-diamino-3, 3, 5, 5-tetra-(p-chlorophenoxy) cyclotri-phosphazene(ACPP) was prepared from hexachlorocyclotriphosphazene and used for the curing agent of bisphenol A type epoxy resin and phenol novolak. The resistance to chemicals and water of the cured epoxy resins were examined by DMTA and compared with those of the epoxy rosins cured with phosphazene derivatives and 4, 4'-diaminodiphenylmethane. The effect of the curing agent on resistance to chemicals and water of the cured epoxy resins were investigated. The epoxy resins cured with 1, 1-diamino-3, 3, 5, 5-tetrachlorocyclotriphosphazene and 1, 1- diamino-3, 3, 5, 5-tetra- (p-bromophenoxy)cyclotriphosphazene showed superior resistance to chemicals and water to those of 1, 1-diamino-3, 3, 5, 5-tetra- (p-chlorophenoxy)cyclotriphosphazene and 4, 4'-diaminodiphenylmethane. It is an effective curing agent for epoxy resins to enhance the resistance to chemicals, water and tome proofing.

• International Journal of Precision Engineering and Manufacturing
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• 제1권1호
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• pp.33-41
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• 2000

Fiber reinforced metal laminates(FRMLs) were new type of hybrid materials. FRMLs consist of high strength metals(Al 5052-H34) and laminated fiber with structural adhesive bond. The effect of resin mixture ratios on the fatigue crack propagation behavior and mechanical properties of aramid fiber reinforced aluminum composites was investigated. The epoxy, diglycidylether of bisphenol A(DGEBA), was cured with methylene dianiline(MDA) with or without an accelerator(K-54). Eight kinds of resin mixture ratio were used for the experiment ; five kinds of FRMLs(1)(mixture of epoxy and curing agent) and three kinds of FRMLs(2)mixture of epoxy, curing agent and accelerator). The characteristic of fatigue crack propagation behavior and mechanical properties FRMLs(2) shows more effecting than that of FRMLs(1).

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1995년도 추계학술대회 논문집
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• pp.198-201
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• 1995

Carbons are the materials which are known to be usable at highest temperature in existing materials and are being increased their mechanical Properties to 2000$^{\circ}C$. They have many advantageous characteristics such as electrical and thereat conductivity. But, inspire of their properties, this materials have covalant bonding that strong1y link their atoms. the covalant bondings are too strong to occur atomic diffusions or shirinkages during the sintering. because of this sintering mechanism, carbon materials must be produced by using some binders. To obtain a good carton material, it is important that the function of binders. And to obtain a good binder, it reqired the additive which can improve the properties of the binder, so called curing agent. In this study, we make a curing agent that can improve the properties of binders to evaluate the yield of carbon from binders and to shirink the substrate. and compared the carbon materials treated with the binder containing the curing agent to that treated with common binder.