• Bulletin of the Korean Chemical Society
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• 제30권6호
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• pp.1325-1330
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• 2009

A general method has been developed for the solid phase synthesis of drug-like 7-aryl-benzo[b][1,4]oxazin-3(4H)- one derivatives 6. The method relies on a novel, microwave irradiation promoted cyclization reaction of the BOMBA resin bound, N-substituted-$\alpha$-(2-chloro-4-bromophenoxy)acetamide 3 that takes place via a Smiles rearrangement. The 7-bromobenzo[1,4]oxazine 4, produced in this process is converted to 7-aryloxazin analogs 5 by utilizing Suzuki coupling with various substituted arylboronic acids. Finally, the target 7-aryl-benzo[b][1,4]oxazin-3(4H)-ones 6 are liberated from the resin by treatment with 5% TFA. The progress of the reactions involved in this preparative route can be monitored by using ATR-FTIR spectroscopy on a single bead. The target compounds, obtained by using this five-step sequence, are produced in high yields and purities.

• Bulletin of the Korean Chemical Society
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• 제33권12호
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• pp.4109-4116
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• 2012

An efficient solid-phase methodology has been developed for the synthesis of 2-amino and 2-amidobenzo[d]-oxazole derivatives. The key step in this procedure involves the preparation of polymer-bound 2-aminobenzo-[d]oxazole resins 4 by cyclization reaction of 2-hydroxy-phenylthiourea resin 3. The resin-bound 2-hydroxyphenylthiourea 3 is produced by the addition of 2-aminophenol to the isothiocyanate-terminated resin 2 and serve as a key intermediate for the linker resin. This core skeleton 2-aminobenzo[d]oxazole resin 4 undergoes functionalization reaction with various electrophiles, such as alkylhalides and acid chlorides to generate 2-amino and 2-amidobenzo[d]oxazole resins 5 and 6 respectively. Finally, 2-amino and 2-amidobenzo[d]oxazole derivatives 7 and 8 are then generated in good yields and purities by cleavage of the respective resins 5 and 6 under trifluoroacetic acid (TFA) in dichloromethane ($CH_2Cl_2$).

• Advances in concrete construction
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• 제15권2호
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• pp.115-126
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• 2023

This paper investigates creep analysis of a plate made of Al-SiC functionally graded material using Mendelson's method of successive elastic solution. All mechanical and thermal material properties, except Poisson's ratio, are assumed to be variable along the thickness direction based on the volume fraction of reinforcement and thickness. First, the basic relations of the plate are derived using the Love-Kirchhoff plate theory. The solution of governing equations yields an elastic solution to start creep analysis. The creep behavior is demonstrated through Norton's equation based on Pandey's experimental results extracted for Al-SiC functionally graded material. A linear variation is assumed for temperature distribution along the thickness direction. The creep strain, as well as the thermal strain, are included in the governing equations derived from classical plate theory for mechanical strain. A successive elastic solution based on Mendelson's method is employed to derive the history of stresses, strains, and displacements over a long time. History of stresses and deformations are obtained over a long time to predict damage to the plate because of various loadings, and material composition along the thickness and planar directions.

• 한국분말재료학회지
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• 제29권6호
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• pp.485-491
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• 2022

Lithium lanthanum titanium oxide (LLTO) is a promising ceramic electrolyte because of its high ionic conductivity at room temperature, low electrical conductivity, and outstanding physical properties. Several routes for the synthesis of bulk LLTO are known, in particular, solid-state synthesis and sol-gel method. However, the extremely low ionic conductivity of LLTO at grain boundaries is one of the major problems for practical applications. To diminish the grain boundary effect, the structure of LLTO is tuned to nanoscale morphology with structures of different dimensionalities (0D spheres, and 1D tubes and wires); this strategy has great potential to enhance the ion conduction by intensifying Li diffusion and minimizing the grain boundary resistance. Therefore, in this work, 0D spherical LLTO is synthesized using ultrasonic spray pyrolysis (USP). The USP method primarily yields spherical particles from the droplets generated by ultrasonic waves passed through several heating zones. LLTO is synthesized using USP, and the effects of each precursor and their mechanisms as well as synthesis parameters are analyzed and discussed to optimize the synthesis. The phase structure of the obtained materials is analyzed using X-ray diffraction, and their morphology and particle size are analyzed using field-emission scanning electron microscopy.

• Journal of Microbiology and Biotechnology
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• 제33권7호
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• pp.926-933
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• 2023

Aspergillus oryzae KCCM 11372 was used to enhance the production of β-glucan using humidity control strategies. Under conditions of 60% humidity, solid-state fermentation (SSF) increased the yields of enzymes (amylase and protease), fungal biomass (ergosterol), and β-glucan. The maximum concentrations obtained were 14800.58 U/g at 72 h, 1068.14 U/g at 120 h, 1.42 mg/g at 72 h, and 12.0% (w/w) at 72 h, respectively. Moreover, the β-glucan containing fermented brown rice (β-glucan-FBR) extracts at concentrations of 25-300 ㎍/ml was considered noncytotoxic to 3T3-L1 preadipocytes. We then studied the inhibitory effects of the extracts on fat droplet formation in 3T3-L1 cells. As a result, 300 ㎍/ml of β-glucan-FBR extracts showed a high inhibition of 38.88% in lipid accumulation. Further, these extracts inhibited adipogenesis in the 3T3-L1 adipocytes by decreasing the expression of C/EBPα, PPARγ, aP2, and GLUT4 genes.

• 한국식품과학회지
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• 제15권2호
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• pp.136-140
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• 1983

도정수율별 보리의 수화특성(水和特性)을 $20{\sim}60^{\circ}C$ 범위에서 조사하고 속도론적으로 해석하였다. 흡수량(吸水量)은 수화시간(水和時間)의 평방근에 비례하였으며 흡수양상(吸水樣相)은 흡수량(吸水量) $0.45{\sim}0.55g\;H_2O/g$ solid 이후에서 변화하였다. 수화속도(水和速度)는 도정수율 50>70>95>90%>무도정맥의 순서였으며 수화온도(水和溫度)가 높을수록 증가하였다. 이 때 곡립내부(穀粒內部)로의 물의 확산도(擴散度)는 Arrhenius방정식에 의거하여 변화하였으며 활성화에너지는 도정맥의 경우 $6.9{\sim}9.5Kcal/mole$, 무도정맥의 경우 11.6Kcal/mole이었다.

• KSBB Journal
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• 제18권4호
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• pp.306-311
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• 2003

융합단백질의 절단을 위해 EK를 고정화하여 액상 절단반응과 같은 80％의 절단수율을 얻을 수 있었다. 그리고 니켈 친화칼럼을 이용하여 간단한 정제공정을 구축하였다. 공유결합한 EK의 경우 니켈친화 결합한 EK보다 높은 재접힘 수율을 나타내었고 풀림과 재접힘을 이용하여 효소의 초기 활성을 회복함에 따라서 반복사용을 통한 경제적인 절단공정을 구축할 수 있게 되었다. 그러나 고정화 과정에서 효소의 활성이 감소하는 문제점과 고정화 수율을 높이기 위한 연구가 필요하다.

• 한국작물학회지
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• 제46권1호
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• pp.29-34
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• 2001

A sweet sorghum [Sorghum bicolor (L.) Moench] cultivar was planted on 9 and 30 June 2000 at plant densities of 4, 6, 8, 10, and 12 plants $m^{-2}$ to determine the optimum plant density in Jeju region. There were no significant planting date x plant density interactions for most traits measured. Delaying planting from 9 to 30 June delayed 21 days in heading date, and significantly decreased plant height, the number of productive stems $m^{-2}$/, and lodging. Fresh stem yield tended to be higher at the 9 June planting date than at the 30 June planting date, but total sugar and ethanol yields were not significantly affected by planting date. Percentage of soluble solid was higher at the 30 June planting date compared with the 9 June planting date. Fresh stem, total sugar, and ethanol yields quadractically increased from 22.9 to 36.7 $t^{-1}$, from 1.66 to 2.54 $t^{-1}$, and from 945 to 1440 $L^{-1}$, respectively, with increasing plant density. The optimal plant densities for the maximum fresh stem, total sugar, and ethanol were estimated to be 10.7, 9.6, and 9.9 plants $m^{-2}$ respectively.

• 대한화학회지
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• 제36권6호
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• pp.933-940
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• 1992

Calix[6]arene을 포름알데히드와 이차아민과 반응시키면 물에 녹는 칼릭세린 염기가 얻어진다. 이를 메틸요오드로 처리하여 암모늄 염을 만들고 다양한 친핵성 물질과 반응시키면 칼릭세린의 파라위치에 작용기가 포함된 calix[6]arene이 얻어진다. Calix[6]arene도 포름알데히드와 이차의 아릴아민과 반응시켜 물에 녹는 칼릭세린 아민을 만들었다. 이렇게 합성된 칼릭세린중 물에 녹는 아민과 산기가 포함된 calix[6]arene과 calix[8]arene을 운반체로 이용하여 중성의 방향족 물질들을 통과시키는 연구를 U 형태의 유리관을 이용하여 수행하였다. 방향족 기질들로는 나프탈렌, 안트라센, 파이렌, 풀우란텐 등의 고체물질을 사용하였다.

• 분석과학
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• 제14권5호
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• pp.392-399
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• 2001

생물시료에 존재하는 휘발성 유기화합물 중 n-butylbenzene과 1,2-dibromo-3-chloropropane (DBCP)를 기체크로마토그래피/질량분석기-선택이온검색법에 의해 수행하였다. 시료 중 휘발성 유기화합물은 $100{\mu}m$ polydimethyl siloxane (PDMS) fiber를 사용하여 headspace solid phase microextractio (SPME) 및 purge & trap 방법에 의해 추출 및 비교하였다. SPME에 의한 회수율은 n-butylbenzene의 경우 85.8%, DBCP의 경우 92.4%로 나타났고 검출한계는 각각 $0.15{\mu}g/kg$, $0.05{\mu}g/kg$로 나타났다. 반면, purge & trap의 경우 회수율은 n-butylbenzene의 경우 115.2%, DBCP의 경우는 80.9%로 나타났고 검출한계는 각각 $0.04{\mu}g/kg$ 및 $0.70{\mu}g/kg$로 나타나 두 방법에 있어 국내에서 규제하는 검출한계측면에서 큰 차이는 없었다.