• Title/Summary/Keyword: Hindrance factor

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Chirality Conversion of Dipeptides in the Schiff Bases of Binol Aldehydes with Multiple Hydrogen Bond Donors

  • Park, Hyun-Jung;Hong, Joo-Yeon;Ham, Si-Hyun;Nandhakumar, Raju;Kim, Kwan-Mook
    • Bulletin of the Korean Chemical Society
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    • v.30 no.2
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    • pp.409-414
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    • 2009
  • Novel binol aldehydes derivatized at 2' hydroxy position with both uryl and acetamide groups (2), and diuryl groups (3) have been synthesized. Both were designed for streospecific binding and chirality conversion of general dipeptides with support of multiple hydrogen bonding donor sites in the receptors. The receptors, 2 and 3, converted the chirality of N-terminal amino acids of peptides such as Ala-Gly, Met-Gly, Leu-Gly and His-Gly with stereoselectivity on D-form over L-form. The stereoselectivity ratios were in the range of 5-11, somewhat higher than those of the binol receptor with mono uryl group (1). The DFT calculation at the B3LYP/6-31G$^*$//MPWB1K/6-31G$^*$ level revealed that 3-D-Ala-Gly was 2.2 kcal/mol more stable than 3-L-Ala-Gly. The considerable steric hindrance between the methyl group of the alanine and the imine CH moiety of the receptor seems to be the main contributing factor for the thermodynamic preference.

High-performance photovoltaics by double-charge transporters using graphenic nanosheets and triisopropylsilylethynyl/naphthothiadiazole moieties

  • Agbolaghi, Samira;Aghapour, Sahar;Charoughchi, Somaiyeh;Abbasi, Farhang;Sarvari, Raana
    • Journal of Industrial and Engineering Chemistry
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    • v.68
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    • pp.293-300
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    • 2018
  • Reduced graphene oxide (rGO) nanosheets were patterned with poly[benzodithiophene-bis(decyltetradecyl-thien) naphthothiadiazole] (PBDT-DTNT) and poly[bis(triiso-propylsilylethynyl) benzodithiophene-bis(decyltetradecyl-thien) naphthobisthiadiazole] (PBDT-TIPS-DTNT-DT) and used in photovoltaics. Conductive patternings changed via surface modification of rGO; because polymers encountered a high hindrance while assembling onto grafted rGO. The best records were detected in indium tin oxide (ITO):poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS):PBDTDTNT/rGO:PBDT-DTNT:LiF:Al devices, i.e., short current density $(J_{sc})=11.18mA/cm^2$, open circuit voltage $(V_{oc})=0.67V$, fill factor (FF) = 62% and power conversion efficiency (PCE) = 4.64%. PCE increased 2.31 folds after incorporation of PBDT-DTNT into thin films. Larger polymer assemblies on bared-rGO nanosheets resulted in greater phase separations.

The autecology of Zostera marina and Z. japonica at Sagumi Bay in the southwestern coast of Korea (남해 서부연안의 사구미 만에서 거머리말(Zostera marina)과 애기거머리말(Z. japonica)의 개체생태학)

  • Ok, Jae-Seung;Lee, Sang-Yong
    • Journal of Environmental Science International
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    • v.23 no.9
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    • pp.1563-1572
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    • 2014
  • The autecology of the Zostera marina and Z. japonica was studied in populations growing in the same locality (Sagumi Bay, southwestern coast of Korea). Environmental factors and plant characteristics were examined monthly from August 2008 to September 2011. Along intertidal zone, Z. japonica (0.1-0.5 m above mean lower low water, MLLW) occurred above Z. marina (0.5-2.5 m MLLW). Tidal exposure at low tide during day was the highest in the spring and the lowest in the summer. Underwater Irradiance showed seasonal fluctuation that was the highest in spring and summer caused by tidal pattern. Strong seasonal patterns in water temperature appeared to control the seasonal variations in morphology, biomass and leaf growth. The seasonal pattern of Z. japonica resembled that of the Z. marina in morphological characteristics, above-and below-ground biomass, whereas it differed in shoot density and leaf elongation. Despite some similarities in seasonal growth patterns, the patterns of Z. japonica were lagged by 2 month of Z. marina. Seasonal variation in the above biomass of Z. marina was caused by changes in density and plant size, whereas that of Z. japonica was mainly caused by changes in shoot density. Zostera marina was more sensitive to high temperatures than Z. japonica, and the increasing water temperature during the summer became the factor that inhibits the growth of the Z. marina. Zostera Japonica, there is no clear change according to the amount of the light. It is because its habitat locates above that of Zostera marina so that the amount of the light that is necessary to growth is enough and in this condition, any preventing factor does not seem to work at all. Although underwater light getting into Zostera marina's habitat is very low level and there is no any hindrance to the survival of them, it prevents them from their productivity a bit.

A Study on the Impact of Organizational Capabilities of the Criminal Investigation Police upon Organizational Concentration (수사경찰의 조직역량이 조직몰입에 미치는 영향에 관한 연구)

  • Ko, Hyun Gyoo;Lee, Yun Hwan
    • Journal of Digital Convergence
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    • v.10 no.9
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    • pp.59-72
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    • 2012
  • The police, as an advance guard for performing governmental functions, should conduct their duties to protect lives, physical bodies, and properties in the nation against various kinds of crimes, prevent from a public risk by detecting a factor that can menace public safeguard and public order and suppress it when a risk factor occurs. Practically it is impossible to protect lives, physical bodies, and properties in the nationprovided that social stability is not taken as security. The roles of the criminal investigation police that take a countermeasure to prevent a risk in prior by detecting hindrance factor of social stability and process any occurred crime in conformity with pertinent laws could control a successful performance in each of the police activities themselves. The study assumes that the organizational capabilities of the criminal investigation police exercises a significant influence upon organizational concentration. In spite of the fact that it is natural that the organizational capabilities of the criminal investigation police exercises a significant influence upon organizational concentration, until now it is very deficient in studies of this field. It is a viewpoint that an organizational concentration would be improved when a capability of the organizational staff will be improved, they would have a targeting capability for sharing organizational goals and vision and a systematic capability would be supported by the dimension of the criminal investigation police. The study was aimed to deduce a developmental method for the criminal investigation police by conducting an analysis on the impact of the organizational capabilities of the criminal investigation police upon organizational concentration that it suggest method that the criminal investigation police will make a contribution for maintaining a social order.

Effect of Truncation of 38 Amino Acids in N-terminal Region of ErmSF, a MLSB Antibiotic Resistance Factor Protein, on Enzymatic Activity (MLSB 항생제 내성인자인 ErmSF의 N-terminal 38개 아미노산 제거가 항생제 내성 효소활성에 미치는 영향)

  • Lee, Hak Jin;Jin, Hyung Jong
    • Korean Journal of Microbiology
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    • v.50 no.3
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    • pp.239-244
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    • 2014
  • ErmSF is one of the four antibiotic resistance factor proteins expressed by Streptomyces fradiae, antibiotic tylosin producer, which renders $MLS_B$ (macrolide-lincosamide-streptogramin B) antibiotic resistance through dimethylating A2058 of 23S rRNA, thereby reducing the affinity of antibiotic to ribosome. Unlike other Erm proteins, ErmSF harbors long N-terminal end region. To investigate its role in enzyme activity, mutant ErmSF deleted of 1-38 amino acids was overexpressed and activity in vivo and in vitro was observed. In vitro enzymatic assay showed that mutant protein exhibited reduced activity by 20% compared to the wild type enzyme. Due to the reduced activity of the mutant protein, cells expressing mutant protein showed weaker resistance to erythromycin than cells with wild type enzyme. Presumably, the decrease in enzyme activity was caused by the hindrance in substrate binding and (or) product release, not by defect in the methyl group transfer occurred in active site.

The Analysis of Change Factors and Improvement of the Planning techniques on the Number of Floor in Multi Housing Complex Planning -Focus on Planning Index- (공동주택 층수계획 변화요인 분석과 계획기법 개선에 관한 연구 -계획지표를 중심으로-)

  • Cho, Sung-Hak
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.4
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    • pp.428-437
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    • 2017
  • Recently, local government has established a development strategy which takes into account the quality of each area, in order to solve the problems posed by poor development, hindrance of the urban landscape, the limits imposed by relevant laws, etc. However, the number of floors is an important factor which determines the urban landscape, planning density and quality of the external space. This planning factor has a very different effect according to the terrestrial circumstances, number of households, underparking ratio, green space ratio and floor area ratio. Therefore, in this study, a case analysis and case study are conducted and the correlation between each index is clarified. The conclusions of this study are follows. Firstly, flexibility should be ensured by taking into consideration the density indicators, average number of floors, and residential environmental performance measures in related laws and systems. Secondly, it is necessary to develop a wide-area planning method that extends the planning concept from the beginning of planning to neighboring blocks or cities. Thirdly, deregulation measures should be implemented, such as establishing specialized strategies for each region, and regulatory measures for encouraging different types of development.

Renewable Energy Potentials and Promotion Policies in Indonesia (인도네시아 신재생 에너지 잠재력 및 보급 정책)

  • Yurnaidi, Zulfikar;Kim, Suduk
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.11a
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    • pp.137.1-137.1
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    • 2010
  • For Indonesia, sustainable energy supply is an important factor to preserve the stable economic growth. One important strategy is development of renewable energy, which has not been fully exploited yet. The paper examines the potency of renewable energy in Indonesia. Currently, biomass composes 23% of total primary energy supply, while geothermal and hydropower has a combined share of 3%. But according to the overall potency of renewable energy, hydropower is found to have the highest available resource of 76 GW, followed by biomass and geothermal by 49.81 GW and 28.53 GW, respectively. Although the solar radiation is only at modest level ($4.80kWh/m^2/day$), the tropical all year sunlight can boost the competitiveness of solar photovoltaic and thermal application. As for wind energy, the average speed of 3-6 m/s requires the development of low speed wind turbine. The examination of electricity and petroleum product prices through international comparison for non-OECD countries shows fifth lowest price level for both of petroleum products and electricity for industrial use. As for household electricity price, Indonesia is placed the second among all the countries compared. The energy subsidy and price structure are examined in detail because it could be a source of hindrance to renewable energy promotion. The examination of renewable energy potency in this study could provide insights about recent development of renewable energy in Indonesia. As an outcome of policy examination, the price comparison analysis suggests Indonesia to reduce or even remove the energy subsidies in the long run. These findings can be utilized to formulate effective policies for renewable energy promotion.

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A Study on the Nuclear Structure through the Multipurpose Coincidence Measurement System Development ( I ) - The Electromagnetic Properties of the Gamma Transitions in $^{75}As$- (다목적 동시측정 장치 개발에 의한 원자핵 구조 연구(I) - $^{75}As$의 감마 전이에 대한 전자기적 특성 -)

  • Chung, Won-Mo;Chung, Kap-Soo;Joo, Koan-Sik;Na, Sang-Kyun;Hwang, Han-Yull
    • Journal of Radiation Protection and Research
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    • v.18 no.1
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    • pp.53-61
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    • 1993
  • The gamma-gamma coincidence measurements and angular correlation measurement associated with the electron capture of $^{75}Se$ have been carried to understand the structure for the odd nuclei $^{75}As$ with two HPGe detectors. As a result, we could determined the band structure of 5/2 state to be of 1/2 [310] band which is based on $f_{5/2}$ proton state. Also we obtained the multipole admixture in the state of 279.5keV by using the mixing ratios of $121.1{\sim}279.5keV$ cascade. Subsequently, it is determined that 25.56% electric quadrupole transition is involved in the state of 279.5keV.

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A Study on characteristics analysis of autotrophic denitrification microbial community using sulfur granule (황입자를 이용한 T. denitrificans에 의한 질소제거 최적화 연구)

  • Yoon, Su Chul;Joo, Jae-Young;Nam, Duck-Hyun;Park, Chul-Hwi
    • Journal of Korean Society of Water and Wastewater
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    • v.22 no.2
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    • pp.259-265
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    • 2008
  • Generally speaking, there are two widely used methods of Nitrogen removal from waste water: 1) nitrification using autotrophic microorganisms, and 2) denitrification using heterotrophic microorganisms. The C/N ratio is an important factor of the denitrification process. In this case, if methanol is added to increase the lacking organic matter, a high economic cost is incurred and methanol is left in the processed water. In an effort to fix these issues, autotrophic denitrification through the use of Hydrogen, Iron and Sulfur is being studied, and among those Sulfur is cheaper and carries out denitrification effectively, and therefore is being studied the most. In this study, after cultivating T. denitrificans, the presence of T. denitrificans was determined and the effectiveness of denitirification via T. denitrificans was studied. In order to find out about the inhibition of T. denitrificans from the loading of organic matter, this shows that the greater the loading of organic matter, the more the denitrification ability of T. denitrificans is hindered. In order to research the hindrance of T. denitrificans resulting from the loading of $NO_3{^-}-N$, these results show that concentrations less than 100mg/L per 100mL of gel volume do not hinder T. denitrificans. In order to research the optimization of denitrification resulting from T. denitrificans, three 500mL samples of Sulfur granules were prepared: 1) one with only T. denitrificans attached (Mode I), 2) one with both T. denitrificans and active sludge attached (Mode II), and 3) one with only active sludge attached (Mode III). The results showed that autotrophic denitrification using S from Mode I was the most active.

Improvement of Channel Water Quality Module in SWAT (SWAT 모형의 하도 수질 모듈의 개선)

  • Kim, Nam-Won;Shin, Ah-Hyun
    • Journal of Korean Society on Water Environment
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    • v.25 no.6
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    • pp.902-909
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    • 2009
  • With various reservoirs, dams and reduction of water velocity in downstream, rivers in Korea often have characteristics of accumulation of pollutants. Therefore, the main focus of water quality modeling in Korea needs to be shifted from DO to algae and organic matter. Moreover the structures of water quality models should be modified to have capability of simulating BOD which is a key factor of total water pollution load management in Korea as laboratory experiment BOD (Bottle $BOD_5$). In the SWAT model which is one of the widely used water quality models in Korea, the channel water quality module is using main algorithm of the QUAL2E model which has limitations in simulating algae, organic matter and Bottle BOD5 etc. To overcome this hindrance, in this study, the improved channel water quality module of the SWAT model (Q-SWAT) was proposed by linking the algorithms of the QUAL-NIER model which was developed based on the QUAL2E model to the SWAT model. The algorithms estimating the increase of internal organic matter by fractionization algal metabolism process and calculating Bottle $BOD_5$ were added and the results of proposed model were compared to those of the original SWAT model. The results of comparison test are showing that more accurate BOD values can be obtained with the Q-SWAT model and it is anticipated that the Q-SWAT model can be used as an effective tool of decision support through the water quality simulation and long term pollution source analysis.