• Title/Summary/Keyword: Consistent

Search Result 9,959, Processing Time 0.038 seconds

Effect of Nonsolvent Additive in Casting Solutions on Polysulfone Membrane Preparation (Polysilfone 막의 제조에 있어 제막용액에 첨가된 비용매의 영향)

  • 한명진
    • Membrane Journal
    • /
    • v.6 no.3
    • /
    • pp.157-165
    • /
    • 1996
  • Polysulfone(PS) membranes were prepared from homogeneous PS solutions by the phase inversion technique. When propionic acid(PA) was added into a casting solution of n-methylpyrrolidone(NMP) and PS, precipitation rate of the solution film was accelerated. This kind of acceleration was consistent, even though a precipitating nonsolvent was changed from water to isopropanol. These phenomena were caused by decrease of nonsolvent tolerance in the casting solution due to addition of PA. PS powder was prepared by precipitation of a 3wt% solution in dimethylformamide(DMF) using ethanol as nonsolvent. Gas adsorption analysis of the powder showed that the capillary condensation sites were found in the powder structure. Membranes prepared from PS solution(15wt%) in NMP had the following characteristics of gas adsorption and water permeation. In gas adsorption analysis, the membrane precipitated using isopropanol showed low uptake of nitrogen gas and the capillary condensation sites were not found. On the contrary, a significant amount of the capillary condensation sites was found in the membrane coagulated by water, which was related to increase of nitrogen uptake. tn the membrane prepared froin the solution including PA, an increase of the Henry's law sites and the Langmuir sites was not found clearly. However, the capillary condensation sites were significantly increased, and the water transport also increased.

  • PDF

Experiments on the stability of the spatial autocorrelation method (SPAC) and linear array methods and on the imaginary part of the SPAC coefficients as an indicator of data quality (공간자기상관법 (SPAC)의 안정성과 선형 배열법과 자료 품질 지시자로 활용되는 SPAC 계수의 허수 성분에 대한 실험)

  • Margaryan, Sos;Yokoi, Toshiaki;Hayashi, Koichi
    • Geophysics and Geophysical Exploration
    • /
    • v.12 no.1
    • /
    • pp.121-131
    • /
    • 2009
  • In recent years, microtremor array observations have been used for estimation of shear-wave velocity structures. One of the methods is the conventional spatial autocorrelation (SPAC) method, which requires simultaneous recording at least with three or four sensors. Modified SPAC methods such as 2sSPAC, and linear array methods, allow estimating shear-wave structures by using only two sensors, but suffer from instability of the spatial autocorrelation coefficient for frequency ranges higher than 1.0 Hz. Based on microtremor measurements from four different size triangular arrays and four same-size triangular and linear arrays, we have demonstrated the stability of SPAC coefficient for the frequency range from 2 to 4 or 5 Hz. The phase velocities, obtained by fitting the SPAC coefficients to the Bessel function, are also consistent up to the frequency 5 Hz. All data were processed by the SPAC method, with the exception of the spatial averaging for the linear array cases. The arrays were deployed sequentially at different times, near a site having existing Parallel Seismic (PS) borehole logging data. We also used the imaginary part of the SPAC coefficients as a data-quality indicator. Based on perturbations of the autocorrelation spectrum (and in some cases on visual examination of the record waveforms) we divided data into so-called 'reliable' and 'unreliable' categories. We then calculated the imaginary part of the SPAC spectrum for 'reliable', 'unreliable', and complete (i.e. 'reliable' and 'unreliable' datasets combined) datasets for each array, and compared the results. In the case of insufficient azimuthal distribution of the stations (the linear array) the imaginary curve shows some instability and can therefore be regarded as an indicator of insufficient spatial averaging. However, in the case of low coherency of the wavefield the imaginary curve does not show any significant instability.

A Study on Dementia Alzheimer's type published to chinese magazine (중의잡지(中醫雜誌)에 보고(報告)된 Alzheimer형(型) 치매에 대(對)한 고찰(考察))

  • Chae, Jong-gul;Lee, Sang-ryong
    • Journal of Haehwa Medicine
    • /
    • v.10 no.1
    • /
    • pp.453-469
    • /
    • 2001
  • This study attempted to analyze the contents of the research papers concerning the diagnosis and treatment of Alzheimer-type dementia presented in the magazine of Chinese Medicine published in China over the period between 1998 and 2000. As a result, the following conclusion was drawn: 1. The Chinese medical category of Alzheimer-type dementia includes amnesia, dementia, stupidity, depression symptom complex, insanity and the like and uses the as the criterion for diagnosis and treatment effect evaluation. 2. The clinical symptoms of Alzheimer-type dementia include lowered intelligence, deterioration of memory, understanding and judgemental power, retardation of the reaction, emotional changes, character changes, behavioral changes and the like and are divided into mild, medium and serious according to the degree of symptom. 3. From the perspective of Bon-Heo-Pyo-Shil(state of deficient vital essence and excessive pestilential vapor), the pattern of Byun-Sung(identification) is divided into deficiency symptom complex, excessive symptom complex and indiscernible fullness and emptiness. The deficiency symptom complex includes deficiency of the liver and kidney, deficiency of essence of the kidney, deficiency of the reservoir of marrow and the like. The excessive symptom complex includes internally blocked stagnant blood, blocking of the passageway due to turbid phlegm, blood stasis due to stagnation of chi, and the like. The indiscernible fullness and emptiness symptom complex includes the deficiency of essence of kidney, blocking of the passageway due to stagnant phlegm, blood stasis due to the deficiency of kidney, blood stasis due to the deficiency of heart and the like. 4. The therapeutics and' prescription of Alzheimer-type dementia include the following: Bo-Shin-Ik-Su-Tang for tonifying the kidney, replenishing the marrow and plugging the essence; Ki-Guk-Ji-Hwang-Hwan-Ga-mi for reinforcing the vital essence of the liver and kidney; Kwi-Bi-Tang-Hap-Yang-Shim-Tang for invigorating the functioning of the spleen and nourishing the heart; Hyel-Bu-Chuk-Eo-Tang-Ga-Mi for activating the blood and resolving the stagnancy of the blood; Bo-Yang-Hwan-Oh-Tang for replenishing chi, activating the blood and resolving the stagnancy of the blood; Beoh-Kwang-Mong-Sung-Tang for invigorating the functioning of the spleen, replenishing the kidney, resolving the phlegm and enlivening the brain; n-Dam-Tang-Ga-Mi for invigorating the functioning of the spleen, replenishing chi, and removing the phlegm and unclogging the passageway); Se-Shim-Tang-Ga-Mi for removing the stagnancy of the liver and resolving the phlegm; and the like. 5. The research papers on, the medication cases of Alzheimer-type dementia understand the pathology of Alzheimer-type dementia from a consistent perspective. They view the pathology of Alzheimer-type dementia as the disease of Bon-Heo-Pyo-Shil(state of deficient vital essence and excessive pestilential vapor) with the combination of the deficiency of essence of the kidney, the deficiency of the brain marrow, blood stasis and blocked phlegm and the like and recommend the prescription of using Bo and Sa simultaneously for treating Alzheimer-type dementia. 6. The research papers on the medication cases of Alzheimer-type dementia reported that the use of creative prescriptions such as Si-Sam-Hang-Ji-Tang, Ji-Yung-Tang, Ka-Mi-Yunh-Ji-Hwan, Ja-Sin-Hwal-Hyel-Tang, Kal-Chang-Ik-Ji-Tang, Ho-Su-Bok-Ji-Tang, Kun-Noe-Ok-Ji-Hap-Je and the like led to the average high efficacy of 85.5%.

  • PDF

Characteristics of Bird Community in Sihwa South Grassland, Korea (시화호 남측 초지지역의 조류 군집 특성)

  • Park, Chi-Young;Kim, Ho-Joon;Paik, In-Hwan;Yu, Jae-Pyoung;Paik, Woon-Kee;Lee, Joon-Woo
    • Korean Journal of Environment and Ecology
    • /
    • v.29 no.4
    • /
    • pp.516-524
    • /
    • 2015
  • This study was characteristics of bird community conducted to from 2009 to 2010 in Sihwa South Grassland, Gyeonggi-do, Korea. Total 49 species were recorded and the sum of maximum counts was 2,258 individuals. Species diversity was 2.21 and the species richness was 6.22. In South Reclaimed, we recorded maximum score of 38 species. and maximum score of 1,083 individuals in Dinosaur Egg Fossil. Comparison between areas were use average species diversity and species richness. Mostly Dinosaur Egg Fossil and South Reclaimed were higher than Sihwa Lake upstream. As a results of the ANOVA test, all areas were different. also, Sihwa Lake upstream only difference was that the bird community. In the season there was a significant difference between the Number of species and species richness. Number of species and species richness were significant differences depending on the season. but individuals and species diversity were no significant differences. In the year there was a no significant difference between the Number of species and individuals. but species diversity and species richness were significant differences. As a result, Between areas was different patterns of bird communities. but including water space Dinosaur Egg Fossil and South Reclaimed were showed a similar bird communities and bird diversity was higher. In the season, the resident was using of consistent patterns. but, There were differences depending on the migratory patterns of populations. In the year, every year was communities of a similar patterns. Sihwa South Grassland is of the high conservation value ecosystem as the only domestic. Propose an opinion for maintaining biodiversity when planning future habitat composition and environmental decrease.

Concentration Levels and Distribution Characteristics of Polycyclic Aromatic Hydrocarbons (PAHs) at Ambient Air in Industrial Complex Area (공단지역 대기 중 다환방향족탄화수소화합물(PAHs)의 농도수준 및 분포특성)

  • Jung, Jong-Hyeon;Phee, Young-Gyu;Cho, Sang-Won;Ok, Gon;Shon, Byung-Hyun;Lee, Kwan;Lim, Hyun-Sul
    • Clean Technology
    • /
    • v.17 no.4
    • /
    • pp.379-388
    • /
    • 2011
  • The purpose of this study was to investigate the concentration levels, distribution characteristics and blood concentration of Polycyclic Aromatic Hydrocarbons (PAHs) at ambient air in Industrial Complex Area. The samples were collected at 4 sites in Industrial Complex Area and its vicinities. The result indicated that there was the difference of PAHs concentration as followed local characteristics. The level of average concentration of PAHs in the air in Industrial Complex Area was $14.52{\sim}193.48ng/m^3$. The level of average concentration of six materials with possibility of cancer creation was $1.65{\sim}13.44ng/m^3$. The concentrations of PAHs were generally low, but Jechul-dong is considered an area where consistent monitoring of PAHs is required. In addition, benzo(a)pyrene was detected in every atmospheric sample, however the concentration was not high. The level of concentration of benzo(a)pyrene in the air in the Jechul-dong was $2.89ng/m^3$. But, the concentration of the PAHs in Jechul-dong showed that the Benzo(a)pyrene concentration is above $1ng/m^3$ of air quality standard(EU). The results of the concentration level of PAHs in the blood from 240 persons who were exposed directly were surveyed, it was $1.12{\sim}11.45ng/m^3$ for man and $1.20{\sim}26.89ng/m^3$ for woman. It was indicated that the difference between the genders was very little. The accumulation inside human was anticipated as the PAHs concentration in the blood for the aged was very high. Industrial Complex Area and its vicinities are an area which has been greatly influenced by PAHs and environmental contaminants. It is necessary to control the emission sources of PAHs and to construct an observation system at Industrial Complex Area from now on. It is time to reduce the risk factors for health and environmental disease to protect the health of resident in Industrial Complex Area and its vicinities.

A Study on the Hydraulic Characteristics of Rashig Super-Ring Random Packing in a Counter-Current Packed Tower (역류식 충전탑에서 Raschig Super-ring Random Packing의 수력학적 특성에 대한 연구)

  • Kang, Sung Jin;Lim, Dong-Ha
    • Clean Technology
    • /
    • v.26 no.2
    • /
    • pp.102-108
    • /
    • 2020
  • In recent years, packed column has been widely used in separation processes, such as absorption, desorption, distillation, and extraction, in the petrochemical, fine chemistry, and environmental industries. Packed column is used as a contacting facility for gas-liquid and liquid-liquid systems filled with random packed materials in the column. Packed column has various advantages such as low pressure drop, economical efficiency, thermally sensitive liquids, easy repairing restoration, and noxious gas treatment. The performance of a packed column is highly dependent on the maintenance of good gas and liquid distribution throughout a packed bed; thus, this is an important consideration in a design of packed column. In this study, hydraulic pressure drop, hold-up as a function of liquid load, and mass transfer in the air, air/water, and air-NH3/water systems were studied to find the geometrical characteristic for raschig super-ring experiment dry pressure drop. Based on the results, design factors and operating conditions to handle noxious gases were obtained. The dry pressure drop of the random packing raschig super-ring was linearly increased as a function of gas capacity factor with various liquid loads in the Air/Water system. This result is lower than that of 35 mm Pall-ring, which is most commonly used in the industrial field. Also, it can be found that the hydraulic pressure drop of raschig super-ring is consistently increased by gas capacity factor with various liquid loads. When gas capacity factor with various liquid loads is increased from 1.855 to 2.323 kg-1/2 m-1/2 S-1, hydraulic pressure drop increases around 17%. Finally, the liquid hold-up related to packing volume, which is a parameter of specific liquid load depending on gas capacity factor, shows consistent increase by around 3.84 kg-1/2 m-1/2 S-1 of the gas capacity factor. However, liquid hold-up significantly increases above it.

Effect of Feeding Thymus vulgaris Powder on the Productivity, Egg Quality and Egg Yolk Fatty Acid Composition in Laying Hens (Thymus vulgaris 분말의 급여가 산란계의 생산능력, 난품질 및 난황 내 지방산 조성에 미치는 영향)

  • Park, Seong-Bok;Lee, Kyeong-Jin;Lee, Wang-Hyu;Ryu, Kyeong-Seon
    • Korean Journal of Poultry Science
    • /
    • v.39 no.2
    • /
    • pp.157-161
    • /
    • 2012
  • The objective of this study was to evaluate the effects of feeding dried Thymus vulgaris powder (TVP) on the layer performance, egg quality and egg yolk fatty acid composition. Two hundred eighty eight, 35 weeks old Brown nicks were allocated in the cage for five TVP (0, 0.25, 0.5, 1.0 and 2.0%) diets with four replicates in each treatment. Each basal diet contained 16.0% CP and 2,800 kcal/kg ME and supplied to layers for 8 weeks. Egg production and egg weight were not statistically different but numerically increased in birds fed 2.0% TVP than other treatments. Egg mass was not consistent depending on the TVP addition levels in diets. Feed intake was significantly lower in TVP addition treatments than the control (p<0.05), however, feed conversion was not significantly differed among control and treatments (p<0.05). Dietary addition of 2.0% TVP showed high values on albumin height, Haugh unit and egg yolk color and they are 7.93, 86.79 and 7.20, respectively (p<0.05). Palmitic and arachidonic acids were remarkably lowered when 2.0% TVP added to basal diets and then fed to birds for 8 weeks, in contrast, significantly higher linolenic acid composition was determined in birds fed 2.0% TVP (p<0.05). As the results, the highest unsaturated fatty composition and UFA/SFA ratio were observed in 2.0% TVP treatment as compared to those of control and other treatments. Therefore, the results indicate that the Thymus vulgaris powder addition to basal diet tended to have positive effects on egg quality and egg yolk fatty acids composition, and the optimum addition of Thymus vulgaris powder may be 2.0%.

Bond Orbital Theory of Chemical Reactivity (反應性의 結合 Orbital 理論)

  • Yang, Kang;Ree, Tai-Kyue
    • Journal of the Korean Chemical Society
    • /
    • v.8 no.1
    • /
    • pp.20-24
    • /
    • 1964
  • The linear combination of bond orbitals method is used to investigate the reactivity of halomethanes in abstraction reactions by atoms. The activation energy is evaluated on the assumption that, in an activated complex, two electrons in a bond to be broken become completely isolated from the rest of the ${\sigma}$-electron systems. Such a model leads to an intuitively attractive concept that the interactions between the reactive bond and the neighboring bonds govern the reactivity of ${\sigma}$-electron systems. The resulting equation for the activation energy, ${\varepsilon},\;is:\;{\narepsilon}= ${\varepsilon}={\zeta}+$$${\sum}_{i=1}^3$${\eta}c-I,$ c-4 Here, subscript C-4 indicates the bond to be broken, while C-i represents the other three bonds surrounding the reactive bond; ξ is the activation energy of a hypothetical reaction of an isolated C-4 bond and an attacking atom; and ${\eta}$C-i,C-4 stems from the stabilizing interacting of C-4 bond with neighboring C-i bonds. A choie of η′s consistent with bond strength data simplifies the above equation to a form ${\varepsilon}={\zeta}\;+\;N{\eta}c$-H, C-4 where N denotes the number of C-H plus C-F bond in halomethanes. In agreement with this equation, experimental -values increase linearly with increasing N.

  • PDF

Strategies of Large Park Development and Management through Governance - Case Studies of The Presidio and Sydney Harbour National Park - (거버넌스를 통한 대형 도시공원의 조성 및 운영관리 전략 - 프레시디오 공원과 시드니 하버 국립공원 사례를 중심으로 -)

  • Sim, Joo-Young;Zoh, Kyung-Jin
    • Journal of the Korean Institute of Landscape Architecture
    • /
    • v.44 no.6
    • /
    • pp.60-72
    • /
    • 2016
  • This study aims to suggest strategies of development and management for large parks by examining experimental cases of park governance models related to a shift away from public administration. The shifts towards governance as well as public-private partnership in city parks have involved the need for new public management. This study has analyzed two exemplary cases of Presidio Park and Sydney Harbour National Park in the aspects of planning process and management strategies, as the results derived the meaning and effect of park governance management and is also an essential prerequisite for the achievement of the model. There are six dimensions of research frames--namely policy, governance, partnership, finances and funds, design and maintenance-management, and evaluation-monitoring-taken as the basis for this study. Through the analysis, several key characteristics of these cases were elicited. First, the park planning process must be consistent in carrying a policy from planning to implementation, and furthermore, an independent operation body which can properly authorize an execution and uphold its responsibility from the public could serve in adaptable park services. Second, it has been suggested to build various partnerships with PAs and NGOs, private corporations, community groups, and academic institutes that allow it to expand the diversity of the park activities. Third, there has been experimental exploration to achieve a financially self-sufficient model by establishing internal revenue models and hence allow the reduction of reliance on public finances. The result of this type of park management would allow for improving park quality and make the park space a vital part of the local economy. Fourth, the strategies for a local community's participation are needed to allow the community to become a producer as well as a consumer. This study shows that the direction and significance of the park governance model regarding the fact that the plans sought by the two parks are extending the layout of public-centered discussion to the private sector and the third non-governmental sector including to the local community group. This shows both implications and limitations, such as the risk of privatization through non-governmental activities at the park or the violation of essential functions as a public good due to a profit-generating management policy for securing financial self-sufficiency. At the current point in which plans are under way for the development and management of large parks, a park governance model requires continuous study and expansion of discussion in the future.

What Do Female Jobs Do for Women's Job Continuity? : Occupational Sex Segregation and Women's Job Exits in the U.S.

  • Min, Hyeon-Ju
    • Korea journal of population studies
    • /
    • v.29 no.1
    • /
    • pp.185-207
    • /
    • 2006
  • Predominant explanations of the persistence of sex segregation ill occupations link job choices to profoundly gendered responses to childbearing and other family demands, arguing that women are more likely to seek jobs which are in some sense compatible with motherhood, either because they are family friendly (flexible, low intensity work) or because they are easy to exit and re-enter. In this paper, I examine the effect of occupational sex segregation on job exits into the labor market among women, with a special attention to the role of childbearing and child rearing. I use data from detailed employment histories gathered from the National Longitudinal Survey of Youth (NLSY) in continuous time event history models. My results indicate that women in female dominated jobs are less likely to exit their jobs than women in other types of occupations. Further this relationship is not shaped by motherhood. While mothers or pregnant women are more likely to leave work, mothers in female-dominated occupations are slightly less likely to leave employment than mothers in other occupations. These results are not consistent with the ideas that women's choice of female-dominated occupations expresses a gendered identity and women strategically seek jobs which accommodate maternal roles. Taken together, my findings do not provide support to the idea that women choose female-dominated occupations because they are easier to integrate with motherhood (except for the pregnancy period).