• Title/Summary/Keyword: absorption medium

Search Result 370, Processing Time 0.027 seconds

Self-assembly of Amphiphilic Zinc Chlorins in an Aqueous Medium as a Model for Chlorosome of Green Photosynthetic Bacteria

  • Miyatake, Tomohiro;Kato, Syuusaku;Tamiaki, Hitoshi;Fujiwara, Manabu;Matsushita, Takayuki
    • Journal of Photoscience
    • /
    • v.9 no.2
    • /
    • pp.347-349
    • /
    • 2002
  • Synthetic zinc chlorins possessing a hydrophylic polyoxyethylene chain at the 17 -position were prepared. An amphiphilic zinc chlorin possessing a single chIorin moiety showed absorption maxima at 675 nm in an aqueous medium, indicating that the zinc chIorin did not form large aggregates but a dimeric structure. In contrast, amphiphilic zinc chlorin dyads in which two zinc chlorin moieties were connected with a hydrophilic polyoxyethylene linkage showed red-shifted absorption band around 720-740 nm in an aqueous medium. The result indicated that the amphiphilic zinc chlorin dyad self-aggregated to form chlorosome-like oligomer.

  • PDF

A study on the heat transfer characteristics of gas-radiative medium into a high temperature generator of an absorption refrigerator (흡수식 냉동기 고온재생기 내의 가스복사체 열전달 특성에 관한 연구)

  • Jung, Dae-In;Kim, Yong-Mo;Bae, Suk-Tae
    • Solar Energy
    • /
    • v.18 no.1
    • /
    • pp.81-89
    • /
    • 1998
  • In this paper an experimental was done to design combustion chambers which is required radiation strength of high temperature generator of absorption rigerator. Partiqularly, in combustion chamber radiative mediums were set and basic experiments were done according to its size by radiation strength and effects of heat transfer promotion. The results are as follows : 1) When radiative mediums were set in small combustion furnace burning nonframely radiative heat transfer was effected. 2) In case that area ratio($A/A_o$) of radiative medium is 0.82 or over, temperature fluctuation effects of furnace inside were not nearly. 3) In experimental boundary heat transfer effects were 1.8 times by setting up radiative medium. Specially, $q/{\Delta}T$ values of furnace inside were uniformed nearly by setting up radiative mediums.

  • PDF

암모니아/물 흡수식 냉동기의 대향류 판형 재생기의 수치모델

  • 지제환;정은수;정시영
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.13 no.10
    • /
    • pp.1034-1041
    • /
    • 2001
  • A numerical model which simulates the flow boiling process of the ammonia/water solution within a plate type generator for ammonia/water absorption refrigerators was developed. The ammonia/water solution flows downward under gravity and the ammonia/water vapor generated by flow boiling flows upward. The heating medium flows counter to the ammonia/water solution. The flow pattern within the generator was assumed to be a bubbly flow, and the liquid and vapor phases were assumed to be saturated. It was shown that the boiling of ammonia occurred mainly in the upper part of the generator. The effects of the heating medium inlet temperature, the mass flow rate of the heating medium and the mass flow rate of ammonia/water solution into the generator on the generation of ammonia/water vapor were investigated.

  • PDF

Effect of Germanium Treatment in Culture Medium on Germanium Absorption by Callus Induced from Brown Rice (배지내 게르마늄 처리가 현미 유도 캘러스의 게르마늄 흡수에 미치는 영향)

  • 권태오;남궁승박;박병우
    • KOREAN JOURNAL OF CROP SCIENCE
    • /
    • v.41 no.6
    • /
    • pp.729-735
    • /
    • 1996
  • This study was carried out to investigate the effect of Germaniwn(Ge) treatment in the culture media on the Ge absorption by the callus induced from brown rice cv. Dongjinbyeo. MS medium was more effective on the growth ratio of callus and the content of Ge and some inorganic elements except K in callus than N$_{6}$ medium. The more Ge treatment in the N$_{6}$ or MS medium, the more Ge absorption by the callus, but the growth ratio of callus and the content of Ca, Mg, and K in callus were decreased. The content of Fe, Mn, Zn, and Cu was increased under treatment up to 100~200mg /$\ell$ Ge, but tended to be decreased under treatment more than that of Ge concentration. Under treatment less than 150mg /$\ell$ Ge, GeO$_2$(inorganic Ge) was more effective on the Ge absorption by callus than Ge-132(organic Ge), but Ge-132 was more effective on the Ge ab-sorption by callus and the activity of callus in case of treatment more than 150mg /$\ell$ Ge. The lower pH of culture medium, the higher Ge content in the callus. When callus was cultured on medium supplemented with Ge and 0.1~1.0mM of citric acid or myo-inositol, content of Ge and some inorganic elements in callus, as well as growth and dry weight of callus, were tend to increase in comparison to control, but myo-inositol was more effective on them than citric acid.cid.

  • PDF

The Effect of Dietary Pectin on the Absorption of Vitamin $B_12$ in Rats in Various Vitamin $B_12$ Status (상이한 비타민 $B_12$ 영양상태에 있는 흰쥐에 있어서 식이중의 펙틴이 비타민 $B_12$의 흡수에 미치는 영향)

  • Kim, Jung-In
    • Journal of the Korean Society of Food Science and Nutrition
    • /
    • v.23 no.3
    • /
    • pp.396-401
    • /
    • 1994
  • The effect of vitamin B12 status and pectin feeding on vitamin B12 absorption in rats were studied. Rats in low, medium, and high vitamin B12 status were fed either fiber-free or 10% pectin diet and absorption of a single oral dose of vitamin B12 status of rats was verified by urinary methylmalonic acid and liver vitamin B12 measurements. Absorption of vitamin B12 tended to increase as the rats became deficient in vitamin B12 , although the difference was not significant . Pectin inhibited absorption of vitamin B12 regardless of the vitamin B12 status of the rats. The results demonstrated that inhibition of vitamin B12 absorption by pectin would be a possible mechanism for the impairment of vitamin B12 status due to chronic pectin feeding.

  • PDF

Surface Plasmon Resonances of Metal Colloidal Particles Synthesized by a Photo-Chemical Process (광화학적 방법을 이용한 금속입자의 합성과 광학적 특성 연구)

  • Ko, Min-Jin;Plawsky, Joel
    • Journal of the Korean Chemical Society
    • /
    • v.43 no.1
    • /
    • pp.1-7
    • /
    • 1999
  • Metal colloidal particles have been prepared by a photo-chemical process in an aqueous solution containing semiconductor nanocrystallites. Metal colloidal particles produced in CdS and AgBr exhibit different absorption spectra. Au particles produced in solution with CdS show typical Au plasmon resonance absorption spectra. On the other hand Ag particles in solution with AgBr shows surface plasmon resonance absorption spectra which are red-shifted, as compared to that of a dispersion of homogeneous Ag colloidal particles in the same host. The extent of red-shift depends on the UV illumination time. This phenomenon is interpreted within the context of effective medium theory for small volume fractions. From the theory, a metal coated particle predicts Ag plasmon resonance, red shifted with respect to 400 nm that would be associated with a silver particle in solution. The absorption peak position is very sensitive to the coating thickness.

  • PDF

The study was to analyze the effect of various ultrasound transmission media (초음파 투과성 매질들의 여러 특성에 관한 연구)

  • Ghang, Goon-Yong;Kim, Young-Bae
    • Journal of Korean Physical Therapy Science
    • /
    • v.9 no.4
    • /
    • pp.185-192
    • /
    • 2002
  • Ultrasound has been found useful as a therapeutic modality for the reduction of muscular and tendinous spasm. It has also been utilized for pain and other pathologic conditions through the ability of soundwaves to introduce molecules of chemical substances through the skin by a process. Choice of the transmission medium is very important for effective ultrasound treatment in clinical field. The purpose of this study was to analyze the effects of various ultrasound conduction media in regard to ultrasound conductivity and degree of absorption, evaporation and of skin irritation. The media used in this study were Antiphlamine, Sacch lotion, Stereogel, Trastgel, Antiphlamine S lotion, and Mentholatum lotion that have been used in clinical medicine. The study revealed that Antiphlamine was not compatible with a good ultrasound transmitter. Other media excluding Antiphlamine were compatible with a good ultrasound conductor, but they had some drawback with their nature of higher absorption, evaporation and skin irritation. The medium that was prepared by mixing of Antiphlamine with Gel in 1 to 10 ratio was a good ultrasound transmitter and extents of absorption and evaporation and of skin irritation of it were less than the other media.

  • PDF

Dissoultion and Rectal Absorption of Acetaminophen from Suppositories (아세트아미노펜 좌제의 용출과 직장흡수)

  • 한정선;심창구;김신근
    • YAKHAK HOEJI
    • /
    • v.31 no.5
    • /
    • pp.286-295
    • /
    • 1987
  • The relationship between in vitro release and in vivo bioavailability of acetaminophen from suppositories was investigated. Effect of glycyrrhizin on the drug release and rectal absorption in rats was also examined. Suppositories containing 25mg of acetaminophen were prepared with Wecobee FS (fatty base) or PEG (water-soluble base) bases. The release from the suppositories were determined with USP rotating basket dissolution apparatus and with the suppository release tester. The temperature of the dissolution medium was very critical for the dissolution of acetaminophen from Wecobee FS suppositories. The bioavailability of acetaminophen was calculated from the plasma concentration-time curve after rectal administration of the suppositories to the rats. There were no significant differences in AUC following rectal administration of Wecobee FS and PEG suppositories, but the release and absorption from the Wecobee FS suppositories were faster than those from PEG suppositories. The dissolution rate obtained by the suppository release tester was better correlated with in vivo absorption rate constant than that by the USP dissolution apparatus. It suggests that the partitioning between rectal fluid and suppository base is the rate-limiting step in the rectal absorption of acetaminophen from suppositories. Glycyrrhizin was found not to affect in vitro dissolution and rectal absorption of acetaminophen.

  • PDF

X-RAYING LARGE-SCALE STRUCTURE

  • HENRY J. PATRICK
    • Journal of The Korean Astronomical Society
    • /
    • v.37 no.5
    • /
    • pp.371-374
    • /
    • 2004
  • We review the observational evidence for the existence of a warm-hot intergalactic medium (WHIM). We expect that the morphology of this material is similar to that of cosmic rays and magnetic fields in large-scale structure, i.e., filaments connecting clusters of galaxies. Direct evidence for the WHIM, either in emission or absorption, is weak.

EFFECTS OF RADIATION AND HEAT GENERATION ON MHD AND PARABOLIC MOTION ON CASSON FLUIDS FLOW THROUGH A ROTATING POROUS MEDIUM IN A VERTICAL PLATE

  • J. PRAKASH;A. SELVARAJ
    • Journal of applied mathematics & informatics
    • /
    • v.42 no.3
    • /
    • pp.607-623
    • /
    • 2024
  • This article studies the effects of heat generation/absorption and thermal radiation on the unsteady magnetohydrodynamic (MHD) Casson fluid flow past a vertical plate through rotating porous medium with constant temperature and mass diffusion. It is assumed that the plate temperature and concentration level are raised uniformly. For finding the exact solution, a set of non-dimensional partial differential equations is solved analytically using the Laplace transform technique. The influence of various non-dimensional parameters on the velocity are discussed, including the effects of the magnetic parameter M, heat generation/absorption Q, thermal radiation parameter R, Prandtl number Pr, Schmidt number Sc, permeability of porous medium parameter, Casson fluid parameter γ, on velocity, temperature, and concentration profiles, which are discussed through several figures. It is found that velocity, temperature, and concentration profiles in the case of heat generation parameter Q, Casson fluid parameter γ, thermal Grashof number Gr, mass Grashof number Gc, Permeability Porous medium parameter K, and time t have retarding effects. It is also seen that the magnetic field M, Thermal Radiation parameter R, Prandtl field Pr, Schmidt number Sc have reverse effects on it.