排序方式: 共有19条查询结果,搜索用时 15 毫秒
1.
Young Hyun Cho Wanno Lee Kun Ho Chung Geun Sik Choi Chang Woo Lee 《Journal of Radioanalytical and Nuclear Chemistry》2007,274(3):531-538
The seasonal variation of the 7Be activities in air and the size distribution of the 7Be aerosols were studied by using a continuous air sampler and a five stage cascade impactor. The mean monthly activity level
of 7Be at the Korea Atomic Energy Research Institute (KAERI) site varied from 0.5 to 4.8 Bq·m−3 and revealed a seasonal variation, in which the 7Be activity levels were high in winter and low in summer. The mass size distribution showed a bi-modal distribution with a
higher peak around 0.49 μm and a smaller peak between 3 μm and 7.2 μm. The activity median aerodynamic diameter (AMAD) decreased
with increasing ambient 7Be concentrations. The mean residence times by using a mean growth rate of 0.004 μm·h−1 were estimated to be 2.5–6.4 days. The AMAD has an increasing tendency with higher relative humidity. It seemed that the
high humidity condition facilitated the growth of the aerosol, resulting in increased deposition rates of the aerosols and
the low 7Be content in the surface air. The AMAD of the 7Be aerosols increased with an increasing temperature, but the temperature dependency of AMAD should be explained with geological
and meteorological conditions. 相似文献
2.
Sauvarop Bualek‐Limcharoen Sayant Saengsuwan Taweechai Amornsakchai Banchob Wanno 《Macromolecular Symposia》2001,170(1):189-196
Blends of various grades of polypropylene (PP) with a thermotropic liquid crystalline polymer (TLCP), namely a copolymer of p‐benzoic acid and ethylene terephthalate (60/40 mole ratio) were prepared as extruded films. A thermoplastic elastomer styrene (ethylene‐butylene) styrene (SEBS) was used as a compatibilizer. Melt viscosities of all specimens were measured using a plate‐and‐plate rheometer with oscillating mode in the shear rate region of 1 ‐ 200 rad/s. Addition of SEBS compatibilizer resulted in an increase of the blend viscosity. Observation of the blend morphology revealed an improvement of TLCP dispersion. The TLCP fiber aspect ratio (length to diameter) in the extruded film also increased after addition of SEBS. As a result, the film modulus in extrusion direction was enhanced. The tensile strength of the film specimen was also increased due to an improvement of interfacial adhesion. 相似文献
3.
Promthong Niwat Tabtimsai Chanukorn Rakrai Wandee Wanno Banchob 《Structural chemistry》2020,31(6):2237-2247
Structural Chemistry - The adsorptions of CO and CO2 on pristine and transition metal-doped graphene nanoflakes (GNFs) were theoretically investigated using the density functional theory. Doping of... 相似文献
4.
Siwinee Tetasang Somchai Keawwangchai Banchob Wanno Vithaya Ruangpornvisuti 《Structural chemistry》2012,23(1):7-15
The structures of mono- and di-podal pyrrolic amides functionalized (5,5) single-walled carbon nanotubes (SWCNTs) and their
complexes with fluoride, chloride, and bromide ions were obtained using the two-layered ONIOM(MO:MO) and density functional
theory (DFT) methods. The binding energies between halide ions and all the receptors and their charge transfers were obtained
using DFT method. The computational results indicate that the pyrrolic amide functionalized on the SWCNT affects to the density
of state and energy gap of SWCNT. All the free receptors, mono-, di-podal pyrrolic amides and the functionalized SWCNT forming
the strongest complexes were found. 相似文献
5.
Chang Woo Lee Mun Ja Kang Wanno Lee Geun Sik Choi Young Hyun Cho Hee Reyoung Kim Kun Ho Chung 《Journal of Radioanalytical and Nuclear Chemistry》2009,279(2):519-522
210Po in the daily diet in Korea was analyzed and the ingestion dose from an intake of 210Po was estimated by considering the dietary habit of a Korean person. The 210Po concentrations of a leafy vegetable (0.36 Bq·kg−1 for lettuce) in the terrestrial food were higher than those of grain, whereas Chinese cabbage had a lesser 210Po concentration (0.019 Bq·kg−1). The 210Po concentration of the animal product was similar to those detected in the grain and vegetable. The 210Po concentrations in the shell and crustaceous were high from 19.1 to 33.0 Bq·kg−1, however, its value fell in the overall range of the reported values. The effective dose from 210Po for an adult from the Korean population was about 269.4 μSv·y−1. Nearly 80% of the ingestion dose from the intake of 210Po was attributed to the consumption of seafood. It suggests that the marine food ingestion is a critical pathway for natural
210Po to the Korean population. 相似文献
6.
Thianthan Taweetanavanich Banchob Wanno Thawatchai Tuntulani Buncha Pulpoka Chatthai Kaewtong 《中国化学会会志》2019,66(5):493-499
A rhodamine‐based colorimetric and fluorescent pH chemosensor ( RhA ) was designed and synthesized via a coupling reaction between rhodamine ethylenediamine and succinic anhydride. RhA showed excellent pH response in aqueous solutions. In addition, common cations (Na+, K+, Ag+, Mg2+, Ca2+, Pb2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Hg2+, Al3+, Cr3+, Fe3+, Au3+, Pt2+, and Ru2+) did not interfere with the pH response. As it has the potential to be used as a portable pH sensor, RhA was immobilized on activated cellulose paper using N,N'‐dicyclohexylcarbodiimide (DCC) and N,N'‐dimethylpyridin‐4‐amine (DMAP) as the coupling reagent to obtain a composite pH sensor ( CP‐RhA ). CP‐RhA was characterized by ATR‐FTIR, UV–vis, and fluorescence spectroscopy, and by scanning electron microscopy (SEM). CP‐RhA showed a rapid response in the pH range 1–8 through color and fluorescence changes. DFT calculations showed a blue‐shifted spectrum in the protonated form compared to the neutral form. Moreover, the pH sensor paper could be reused by dipping in NaOH. Thus, our work demonstrates the potential of the rhodamine dye composite for visualizing pH changes in real systems. 相似文献
7.
8.
Sirichai Piyaauksornsak Totsaporn Tangthongkul Raina Wanbayor Banchob Wanno Vithaya Ruangpornvisuti 《Structural chemistry》2009,20(5):767-780
The structures of 8,8′-bis(3-phenylthioureidomethyl)-2,2′-binaphthalene (1), 8,8′-bis(3-butylthioureidomethyl)-2,2′-binaphthalene (2) and their complexes with anionic guests such as carboxylate ions (acetate, oxalate, malonate, succinate, glutarate, adipate,
pimelate, suberate, and azelate), inorganic oxygen-containing anions (nitrate, sulfate, bicarbonate, hydrogen phosphate, and
dihydrogen phosphate), and halide ions (fluoride, chloride, and bromide) were obtained using the ONIOM approach. The binding
abilities of receptors 1 and 2 to anionic species in terms of binding energy, thermodynamic properties, and selectivity coefficient were obtained at the
ONIOM(B3LYP/6-31G(d):AM1) and BSSE-corrected B3LYP/6-31G(d)//ONIOM(B3LYP/6-31G(d):AM1) levels of theory. The multipoint hydrogen
bonding between receptors (either the receptor 1 or 2) and anionic guests were found. The hydrogen phosphate is the most preferable ion to bind with either the receptor 1 or 2. 相似文献
9.
Effect of melt viscosity of polypropylene on fibrillation of thermotropic liquid crystalline polymer in in situ composite film 总被引:1,自引:0,他引:1
Various grades of polypropylene were melt blended with a thermotropic liquid crystalline polymer, a block copolymer of p-hydroxy benzoic acid and ethylene terephthalate (60/40 mole ratio). The blends were extruded as cast films at different values
of draw ratio (slit width/film thickness). Fibrillation of TLCP dispersed phase with high fiber aspect ratio (length/width)
was obtained with the matrix of low melt flow rate, i.e., high viscosity and with increasing film drawing. Melt viscosities
of pure components and blends measured using capillary rheometer were found to decrease with increasing shear rate and temperature.
Viscosity ratios (dispersed phase to matrix phase) of the systems being investigated at 255 °C at the shear rate ranged from
102 to 104 s−1, were found to lie between 0.04 and 0.15. The addition of a few percent of elastomeric compatibilizers; a tri-block copolymer
SEBS, EPDM rubber and maleated-EPDM, was found to affect the melt viscosity of the blend and hence the morphology. Among these
three compatibilizers, SEBS was found to provide the best fibrillation.
Received: 10 January 2000/Accepted: 24 January 2000 相似文献
10.
Kun?Ho?ChungEmail author Geun?Sik?Choi Wanno?Lee Young?Hyun?Cho Chang?Woo?Lee 《Accreditation and quality assurance》2006,10(11):603-605
The practical experience on the implementation of ISO/IEC 17025 compliant quality system in a nuclear analytical laboratory of the Korea Atomic Energy Research Institute (KAERI) is described. This paper summarizes the need for a quality system and accreditation, the process of a quality system implementation, the quality system structures, and the formal accreditation of our laboratory by the Korean Laboratory Accreditation Scheme (KOLAS). Also, the improvements in the management, technical and service quality which resulted from implementation of this system are briefly reported. 相似文献