• YAKHAK HOEJI
• /
• v.13 no.1
• /
• pp.47-50
• /
• 1969

The ether extract of Dang-Gui, the dried root of Angelica gigas N$_{AKAI}$, was placed into a column with aluminium oxide gel. The elution of it with a mixture of n-hexane and ethyl acetate afforded Nodakenetin (I) and the elution with a mixture of n-hexane, ethyl acetate, acetone and methyl alcohol yielded Umbelliferon (II) and Nodakenin (III). Three coumarin derivatives were identified by comparing with authentic samples. The existence of sucrose and glucose was also proved.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
• /
• v.4 no.1
• /
• pp.79-90
• /
• 1993

With immunohistochemical method, We have examined the distribution, the size, the number, and the morphology of somatostatin-immunoreactive neurons in the cerebral cortex of rats at the 1st. 2nd, 3rd, 4th postnatal week and the 2nd and 3rd months of age. The results are summarized as follows : 1) Strongly immunoreactive somatostatin neurons were found in the layer V and VI at the first postnatal week and then they were observed to be densely populated in the layer II and III from the 3rd postnatal week on as in the adult rat. 2) The size of the neuron was largest at the 2nd postnatal week while the number of the neurons was greatest in the 1st or 2nd postnatal week, depending on the different areas of the cortex. Overall the postnatal development of somatostatin neurons are well corresponds with the general principle of neuronal development of CNS.

• Korean Journal of Soil Science and Fertilizer
• /
• v.44 no.5
• /
• pp.727-733
• /
• 2011

A new Korean standard for the determination of Cr(VI) in soils has been officially published as ES 07408.1 in 2009. This analytical method is based on the hot alkaline digestion and colorimetric detection prescribed by U.S. EPA method 3060A and 7196A. The hot alkaline digestion accomplished using 0.28 M $Na_2CO_3$ and 0.5 M NaOH solution (pH 13.4) at $90{\sim}95^{\circ}C$ determines total Cr(VI) in soils extracting all forms of Cr(VI), including water-soluble, adsorbed, precipitated, and mineral-bound chromates. This aggressive alkaline digestion, however, proved to be problematic for certain soils which contain large amounts of soluble humic substances or active manganese oxides. Cr(III) could be oxidized to Cr(VI) by manganese oxides during the strong alkaline extraction, resulting in overestimation (positive error) of Cr(VI). In contrast, Cr(VI) reduction by dissolved humic matter or Fe(II) could occur during the neutralization and acidic colorimetric detection procedure, resulting in underestimation (negative error) of Cr(VI). Futhermore, dissolved humic matter hampered the colorimetric detection of Cr(VI) using UV/Vis spectrophotometer due to the strong coloration of the filtrate, resulting in overestimation (positive error) of Cr(VI). Without understanding the mechanisms of Cr(VI) and Cr(III) transformation during the analysis it could be difficult to operate the experiment in laboratory and to evaluate the Cr(VI) results. For this reason, in this paper we described the theoretical principles and limitations of Cr(VI) analysis and provided useful guidelines for laboratory work and Cr(VI) data analysis.

• Korean Journal of Ichthyology
• /
• v.24 no.3
• /
• pp.227-229
• /
• 2012

Based on a single juvenile specimen (20.7 mm SL) collected from Jeju Island, Apogon semiornatus was described as a new Korean record. The species is characterized by having VI-I, 9 dorsal fin rays, 12 pectoral fin rays; II, 8 anal fin rays and two blackish oblique bands on yellowish red body. A new Korean name, "Geom-eun-du-jul-bulg-eun-dong-gal-dom", is proposed.

• 전기의세계
• /
• v.17 no.2
• /
• pp.16-26
• /
• 1968

Cds is possible to add excess donors and to compensate partially using other group metals as acceptors. The impurities can ble incorporated either during crysta growth or by diffusion into a bulkcrystal. The addition of rimpurities leads also to the production of vacancies in a manner depending on the atmosphere surrounding the crystal during growth, during the diffusion process or using bulk. Cds of the mentioned above affects spectral sensitivity, speed of response, the variation on photocurrent, electron life time, and decay of photoconductivity with temperature and with intensity of illumination. In the work to be deseribed, these properties have been studied between liquid nitrogen and room temperature. In addition, the electron trap distribution has been correlated with speed of response, variation of photocurrent with temperature in various atmosphere. Four major trapping levels have been observed, and their identification with impurity and vacancy levels is discussed. And also the effects of lattice imperfections on the photoconductive properties CdS were investigated in detail.

• The Journal of Korean Academy of Prosthodontics
• /
• v.22 no.1
• /
• pp.23-32
• /
• 1984

The effects between preexisting four types and one that author had designed of posterior palatal seal on the retention of denture base were compared and observed from six systemically healthy edentulous subjects. Using one without posterior palatal seal as the control, the retention of each type was measured and analyzed six times with cantilever type Load cell after adaptation of denture base, which were constructed with usual manner. The following results wear obtained. 1. Morphological and positional changes of posterior palatal seal effected on denture retention. 2. No specific type showed most desirable effect in every experimental subject. 3. Experimental subject I, II, VI showed higher retention on the control in every type. 4. In five types of posterior palatal seal, for subject III, VI F types and for subject II, V C types were most effective. 5. In each experimental subject F type showed higher retention than the control.

• Development and Reproduction
• /
• v.17 no.2
• /
• pp.87-97
• /
• 2013

The seminiferous epithelium cycle and developmental stages of spermatids in Clethrionomys rufocanus were observed under a light microscope. The seminiferous epithelium cycle was divided into 8 stages. Type Ad spermatogonia appeared through all stages. Type Ap, In, and B spermatogonia appeared in stages I, II, III, and IV. In the first meiosis prophase, the leptotene spermatocytes appeared from stage V, the zygotene spermatocytes in stages I, VI, VII, VIII, the pachytene spermatocytes from stages II to VI, the diplotene spermatocytes in stage VII. The meiotic figures and interkinesis spermatocytes were observed in stage VIII. Developing spermatids were subdivided into 10 steps, based on the morphological characteristics such as the acrosome formation changes in spermatozoa, nucleus, cytoplasm, and spermiation changes. The C. rufocanus spermatocytogenesis and spermiogenesis results displayed similar results with Apodemus agrarius coreae and A. speciosus peninsulae. Considering all the results, the spermatogenesis may be useful information to analyze the differentiation of spermatogenic cells and the breeding season.

• Journal of environmental and Sanitary engineering
• /
• v.22 no.1 s.63
• /
• pp.49-56
• /
• 2007

The effects of pH, time, dielectric constant of solvent and crosslink on adsorption of metal ions by 1-aza-18-crown-6-styrene-DVB(divinylbenzene) resin(resin) adsorbent were investigated. The metal ions were showed fast adsorption on the resins in over pH 3. The equilibrium time for adsorption of metallic ions was about two hours and the adsorption selectivity determined in methanol was in increasing order $UO_2^{2+}>Mg^{2+}>Ho^{3+}$ ions. The adsorption was in the order of 1%, 2% and 4% crosslink resin and adsorption of resin decreased in proportion to the order of dielectric constant of solvents.

• Journal of environmental and Sanitary engineering
• /
• v.17 no.3
• /
• pp.31-36
• /
• 2002

The effects of pH, time, dielectric constant of solvent and crosslink on adsorption of metal ions by resin(cryptand resin) adsorbent were investigated. The metal ions were showed fast adsorption on the resins in over pH 3. The equilibrium time for adsorption of metallic ions was about two hours and the adsorption selectivity determined in methanol was in increasing order $UO^{2+}$ > $Mn^{2+}$ > $Gd^{3+}$ ion. The adsorption was in the order of 1%, 2% and 5% crosslink resin and adsorption of resin decreased in proportion to the order of dielectric constant of solvents.

• Applied Microscopy
• /
• v.27 no.3
• /
• pp.257-263
• /
• 1997

Microstructural characterizations of II-VI blue laser diodes which consist of quaternary $Zn_{1-x}Mg_xS_ySe_{l-y}$ cladding layer, ternary $ZnS_ySe_{l-y}$ guiding layer and $Zn_{0.8}Cd_{0.2}Se$ quantum well as active layer were carried out using the transmission electron microscope working at 300 kV. Even though the entire structure is pseudomorphic to GaAs substrate, the structure had contained numerous extended stacking faults and dislocations which had created at ZnSe/GaAs interfaces and then further grown to the top of the epilayers. These faults might be expected to cause the degradation and shortening the lifetime of laser devices.