• Korean Journal of Soil Science and Fertilizer
• /
• v.26 no.1
• /
• pp.37-42
• /
• 1993

Influences of metal concentration, pH and temperature on metal-ligand precipitate formation were investigated, as a part of projects for removing heavy metals from aqueous solution employing the principles in metal-ligand complexation. Aqueous solutions of HA or FA were reacted with those of heavy metals with 1:1 ratio. Efficiency of humic (HA) or fulvic acid (FA) on removing metals was evaluated by separating the precipitates from soltuions with the filtering method. When HA was a counter ligand, there existed three ranges of metal concentrations affecting precipitation : precipitate fromation was not available, was reached to the maximum, and afterwards was decreased again. The concentration ratios of metal to HA for initiating complexation were dependent upon kinds of metal and concentrations of ligand. Amount of Pb to form maximum precipitates per unit mg of HA was 1.3 times higher than that of Cu. When FA was a counter ligand, concentrations of metal-FA precipitates were increased proportionally with the treated metal concentrations. Efficiency of FA fro removing Pb was nearly 100%, but it was ranged from 12 to 19% for Cu, depending on FA concentration. pH exerted a considerable effect on complexation between Pb and FA, showing precipitates were increased six times at most per unit increase of pH. Ranges of pH increasing significantly the mounts of precipitates were coincied with pH jump ranges of the titration curve of organic ligands. As increasing temperature from 15 to $55^{\circ}C$, increases of FA-Cu precipitates were doubled, but those of FA-Pb were accounted for only 6%, However, HA-metal complexation was not affected by temperature.

• Applied Biological Chemistry
• /
• v.19 no.1
• /
• pp.36-40
• /
• 1976

The mucilage of the root of Abelmoschus manihot, MEDIC is important for production of Korean traditional hand-made paper. This study was proceeded to detect the variation of the amount of free reducing sugars and of the viscosity in the mucilage. The results as follow. 1. The mucilage of the root of Abelmoschus manihot, MEDIC has contained some of free reducing sugars, 2. The viscosity of the mucilage isolated from the root decreases with time at the constant temperature, but the amount of reducing sugars show a little change. 3. The amount of the reducing sugars is not changed on the agitation. 4. When $1{\sim}2%$ ammonium sulfate solution is added, the viscosity of the mucilage decreases very gradually, and the amount of the free reducing sugars in the mucilage shows a little change.

• Korean Chemical Engineering Research
• /
• v.52 no.3
• /
• pp.382-387
• /
• 2014

The PC/ABS blends were manufactured with high shear rate processing. Changes of the blend morphology were analyzed according to the screw speed and processing time. To find optimal conditions of the high shear rate processing of the PC/ABS blend, blend morphology and size of the dispersed phase, ABS, were observed with a SEM. Also, tensile properties of the PC/ABS blends were measured to investigate the effect of the high shear rate process with the screw speed of 500 rpm to 3000 rpm for processing times of 10s to 40s. Especially, to observe the dispersed phase of the PC/ABS blend clearly, fracture surfaces of the PC/ABS blend were etched with chromic acid solution. As screw speed and processing time increase, dispersed phase size of the PC/ABS blend decreases and mechanical properties of the blend decrease as well. Especially, at screw speed over than 1000 rpm of high shear rate processing, mechanical properties of the PC/ABS blends decrease drastically due to the degradation of the blend during the high shear rate processing. Consequently, the optimal condition of screw speed of the high shear processing of the PC/ABS blend is set at 1000rpm, in this study. Under optimal condition, the PC/ABS blend has relatively high mechanical properties with the relatively stable micro-structure having nanometer scale dispersed phase.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.31 no.3
• /
• pp.381-390
• /
• 2004

The purpose of this in vitro study was to investigate the effects of Nd:YAG laser irradiation and fluorides on acid drink demineralized enamel. The materials were 30 freshly extracted permanent premolars with intact smooth enamel surfaces. They were demineralized with Coca-cola at $37^{\circ}C$ for 12hours and then irradiated by Nd:YAG laser with 6W power, $50mJ/cm^2$ energy density, and 20Hz pulse repetition. After laser irradiation, teeth were treated by three kinds of fluorides; (1)0.05% NaF fluoride solution (2)1.23% APF gel and (3)0.1%F fluoride varnish, microhardness(VHN) and Diagnodent scores were measured and the surfaces of each treated specimens were also observed with SEM under 1500 magnification. The results were as follows: 1. In the change of microhardness(VHN), it decreased to 34.68% from the initial micrhardness, increased to 78.37% after laser irradiation and increased to 82.62% after fluoride treatment, there were significant differences except when it was irradiated and treated with fluoride(P<0.05). 2. In the change of Diagnodent scores, it was decreased to 28.08% from the initial scores after demineralization, and then increased to 59.81% after laser irradiation, and increased to 82.17% after fluoride treatment. Scores were different significantly between the scores of initial, demineralization, laser irradiation and fluoride treatment(P<0.05). All the scores were not different significantly between fluoride types. 3. SEM observation showed that the lased enamel surfaces after demineralization were thermally degenerated and showed molten lava-like appearance and crater with cracks and many microholes.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.8 no.1
• /
• pp.20-30
• /
• 1975

It is matter of fact processing technology must affects the quality and yield of final product and these also depend on the selection of raw material directly or indirectly. So that the estimation of tile preprocessing condition of shellfish is of great importance for distributors and processors. This study was attempted to establish the basic data for evaluating the processing suitability of baby clam, which is one of the five important shellfishes for domestic use and export. The important results are as follows: 1. The ratio of meat volume and meat weight to the holding capacity by shells may be useful for measuring the condition index of baby clams. 2. Baby clams grown in the beds with the composition of a large quantity of gravel were low in condition index value than in sand and mud. 3. If the green feed phenomenon was the prime consideration for canned baby clams, tile most suitable harvest season if October. In this period, the digestive tract in body was almost colorless. 4. As a whole, seasonal changes of moisture and fat content in baby clams were reversely correlated. Protein content increased from April and slightly decreased for a while from July to August and increased again from September. In March, the content of glycogen was 6.3 to 6.8 percent. From this period to October, glycogen was rapidly decreased. In October, it was only 0.1 to 0.2 percent but increased from November. There were little seasonal changes in pH value and crude ash content. The pH value of meat was 6.0 to 6.2 and crude ash content was about 2 percent. 5. By the results of condition index and chemical composition of baby clams, the suitable harvest season as raw materials for processing was from March to June and from September to October. 6. The steamed baby clam meat was packed with 2 percent salt solution containing 0.15 percent, citric acid or 0.5 percent $Na_2$ EDTA in a round sanitary tin can coated with C-enamel that is 203.9 ml by volume and sterilized for 60 minutes at $112^{\circ}C$. The canned product has shown a good result to reserve the natural characteristics of baby clam through six month storage at room temperature.

• Korean Journal of Agricultural Science
• /
• v.10 no.2
• /
• pp.354-364
• /
• 1983

Confonmation of (Z)-cinnamonitrile have been studied by molecular orbital theoretically using extended Huckel theory(EHT) and CNDO/2 molecular orbital calculation methods. The results indicate that the stability of conformation is(Z)-gauch>(Z)-planar. The rate constants for alkalie hydrolysis of cinnamonitrile at pH 7.0-14.0 range have been determined by ultra-violet spectrophotometry in 50% methanol at $25^{\circ}C$ and the following rate equation which can be applied over wide pH range was obtained; $${\therefore}k=({\frac{1.41{\times}10^{-14}+1.21{\times}10^7/[H_3O^+]}{2.65{\times}10^{-7}+1.64/[H_3O^+]})+9.14{\times}10^9/[H_3O^+]$$ The rate equation reveals that, at pH 7.0-10.0, the reaction is initiated by the addition of water molecule to unsaturated cabon-carhon double bond of cinnamonitrile and ${\alpha}C-{\beta}C$ bond scission follow subsequently in neutral and alkalie media. At pH 12.0-14.0, in strong alkalie solution, that so-called Michael type nucleophilic addition that the over-all rate constants is only dependent upon the concentration of hydroxide ion occurs competitively and are very complicated. Hence, the reaction mechanism of alkalie hydrolysis of cinnamonitrile which did not carefully before can be fully explained.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.32 no.1 s.55
• /
• pp.45-51
• /
• 2006

In the field of makeup cosmetics, especially, powder-based foundations such as two-way cake, pact and face powder, the quality of which is known to be strongly influenced by the properties of powder, surface treatment technology is widely used as a method to improve the various characteristics of powder texture, wear properties, dispersion ability and so on. The two-way cake or pressed-powder foundation is one of the familiar makeup products in Asian market for deep covering and finishing purpose. In spite of the relent progress in surface modification method such as composition of powders with different characteristics and application of a diversity of coating ingredient (metal soap, amino acid, silicone and fluorine), this product possess a technical difficulty to enhance both of the adhesion power and spreadability on the skin in addition to potential claim of consumer about heavy or thick feeling. This article is covering the preparation and coating method of nano-vesicle that mimic the double-layered lipid lamellar structure existing between the corneocytes of the stratum corneum in the skin for the purpose of improving both of two important physical characteristic of two-way cake, spreadability and adhering force to skin, and obtining better affinity to skin. Nano-vesicle was prepared using the high-pressure emulsifying process of lecithin, pseudo ceramide, butylene glycol and tocopheryl acetate. This nano-sized emulsion was added to powder-dispersed aqueous phase together with bivalent metal salt solution and then the filtering and drying procedure was followed to yield the nano-vesicle coated powder. The amount of nano-vesicle coated on the powder was able to regulated by the concentration of metal salt and this novel powder showed the lower friction coefficient, more uniform condition of application and higher adhesive powder comparing with the alkyl silane treated powder from the test result of spreadability and wear properties using friction meter and air jet method. Two-wav cake containing newly developed coated powder with nano-vesicle showed the similar advantages in the frictional and adhesive characteristics.

• Korean Journal of Food Science and Technology
• /
• v.45 no.6
• /
• pp.693-699
• /
• 2013

A simple, sensitive, and specific method for quantifying the nicotine content of synthetic favoring substances (SFS) was developed using high performance liquid chromatography (HPLC) with a photo-diode array detector (PDA). Nicotine was extracted from SFS samples by using an acid-base liquid-liquid extraction method with dichloromethane and distilled water. The nicotine content was quantified by HPLC/PDA (261.9 nm) with a $C_{18}$ column under a gradient of 10% acetonitrile with 20 mM ammonium formate (ammonia solution adjusted to pH 8.7) to 100% acetonitrile. The calibration curve, analyzed from concentration standards between 0.1 to 2 mg/L, presented linearity with a correlation coefficient ($r^2$)>0.9999. The limit of quantitation (LOQ) of nicotine in SFS was 0.4 mg/kg, and the average recoveries ranged from 76.4% to 96.3%. The repeatability of measurements, expressed as the coefficient of variation (CV%), ranged from 1.74 to 5.12%. This newly developed method for nicotine quantification in SFS can be considered an analytical method with an acceptable level of sensitivity and repeatability.

• Journal of Embryo Transfer
• /
• v.22 no.1
• /
• pp.63-67
• /
• 2007

This study was performed to evaluate the efficacy of sodium carboxymethylcellulose (SCMC) for the prevention of postoperative uterus and ovary adhesion formation in the Korean black goats. Twenty adult female Korean black goats randomly were divided into five groups with four animals in each group. After the routine laparotomy, catheter for injection was inserted into the abdomen. Before abdominal closure, saline, 1% SCMC, 2% SCMC or 0.4% HA solution (50ml/10kg of body weight/head) were injected in the abdominal cavity in each group. Three weeks after surgery, second laparotomy was performed and the adhesions were scored on a scale of 0 to 10 according to their vascularity and adhesion size in uterus and ovary. This trial was repeated the four times with the interval of three weeks. In the first and second trial, the group treated with 2% SCMC significantly reduced the adhesion formation than other treatment groups (P<0.05). In the third trial, the adhesion formation was significantly reduced in 2% SCMC and 1% SCMC (P<0.05). In the fourth trial, 2% SCMC reduced the adhesion formation. However, there was no significant difference among other groups. This study showed that the 2% SCMC administered at the end of the surgery reduced the adhesion formation in the Korean black goats.

• Journal of Sericultural and Entomological Science
• /
• v.2
• /
• pp.1-31
• /
• 1962

The purpose of this treatise is to prove the presence of cystine in silk fiber through wide sampling throughout all the sericultural processes of Bombyx mori.; also to show that disulfide cross linkages exist in the silk fiber. The conclusions reached were as follows: 1. Crystalline cystine was obtained from silk fibroin using Folin's Method. 2. Analytical data showing the cystine content of silk fiber and its related materials were obtained using Sullvan's Method as follows: Material Percent Cystine A. Mulberry leaf protein 0.175 B. Silkworm egg 0.33 C. Silkworm Body, matured, fat extracted, without silk gland 0.41 D. Silk gland, matured 1.23 E. Silkworm feces none F. Silkworm pupa, fat extracted 0.30 G. Silkworm moth, fat extracted 0.60 H. Raw Silk 0.22 I. Fibroin 0.175 J. Sericin 0.30 3. The presence of cystine in the silkworm was substantiated the existence of 0.175 % methionine in mulberry leaves and 0.12% methionine in the silk gland. 4. Part of the sulfhydryl compounds in the silk gland is believed to transfer to serine and methionine, with the former being secreted into the liquid silk finally as silk fiber and the latter used for nutritive purposes in the growing of silk gland tissue. 5. The cystine content is variable by mulberry species, silkworm species, sex, breeding process, and other culturing environments. 6. Hybrid silkworms require more nutritive amino acids for effective growth than the original parents, and secrete less of them as silk fiber. 7. From such an observation, the amino acid composition of silk fiber is believed to be fairly flexible. Cystine if included in the amorphous part of the fiber, especially in sericin. 8. The result from enriching the silkworm diet with pure cystine or wool cystine did not result in any advantage, therefore it is believed that the natural cystine and methionine contents in the mulberry leafaregoodenoughforsilkwormnutrition. 9. The disulfide cross linkage in silk fiber was verified by using the Harris Method. Contraction took place following the treatment of the fiber with various salts and acids. Comparisons were made with wool fiber. 10. During these experiments, the fibrious structure of silk fiber and the net-globular liquid form were photographed microscopically. It is believed that the globules of liquid silk are net-formed by the inter attraction of the OH ion of the globular peptide and the H ion of water as shown by the hair cracking behavior of the film. The net-globular protein precipitation from the mulberry protein solution showed that mulberry is a proper diet for the formation of fibrous protein in the silk fiber. 11. The significance of the presence of cystine in silk fiber as emphasized in this paper should result in modification of the general conception that cystine is absent from this fiber. NOTICE: A part of this treatise was presented at the annual Korea Sericultural Society meeting held in 1961.