• YAKHAK HOEJI
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• v.40 no.6
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• pp.659-665
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• 1996

Zinc white is mainly used as a mild astringent, protectant. and has weak antiseptic action. It is well known that the yield of zinc white produced is greatly affected by the syn thetic conditions such as the reactant concentration, reaction temperature, washing water temperature, mole ratio of reactants, and drying temperature, calcination temperature, etc. The purpose of this study is to investigate the optimal synthesis conditions of zinc white produced. A randomized complete block design suggested by G.E.P. Box and K.B. Wilson was applied for this purpose. Basic zinc carbonate was prepared by reacting zinc sulfate and sod. carbonate solution in this study. Zinc white comes when prepared by calcination of basic zinc carbonate. The optimum synthesis conditions of zinc white obtained from this study is as follows: 1) The reacting temperature range is: 92-100$^{\circ}C$, 2) The concentration of reactant solution is 23.6-27%, 3) The optimum mole-ratio: [ZnSO4]/[Na2CO3] is 1.74~1.96, 4) The washing water temperature is 36$^{\circ}C$, 5) The drying temperature range is 68-74$^{\circ}C$, 6) The calcination temperature is 600$^{\circ}C$. The outcome of DSC indicated a desolvation of basic zinc carbonate occurred at about 133.3$^{\circ}C$. The dehydration of the compound ceased at about 267.9$^{\circ}C$ and the decarboxylation ceased at about 379.9$^{\circ}C$. The physical and chemical properties of zinc white as medicine were studied by use of Volume Test.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.1
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• pp.10-15
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• 1987

The experiment was designed to determine the proper shading rate and shading materials to decrease the excessive dried leaves during cure of burley tobacco. Five shading rates and seaven shading materials were applied on the pipe vinyl house from initial stage or yellow stage of cure. Temperature was lower and weight-loss of leaves delayed with shading from initial stage to browning stage of cure. Excessive dried leave were largely decreased as shading rate was increased to 70%. However, at shading rate more than 70%, its decreasing extent was fewer. Price per kg and physical properties improved considerably at shading rate of 50%. Shading materials alone could not completely prevent excessive dried leaves but it could decrease them. Orange, white and purple color vinyl among shading materials had so effects of shading as the black shading cloth during curing. However, white color vinyl didn't endure more than a few months due to sunshine. A difference of light quality in visible light was no significance on air curing.

• Korean journal of food and cookery science
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• v.32 no.1
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• pp.1-8
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• 2016

This study aimed to enhance the applications of dates as a food material that can be utilized and stored easily by improving the inefficient process of the traditional cooking procedure. To this end, this study investigated the physico-chemical and nutritional properties of jujube pulp powder, and compared the traditional and newly developed methods of making yakbap, yakpyon, and jujube porridge. According to the analysis of physical and chemical properties, the jujube pulp powder contained 5.4% moisture, 2.6% crude ash, 6.6% crude protein, 0.35% crude fat, and 4.7% crude fiber. The water activity was 0.95% in jujube pulp while it was 0.24% in jujube pulp powder. In addition, the jujube pulp powder had a total sugar content of 70.4% and reducing sugar content of 6.3%. The vitamin C was content was estimated to be 68.5 mg/100 g in the jujube pulp powder and the jujube pulp contained 6.2 g/100 g of dietary fiber. Major minerals were K, Mg, and Ca. After appointing jujube pulp powder (new method) to a test group and jujube pulp (traditional method) to a control group, the sensory evaluation and acceptance testing were conducted for yakbap, yakpyon, and jujube porridge. As a result, there was no significant difference in any sensory factors tested (p<0.05). It was found that making and storing jujube pulp powder by drying jujube pulp is a useful way of utilizing jujube because Yakbab, Yakpyun and jujube porridge were found to have a relatively good appearance, color, flavor, taste, texture and overall acceptance.

• Applied Chemistry for Engineering
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• v.19 no.3
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• pp.345-350
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• 2008

Polymer Impregnated Concrete (PIC) prepared from Ordinary Portland Cement Concrete (OPC) has excellent mechanical properties as well as physico-chemical properties. For the manufacturing of PIC, drying process of basis concrete (precast concrete), impregnation process with evacuation system and ultrasonic vibration system, polymerization process of monomers are essential. Modified microwave reactor using magnetron was used for polymerization of styrene/MMA (1 : 1) impregnated in pore volume of basis concrete. From the experimental results, the degree of polymerization increased up to 30% and more homogeneous PIC was prepared as compared to the conventional thermal method. Also the mechanical strengths increased more than 400% ($800{\sim}1200kg_f/cm^2$) and the resistance for corrosion to acids was improved up to 25%. AIBN and BPO as initiators for polymerization were used at the concentration less than 1%. Optimum conditions for polymerization were obtained at the frequency of microwave of 400 W and 2450 MHz, and optimum reaction temperature was $120^{\circ}C$ at an atmospheric pressure.

• Membrane and Water Treatment
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• v.10 no.4
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• pp.259-264
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• 2019

Cost effective clay adsorptive microfiltration membranes were synthesized to remove Cr (III) from high polluted water. Raw and calcined bentonite were mixed in order to decrease the shrinkage and also increase the porosity; then, 20 wt% of carbonate was added and the samples, named B (without carbonate) and B-Ca20 (with 20 wt% calcium carbonate) were uniaxially pressed and after sufficient drying, fired at $1100^{\circ}C$ for 3 hours. Then, physical and mechanical properties of the samples, their phase analyses and microstructure and also their ability for Cr(III) removal from high polluted water (including 1000 ppm Cr (III) ions) were studied. Results showed that the addition of calcium carbonate lead the porosity to increase to 33.5% while contrary to organic pore formers like starch, due to the formation of wollastonite, the mechanical strength not only didn't collapse but also improved to 36.77 MPa. Besides, sample B-Ca20, due to the presence of wollastonite and anorthite, could remove 99.97% of Cr (III) ions. Hence, a very economic and cost effective combination of membrane filtration and adsorption technology was achieved for water treatment which made microfiltration membranes act even better than nanofiltration ones without using any adsorptive nano particles.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.38 no.2
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• pp.133-138
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• 2012

The purpose of this study was to examine the correlation between physical properties of dried coacervate films and dry feel for shampoo composition. Simple shampoo compositions were made of two different cationic charge density polymers in the same surfactant compositions. The simple shampoo compositions were diluted with distilled water to make coacervate. Formed coacervate was collected by centrifuge (3,000 rpm, 30 min). Coacervate was coated on the glass plates and dried in drying oven (for 1 h, $50^{\circ}C$) to make the thin film. We carried out an experiment on measurement of contact angle, moisture loss ratio and SEM image analysis of the dried coacervate film. Dry feelings of the shampoos were evaluated by panel using hair tresses. Results show that the properties of dried coacervate films affect the dry feel of the after shampooing.

• Journal of the Society of Naval Architects of Korea
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• v.56 no.6
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• pp.532-540
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• 2019

This study describes a test method for evaluating the ice friction and abrasion performance of polar coatings. The evaluation methods of physical properties of general coatings for ocean-going vessels and polar coatings for ice-going vessels were investigated and their limitations were analyzed. We have also reviewed previous researches related to the development of polar paints and confirmed the necessity of developing test techniques. A flat steel plate was coated with several types of commercial coating, and cold model ice was used to cause ice friction and abrasion events between coated surface and ice. For evaluation of ice friction and abrasion performances, test procedures such as measurement of coating surface roughness, measurement of frictional force using model ice, implementation of ice abrasion and drying of coating surface were developed. The friction and abrasion characteristics of each coating are analyzed and summarized through the change of friction force and roughness data according to the progress of ice abrasion.

• Journal of Powder Materials
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• v.28 no.3
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• pp.227-232
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• 2021

The purpose of this study is to optimize the powder formulation and manufacturing conditions for the solidification of an extract of the herb Bangpungtongseong-san (BPTS). To develop BPTS-loaded particles for the tablet dosage form, various BPTS-loaded particles composed of BPTS, dextrin, microcrystalline cellulose (MCC), silicon dioxide, ethanol, and water are prepared using spray-drying and high shear granulation (high-speed mixing). Their physical properties are evaluated using scanning electron microscopy and measurements of the angle of repose, Hausner ratio, Carr's index, hardness, and disintegration time. The optimal BPTS-loaded particles exhibit improved flowability and compressibility. In particular, the BPTS-loaded particles containing silicon dioxide show significantly improved flowability and compressibility (the angle of repose, Hausner ratio, and Carr's index are 35.27 ± 0.58°, 1.18 ± 0.06, and 15.67 ± 1.68%, respectively), hardness (18.97 ± 1.00 KP), and disintegration time (17.60 ± 1.50 min) compared to those without silicon dioxide. Therefore, this study suggests that particles prepared by high-speed mixing can be used to greatly improve the flowability and compressibility of BPTS using MCC and silicon dioxide.

• Journal of Pharmaceutical Investigation
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• v.5 no.3
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• pp.50-57
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• 1975

Bismuthsubgallate is a compound of indefinite composition containing bismuth and gallic acid. Because its structure was indefinite, many papers have been reported for it. But these are different one another and the relationship between the physical properties, structure and manufacturing condition has not been yet reported. In this experiment, bismuthsubgallate was prepared from bismuthsubgallate and gallic acid in an acetic medium at $65^{\circ}$, and dried at four different temperatures $30^{\circ}\;65^{\circ}\;105^{\circ}\;and\;155^{\circ}$. And some of the other relative bismuth organic compounds were prepared. To each product. elemental analysis, IR spectra and DTA, TGA curves were determined. These results revealed the followings; l. The structure of bismuthsubgallate is comfirmed as a complex form of gallomonohydroxo-bismutic acid monohydrate and its yellow colour dependent upon complex anion in the structure. 2. According to the drying temperature, the hydrate content of bismuthsubgallate is quite different: dihydrate at room temperature, mono-hydrate at. $65^{\circ}$, anhydrous at $105^{\circ}$ and decomposed partial1y oganic substance of the structure above $155^{\circ}$.

• Journal of the Korean Applied Science and Technology
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• v.20 no.3
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• pp.237-242
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• 2003

The high-solid coatings were prepared by blending the synthesized acrylic resin in the previous paper and hexamethylene diisocyanate-trimer and curing it at room temperature. The characterization of the films of the prepared coatings was performed. The impact resistance, $60^{\circ}C$ specular gloss, cross-hatch adhension, and heat resistance of the films proved to be good, and the pencil hardness and drying time proved to be slightly poor. Especially, there was a remarkable improvement in the heat resistance. This improvement may stem from the regular arrangement of ethyl groups introduced into the acrylic resin. From a viscoelastic measurement using a rigid-body pendulum, curing was accelerated with the $T_g$ value. With the increase in $T_g$, log damp value was lowered and dynamic viscoelasic $T_g$ of a cured film was increased.