• Korean Journal of Heritage: History & Science
• /
• v.52 no.1
• /
• pp.4-21
• /
• 2019

In this paper, 23 Silla gold earrings from the sixth and seventhand centuries, excavated from the Yeongnam region, were analyzed. Based on the silver content of the gold plate, they were classified into three types. The classifications included type I(20-50wt%), type II(10-20wt%) and type III (less than 10wt%). In the analysis process, the composition and morphological differences were identified on the surface of the gold plate. In the case of type I and II earrings, it was observed that the fine holes were concentrated in a relatively higher part of the gold content. The causes of the difference in the surface composition of the gold plate were divided into four categories: 1) surface treatment, 2) thermal diffusivity in the manufacturing process, 3) differences in composition of alluvial gold, and 4) the refining method of gold. It is possible that depletion gilding was attempted to increase the gold content while intentionally removing the other metals from the surface of the gold alloy in the portion where the gold deposit is relatively concentrated on the surface of the gold plating. The highest copper content was detected in the earring with the highest gold content of the analyzed earrings, and it was assumed that thermal diffusion had occurred between the gold plate and the metal rod during the manufacturing process rather than intentional addition. Copper was detected only in the thin ring earring type, and copper was not detected in the thick ring earring type or pendant type. It also proves that this earring has a high degree of tightness at higher temperatures, as there was an invisible edge finish on other earrings and horizontal wrinkles on the gold plate surface. In terms of the material of the gold plate, we examined whether the silver content of the gold plate was natural gold or added by alloy through analyzing the alluvial gold collected in the region. As a result of the analysis, it was found that on average about 13wt% of silver is included. This suggests that type II is natural gold, type III is refined gold, and type I seems to have been alloyed with natural gold. Here, we investigated the refining method introduced in the ancient literature, both at home and abroad, about the possibility of alloying silver after the refining process of type III earrings and then making pure gold. It was found that from ancient refining methods, silver which had been present in the natural gold was removed by reacting and combining with silver chloride or silver sulfide, and long-term efforts and techniques were required to obtain pure gold through this method. Therefore, it was concluded that the possibility of adding a small amount of silver in order to increase strength after making pure gold through a refining process is low.

• Asian-Australasian Journal of Animal Sciences
• /
• v.27 no.7
• /
• pp.965-973
• /
• 2014

Three studies were conducted to investigate whether a chelated Cu can replace $CuSO_4$ as a growth promoter in pigs. In Exp. 1, a total of 240 piglets (Large White${\times}$Landrace, $7.36{\pm}0.10kg$) were randomly allocated to 1 of 3 treatments with 8 replicates and 10 piglets per pen. Treatments included a NRC control ($CuSO_4$, 6 mg/kg), two Cu supplementations from either $CuSO_4$ or $Cu(HMTBa)_2$ at 170 mg/kg. Pigs fed $Cu(HMTBa)_2$ were 6.0% heavier than pigs fed either the NRC control or 170 mg/kg $CuSO_4$ (p = 0.03) at the end of the experiment. During the 42 days of experimental period, pigs fed $Cu(HMTBa)_2$ gained 9.0% more (p = 0.01), tended to eat more feed (p = 0.09), and had better feed efficiency (p = 0.06) than those fed $CuSO_4$. Compared with the 6 mg/kg $CuSO_4$ NRC control, liver Cu was increased 2.7 times with 170 mg/kg $CuSO_4$ supplementation, and was further increased with $Cu(HMTBa)_2$ (4.5 times, p<0.05). In Exp. 2, a total of 616 crossbred piglets (PIC, $5.01{\pm}0.25kg$) were randomly allocated to 1 of 4 treatments with 7 replicates and 22 piglets per pen. Treatments included a NRC control (from $CuSO_4$), and three pharmaceutical levels of Cu (150 mg/kg) supplemented either from C$CuSO_4$, tri-basic copper chloride ($Cu_2[OH]_3C1$), or $Cu(HMTBa)_2$. Pigs fed $CuSO_4$ or $Cu(HMTBa)_2$ had better feed efficiency (p = 0.01) and tended to gain more (p = 0.08) compared with those fed the NRC control. Pigs fed $Cu_2[OH]_2C1$ were intermediate. Pigs fed $Cu(HMTBa)_2$ had the highest liver Cu, which was significantly higher than those fed ($Cu_2[OH]_3C1$) or the negative control (p = 0.01). In Exp. 3, a total of 1,048 pigs (PIC, $32.36{\pm}0.29kg$) were allotted to 6 treatments with 8 replicates per treatment and 20 to 22 pigs per pen. The treatments included a NRC control with 4 mg/kg Cu from $CuSO_4$, a positive control with 160 mg/kg Cu from $CuSO_4$, and incremental levels of $Cu(HMTBa)_2$ at 20, 40, 80, and 160 mg/kg. During the overall experimental period of 100 days, no benefit from 160 mg/kg $CuSO_4$ was observed. Pigs fed $Cu(HMTBa)_2$ had increased ADG (linear and quadratic, $p{\leq}0.05$) and feed efficiency (linear and quadratic, $p{\leq}0.05$) up to 80 mg/kg and no further improvement was observed at 160 mg/kg for the whole experimental period. Pigs fed 80 mg/kg $Cu(HMTBa)_2$ weighed 1.8 kg more (p = 0.07) and were 2.3 kg heavier in carcass (p<0.01) compared with pigs fed 160 mg/kg $CuSO_4$. In addition, loin depth was increased with increased $Cu(HMTBa)_2$ supplementation with pigs fed 80 mg/kg $Cu(HMTBa)_2$ had the greatest loin depth (p<0.05). In summary, $Cu(HMTBa)_2$ can be used to replace high $CuSO_4$ as a growth promoter in nursery and grower-finisher pigs.

• Journal of Life Science
• /
• v.25 no.9
• /
• pp.1027-1035
• /
• 2015

A strain GP32 which produces a highly viscous extracellular polysaccharide was conducted with soil samples and identified as Pseudomonas species. The culture flask conditions for the production of extracellular polysaccharide by Pseudomonas sp. GP32 were investigated. The most suitable carbon and nitrogen source for extracellular polysaccharide production were galactose and (NH₄)₂SO₄. The optimum carbon/nitrogen ratio for the production of extracellular polysaccharide was around 50. The optimum pH and temperature for extracellular polysaccharide production was 7.5 and 32℃, respectively. In batch fermentation using a jar fermentor, the highest extracellular polysaccharide content (15.7 g/l) was obtained after 70 hr of cultivation. The extracellular polysaccharide produced by Pseudomonas sp. GP32 (designated Biopol32) was purified by ethanol precipitation, cetylpyridinium chloride (CPC) precipitation, and gel permeation chromatography. Biopol32, which has an estimated molecular weight of over 3×10⁷ datons, is a novel polysaccharide derived from sugar components consisting of galactose, glucose, gulcouronic acid and galactouronic acid in an approximate molar ratio of 1.85 : 3.24 : 1.00 : 1.42. The solution of Biopol32 showed non-Newtonian characteristics. The viscosity of Biopol32 exhibited appeared to be higher at all concentration compared to that of zooglan from Zoogloea ramigera. An analysis of the flocculating efficiency of Biopol32 in industry wastewater (food, textile, and paper wastewater) revealed chemical oxygen demand (COD) reduction rates 58.4-67.3% and suspended solid (SS) removal rates 82.6-91.3%. Based on these results, Biopol32 is a possible candidate for industrial applications such as wastewater treatment.

• Korean Journal of Food Science and Technology
• /
• v.9 no.2
• /
• pp.123-130
• /
• 1977

A laboratory study was made to develop a simple and economic model method for the systematic determination of functional properties of 'Soy Protein Isolates (SPI)' prepared from defatted soybean meal. These are required to evaluate and to predict how SPI may behave in specific systems and such proteins can be used to simulate or replace conventional proteins. Data concerning the effects of pH, salt concentration, temperature, and protein concentration on the functional properties which include solubility, heat denaturation, gel forming capacity, emulsifying capacity, and foaming capacity are presented. The results are as follows: 1) The yield of SPI from defatted soybean meal increased to 83.9 % as the soybean meal was extracted with 0.02 N NaOH. 2) The suitable viscocity of a dope solution for spinning fiber was found to be 60 Poises by using syringe needle (0.3 mm) with 15 % SPI in 0.6 % NaOH. 3) Heat caused thickening and gelation in concentration of 8 % with a temperature threshold of $70^{\circ}C$. At $8{\sim}12\;%$ protein concentration, gel was formed within $10{\sim}30\;min$ at $70{\sim}100\;^{\circ}C$. It was, however, disrupted rapidly at $125\;^{\circ}C$ of overheat treatment. The gel was firm, resilient and self-supporting at protein concentration of 14 % and less susceptible to disruption of overheating. 4) The emulsifying capacity (EC) of SPI was correlated positively to the solubility of protein at ${\mu}=0$. At pH of the isoelectric point of SPI (pH 4.6), EC increased as concentration of sodium chloride increased. Using model system$(mixing\;speed:\;12,000\;r.p.m.,\;oil\;addition\;rate:\;0.9\;ml/sec,\;and\;temperature\;:\;20{\pm}1\;^{\circ}C)$, the maximum EC of SPI was found to be 47.2 ml of oil/100 mg protein, at the condition of pH 8.7 and ${\mu}=0.6$. The milk casein had greater EC than SPI at lower ionic strength while the EC of SPI was the same as milk casein at higher ionic strength. 5) The shaking test was used in determining the foam-ability of proteins. Progressively increasing SPI concentration up to 5 % indicated that the maximum protein concentration for foaming capacity was 2 %. Sucrose reduced foam expansion slightly but enhanced foam stability. The results of comparing milk casein and egg albumin were that foaming properties of SPI were the same as egg albumin, and better than milk casein, particularly in foam stability.

• Journal of the Korean Wood Science and Technology
• /
• v.13 no.3
• /
• pp.49-53
• /
• 1985

The effects of pre-treatments, the hot water extraction of wood meal and the addition of chemical ($CaCl_2$) to wood-cement water system on the properties of wood-cement composite such as modulus of rupture (MOR), modulus of elasticity (MOE), water sorption ratio and swelling ratio of resulting boards were studied in this experiment. The wood meals through 0.83mm(20 mesh) and retained on 0.42mm(35 mesh) screen were prepared from Pinus densiflora S. at Z. and Larix leptolepsis G. For hot water extraction, 500 grams of wood meal for each species were heated to boiling with 1,500ml of distilled water in 2-liter beaker for 6 hours. Every 2 hours, the wood meals were washed with boiling distil1ed water and reheated to boiling again. After 6 hours boiling, the boiled wood particles were collected by pouring this particles on 200 mesh screen. The collected particles then washed twice with hot distilled water and dried for 24 hours in an oven at $109{\pm}20^{\circ}C$. A mixture of 663.4 grams of cement with 331.7 grams of wood meal based on oven-dry weight were dry-mixed in a plastic vessel. The mixture was kneaded with 497.6ml of distilled water in the ratio of 1.5ml of water to a gram of wood meal. To add calcium chloride to the mixture as an accelerator, $CaCl_2$ 4% solution by weight per volume, was added to pine-or larch-cement board in the ratio of 3% to cement weight. To set wood-cement board, this mixture was clamped at 30cm ${\times}$ 30cm, in thickness of 1.5cm for 3 days at room temperature, declamped and then placed at open condition for 17 days. The target density was 1.0. The four specimens sized to 5cm in width and 28cm in length were used for MOR and MOE test for each treatment. After MOR test, the tested specimens were cut to the size of 5cm ${\times}$ 5cm for water sorption and swelling test. The twenty specimens used to measure the water sorption ratio (soaking 24 hours) and ten of these were used for swelling ratio measurement The results obtained were as follows: 1) Larch was not suitable for wood-cement boards because larch-cement board developed no strength, but pine showed 97.9kg/$cm^2$ by hot water extraction. 2) To increase MOR, hot water extraction was more effective than the addition of $CaCl_2$ in pine and larch because the $CaCl_2$ addition was seemed to speed up the ratio of cement hydration without reacting with the wood substances. 3) The water sorption ratio was lowered by the addition of $CaCl_2$ to wood-cement system because the chemical additive accelerated the rate of cement hydration. 4) In pine-cement board, the swelling ratio from 0.37 to 0.42 percent was observed in length and the swelling ratio from 0.88 to 2.0 percent in thickness. As a rule, the swelling ratio of wood-cement board was very low and the swelling ratio in thickness was higher than in length.

• Applied Biological Chemistry
• /
• v.9
• /
• pp.119-124
• /
• 1968

In order to learn the effect of timing and rate of potash fertilization in the rice plant nursery on the root growth and the vegetative growth of later stage a pot experiment was carried out employing 'Jaekun' a rice variety. Potassium Chloride was applied at the rate of $0{\sim}100g\;K_{2}O/3.3m^2$ right before, and 30 days after seeding. Forty-day old seedlings were transplanted three times successively at the one week intervals with the roots cut each time. Each subject was observed in rooting and other useful traits. A part of seedlings after the third root scission were cultured intact thereafter and the yield characters examined. The results were shown as: 1. The rate of sound seedlings was high in the case that a small amount of potassium was applied as the basic placement while the application of the fertilizer over $75g/3.3m^2$ (as $K_{2}O$) yielded a far less crops. 2. The plant height, number of tillers, number of leaves, and grass weight increased as the amount of potassium was elevated. However, the application of $50g\;K_{2}O/3.3m^2$ in the basic placement and that of $75g\;K_{2}O/3.3m^2$ were the peaks over which the above mentioned characters were weakened. 3. As the amount of potassium was increased the increment in number of rooting was notable, especially when the scission of roots was repeated within the limit of $50{\sim}75g\;K_{2}O/3.3m^2$. 4. In the maximum root newly shooted length indicated was about the same tendency although no statistical significance was observed. 5. The plant height, number of tillers, and variation of weight between grass and root indicated a similar tendency as the number of root shoot. 6. The differences in number of ears, grain yield, and weight of straw between the treatments were not so great but showed somewhat similar trend as in the growth of transplanted plants. In the treatment-100g $K_{2}O/3.3m^2$ the yield (ears, grain and straw) decreased as in the non-fertilized.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.5 no.3
• /
• pp.171-177
• /
• 2007

This study suggested a new method to stabilize molten salt wastes generated from the pyre-process for the spent fuel treatment. Using conventional sol-gel process, $SiO_2-Al_2O_3-P_2O_5$ (SAP) inorganic material that is reactive to metal chlorides were prepared. In this paper, the reactivity of SAP with the metal chlorides at $650{\sim}850$, the thermal stability of reaction products and their leach-resistance under the PCT-A test method were investigated. Alkali metal chlorides were converted into metal aluminosilicate($LixAlxSi1-_xO_{2-x}$) and metal phosphate($Li_3PO_4\;and\;Cs_2AlP_3O_{10}$) While alkali earth and rare earth chlorides were changed into only metal phosphates ($Sr_5(PO_4)_3Cl\;and\;CePO_4$). The conversion rate was about $96{\sim}99%$ at a salt waste/SAP weight ratio of 0.5 and a weight loss up to $1100^{\circ}C$ measured by thermogravimetric analysis were below 1wt%. The leach rates of Cs and Sr under the PCT-A test condition were about $10^{-2}g/m^2\;day\;and\;10^{-4}g/m^2\;day$. From these results, it could be concluded that SAP can be considered as an effective stabilizer for metal chlorides and the method using SAP will give a chance to reduce the volume of salt wasteform for the final disposal through further researches.

• Journal of Korean Society of Environmental Engineers
• /
• v.31 no.4
• /
• pp.263-271
• /
• 2009

This study evaluated the flocs forming characteristics in the mixing zone to increase the coagulation effect in the drinking water plant. As a measuring tool of formed flocs, on-line particle dispersion analyzer (iPDA) was used in Y drinking water plant. To evaluate the forming flocs, many parameters such as poly amine, coagulant dosing amount, raw water turbidity, and pH was applied in this study. During the periods of field test, poly aluminium chloride (PACl) as a coagulant was used. With the increase of the raw water turbidities, poly amine was also added as one of aids for increasing in coagulation efficiency. The turbidity and pH of raw water was ranged from 7 to 9 and from 25 to 140 NTU, respectively. The increasing of raw water turbidity brought the bigger floc sizes accordingly. From a regression analysis, $R^2$ value was 0.8040 as a function of T, raw water turbidity. Floc size index (FSI) was obtained from a correlation equation as follows; FSI = 0.9388logT - 0.3214 Also, polyamine gave the bigger flocs the moment it is added to the coagulated water in the rapid mixing zone. One of parameters influencing the floc sizes was the addition of powdered active carbon(PAC) in the mixing zone. In case of higher turbidity of raw water, $R^2$ value was 0.9050 in the parameters of [PACl] and [PAC]; FSI = $0.0407[T]^{0.324}[PACI]^{0.769}[PAC]^{0.178}$ On-line floc monitor was beneficial to evaluate the flocs sizes depending on the many parameters consisting raw water properties, bring the profitable basic data to control the mixing zone more effectively.

• Applied Biological Chemistry
• /
• v.13 no.2
• /
• pp.171-180
• /
• 1970

The yeasts in the soy sauce mash were isolated and identified, and they were classified by coloring with the treatment of TTC(2, 3, 5, triphenyltetrazolium chloride) agar and counted in process of time. The results obtained were as follows: a) The number of ordinary and osmophilic yeasts in 1 ml. of the soy sauce mash showed a tendency to be increased from the mashing to the mature stages and to decrease in the aging stages: $127{\times}10^3$ immediately after mashing, $83{\times}10^3$ 1 month after, $356{\times}10^3$ 3 months after, $1250{\times}10^3$ 6 months after and $65{\times}10^3$ 2 years after mashing in the case of ordinary yeasts, and 0 after mashing, $40{\times}10^3$ 1 month after, $81{\times}10^3$ 3 months after, $358{\times}10^3$ 6 month after and $23{\times}10^3$ 2 years after mashing in the case of osmophilic yeasts. b) 50 strains of yeasts were isolated from the soy sauce mash optionally in process of fermentation period, and they were identified as 7 genera and 18 species: 10 strains of Saccharomyces rouxii, 1 strain of Saccharomyces marxianus, 3 strains of Saccharomyces rosei, 1 strain of Saccharomyces fermentati, 6 strains of Saccharomyces mellis, 1 strain of Saccharomyces acidifaciens, 1 strain of Saccharomyces pastori, 3 strains of Pichia polymorpha, 2 strains of Hansenula anomala, 1 strain of Hansenula saturnus, 2 strains of Hansenula suaveolens, 5 strains of Nadsonia fulvescens, 8 strains of Debaryomyces hasenii, 1 strain of Debaryomyces nicotianae, 1 strain of Debaryomyces kloeckeri, 2 strains of Torulopsis sake, 1 strain of Torulopsis holmii and 1 strain of Candida pelliculasa. c) Distribution of yeasts according to the fermentation period was as follows: i) Saccharomyces rouxii, Saccharomyces marxianus, Saccharoymces rosei, Pichia polymorpha, Debaryomyces hansenii, Torulopsis sake, Candida pelliculosa, Debaryomyces nicotianae, Nadsonia fulvescens, Hansenula suaveolens and Hansenula saturnus were found in the early stages of fermentation. ii) Saccharomyces rouxii, Saccharomyces rosei, Saccharomyces fermentati, Saccharomyces mellis, Saccharomyces pastori, Hansenula anomala, Saccharomyces acidifaciens and Debaryomyces hansenii appeared in the mature stages. iii) Saccharomyces rouxii, Saccharomyces mellis, Nadsonia fulvescenes, Dedaryomyces hansenii, Debaryomyces kloeckeri, Torulopsis sake and Torulopsis holmii were distributed in the aging stages. d) TTC white yeasts were found in abundance in the early stages of fermentation and TTC red yeasts appeared more than 50 per cent in the mature and aging stages. e) The yeasts belonging to Saccharomyces mellis and Saccharomyces pastori were classified as TTC red yeasts, Saccharomyces acidifaciens were reel pink, Hansenula saturnus Debaryomyces kloeckeri, and Torulopsis holmii were pink, Saccharomyces marxianus and Nadsonia fulvescens were white and the others were the same as the description in the previous report. Saccharomyces rouxii ware classified for the most part as TTC red yeasts, and while some of them were red pink. f) Species of yeasts in the soy sauce mash were similar to those in the soy sauce koji, but the latter were not osmophilic and in the former case, the osmophilic yeasts were increased in process of fermentation period.

• Korean Journal of Microbiology
• /
• v.51 no.4
• /
• pp.355-363
• /
• 2015

The present work quantified the growth of young biofilm in a model distribution system that was fed with chlorinated drinking water at a hydraulic retention time of 2 h. Bacterial biofilms grew on the surface of polyvinyl chloride (PVC) slides at a specific growth rate of $0.14{\pm}0.09day^{-1}$ for total bacteria and $0.16{\pm}0.08day^{-1}$ for heterotrophic bacteria, reaching $3.1{\times}10^4cells/cm^2$ and $6.6{\times}10^3CFU/cm^2$ after 10 days, respectively. The specific growth rates of biofilm-forming bacteria were found to be much higher than those of bulk-phase bacteria, suggesting that biofilm bacteria account for a major part of the bacterial production in this model system. Biofilm isolates exhibited characteristic kinetic properties, as determined by ${\mu}_{max}$ and $K_S$ values using the Monod model, in a defined growth medium containing various amounts of acetate. The lowest ${\mu}_{max}$ value was observed in bacterial species belonging to the genus Methylobacterium, and their slow growth seemed to confer high resistance to chlorine treatment (0.5 mg/L for 10 min). $K_S$ values (inversely related to substrate affinity) of Sphingomonas were two orders of magnitude lower for acetate carbon than those of other isolates. The Sphingomonas isolates may have obligate-oligotrophic characteristics, since the lower $K_S$ values allow them to thrive under nutrient-deficient conditions. These results provide a better understanding and control of multi-species bacterial biofilms that develop within days in a drinking water distribution system.