• Journal of Korea Foundry Society
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• v.2 no.3
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• pp.2-15
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• 1982

In this study, the influenced of graphite shape on the boriding of cast iron and boride structure was investigated. Gray cast iron, ferritic and pearlitic ductile cast iron were borided at 750,850,900 and $950^{\circ}C$ for 1,3 and 5 hours by powder pack method with the mixture of $B_4C_9\;Na_2B_4O_7$, $KBF_4$ and Shc. The boride layer was consisted of FeB(little), $Fe_2B$ (main) and graphite. Some possibility of the existence of unknown Fe-B-C compound in the boride layer was suggested. And precipitates in the diffusion zone was $Fe_3(B,C)$. The concentration of Si and precipitation of $Fe_3(B,C)$ in the ${\alpha}$ layer raised the hardness of this Zone. The depth and hardness of boride layer increased with the increase of treating temperature and tim. But high temperature (over $950^{\circ}C)$ caused pore at graphite position and long treating time (5hrs) sometimes caused formation of graphite layer beneath the boride layer. So, for the practical application of borided cast iron, treating in short time and at low temperature was recommended. And for ductile cast iron, ferritizing or pearlitizing heat treatment was seemmed to be possible at the same time with boriding. The graphite in the boride layer was deeply concerned with the qualitx and characteristics of the boride layer. And it greatly influenced on the shape of the boride phase, structure of the boride layer. Generally speaking, the existance of graphite restrained the growth of the boride phase. But the boundary between the gsaphite and the matrix acted as the shortcut of boron diffusion. So, for gray cast iron, the graphite layed length-wise led the formation of boride layer.

• Explosives and Blasting
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• v.27 no.1
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• pp.32-37
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• 2009

To look over the effect of mixed proportion of cement, sand and water on strength, 162 tests were made for 9 mix proportions. It was observed that strength increased as water in the mixture is reduced. As a result of the control of sand ratio by 50%, the execution strength increased when the sand ratio is raised. Strength was consistent during curing period on each mix proportion, but there were sections where it suddenly increased. Poisson's ratio widely ranged from 0.13 to 0.27, and Young's modulus also broadly ranged from 13.79MPa to 33.25MPa. Poisson's ratio had nothing to do with uniaxial compressive strength, wheras Young's modulus was concerned with it. Young's modulus from theory and experiment showed similar outcome on the 3rd curing day, however, the strength from theory was higher than that from test after 3rd day. In consequence, there was a great change of strength between 3rd and 7th curing day. In addition, it is more efficient to use field strength value between the 3rd and 7th day and to apply Young's modulus on it for determining the exact time.

• Toxicological Research
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• v.19 no.4
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• pp.277-283
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• 2003

Polychlorinated biphenyls (PCBs) has been widely used as plasticizer, insulator, lubricant, paint and ink. The persistence of PCBs in the environment and their bioaccumulation in living organism make a raise concerns regarding their toxic effects in immune system and subsequent effects on human health. However little has been known about effect of PCB, an endocrine disrupter, on splenocytes. In this study, for identifying the effect on the organs and immune cell of mice by the concentration and time of commercial PCB mixture (Aroclor 1254), each 3 mice were tested at the concentration of 3, 30, 300, 1,000 mg/kg respectively, and their organ's weight were measured in 4, 7, 14 days, respectively. Also according to concentration and time, PCB was evaluated for the effects on splenocyte viability and lipopolysaccaride (LPS) and concanavaline A (Con A)-induced splenocyte proliferation on mice spleen. In liver and lung, there were significantly defferent by concentration and time of PCB (p < 0.0001). In respect of concentration of PCB, no significant effects on mice's liver by Aroclor 1254 concentration below than 300 mg/kg were observed except at the concentration of 1,000 mg/kg doses (p < 0.0001). But there was not significant different change in mice spleen by concentration and time of PCB (p=0.2206) and the mode of weight change of spleen was different to of liver and of lung. Viabilities of splenocytes were decreased following treatment with high concentration of PCB. Also, LPS and Con A-induced cell proliferations were decreased by Aroclor 1254 at 1,000 mg/kg. These data suggest that Aroclor 1254 is the immunotoxic compound that may have an effect on mouse immune system.

• Journal of Oriental Neuropsychiatry
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• v.21 no.3
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• pp.29-44
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• 2010

Objectives : The purpose of this research is to examine the efficacy of Gamisoyosan on anxiety of generalized anxiety disorder according to dosage form. Methods : In this randomized, double blinded, placebo-controlled study, we planned to give Gamisoyosan simple extract mixture or Gamisoyosan compound extract or controlled medication for major symptoms of generalized anxiety disorder. As preparatory research, Hamilton rating Scale for Anxiety(HAM-A) was measured as the 1st evaluative instrument, and Korean State-Trait Anxiety Inventory(STAI-K), Penn State Worry Questionnaire(PSWQ) Korean Beck's Depression Inventory (BDI-K), Symptom Checklist-90-Revised(SCL-90R), WHO Quality of Life Abbreviated(WHOQOL-BREF) and Heart Rate Variability(HRV) were also measured as the 2nd evaluative instrument at the before treatment. Results : Demographic characteristics showed that there are Clinical characteristics-vital signs are within the normal range. The characteristics of disease-chief complaint, pattern Identification and etiological factor of the highest frequency number were worry, heart deficiency with timidity(心膽虛怯), family matters. The average period of disease in subjects is 6.31years. The results of Chest PA, EKG and clinicopathologic examination are within the reference range. The Scores of HAM-A, STAI-K, PSWQ were measured above the cutoff point. There are significant positive correlations among HAM-A, STAI-K, BDI-K and among HAM-A, STAI-K, PSWQ. There are no significant correlations between PSWQ and BDI-K. Conclusions : We considered that selection of subjects in this research is appropriately accomplished And this methodology is expected to be applied to the subsequent research. And also, we hope to make up for this study through various study and discussion.

• Journal of the Korean Wood Science and Technology
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• v.37 no.1
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• pp.73-77
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• 2009

This study was carried out to investigate the valuable antioxidative compound from extracts of Alnus hirsuta Turcz. which has a nationwide distribution. The bark (2 kg) was extracted with 70% aqueous acetone and fractionated, and the ethyl acetate and $H_2O$ fractions, separately, were chromatographed on a Sephadex LH-20 column to purify the mixture and to give two diarylheptanoid compounds. The isolated compounds were analyzed by NMR spectroscopy, including $^1H$, $^{13}C$ and two-dimensional NMR, and identified as oregonin (1) and 1,7-bis-(3,4-dihydroxyphenyl)-heptane-5-O-${\beta}$-D-xylopyranoside (2). The antioxidative activity was evaluated by DPPH method using two diarylheptanoids and acid-hydrolyzed oregonin derivative which indicated higher activity potential. Of those the acid-hydrolyzed oregonin derivative showed highly active potential with the value of 2.6 of $IC_{50}$.

• Korean Journal of Medicinal Crop Science
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• v.22 no.2
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• pp.147-153
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• 2014

The Ponciri fructus immaturus (Poncirus trifoliata Rafinesque) has been used in oriental medicine for uterine contraction, stomachache, abdominal distension and cardiovascular diseases. Two main compounds, poncirin and naringin were successfully analyzed by high performance liquid chromatography (HPLC) and carried out method validation according to ICH guideline. A successful resolution and retention times were obtained with a $C_{18}$ reversed phase column, at an $1m{\ell}min^{-1}$ flow rate, with a gradient elution of a mixture of methanol, water and acetonitrile. Poncirin and naringin showed good linearity ($R^2$ > 0.999) in relatively wide concentration ranged. The recovery of each compound was 95.81 ~ 101.48% with R.S.D. values less than 1.0%. The application of ultrasound-assisted extraction was shown to be more efficient in extracting poncirin and naringin from Ponciri fructus immaturus. The predicted optimal poncirin and naringin yield were poncirin 2.15%, naringin 1.65% under an extraction temperature of $40^{\circ}C$, an extraction time of 10 min in a solvent of 70% methanol.

• Korean Journal of Environmental Agriculture
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• v.36 no.1
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• pp.36-42
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• 2017

BACKGROUND: Yuza seed by-product has been produced in a large amount from the agricultural farms in the southern area of Korea. It has been mostly abandoned after commercial process for the production of juice, jam and tea. The study on the reuse of the yuza seed by-product has received much attention as a bio-resource material for the production of active compound in agriculture. METHODS AND RESULTS: Insecticidal rhamnolipid-producing Pseudomonas sp. EP-3 was grown in mineral salt media with the yuza seed by-product at 2, 20, 50 and 100 g/L. The growth of EP-3 was accompanied by a increase in insecticidal activity against green peach aphid. The highest insecticidal activity was observed when EP-3 was grown in the medium containing 50 g/L of the seed sample, producing approximately 996 mg/L of rhamnolipid at 96 h. Palmitic acid, stearic acid, oleic acid and linoleic acid were determined as the major fatty acids of the seed sample. The EP-3 cultures grown on the fatty acid mixture extracted from the seed sample showed a aphid mortality similar to that of cultures grown on the seed sample. The EP-3 cultures grown on 50 g/L of the seed sample showed aphid mortality more than 90% under greenhouse conditions. CONCLUSION: This study suggested that the yuza seed by-product may be used as a renewable material for microbial production of rhamnolipid against green peach aphid.

• Mass Spectrometry Letters
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• v.6 no.3
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• pp.71-74
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• 2015

Low temperature plasma (LTP) ionization mass spectrometry (MS) is one of the widely used ambient analysis methods which allows soft-ionization and rapid analysis of samples in ambient condition with minimal or no sample preparation. One of the major advantages of LTP MS is selective analysis of low-molecular weight, volatile and low- to medium-polarity analytes in a sample. On the contrary, the selectivity for particular class of compound also implies its limitation in general analysis. One of the critical factors limiting LTP ionization efficiency is poor desorption of analytes with low volatility. In this study, a home-built LTP ionization source with Peltier heating sample stage was constructed to enhance desorption and ionization efficiencies of analytes in a sample and its performance was evaluated using standard mixture containing fatty acid ethyl esters (FAEEs). It was also used to reproduce the previous bacterial identification experiment using pattern-recognition for FAEEs. Our result indicates, however, that the bacterial differentiation from FAEE pattern recognition using LTP ionization MS still has many limitations.

• Applied Chemistry for Engineering
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• v.10 no.8
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• pp.1186-1191
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• 1999

By using a liquid-mix precursor, we prepared the hollow glass spheres(HGS) as an additive of polymer compound which are used in the field of modifier, promoter, filler, and reinforcement. Liquid-mix precursor is a mixture of 40% sodium silicate aqueous solution, boric acid as a insolubilizing agent, and urea as a blowing agent. To obtain the precursor particles which are fed into a gas flame furnae, the above liquid-mix precursor was dried in oven and crushed with ball mill. We assumed the size of precursor particles ($53{\sim}63{\mu}m$, $63{\sim}180{\mu}m$), temperature of furnace($800{\sim}1200^{\circ}C$), and amount of urea(0~30 g) as the parameters affecting on the properties of HGS. As a result mean particle size of HGS increases with increasing the temperature of furnace and the amount of urea and with decreasing the size of precursor particles. Also, we found that incresing the amount of urea is related to a decrease of the crush strength of HGS.

• Journal of Energy Engineering
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• v.2 no.1
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• pp.54-67
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• 1993

Two turbulent reaction models of the premixed CC1$_4$/CH$_4$/air mixture are successfully incorporated in a 3-dimensional computer program and is applied for Dow Chemical incinerator equipped with two main off-center burners. The first reaction model is fast chemistry model(model 1), in which chemical reaction is governed by the turbulent mixing itself. And the second one is nonequilibrium model(model 2), where the effect of the chemical kinetics due to the presence of CC1$_4$is considered by the incorporation of the burning velocity data of CC1$_4$. The second model not only shows the flame inhibition trend due to the presence CC1$_4$compound, but also predicts qualitatively the vortical stratification of the CC1$_4$concentration appeared experimentally at the kiln exit. Other comparisions of two models are made in detail.