• Korean Journal of Soil Science and Fertilizer
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• v.23 no.4
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• pp.293-296
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• 1990

The effect of wallastonite, potassium chloride and potassium sulphate on the ammonification and nitrification of urea was studied in a non-planted green house experiment, filling with 500g soil in plastic pot and incubating for 17 days. Potassium sulphate gave superior effect on the neutralizing soil acidity of wallastonite than potassium chloride and raised soil pH which promoted ammonification and subsequent nitrification of urea. Less than 20% $NO_3-N$ against the sum of $NH_4-N$ and $NO_3-N$ was accumulated in soils incubated bellow pH 6.0. It seemed that pH 5.2 to 6.0 was the critical range for the nitrification of ammonium, or raising the concentration of ammonia in soils to the toxic level to the nitrification. It appeared that the nitrification could be occuring in low moisture, air dried, conditions of soil.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.2
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• pp.118-122
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• 2006

This experiment was carried out on plastic pots ($40cm{\times}25cm{\times}30cm$) filled with sand soil at greenhouse using two soybean cultivars with small seed; one was Pungsannamulkong (PSNK) recognized as a tolerant cultivar against excessive water stress and the other one was Sobaeknamulkong (SBNK) recognized as a susceptible cultivar. Seed was sown with 30 plants of 2 hills, and the amount of applied fertilizer was N; 3.0 g, P; 3.0 g, and K; 3.4 g per $m^2$ with all basal fertilizations. Plants were grown under photoperiod of natural light with day temperature of $31{\pm}5^{\circ}C$ and night temperature of $22{\pm}1^{\circ}C$. The flooding treatment was done for 3, 5, 7 and 10 days by filling pots with tap water up to 1 cm above the level of the soil surface when plants were 2 days after emerging. Nitrogen uptake by leaves of soybeans decreased significantly by the flooding after 6 days. This significant reduction of N uptake by flooding was evidently recognized from the chlorosis of leaves. The dry matter of flooded soybean seedlings significantly decreased compared to non-flooded soybean seedlings at 10 days. The dry matter of roots also showed similar result of the shoot. Shoots had more N reduction than roots under the flooding. This N reduction was more pronounce in SBNK than in PSNK. Chlorophyll content of flooded soybeans showed decreasing or non-increasing tendency, and the reduction of chlorophyll content was more in SBNK than in PSNK from the flooding stress. Nitrate content of soybean seedlings with flooding stress showed decreasing tendency in shoot and root parts. Ammonium content, however, was higher in flooding stress compared to the non-flooding. Flooding caused a remarkable change in the AA (amino acid) composition and TAA (total amino acid) concentration in the leaves of soybean seedlings.

• Journal of Biosystems Engineering
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• v.23 no.3
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• pp.229-244
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• 1998

This study was performed to determine proper fan and heater management schemes for natural air drying of rough rice in round steel bin with stirring device under Korean weather conditions. A computer simulation model was developed to predict moisture content changes, energy requirements, and drymatter losses during drying of rough rice by natural air. Drying test was conducted to validate the simulation model using round steel bin of holding capacity of 300ton at Rice Processing Complex in Jincheon. The bin was filled with rough rice every day and mixing by stirring device. Moisture contents, ambient air temperatures, relative humidities, static pressures in plenum chamber in the bin, airflow rates, and electrical and fuel energy were measured. Relative errors of moisture content changes predicted by the simulation model were below 5ft, and relative errors of final moisture content, final grain weight, required energy ranged from 0.9% to 6%. These not levels indicated that the simulation model can satisfactorily predict the performance factors of natural air drying system such as drying rates and energr consumptions comparing error level of 10% to 15% in other drying simulation models generally used in dryer desists. Twelve different fan and heater management schemes were evaluated using the computer simulation model based on three hourly weather data from Suweon for the period of 1952-1994. The best management schemes were selected comparing the drymatter losses, required drying times, required energy consumptions. Operating fan without heating only when ambient relative humidity was below 85% or 90% appeared to be the most effective method of In operation in favorable drying weather. Under adverse drying climates or to reduce required drying time, operating fan continuously, and heating air with $1.5^{\circ}C$ temperature rise only when ambient relative humidity was over 85% appeared to be the most suitable method.

• Journal of Korea Foundry Society
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• v.35 no.4
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• pp.80-87
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• 2015

The Al die casting process has been widely used in the manufacturing of automotive parts when the process requires near-net shape casting and a high productive rate. However, porosity arises in the casting process, and this hampers the wider use of this method for the creation of high-durability automotive components. The porosity can be controlled by the shot condition, but, it is critical to set the shot condition in the sleeve, and it remains difficult to optimize the shot condition to avoid air entrapment efficiently. In this study, the 4.5 mm, 2.0 mm plate die castings were fabricated under various shot conditions, such as plunger velocities of 0.7 m/s ~ 3.0 m/s and fast shot set points of the cavity of -25%, 0%, 25%, and 50%. The mold filling behavior of Al melts in the cavity was analyzed by a numerical method. Also, according to the shot conditions, the results of numerical analyses were compared to those of die-casting experiments. The porosity levels of the plate castings were analyzed by X-ray CT images and by density and microstructural analyses. The effects of the porosity on the mechanical properties were analyzed by tensile tests and hardness tests. The simulation results are in good general agreements with the die-casting experimental results. When plunger velocity and fast shot set point are 1.0 m/s and cavity 25% position, castings had optimum condition for good mechanical properties and a low level of porosity.

• Journal of the Korean Electrochemical Society
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• v.10 no.2
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• pp.94-103
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• 2007

The transition of interconnection metal from aluminum alloy to copper has been introduced to meet the requirements of high speed, ultra-large scale integration, and high reliability of the semiconductor device. Since copper, which has low electrical resistivity and high resistance to degradation, has different electrical and material characteristics compared to aluminum alloy, new related materials and processes are needed to successfully fabricate the copper interconnection. In this review, some important factors of multilevel copper damascene process have been surveyed such as diffusion barrier, seed layer, organic additives for bottom-up electro/electroless deposition, chemical mechanical polishing, and capping layer to introduce the related issues and recent research trends on them.

• Journal of Korean society of Dental Hygiene
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• v.12 no.3
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• pp.553-562
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• 2012

Objectives : The purpose of this study was to examine actual conditions of smoking and alcohol drinking behaviors among high school students, so that it could recognize possible harmful effects of smoking on oral health and could give positive motivations for students to quit smoking and drinking. Methods : This research was based on self-filling survey which 1,385 high school students in metropolitan area in Korea from September 5 to October 28, 2011. Surveyed data were analyzed by descriptive statistics, ${\chi}^2$-test and logistic analysis using SPSS WIN 12.0 program and its signification level was 0.05. Results : 1. As for smoking rate and drinking rate, boy students accounted for 11.6% and 25.4%, thereby having been higher than girl students(p<.001). It was the highest in over 180 cm(16.0%, 35.0%, p<.001) for height, in 60-under 70 kg for weight(13.4%, 23.5%, p<.001), and in a case of profession for mother's job(13.8%, 28.4%, p<.005). 2. The perceived oral symptoms had relationship with the less than 10 cigarettes of smoke (OR=2.41; 95% CI:1.31-4.41), more than 11 cigarettes of smoke (OR=3.16; 95% CI:1.42-7.00) and more than 1 bottle of alcohol (OR=1.75; 95% CI:1.00-3.06). Conclusions : This result implies that adolescents' smoking and drinking have correlation with oral health status, which makes uncomfortable sense felt given chewing along with the pain in teeth and gum. Based on the above findings, a school or community needs to reinforce education for preventing smoking and drinking and to offer environment available for practicing anti-smoking and anti-drinking plan, in order to reduce adolescents' smoking and drinking.

• Journal of Veterinary Clinics
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• v.29 no.3
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• pp.250-254
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• 2012

An eight-year-old, castrated male, a Schnauzer dog was presented with dysuria, hematuria and intermittent vomiting. Retrograde positive contrast urethrography was performed under fluoroscope. On the contrast examination, the leakage was observed in the prostatic urethra region and irregular filling defect was also shown from the prostatic urethra and the level of the trigon of the bladder. Surgical treatment was selected because of partial urethral obstruction and dysuria. The metastasis at the time of surgery was suspected, and the owner decided euthanasia. We detected lymph metastasis with immunohistochemical staining for pan-cytokeratins (CK) AE1/AE3, confirming their epithelial origin. This report described typical clinical findings, diagnostic imaging and histopathological examination of a prostatic adenocarcinoma.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.10 no.4
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• pp.13-25
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• 2015

It seems crucial for entrepreneurship researchers to study how individual creativity is influenced by a number of entrepreneurship related traits. This is because individuals aiming to become entrepreneurs by launching their own start-ups need to enhance their creativity level to compete successfully in the target market. In the field of entrepreneurship studies, however, there is no literature about exploring the relationship between individual creativity, and entrepreneurship related constructs such as intrinsic motivation, parasocial interaction, prosocial motivation, and perspective taking. In this sense, our proposed research model focuses on filling the research void like this. To verify the proposed research model. we collected valid data from college students. To add rigor to our study, we allowed participants to view a talk show content where a successful entrepreneur was telling his story. Empirical test results were robust statistically enough to prove the validity of our proposed research model.

• Journal of Korean Neurosurgical Society
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• v.52 no.5
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• pp.435-440
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• 2012

Objective : The purpose of this study is to find the optimal stiffness and volume of bone cement and their biomechanical effects on the adjacent vertebrae to determine a better strategy for conducting vertebroplasty. Methods : A three-dimensional finite-element model of a functional spinal unit was developed using computed tomography scans of a normal motion segment, comprising the T11, T12 and L1 vertebrae. Volumes of bone cement, with appropriate mechanical properties, were inserted into the trabecular core of the T12 vertebra. Parametric studies were done by varying the volume and stiffness of the bone cement. Results : When the bone cement filling volume reached 30% of the volume of a vertebral body, the level of stiffness was restored to that of normal bone, and when higher bone cement exceeded 30% of the volume, the result was stiffness in excess of that of normal bone. When the bone cement volume was varied, local stress in the bony structures (cortical shell, trabecular bone and endplate) of each vertebra monotonically increased. Low-modulus bone cement has the effect of reducing strain in the augmented body, but only in cases of relatively high volumes of bone cement (>50%). Furthermore, varying the stiffness of bone cement has a negligible effect on the stress distribution of vertebral bodies. Conclusion : The volume of cement was considered to be the most important determinant in endplate fracture. Changing the stiffness of bone cement has a negligible effect on the stress distribution of vertebral bodies.

• Journal of Veterinary Clinics
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• v.37 no.2
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• pp.91-95
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• 2020

A 13-year-old, intact male, Yorkshire terrier dog with oliguria and hematuria was presented to the Small Animal Clinic at the Gyeongsang National University animal medical center. There were no remarkable findings on serum chemistry values and complete blood counts. Abdominal radiographs revealed mild elevation of the descending colon at the pelvic level. On the excretory urographic images, a large filling defect was identified in urinary bladder with narrow urinary bladder wall contact and there were no remarkable findings in kidneys and ureters. The abdominal ultrasonography revealed that an irregularly marginated, heterogeneous mass in urinary bladder, central cavitary lesion and mild vascular flow were also observed. Computed tomography showed a heterogeneously attenuated mass within urinary bladder. The mass was surgically excised, and leiomyosarcoma was confirmed by histopathological examination. The patient was followed up for two months and there were no complications. This case is of interest because of the unusual findings of leiomyosarcoma of urinary bladder in a small breed dog.