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The Changes in the Physical Properties of Soil with Tillage Methods (I)
Park, Jun-Gul,Lee, Gu-Seung,Cho, Sung-Chan,Chang, Young-Chang,Noh, Kwang-Mo,Chung, Sun-Ok Korean Society for Agricultural Machinery 2005 Agricultural and Biosystems Engineering Vol.6 No.2
In the study, the cone index, the cohesion and the internal resistant angle of soil were measured before and after tillage in order to suggest relative improvement in soil properties. The tillage methods tested in the study were five combinations of plow and rotary tillage operation and the experiments were performed on five selected test fields. The maximum tillage depth was 20 cm under the ground. The CIs for all the tillage operations were improved in comparison with those before tillage. The best combination of tillage operations for improving the CIs of soil was one plow operation followed by one rotary. After applying the tillage operations, the internal resistance angle reduced by 7-8 degree and the cohesion decreased up to about $1N/cm^2$ in comparison with those before tillage. We concluded that the cone index, the cohesion and the internal resistant angle of soil could be used as measures for representing the relative degree of tillage for a specific tillage operation. In addition, the study was useful as a basic research tool for developing an decision making system that determines an optimal tillage method with soil properties.
The Evaluation of Excess Biomass Growth in Sewers
Park, Jin-Hwa,Lee, Young-Ok,Park, Jae-Kwang 한국화학공학회 2003 Korean Journal of Chemical Engineering Vol.20 No.5
A few sections of the sewers in Watertown were experiencing clogging due to an excess biomass growth. It was suspected that the wastewaters discharged from Fisher-Barton's two facilities were causing excess biomass growth. Madison raw sewage had a slightly lower biomass growth than the mixture of industrial wastewater and domestic sewage samples. From microscopic examination biomass, the main cause of excess biomass growth is thought to be toilet tissue. Biomass is attached to toilet tissue, decomposing it gradually and generating extracellular polymeric substances (EPS). Then suspended particulates including graphite and precipitates are attached to the biomass and filamentous organic, especially Sphaerotilus natans, leading to the increase in the biomass volume. We found that the filamentous bacteria were present in biofilm by FISH. A significant amount of graphite was embedded to biomass grown in sewer. Since the major cause of excess biomass appeared to be toilet tissue, it would not be economical to employ a filtration system for complete graphite separation. Instead, it is recommended that the manufacturing process where graphite is used be assessed and a best management practice is in place.
Corrosion behavior of biodegradable Mg-based alloys via femtosecond laser surface melting
Park, Jaeho,Han, Hyung-Seop,Park, Jimin,Seo, Hyunseon,Edwards, James,Kim, Yu-Chan,Ok, Myoung-Ryul,Seok, Hyun-Kwang,Jeon, Hojeong Elsevier 2018 APPLIED SURFACE SCIENCE - Vol.448 No.-
<P><B>Abstract</B></P> <P>The effects of femtosecond (fs) laser treatment on a biocompatible Mg-Ca-Zn alloy were systemically analyzed. The fs laser altered the surface microstructure of the Mg-Ca-Zn alloy, resulting in reduced corrosion through localized melting and rapid solidification. Treatment with appropriate laser energy (500 Hz) generated an exceptionally thin modified layer (∼2 μm) with a uniformly refined microstructure. Laser-induced remelting of the secondary phase reduced galvanic corrosion and prevented the occurrence of pitting corrosion, resulting in overall reduced corrosion. Results reveal that the corrosive nature of the biodegradable Mg alloy can be controlled through surface modification by a fs laser.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Biocompatible Mg-Ca-Zn alloy was treated with femtosecond laser. </LI> <LI> Laser surface treatment reduced secondary phase fraction and galvanic corrosion. </LI> <LI> Surface corrosion resistance of the Mg-based alloy was improved and controllable. </LI> <LI> Mechanical properties and biocompatibility were retained after laser treatment. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Leaf Morphological Characteristics of Sorbus alnifolia Selected Populations
Park, Hyung-Soon,Cho, Yoon-Jin,Byun, Kwang-Ok,Chung, Dong-Jun The Plant Resources Society of Korea 2007 한국자원식물학회지 Vol.20 No.1
The purpose of this study was to establish basic database on Sorbus alnifolia by investigating, analyzing and comparing characteristics of leaf, and then foster good cultivar on each morphological characteristics - leaf length, leaf width, petiole length, left lateral vein, right lateral vein. Leaf length and leaf width in Osan showed distinct tendency in comparison with the whole mean : 103.4mm and 63.3mm, 86.4mm and 62.9mm, respectively. Populations of Mt. Dukyoo and Mt. Halla showed leaf length of 52.8mm and 58.2mm respectively 32.6% and 39% lower than the mean of ten population. Leaf width of Mt. Gwangyang and Mt. Chink was 52.8mm and 51.9mm, respectively 17.6% and 16.2% lower than whole mean, respectively, and showed the lowest tendency among ten selected populations.
Post-market surveillance assay of veterinary medicines in Korea during 2009∼2012
( Kwang Jick Lee ),( Jeong Woo Kang ),( Sung Won Park ),( Jae Jo Kim ),( Seong Joon Joh ),( Heui Jin Kim ),( Meung Ju Chae ),( Soon Ok Jee ),( Seon Jong Yun ),( Byung Jae So ) 한국예방수의학회 2013 예방수의학회지 Vol.37 No.3
As veterinary medicine industry has grown up steadily, the government quality control of veterinary medicine in market has been performed since 1964. The result of post-market surveillance assay from 2009 to 2012 was analyzed in this study. The average violation rate of all veterinary medicines, was 3.2%, 2.8%, 2.8% and 1.4% in 2009, 2010, 2011 and 2012, respectively. The total average violation rate in the category of antibiotics, other drugs except antibiotics, biologics were 1.2%, 4.4% and 0.8%, respectively. The violations due to insufficiency of major active ingredient content occupied 76.7% among the total violations. The most frequent violated in antibiotics were ampicillin and tylosin, followed by sulfonamides, penicillins etc. In case of other drugs except antibiotics, vitamin A and glucocorticoids (dexamethasone and prednisolone) were violated frequently. The overall trend of violation rates gradually decreased from 2009 to 2012, suggesting that quality of veterinary medicines has improved according to Korea Veterinary Good Manufacturing Practice (KVGMP) system settled down in 1988.
Park, Ji Sun,Shin, Dong Ok,Lee, Churl Seung,Lee, Young-Gi,Kim, Ju Young,Kim, Kwang Man,Shin, Kwonwoo Elsevier 2018 ELECTROCHIMICA ACTA Vol.264 No.-
<P><B>Abstract</B></P> <P>A facile method for preparing mesoporous perforated Co<SUB>3</SUB>O<SUB>4</SUB> nanoparticles with hollow channels and a thin carbon layer was newly designed and achieved with sacrificial carbon nanotube (CNT) templates. The threaded Co<SUB>3</SUB>O<SUB>4</SUB> nanoparticles on the CNTs were fabricated through a hybridization process, and a subsequent calcination process produced mesoporous perforated Co<SUB>3</SUB>O<SUB>4</SUB> nanoparticles. With a finely tuned calcination, CNTs were sacrificed to generate hollow channels in the Co<SUB>3</SUB>O<SUB>4</SUB> nanoparticles and to provide a carbon source for the formation of a few nm-thick carbon layer on the surface of the Co<SUB>3</SUB>O<SUB>4</SUB> nanoparticles simultaneously. The prepared mesoporous perforated Co<SUB>3</SUB>O<SUB>4</SUB> nanoparticles with a robust electronic conductive layer enabled not only an enhanced electrochemical reactivity from the greatly increased contact area between the electrolyte and electrode but also a high electronic conductivity of the overall electrode so that excellent electrochemical performances (1115.1 mA h g<SUP>−1</SUP> after 100 cycles; 595.9 mA h g<SUP>−1</SUP> @ 5 C rate) were successfully achieved in the anode application of a lithium-ion battery.</P>