• Journal of Soil and Groundwater Environment
• /
• v.8 no.2
• /
• pp.62-69
• /
• 2003

The aim of research is the evaluation of the $Cr^{6+}$ emission features of the liquid injection through emission experiments in varying conditions, based on a field-mixing ratio. The results showed that the content of $Cr^{6+}$ content in cement measured had an Ordinary Potland Cement (OPC) of 25.3 mg/kg, which constitute the largest portion among the other materials. Likewise, the emission experiment of homo-gel and sand-gel generally satisfied the standard of KSLT (Korea Standard Leaching Test) in waste of 1.5 mg/L, but in case of the standard of KSLT in soil the emission of OPC $Cr^{6+}$ of 4.85 mg/kg. These conditions is a little exceeded the criteria in the ‘Ga’ area in terms of Korea Soil Environmental Preservation Law. In addition, results generated by the mock-up injection facilities revealed that $Cr^{6+}$ emission increased as Water/Cement and injection pressure increased. At injection pressure higher than 4 kg/㎤, $Cr^{6+}$ emission exceeded the water preservation standard of 0.5 mg/L. Similarly, a pattern experiment of C $r^{6+}$ emission according to pH was conducted, in order to evaluate the $Cr^{6+}$ emission features of grout materials in leachate below pH 5 such as pH 4 acid rain or landfill. Results show that $Cr^{6+}$ emission dramatically increased in high acidic or basic state. It indicates that $Cr^{6+}$ emission will probably increase in an environment where grout materials are injected. On the other hand, concentration of leachate was determined in areas where grout materials are used. The results show that the concentration of emission in an ultra purity condition does not manifest intensity, and is affected in the OPC>MC>SC order. It means that the pollutants or $Cr^{6+}$ emission increases with decreasing concentration. As such, $Cr^{6+}$ emission will probably exceed the countermeasure criteria according to the types of gout materials. Similarly, high pressure or injection will cause increased $Cr^{6+}$ emission. Therefore, the selection of materials or mixing ratio should be considered in general as well as according to specific industries, based on the strength and pH of $Cr^{6+}$ emission.

• Korean Journal of Soil Science and Fertilizer
• /
• v.14 no.4
• /
• pp.230-235
• /
• 1982

This study was carried out to select the most effective extractant for Cd analysis in the condition of Korean paddy soil. The various extractants were compared with 0.1 N-HCL common extractant used in Korea. Soil and rice samples were collected at same plot from paddy field adjacent to zinc mining sites. The results ob.tained are as follows. 1. The extractants were able to be arranged in order of higher extractability of cadmium content; 1N-HCL > 0.1N-HCL > 0.075N-Mixture > $1N-NH_4OAC(pH4.8)$ > $DTPA-CaCl_2$ > 5% Acetic acid> $1N-NH_4OAC(pH7.0)$ > $1N-NH_4NO_3$. 2. Although all extractants showed highly significant correlation between Cd content in soil and that in brown rice, $1N-NH_4OAC(pH7.0)$ was considered to be best. 3. The relationship between Cd concentration in soil by extractants and that in brown rice was varied depending on the levels of total Cd content and soil texture. 4. The best extractant under the soil corntions such as total Cd contents and soil texture believed to be $1N-NH_4OAC(pH7.0)$ but Cd concentration extracted in soil was low. 5. The extractant of 0.075N-Mixture was found to be a recommendable one, because it was simillar to 0.1N-HCL in extracting capacity and showed the better correlation between Cd content in soil and brown rice compared to the latter.

• Korean Journal of Weed Science
• /
• v.18 no.3
• /
• pp.179-185
• /
• 1998

This study was conducted to investigate changes in weed occurrence and dominance as affected by seeding dates in water seeded rice paddy under field following two years of no-tillage condition. The pre-emergence weeds in no-tillage paddy were controlled by glyphosate application at 7 days before seeding. The rice seeds were seeded on April 20, May 10 and May 30, respectively with 40kg/ha of seeding rate. The weed species in the paddy occurred included three species (Echinochloa cursgalli, Aneilma keisak, Ottelia alismoides) of annual weed, one species (Alopecurus aequalis) of biennial weed and five species (Eleocharis kuroguwai, Leersia japonica, Sagittaria pygmaea, Sagittaria trifolia, Potamogeton distinctus) of perennial weed respectively. Aneilma keisak was found to be dorminant on April 20 and May 10 but Eleocharis kuroguwai on May 30 based on number of weeds. The number and dry weight of weeds occurred were higher on May 10 as compared to in other seeding dates, while proportion of perennial weeds increased as the seeding date was delayed. In particular, weed dorminance varied marketly with seeding date. The Simpson's indices were 0.736 on April 20, 0.261 on May 10 and 0.281 on May 30, respectively.

• Weed & Turfgrass Science
• /
• v.6 no.3
• /
• pp.203-211
• /
• 2017

This study was conducted to investigate the phytotoxicity of main rice varieties and control efficacy of HPPD inhibitor to major paddy weeds at the time of temperature rise due to climate change. Phytotoxicity of herbicide to rice was increased as temperature was increased, and more severe in root than shoot. The phytotoxicity of japonica rice cultivars for the rice were mild enough to recover. However, glutinous rice, super high yield rice, and Tongil rice varieties were damaged enough to decrease the yield. Shindongjinbyeo transplanted by June 15, showed phytotoxicity enough to recover. However, in the rice field on June 30 and on July 15, the rice showed a remarkable inhibition. The control effect of Monochoria vaginalis and Scirpus juncoides was more than 90% under the temperature condition controlled artificially. However, Echinochloa oryzicola was controlled 40% at $27.5^{\circ}C$, which is a high temperature condition. In rice fields with different transplanting times, annual weeds except for E. oryzicola were highly controlled by 90% or more regardless of the time of transplanting.

• Journal of Chest Surgery
• /
• v.35 no.3
• /
• pp.209-216
• /
• 2002

Background: Valvular heart disease is still the most common health problem in Korea. By the end of the year 1999, there has been 94,586 cases of open heart surgery since the first case in 1958. Among them, 36,247 cases were acquired heart diseases and 20,704 of those had valvular heart disease. But there was no database system and every surgeon and physician had great difficulties in analysing and utilizing those tremendous medical resources. Therefore, we developed a valve registry database program and utilize it for risk factor analysis and so on. Material and Method: Personal computer-based multiuser database program was created using Microsoft AccessTM. That consisted of relational database structure with fine-tuned compact field variables and server-client architecture. Simple graphic user interface showed easy-to-use accessability and comprehensibility. User-oriented modular structure enabled easier modification through native AccessTM functions. Infinite application of query function aided users to extract, summarize, analyse and report the study result promptly. Result: About three-thousand cases of valve replacement procedure were performed in our hospital from 1968 to 1999. Total number of prosthesis replaced was 3,700. The numbers of cases for mitral, aortic and tricuspid valve replacement were 1600, 584, 76, respectively. Among them, 700 patients received prosthesis in more than two positions. Bioprosthesis or mechanical prosthesis were used in 1,280 and 1,500 patients respectively Redo valve replacements were performed in 460 patients totally and 40 patients annually Conclusion: Database program for registry of valvular heart disease was successfully developed and used in personal computer-based multiuser environment. This revealed promising results and perspectives in database management and utilization system.

• The Korean Journal of Nuclear Medicine
• /
• v.32 no.4
• /
• pp.365-373
• /
• 1998

Purpose: The conventional gamma camera is not ideal for scintimammography because of its large detector size (${\sim}500mm$ in width) causing high cost and low image quality. We are developing a small gamma camera dedicated for breast imaging. Materials and Methods: The small gamma camera system consists of a NaI (T1) crystal ($60 mm{\times}60 mm{\times}6 mm$) coupled with a Hamamatsu R3941 Position Sensitive Photomultiplier Tube (PSPMT), a resister chain circuit, preamplifiers, nuclear instrument modules, an analog to digital converter and a personal computer for control and display. The PSPMT was read out using a standard resistive charge division which multiplexes the 34 cross wire anode channels into 4 signals ($X^+,\;X^-,\;Y^+,\;Y^-$). Those signals were individually amplified by four preamplifiers and then, shaped and amplified by amplifiers. The signals were discriminated ana digitized via triggering signal and used to localize the position of an event by applying the Anger logic. Results: The intrinsic sensitivity of the system was approximately 8,000 counts/sec/${\mu}Ci$. High quality flood and hole mask images were obtained. Breast phantom containing $2{\sim}7 mm$ diameter spheres was successfully imaged with a parallel hole collimator The image displayed accurate size and activity distribution over the imaging field of view Conclusion: We have succesfully developed a small gamma camera using NaI(T1)-PSPMT and nuclear Instrument modules. The small gamma camera developed in this study might improve the diagnostic accuracy of scintimammography by optimally imaging the breast.

• The Korean Journal of Nuclear Medicine
• /
• v.28 no.1
• /
• pp.98-105
• /
• 1994

The search for tumor-avid agents for use in nuclear medicine imaging or therapy is a field of ongoing importance. Metallothionein (MT) is an intracellular protein that binds many metals with isotopes having imaging or radiotherapeutic potential. The purpose of the study was to determine whether uptake of radioisotopes that bind to MT is increased in tumor. We measured the uptake of Cd-109 and Ga-67 in tumor and normal tissues of sarcoma-bearing mice. Tumors were grown subcutaneously in female Balb/C mice from cultured Balb/3T3 cells transformed by the Moloney murine sarcoma virus (MMSV). When the tumors reached about 1 cm in diameter, mice were injected subcutaneously with Cd-109 and Ga-67. Eighteen and seventy-two hours later, the mice were sacrified. Organs and tissues were removed, weighed, and activity per mg tissue determined by gamma well-counting. Uptake of Cd-109 by MMSV tumors exceeded that by normal tissues examined, with the exception of liver and kidney (the organs known to be richest in MT). The tumor-to-tissue ratios of uptake for Cd-109 were far greater than those for Ga-67 for many normal tissues of great importance in terms of background activity (bone, intestine, fat, muscle, and blood). We concluded that metals that bind to MT may be useful for oncologic imaging or rediotherapy of cancer.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.12 no.3
• /
• pp.171-175
• /
• 2008

Purpose: There have been something difficulties in locating focuses and quantitative analysis in case of pediatric patients because of the relatively small body compared to adults. This author of this study, therefore, evaluated the usefulness of DFOV (Display Field Of View) according to its changes in PET/CT image reconstruction by means of the phantom experiment and pediatric patients examination. Materials & Methods: 0.023 MBq/cc of $^{18}F$-FDG was put into the uniform NU2-94 phantom, and then emission scan was acquired for 10 minutes. For reconstruction, DFOV values were changed to 50, 45, 40, 35, 30, and 25 cm respectively. As for patient images, 20 patients who were diagnosed as the one or suspicion of the children tumor are targeted from Oct 2007 to Jan 2008. For image reconstruction, 50 cm was the basis of DFOV, and the value was adjusted to DFOV 45 cm to 25 cm respectively. In the phantom and the reconstruction image of pediatric patients, the changes in pixel size and $SUV_{max}$ according to DFOV changes were analyzed. Results: As DFOV decreased to 50, 45, 40, 35, 30, and 25 cm by means of the phantom, the pixel size was changed to 3.906, 3.515, 3.125, 2.734, 2.343, and 1.953 mm respectively. Besides, as a result of reconstruction DFOV in images of pediatric patients to 50, to 25 cm, the different values of $SUV_{max}$ are shown as 3.3, 7.3, 12, 14, 18% and 2.6, 4.3, 5.0, 7.0, 10.0% on respectively when 50 cm was the standard. Conclusion: In $SUV_{max}$ using the phantom, as DFOV decreased every 5 cm, the mean value gradually increased. With 50 cm as the standard, the increase rates were 3.7, 6.5, 11.2, 19.5, and 32.1% respectively. As for pediatric patients image too, as DFOV decreased, the rates increased as in the phantom experiment. In image reconstruction, since DFOV decrease regardless of matrix size change reduced the pixel size, the image quality can be improved. This would be more useful than reconstruction and enlarge images of pediatric patients in the same way of examining adults. However, when the value of 35 cm DFOV was applied, this may result in truncated artifact, and thus the application should be properly controlled. Change of DFOV may produce better image for pediatric patients, but changes of SUV values according to DFOV change should be considered in reading.

• Korean Journal of Organic Agriculture
• /
• v.17 no.1
• /
• pp.95-109
• /
• 2009

This study was carried out to determine the effect of application seasons and rates with animal liquid slurry on the rice yield and quality. The treatments were application seasons (autumn, spring) and application rates of animal liquid slurry 80, 100, 120, 140% N levels of based on 11kg N/10a, chemical fertilizer as control plot. Field experiment was conducted at Cheorwon, Gangwon-Do in 2007. The results was as follows; The plant height and tiller's number at the application of spring season were higher than that at the autumn application. In the plot of 140% level at the spring application, the plant height and tillers were higher, and the color of leaf was darker than that of the chemical fertilizer. The plot of 140% level in spring application was increased the lodging damage of rice. Rice yield was reduced at 7%, 13% in the plot of 120%, 140 N/10a slurry level in the spring application compared to the chemical fertilizer, respectively. But rice yield at the autumn application was not significantly difference between chemical fertilizer and plots of liquid manure. The rice quality of the 120 and 140% slurry in spring application was significantly lower than that of chemical fertilizer. Total nitrogen contents and nitrogen uptake in rice plant were higher at the plot of 120, 140%N in the spring than that of chemical fertilizer. To reduce the lodging damage and increase the yield and quality of rice was needed suitable application of liquid manure In spring season.

• Korean Journal of Organic Agriculture
• /
• v.16 no.4
• /
• pp.409-420
• /
• 2008

The highland area remained bare for the winter and spring seasons and this condition has resulted in soil erosion. In this areas, crop rotation by legume has not been commonly practiced. Thus, this study was carried out to evaluate the effects of the growth characteristics and nitrogen yield as a green manure crop according to sowing seasons of hairy vetch and woolly pod vetch. In this experiment, we was investigated the growth characteristics, winter tolerance, soil coverage and productivities of hairy vetch and woolly pod vetch. We cultivated two hairy vetch(Madison, H1) and two woolly pod vetch(Naomi, Haymaker) varieties in the highland area from 2006 to 2007. The result are summarized as follows; The plant height of hairy vetch increased with the progress of growth stage until flowering stage. The wintering rate of hairy vetch was $79{\sim}83%$ in highland area. But, the wintering rate of woolly pod vetch was $29.5{\sim}39.2%$. The 100% soil coverage of hairy vetch was reached between end of May and beginning of June under autumn sowing, and between end of June and beginning of July under spring sowing. The weeds density of hairy vetch field under autumn sowing was lower than that under spring sowing. Dry matter yield of hairy vetch was significantly higher than that of woolly pod vetch under autumn sowing. The dry matter yield of hairy vetch and woolly pod vetch were $5,255{\sim}5,405kg/ha$ and $3,520{\sim}3,640kg/ha$, respectively. But, hairy vetch in spring sowing was not significantly higher fresh matter yield than that of woolly pod vetch. The nitrogen content in hairy vetch and woolly pod vetch was $2.98{\sim}3.08$ and $2.74{\sim}3.21%$, respectively. There were no significant difference in nitrogen content of the hairy vetch and woolly pod vetch under the spring sowing. N-uptake of hairy vetch was significantly higher than that of woolly pod vetch in autumn sowing. The N uptake was $156{\sim}164\;kg/ha$ in hairy vetch and $96{\sim}101\;kg/ha$ in woolly pod vetch under autumn sowing. It was thought that hairy vetch was better than woolly pod vetch as a green manure crop in autumn sowing considering wintering rate and yield of dry matter in highland area. And woolly pod vetch could use as a green manure crop under spring sowing in highland area.