• Journal of Korea Soil Environment Society
• /
• v.4 no.2
• /
• pp.87-101
• /
• 1999

This study has been carried out to examine the feasibility of washing technique for reducing the heavy metal contamination level of tailing wastes and agricultural soil surrounding abandoned metal mines. Some organic acids with low molecular weight were used as washing solution. Initial contamination levels of copper and lead for some soil samples were found to exceed the standard levels of countermeasure and concern, and those of cadmium to approach the standard level of countermeasure. Experimental results using sequential extraction method revealed that more than half of copper and lead existing in tailing wastes are adsorbed forms available for plants. There are some proportional relationships between metal concentrations determined by using 0.1N HCI solution and those determined by sequential extractions. Citric acid was turned out to be superior to oxalic acid and acetic acid with low molecular weight in washing above three metals. When citric acid is used for washing heavy metals from soil, it is desirable to operate at pH less than 5.5 for better washing effect. Metal removal effect by citric acid solution has been proved to depend upon solution concentration and the mass ratio of solution to soil. Addition of SDS(Sodium Dodecyl Sulfate) to citric acid improved the washing effect of cadmium among three metal most significantly. while copper removal did not change. Washing technique using citric acid for removal of heavy metals from agricultural soil or tailing wastes is recognized to be an effective remediation method.

• Ecology and Resilient Infrastructure
• /
• v.9 no.4
• /
• pp.259-268
• /
• 2022

In this study, seeds of Festuca ovina var. coreana growing in waste coal landfills exposed to heavy metal contamination for a long time were collected, and growth characteristics and heavy metal accumulation capacity were evaluated through greenhouse cultivation experiments with germinated seedlings, and was conducted for the applicability of phytoremediation technology. Concentration gradients of arsenic-treated artificial soil were 25, 62.5, 125, and 250 mg/kg, respectively, lead concentrations were 200, 500, 1000, and 2000 mg/kg, and cadmium concentrations were 15, 30, 60, and 100 mg/kg, respectively In the arsenic, lead, and cadmium-treated experimental groups, the number of leaves of F. ovina var. coreana decreased in all compared to the control group except for the lead-treated groups (200, 500, and 1000 mg/kg). Length growth of the shoot part was increased in all of the arsenic treatment groups compared to the control group, but decreased in all of the root parts. In the 1000 and 2000 mg/kg lead treatment groups, lengths increased compared to the control group, but in the other treatments, they were shorter than the control group. In the case of the cadmium treatment group, all of the shoot parts were increased compared to the control group, and all of the root parts were decreased. In the case of arsenic treatment, the biomass was decreased at all parts and all concentrations compared to the control group. The 200, 500, and 1000 mg/kg lead treatments showed larger biomass than the control group in both shoot and root parts. In the cadmium treatment group, the biomass of both shoot and root parts decreased compared to the control group. As the concentration of heavy metal treatment increased, both the number of leaves and the biomass by plant parts tended to decrease, and the length growth of the shoot part tended to increase slightly, but the root part tended to decrease slightly. The arsenic accumulation concentrations of the shoot and root parts of the 62.5 mg/kg arsenic treatment area were 9.4 mg/kg and 253.3 mg/kg, respectively. While the shoot part of the 250 mg/kg arsenic treatment area withered away, the arsenic accumulation concentration in the root part was analyzed to be 859.1 mg/kg, In the 2,000 mg/kg lead treatment area, the shoot and root parts accumulated 10,308.1 and 11,012.0 mg/kg, which were 1.1 times higher than the root parts. At 100 mg/kg cadmium treatment, the shoot and root parts were 176.0 and 287.2 mg/kg, and the root part accumulated 1.6 times higher than the shoot part. As a result of tolerance evaluation of F. ovina var. coreana, multi-tolerance to three heavy metals was confirmed by maintaining growth without dying in all treatment groups of arsenic, lead, and cadmium. Plant extraction (phytoextraction) of F. ovina var. coreana was verified as a species that can be applied up to 2,000 mg/kg of soil lead contamination.

• Bulletin of the Korean Chemical Society
• /
• v.27 no.9
• /
• pp.1293-1296
• /
• 2006

In this study, a solid phase extraction method has been developed for the preconcentration and separation of the elements Cr(III), Fe(III), Co(II) and Pb(II) at trace levels by using a column packed with Amberlite XAD-1180 resin loaded with 4-(2-pyridylazo)-resorcinol (PAR) reagent. After preconcentrating, the metals retained on the column were eluted with 20 mL of 3 mol/L $HNO_3$ and then determined by flame atomic absorption spectrometry (FAAS). The factors affecting the recovery of the elements, such as pH, type and concentration of eluent, volume of sample and elution solution, and matrix components, were also ascertained. The recoveries of Cr(III), Fe(III), Co(II) and Pb(II) were found to be $99\;{\pm}\;4,\;97\;{\pm}\;3,\;95\;{\pm}\;3$ and $98\;{\pm}\;4$%, respectively, under the optimum conditions at 95% confidence level and the relative standard deviations found by analyzing of nine replicates were $\leq4.4$%. The preconcentration factors for Cr(III), Fe(III), Co(II) and Pb(II) were found as 75, 125, 50 and 75 respectively. The detection limits (DL, 3s/b) were 3.0 $\mu g/L$ for Cr(III), 1.25 $\mu g/L$ for Fe(III), 3.3 $\mu g/L$ for Co(II), and 7.2 $\mu g/L$ for Pb(II). The recoveries achieved by adding of metals at known concentrations to samples and the analysis results of Buffalo river sediment (RM 8704) show that the described method has a good accuracy. The proposed method was applied to tap water, stream water, salt and street dust samples.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.14 no.11
• /
• pp.2485-2490
• /
• 2010

In this paper, gather the sleep environment data of bedroom to sleeping and analyze the relationship between the obtained conditional data and the sleep. Based on this, system provide the optimal sleep environment of individual person by extracting the simulation model. The experiments of system was using H-MOTE2420 sensor composed of temperature/humidity sensor and ambient light sensors. We use difference image method in motion extraction from video for extraction of tossing and turning. In addition, it was entered such as ratio of fatigue, ratio of drinking, ratio of empty stomach as the information of weight can affect to sleep. Resultingly of experience, we can extract the optimal sleep environment. From now on, we will try to enhance to help to lead more pleasant daily life providing proper indoor environment changes depending on the situation even a partial of organic living environments such as eating and work as well as special sleep circumstances.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.36 no.3
• /
• pp.475-480
• /
• 2009

An infraoccluded tooth is a tooth that has failed to erupt to be in line with adjacent teeth in the vertical plane of occlusion. Multiple complications can occur as a result of an infraoccluded tooth. Tipping of neighboring teeth, loss of space opposing teeth elongation, increased susceptibility to dental caries and abnormal eruption path, impaction and rotation of permanent successor are the consequences of infraocclusion of primary molar. Therefore, early diagnosis and treatment is the key to prevent the complications. Treatment options can be periodic follow-up, temporary restoration or extraction of the infraoccluded tooth depending on the presence of the successor, the extent of infraocclusion and the extent of tilting of the neighboring teeth. The infraoccluded primary molars with permanent successors present tend to exfoliate normally. However, failure to do periodic check up of the infraoccluded teeth may lead to serious complications. In these cases, surgical extractions are often necessary after space regaining and space maintainers should be placed until the eruption of the permanent successors are completed.

• Information Systems Review
• /
• v.6 no.1
• /
• pp.53-66
• /
• 2004

In Korea, The Consumer Protection Law in Electronic Commerce, which came into effect in July 2002, forced internet shopping malls to provide a minimum of 7 forms of business information, including the name of the business, the name of the representative, geographical address, telephone number, fax number, e-mail address, and business license number, so that consumers could easily identify them. To investigate the shopping malls which do not provide their business information, can lead to confidence in the electronic commerce environment. To investigate the completeness of the business information with the internet shopping malls, this paper proposes the methods of gathering URLs of internet shopping malls, of extracting business information attributes, and an architecture of the agent system. Information extraction in our research is based on synonyms and indicator words of the attributes. With the experiment we showed that the accuracy of our agent system to find out the right business information is 89.3%.

• Journal of the Korea Society of Computer and Information
• /
• v.16 no.1
• /
• pp.47-52
• /
• 2011

This paper collect sleep environment data of bedroom to sleeping, and analyzing the relationship between conditions with obtained data and sleep. We provide the optimal sleep environment of individual by extracting the simulation model based on it. The experiments was using temperature/humidity sensor(SHT11) and ambient light sensors(GL5507). For extraction of tossing and turning, we use difference image method in motion extraction from video. In addition, the information of weight can affect to sleep, it was entered such as ratio of fatigue, drinking, empty stomach. As a result, we are able to extract the optimal sleep environment. The future, we will try to improve to help to lead more pleasant daily life providing proper indoor environment changes depending on the situation even a partial of organic ubiquitous living environments such as eating, work ete. as well as certain sleep circumstances.

• The Journal of the Korean dental association
• /
• v.58 no.2
• /
• pp.83-92
• /
• 2020

In the anterior maxillary area, dental implants for tooth replacement are challenging due to the need to satisfy high esthetic level as well as functionality. Immediate implant placement and provisionalization can dramatically reduce the edentulous period, and then fulfill patient's demand for esthetics. The aim of present case report is to demonstrate two cases that successfully restored single tooth with immediate implant placement and provisionalization in the anterior maxillary area. A 47 years old female was scheduled to replace her maxillary right central incisor due to crown-root fracture by trauma. Another 54-year-old female was planned to place dental implant following tooth extraction of maxillary right lateral incisor owing to continuous pus discharge despite repetitive treatments including apicoectomy. In these two cases, surgical and prosthetic procedures progressed in a similar way. After minimal flap elevation, atraumatic tooth extraction was performed. Implant was placed in proper 3-dimensional position and angulation with primary stability. Bone graft or guided bone regeneration for peri-implant bone defect was conducted simultaneously. Provisionalization without occlusal loading was carried out at the same day. Each definitive crown was delivered at 7 and 5 months after the surgery. Two cases have been followed uneventfully for 2 to 5 years of loading time. In conclusion, Immediate implant placement and provisionalization could lead to esthetic outcome for single tooth replacement with dental implant under proper case selection.

• Clinical and Experimental Reproductive Medicine
• /
• v.26 no.3
• /
• pp.447-456
• /
• 1999

Objective: The purpose of this study was to evaluate outcome of intracytoplasmic sperm injection (ICSI) using epididymal and testicular sperm in patients with azoospermia. Methods: From March, 1993 to May, 1999, a retrospective clinical analysis was done of a total of 140 cycles in 112 patients who underwent ICSI. Subjects were divided into three groups: ejaculated-ICSI group included 42 cycles in 34 patients with ejaculated sperm who underwent ICSI due to severe oligospermia and past history of failed or poor fertilization in the previous in vitro fertilization and embryo tranfer (IVF-ET) cycles, microsurgical epididymal sperm aspiration and intracytoplasmic sperm injection (MESA-ICSI) group included 50 cycles in 42 patients with congenital absence of the vas deferens (CAVD) or unreconstructable obstructive azoospermia and testicular sperm extraction and intracytoplasmic sperm injection (TESE-ICSI) group included 48 cycles in 36 patients with no spermatozoa which can be retrieved from epididymis or non-obstructive azoospermia. Results: Normal two-pronuclear fertilization rates were similar in three groups: 64.4% for ejaculated-ICSI group, 59.4% for MESA-ICSI group and 60.4% for TESE-ICSI group. The pregnancy rates were 26.2%, 26.0% and 25.0% respectively. There were no significant differences in the fertilization, cleavage, and clinical pregnancy rates among ICSI cycles using ejaculated, epididymal and testicular sperm. Conclusion: Epididymal and testicular sperm obtained in azoospermic patients can fertilize oocyte successfully and may lead to be similar fertilization rates and clinical pregnancy rates to ejaculated sperm.

• Bulletin of the Korean Chemical Society
• /
• v.22 no.8
• /
• pp.821-826
• /
• 2001

Solvent sublation has been studied for the separation and determination of trace Zn(Ⅱ) and Pb(Ⅱ) in water samples. A synergy producing method was utilized to improve the efficiency of extraction in the sublation using an ion-pair of metal-naphth oate {M-(Nph)3- } complexes and tetra-n-butylammonium (TBA+ ) ion. After the M-(Nph)3- complexes were formed by adding 1-naphthoic acid to the sample solution, tetra-n-butylammonium bromide was added in the solution to form the ion-pair. And sodium lauryl sulfate (SLS) was added to make the ion-pair hydrophobic. The ion-pairs of the metal complexes were floated and extracted into methylisobutyl ketone (MIBK) from the aqueous solution by bubbling with nitrogen gas in a flotation cell. Metal ions in MIBK solution were measured by graphite furnace-AAS. Experimental conditions were optimized as follow so. After the pH of a 1.0 L water sample was adjusted to 5.0, 6.0 mL of 0.1 M 1-HNph and 10 mL of 0.03 M TBA-bromide were added to the sample to form ion-pairs, and 2.0 mL of 0.2%(w/v) SLS was added to make the ion-pairs hydrophobic. The solution was bubbled with 30 mL/min N2 gas for 5 minutes in a flotation cell. Linear calibration curves were obtained for the determination of Zn(Ⅱ) and Pb(Ⅱ) in several water samples. Reproducible results of showing a relative standard deviation of < 10% and recoveries of 80-100% could be obtained.