• 한국토양비료학회지
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• 제42권1호
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• pp.29-36
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• 2009

14종의 인산용해미생물을 근권으로부터 분하였고, 16S rRNA gene 염기서열에 의하여 동정하였다 그 중 hydroxyapatite를 첨가한 배지에서 인산용해능력이 가장 뛰어난 Acinetobacter sp., Pseudomonas orientalis, Enterobacter asburiae 3종을 선택하였다. 선택된 3종의 미생물에 의해 용해된 인산의 농도는 $200\;mg\;L^{-1}$에서부터 $2300\;mg\;L^{-1}$까지 이르렀으며, 증가된 인산 농도는 배양액의 pH와 역으로 비례하였다. HPLC를 사용하여 유기산을 측정한 결과 Acinetobacter sp.는 gluconic acid를, P. orientalis는 gluconic acid와 2-ketogluconic acid를 그리고 E. asburiae는 acetic acid와 succinic acid를 분비하였다. 한편 P. orientalis와 E. asburiae는 각각 $372\;mg\;L^{-1}$와 $191\;mg\;L^{-1}$의 IAA 분비하였고, Acinetobacter sp.는 IAA를 생성하지 못했다. 인산용해미생물이 오이의 생장에 미치는 효과를 조사한 결과, P. orientalis를 처리한 시험구가 가장 높았고, E. asburiae, Acinetobacter sp., control 순으로 나타났다. 이러한 식물생장 효과는 인산용해미생물에 의한 불용성 인산용해와 IAA 생산과 관련이 있다고 생각된다.

• 한국응용과학기술학회지
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• 제38권2호
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• pp.476-487
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• 2021

고형분 70% 아크릴수지를 합성하기 위해 n-butyl methacrylate(BMA), methyl methacrylate(MMA), 2-hydroxyethyl methacrylate(2-HEMA) 및 acetoacetoxyethyl acrylate(AAEA)와 caprolactone acrylate(CLA)를 사용하여 공중합체의 유리전이온도(T_g)를 50 ℃로 조정하여 합성하였으며, 합성한 아크릴수지의 점도와 분자량은 수산기가(OH values)의 증가에 따라 증가되었다. 높은 고형분의 아크릴수지 합성에 적합한 반응개시제는 di-tert-amyl peroxide 이었으며, 최적의 합성조건은 반응 개시제 5 wt%, 연쇄이동제 4 wt%, 반응온도 140 ℃에서 적하시간은 4시간이었다. 합성수지의 구조는 FT-IR과 ¹H-NMR spectroscopy로 확인하였고, 수평균 분자량은 1900~2600, 분자량 분포도 1.4~2.1을 얻었다. 합성한 아크릴수지와 무황변성 폴리이소시아네이트인 hexamethylene diisocyanate trimer(Desmodur N-3300)의 NCO/OH 당량비를 1.2/1.0으로 조절하여 아크릴-우레탄 투명도료를 제조하였다. 도료의 물리적 특성으로 점도, 부착성, 건조시간, 가사시간, 연필경도 및 광택을 비교 검토한 결과 부착성, 건조시간, 가사시간, 연필경도 및 광택이 양호한 결과를 나타내었고, 특히 CLA를 10 % 도입한 도료는 부착성이 우수하고 낮은 점도와 높은 경도를 나타내었다.

• 한국유기농업학회지
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• 제26권4호
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• pp.629-647
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• 2018

1. 유기재배구의 토양조건은 배수가 약간 불량한 미사질 양토인 전북통 보통답으로 유효규산이 높은 것을 제외하고는 우리나라 논토양의 화학적 성분과 평균 함량이 유사하였다. 2. 관행재배구와 유기재배구 간에 생육은 초장, 분얼수, 이삭수, 이삭길이 모두 관행재배구에서 높은 것을 확인하였으며 이삭당 입수와 등숙율은 유기재배구에서 다소 높게 나타났다. 3. 병해충 발생정도는 물바구미, 잎집무늬마름병, 혹명나방, 도열병이 유기재배구에서 많이 발생하였고, 이삭누룩병은 관행재배구에서 조금 더 많이 발생하였다. 4. 주요 관리대상 병해충인 잎집무늬마름병(y=-0.2848x+199.57, $R^2=0.704^*$), 혹명나방 발생(y=-0.1361x+92.535, $R^2=0.8049^*$)과 쌀 수량과의 관계에서 유의성이 높은 부의 상관관계가 나타났다. 5. 백미 품질은 유기재배구에서 파쇄미의 증가로 완전립 비율이 낮았지만, 단백질함량이 관행재배구에 비해 낮아 전반적인 품질 및 윤기치가 높아졌다. 6. 쌀 재배 순수익은 관행재배구에서 36만원/10a, 유기재배구에서 61만원/10a로 유기재배구의 순수익이 68% 높게 나타났다.

• 한국구조물진단유지관리공학회 논문집
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• 제23권4호
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• pp.152-158
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• 2019

주차장 바닥재로 많이 사용되는 A사 에폭시 코팅제와 B사 바닥코팅제(A, B type)에 대하여 GC/MS(Gaschromatography/Mass spectrometer)를 이용하여 제품별로 함유하고 있는 휘발성유기화합물(VOCs)의 종류와 함량을 측정해보고, 휘발성유기화합물(VOCs)중 작업자나 입주자들에게 유해한 폼알데하이드(Formaldehyde), 톨루엔(Toluene), 크실렌(Xylene)을 외부 환경에 따른 오차를 줄이고자 가장 안 좋은(밀폐) 환경을 가정하고 가스검지관을 이용하여 가스배출량을 측정해 보았다. 그 결과 A사 에폭시코팅제가 제품 자체에도 휘발성유기화합물(VOCs)을 가장 많은 양 함유하고 있고, A사 에폭시코팅제에 비하여 B사 바닥코팅제 A type은 약 79%, B type은 약 96% 이상의 적은 양을 나타냈다. 또한, 밀폐된 환경 조건에서 1시간과 8시간 경과 후 가스검지관을 이용하여 폼알데하이드(Formaldehyde), 톨루엔(Toluene), 크실렌(Xylene)에 대한 가스배출량을 측정하고 TWA값으로 환산한 결과에서도 A사 에폭시코팅제가 가장 높게 측정되었다. A사 에폭시코팅제보다 B사 바닥코팅제 A type은 약 42.3%이상의 적은 측정값을 나타냈으며, B type의 경우 밀폐된 환경 조건에서도 시간가중평균노출기준(TWA)을 모두 만족하였다.

• 한국환경보건학회지
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• 제45권1호
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• pp.82-96
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• 2019

Objective: The aims of this study were to provide the basic data for establishing a precautionary management policy and to develop a methodology for selecting a radon management priority target area suitable for the Korean domestic environment. Methods: A suitable mapping method for the domestic environment was derived by conducting a quantitative comparison of predicted values and measured values that were calculated through implementation of two models such as IDW and RBF methods. And a qualitative comparison including the clarity of information transmission of the written radon map was carried out. Results: The predicted and measured values were obtained through the implementation of the spatial analysis models. The IDW method showed the lowest in the calculated mean square error and had a higher correlation coefficient than the other methods. As results of comparing the uncertainty using the jackknife concept and the concept of error distance for comparison of the differences according to the model interpolation method, the sum of the error distances showed a modest increase compared with the RBF method. As a result of qualitatively comparing the information transfer clarity between the radon maps prepared with the predicted values through the model implementation, it was found that the maps plotted using the predicted values by the implementation of the IDW method had greater clarity in terms of highness and lowness of radon concentration per area compared with the maps plotted by other methods. Conclusions: The radon management priority area suggests selecting a metropolitan city including an area with a high radon concentration.

• 한국재료학회지
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• 제29권4호
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• pp.205-210
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• 2019

$Pb(Zr,Ti)O_3$ (PZT) is used for the various piezoelectric devices owing to its high piezoelectric properties. However, lead (Pb), which is contained in PZT, causes various environment contaminations. $(K,Na)NbO_3$ (NKN) is the most well-known candidate for a lead-free composition to replace PZT. A single crystal has excellent piezoelectric-properties and its properties can be changed by changing the orientation direction. It is hard to fabricate a NKN single crystal due to the sodium and potassium. Thus, $(Na,K)NbO_3-Ba(Cu,Nb)O_3$ (NKN-BCuN) is chosen to fabricate the single crystal with relative ease. NKN-BCuN pellets consist of two parts, yellow single crystals and gray poly-crystals that contain copper. The area that has a large amount of copper particles may melt at low temperature but not the other areas. The liquid phase may be responsible for the abnormal grain growth in NKN-BCuN ceramics. The dielectric constant and tan ${\delta}$ are measured to be 684 and 0.036 at 1 kHz in NKN-BCuN, respectively. The coercive field and remnant polarization are 14 kV/cm and $20{\mu}C/cm^2$.

• Laboraroty Animal Research
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• 제34권4호
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• pp.317-328
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• 2018

Cognitive impairment responses are important research topics in the study of degenerative brain diseases as well as in understanding of human mental activities. To compare response to scopolamine (SPL)-induced cognitive impairment, we measured altered parameters for learning and memory ability, inflammatory response, oxidative stress, cholinergic dysfunction and neuronal cell damages, in Korl:ICR stock and two commercial breeder stocks (A:ICR and B:ICR) after relevant SPL exposure. In the water maze test, Korl:ICR showed no significant difference in SPL-induced learning and memory impairment compared to the two different ICRs, although escape latency was increased after SPL exposure. Although behavioral assessment using the manual avoidance test revealed reduced latency in all ICR mice after SPL treatment as compared to Vehicle, no differences were observed between the three ICR stocks. To determine cholinergic dysfunction induction by SPL exposure, activity of acetylcholinesterase (AChE) assessed in the three ICR stocks revealed no difference of acetylcholinesterase activity. Furthermore, low levels of superoxide dismutase (SOD) activity and high levels of inflammatory cytokines in SPL-treated group were maintained in all three ICR stocks, although some variations were observed between the SPL-treated groups. Neuronal cell damages induced by SPL showed similar response in all three ICR stocks, as assessed by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, Nissl staining analysis and expression analyses of apoptosis-related proteins. Thus, the results of this study provide strong evidence that Korl:ICR is similar to the other two ICR. Stocks in response to learning and memory capacity.

• 한국환경보건학회지
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• 제47권4호
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• pp.366-377
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• 2021

Background: Polycyclic aromatic hydrocarbons (PAHs) are generated in petrochemical complexes, can spread to residential areas and affect the health of residents. Although harmful PAHs are mainly present in particle phase, gas phase PAHs can generate stronger toxic substances through photochemical reaction. Therefore, the risk assessment for PAHs around the petrochemical complex should consider both particle and gas phase concentrations. Objectives: This study aimed to investigate the concentration characteristics of particle and gas phase PAHs by season in residential areas around petrochemical complexes, and to assess the risk of PAHs. Methods: Samples were collected for 7 days by seasons in 2014~2015 using a high volume air sampler. Particle and gas phase PAHs were sampled using quartz filter and polyurethane foam, respectively, analyzed by GC-MS. Chronic toxicity and probabilistic risk assessment were performed on 14 PAHs. For chronic toxicity risk assessment, inhalation unit risk was used. Monte-Carlo simulation was performed for probabilistic risk assessment using the mean and standard deviation of measured PAHs. Results: The concentration of particle total PAHs was highest in autumn. The gas phase concentration was highest in autumn. The average gas phase distribution ratio of low molecular weight PAHs composed of 2~3 benzene rings was 85%. The average of the medium molecular weight composed of 4 benzene rings was 53%, and the average of the high molecular weight composed of 5 or more benzene rings was 9%. In the chronic toxicity risk assessment, 7 of the 14 PAHs exceeded the excess carcinogenic risk of 1.00×10^-6. In the Monte-Carlo simulation, Benzo[a]pyrene had the highest probability of exceeding 1.00×10^-6, which was 100%. Conclusions: The concentration of PAHs in the residential area around the petrochemical complex exceeded the standard, and the excess carcinogenic risk was evaluated to be high. Therefore, it is necessary to manage the air environment around the petrochemical complex.

• 한국중재학회지:중재연구
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• 제32권4호
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• pp.53-85
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• 2022

Small and medium-sized enterprises ("SMEs") are vulnerable to trade secret misappropriation. Korea's legislation for the protection of SMEs' trade secrets and provision of civil, criminal, and administrative remedies includes the SME Technology Protection Act, the Unfair Competition Prevention Act, the Industrial Technology Protection Act, the Mutually Beneficial Cooperation Act, and the Subcontracting Act. Among these acts, the revised SME Technology Protection Act of 2018 introduced the "administrative technology misappropriation investigation system" to facilitate a rapid resolution of SMEs' technology misappropriation disputes. On September 27, 2021, Korea's Ministry of SMEs announced that it had reached an agreement to resolve the dispute between Hyundai Heavy Industries and Samyeong Machinery through the administrative technology misappropriation investigation system. However, not until 3 years and a few months passed since the introduction of the system could it be used to resolve an SME's technology misappropriation dispute with a large corporation. So there arose a question on the usefulness of the system. Therefore, we conducted a comparative legal analysis of Korea's laws enacted to protect trade secrets of SMEs and to address technology misappropriation, focusing on their legislative purpose, protected subject matter, types of misappropriation, and legal remedies. Then we analyzed the administrative technology misappropriation investigation system and the cases where this system was applied. We developed a proposal to enhance the usefulness of the system. The expert interviews of 4 attorneys who are experienced in the management of the system to check the practical value of the proposal. Our analysis shows that the lack of compulsory investigation and criminal sanctions is the fundamental limitation of the system. We propose revising the SME Technology Protection Act to provide correction orders, criminal sanctions, and compulsory investigation. We also propose training professional workforces to conduct digital forensics, enabling terminated SMEs to utilize the system, and assuring independence and fairness of the mediation and arbitration of the technology misappropriation disputes.

• Journal of Digestive Cancer Research
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• 제5권2호
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• pp.113-119
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• 2017

Background: Second line chemotherapy is often considered in advanced gastric cancers. We assessed irinotecan in combination with fluorouracil in patients experienced diseases progression after first line chemotherapy. Methods: Prospective trial was done at 7 centers in republic of Korea. Patients aged 18 years or older with advanced gastric adenocarcinoma and disease progression on or within 4 months after first-line chemotherapy were assigned to receive irinotecan 180 mg/m² and 5-fluorouraicl 400 mg/m² intravenously bolus injection on days 1 and leucovorin 200 mg/m² for 2 hours and 5-fluorouracil 600 mg/m² for 22 hours intravenously infusion on day 2 of a 14-day cycle (FOLFIRI group). The primary endpoint was objective tumor response (OR). Efficacy analysis was by per-protocol, and safety analysis included all patients who received at least one treatment with study drug. Results: Between January 1, 2014 and December 31, 2016, 28 patients were assigned to FOLFIRI treatment. Of those 20 patients were completed the study protocol. Per-protocol analysis, two patients among 20 subjects (10.0%) showed partial response. Overall survivals of FOLFIRI group; median 10.1 months [95% CI 4.9-15.3] Grade 3 and higher adverse event that occurred about 5%, but grade 3 or higher febrile neutropenia or life threatening complication was not reported. Conclusion: Combination chemotherapy with irinotecan, 5-FU, and LV is feasible in gastric cancer patients previously treated with platinum-based chemotherapy