• 한국환경농학회지
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• 제19권2호
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• pp.160-165
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• 2000

오존$(O_3)$ 처리후 벼 품종의 SOD(Superoxide Dismutase)와 POD(Peroxidase)활성, 기공 저항성의 반응의 차이를 조사하여 내성품종 선발의 기초 자료로 이용하고자 실험을 실시 하였으며, 그 결과는 다음과 같다. 1. SOD활성 조사에서 오존 처리 1시간 후 상남밭벼는 활성이 높아졌고, 백나와 일품벼의 경우 오존 처리 1 시간 후 보다 2 시간 후 활성이 증가하였다. 오존 처리 24시간 후에는 상남밭벼의 활성이 크게 감소하였고, 일품벼는 활성이 증가하는 경향을 보였으며, 한강찰벼는 큰 변화를 보이지 않았다. 2. POD활성 조사에서 오존 처리 1 시간 후에는 한강찰벼, 상남밭벼, 일품벼등이 서로 비숫한 P0D활성을 나타내었지만, 백나는 활성이 매우 낮았고 시간이 지날수록 POD활성은 증가하였다. 오존 처리 24 시간 후의 POD활성은 조사된 품종 모두에서 활성이 90 %이상을 나타냈다. 3. 기공 저항성 조사에서 오존 처리 1 시간 후에는 상남밭벼의 경우 기공 저항성이 감소하는 경향 나타냈다. 오존 처리 24 시간 후의 기공 저항성은 한강찰벼, 상남밭벼, 백나에서 조사 잎 모두 기공 저항성이 감소하였지만, 일품벼에서는 오존 처리 1 시간 후와 비슷한 높은 기공 저항성을 나타냈다.

• 생물정신의학
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• 제8권1호
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• pp.37-46
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• 2001

Whenever a clinician manages the patients with depression, he may meet various problems that make it difficult to treat them. Even though he has good skills and knowledge about depression, some barriers will be appear during his practice. In general, the difficulties in treating depression are treatment-resistance, adverse effects of antidepressants, pregnancy in female patients, comorbid medical conditions, poor compliance, drug-drug interactions, and so on, which are related with pharmacological treatments. Here, only the two of them, the treatment-resistant depression and difficult problems concerned with pregnancy, were discussed. Some level of treatment resistance is the norm rather than the exception. As the treatment failure stems from inadequate treatment, it is important that the clinician should prescribe medications with sufficient doseage and adequate duration. And to overcome the treatment resistant depression the polypharmacy is necessary, in that case, the side effects and toxicities should be explored and managed immediately. So the clinician have to learn more about the pharmacokinetic and pharmacodynamic mechanisms of each drugs used in treatment of depression. When the risk of the fetus by the exposure is higher than the risk of untreated maternal psychiatric disorder, psychotropic medications should be used during pregnancy. Women who are maintained on psychotropics and become pregnant, as well as women with the new onset of psychiatric symptoms during pregnancy, should be carefully reassessed. However, data concerning the potential risk of long-term behavioral changes following prenatal exposure to psychotropics is rare, so further longitudinal follow-up studies are needed.

• 생물정신의학
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• 제23권2호
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• pp.37-40
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• 2016

Treatment-resistant depression (TRD) is a major public health problem. It is estimated that about 30% of patients with major depressive disorder do not show substantial clinical improvement to somatic or psychosocial treatment. Most of studies for TRD have focused on the subjects already known as TRD. Patients with unipolar depressive episodes that do not respond satisfactorily to numerous sequential treatment regimens were included in the TRD studies. Such post hoc experimental design can be regarded only as consequences of having TRD, rather than as causal risk factors for it. Although informative, data derived from such studies often do not allow a distinction to be made between cause and effect. So, we should shift paradigm toward examining the risk for developing TRD in untreated depressed patients. To deal with this problem, untreated depressed patients should be enrolled in the study to identify biological markers for treatment resistance. The peripheral or central biological markers should be explored before starting treatment. Subsequent systematic administration of treatments with appropriate monitoring in the subjects can determine the risk for developing treatment resistance in untreated individuals. Such information could give a cue to improve the initial diagnosis and provide more effective treatment for TRD.

• 소성∙가공
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• 제8권3호
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• pp.309-309
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• 1999

Effects of rare earth metals addition and aging treatment on corrosion resistance and mechanical properties of super duplex stainless steels were investigated using optical/SEM/TEM metallographic examination, an X-ray diffraction test, a potentiodynamic anodic polarization test and a tensile test. The performance of the experimental alloy with 0.32% REM addition was compared with commercial super duplex stainless steel such as SAF 2507 when they were exposed to solution annealing heat treatment and aging treatment. The corrosion resistance in CF environments and mechanical properties of the experimental alloy were found superior to those of the commercial duplex stainless steel. The REM with larger atomic radii than those of Cr, Mo and W may fill vacancies inside the matrix and around the grain boundaries, retarding formation of harmful intermetallic σ and χ phases. In addition, fine REM oxides/oxy-sulfides (1-3㎛) seemed to enhance the retardation effects. With REM additions, strength and ductility increased due to the phase and grain refinement caused by fine REM oxides and oxy-sulfides.

• 한국표면공학회지
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• 제36권3호
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• pp.277-283
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• 2003

Electrochemical techniques were used to study the surface treatment for improving the pitting corrosion resistance of 304L stainless steel by inhibitors in chloride medium. Sodium molybdate (in concentration range : 0.005-80 g/l) , sodium nitrite (in concentration range : 0.001-50 g/l) and their mixture were used for this study. It was found that, molybdate and nitrite were good passivators for 304L stainless steel, but molybdate was not able to prohibit the pitting ; nitrite prevented pitting corrosion of 304L stainless steel only at the concentration more than 25 g/l. The relationship between pitting potentials and concentrations of inhibitors in the logarithm expression obeyed the linear function. It was found that the surface treatment by mixture of two inhibitors enables stainless steel to have increased the corrosion resistance , the pitting corrosion of 304L stainless steel was completely prohibited by the mixtures of molybdate and nitrite in ratio min, with $m\;\geq\;3\;and\;n\;\geq\;10$. The interesting cases on electrochemical measurement of threshold of inhibitors concentration combination for optimum surface treatment were described.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2012년도 춘계학술발표회 논문집
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• pp.177-178
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• 2012

In this experiment, post-nitriding treatment has been performed at $400^{\circ}C$ on AISI 316 stainless steel which is plasma carburized previously at $430^{\circ}C$ for 15 hours. Plasma nitriding was implemented on AISI 316 stainless steel at various gas compositions (25% N2, 50% N2 and 75% N2) for 4 hours. Additionally, during post nitriding Ar gas was used with H2 and N2 to observe the improvement of treatment. After treatment, the behavior of the hybrid layer was investigated by optical microscopy, X-ray diffraction, and micro-hardness testing. Potentiodynamic polarization test was also used to evaluate the corrosion resistance of the samples. Meanwhile, it was found that the surface hardness increased with increasing the nitrogen gas content. Also small percentage of Ar gas was introduced in the post nitriding process which improved the hardness of the hardened layer but reduces the corrosion resistance compared with the carburized sample. The experiment revealed that AISI 316L stainless steel showed better hardness and excellent corrosion resistance compared with the carburized sample, when 75% N2 gas was used during the post nitriding treatment. Also addition of Ar gas during post nitriding treatment were degraded the corrosion resistance of the sample compared with the carburized sample.

• Journal of the Korean Wood Science and Technology
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• 제45권2호
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• pp.195-201
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• 2017

This study was conducted to evaluate the resistance of heat-treated wood using the catalyst to decay caused by fungi for sapwood and heartwood of two tree species, Korean red pine (Pinus densiflora) and Japanese larch (Larix kaempferi), respectively. Wood samples were immersed for 10 min in sulfuric acid (7.5%) and then heat-treated at $130^{\circ}C$ for 90 min. Fomitopsis palustris, a brown-rot fungus, was used to examine the decay resistance of Korean red pine and Japanese larch wood. Weight and density of wood from the all conditions increased after heat treatment using the catalyst. Weight loss after decay resistance test was also dropped with a heat treatment. The lowest weight loss indicated at heat-treated heartwood of Japanese larch. Heat treatment using the catalyst effectively increased the resistance of wood to decay caused by fungi.

• 운동영양학회지
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• 제14권2호
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• pp.75-80
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• 2010

We evaluated the effect of the ginsenoside Re on insulin resistance of glucose transport in muscles of rats made insulin resistant with a high fat diet. After a week of adaptation period to the laboratory environment, 40 male wistar rats were randomly assigned into 2 groups (Chow diet group; CD, n = 20, High fat diet group; HFD, n = 20). After 5-week of high fat diet, Food was removed after 6:00 PM the day before the experiment. The following morning, rats were anesthetized by an intraperitoneal injection of pentobarbital sodium (50 mg/kg body wt), and the soleus muscles were removed. Before incubation, the soleus muscle was split longitudinally into strips with an average weight of 15~20 mg. After the muscle dissection was completed, the abdominal cavity was opened, and the epididymal, mesenteric, and retroperitoneal fat pads were removed and weighed. Treatment of muscles with ginsenoside Re alone had no effect on glucose transport. The high fat diet resulted in ~50% decreases glucose transport rate in soleus muscles. Treatment of muscles with ginsenoside Re in vitro for 90 min completely reversed the high fat diet-induced insulin resistance of glucose transport in soleus muscles. This effect of ginsenoside Re is specific for insulin stimulated glucose transport, as Re treatment did not reverse the high fat diet-induced resistance of skeletal muscle glucose transport to stimulation by contraction. Our results show that the ginsenoside Re induces a remarkably rapid reversal of high fat diet-induced insulin resistance of muscle glucose transport.

• Corrosion Science and Technology
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• 제14권2호
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• pp.93-98
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• 2015

Recently, Stainless steels have been increasingly selected as the fitting or the valve materials of water pipes as the human health issue is getting higher and higher. Therefore, the connectors attached at pipes to deliver water are exposed to more severe environments than the pipes because crevice or galvanic corrosion is apt to occur at the fittings or the valves. Effects of the solid solution annealing, cooling rate after this heat treatment, and passivation on the corrosion properties of the shell mold casted SSC13 (STS304 alloy equivalent) were studied. The heating and quenching treatment more or less reduced hardness but effectively improved corrosion resistance. It was explained by the reduction of delta ferrite contents. Independent of heat treatment, the chemical passivation treatment also lowered corrosion rate but the improvement of corrosion resistance depended on temperature and time for passivation treatment indicating that the optimum conditions for passivation treatment were the bath temperature of $34^{\circ}C$ and operating time of 10 minutes. Therefore it is suggested that the corrosion resistance of SSC13 can be effectively improved with the heat treatment, where SSC13 is heated for 10 minutes at $1120^{\circ}C$ and quenched and passivation treatment, where SSC13 is passivated for at least 10 seconds at $34^{\circ}C$ nitric acid solution.

• 한국표면공학회지
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• 제29권4호
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• pp.268-277
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• 1996

Boronizing treatment of Microalloyed steel has been investigated by mean of Boronizing paste mainly consisted of $B_4C$ at various temperatures and times. The micro hardness of the boride layers were about HV 1200~1500. The thickness of the boride layer were increased with an increase of square root of treatment time at constant temperature. The activation energy for diffusion of boron in the specimen obtained from the slope of Arrhenius plots was 254 kJ/mol, but 197 kJ/mol for the induction heated specimen. The boride layer had a good corrosion resistance in solutions of 20% HCl and 20% $H_2SO_4$, solution. In 20% $HNO_3$ solution, however, its corrosion resistance increased. The boride layer had a good high temperature oxidation resistance at below $800^{\circ}C$, but at temperature above $900^{\circ}C$, the oxidation resistance decreased as the oxidation temperature.