• 한국세라믹학회지
• /
• 제31권6호
• /
• pp.581-586
• /
• 1994

Effect of excess and deficiency of PbO on the sintering and electrical properties of tetragonal Pb(Zr0.5Ti0.5)O3 were investigated. Fired density revealed maximum value with 4 wt% of excess PbO, and decreased with increasing amount of both excess and deficient PbO. Grain size increased with excess PbO, and decreased with deficiency of PbO. It appeared that excess PbO forms a liquid phase to enhance grain growth and completely volatilizes after sintering, whereas ZrO2 particles formed in PbO-deficient PZT inhibit grain growth. The change in the values of the equivalent circuit elements of PZT corresponded well with thar of porosity formed by excess and deficiency of PbO; kp, Co and Cm decreased while Qm, Rm and Lm increased conosiderably with porosity. This change was more pronounced in PbO-deficient type probably due to change in Zr/Ti ratio of PZT.

• Clinical and Experimental Reproductive Medicine
• /
• 제43권4호
• /
• pp.193-198
• /
• 2016

Objective: Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common human enzyme defect. G6PD plays a key role in the pentose phosphate pathway, which is a major source of nicotinamide adenine dinucleotide phosphate (NADPH). NADPH provides the reducing equivalents for oxidation-reduction reductions involved in protecting against the toxicity of reactive oxygen species such as $H_2O_2$. We hypothesized that G6PD deficiency may reduce the amount of NADPH in sperms, thereby inhibiting the detoxification of $H_2O_2$, which could potentially affect their motility and viability, resulting in an increased susceptibility to infertility. Methods: Semen samples were obtained from four males with G6PD deficiency and eight healthy males as a control. In both groups, motile sperms were isolated from the seminal fluid and incubated with 0, 10, 20, 40, 60, 80, and $120{\mu}M$ concentrations of $H_2O_2$. After 1 hour incubation at $37^{\circ}C$, sperms were evaluated for motility and viability. Results: Incubation of sperms with 10 and $20{\mu}M\;H_2O_2$ led to very little decrease in motility and viability, but motility decreased notably in both groups in 40, 60, and $80{\mu}M\;H_2O_2$, and viability decreased in both groups in 40, 60, 80, and $120{\mu}M\;H_2O_2$. However, no statistically significant differences were found between the G6PD-deficient group and controls. Conclusion: G6PD deficiency does not increase the susceptibility of sperm to oxidative stress induced by $H_2O_2$, and the reducing equivalents necessary for protection against $H_2O_2$ are most likely produced by other pathways. Therefore, G6PD deficiency cannot be considered as major risk factor for male infertility.

• 한국전기전자재료학회논문지
• /
• 제17권4호
• /
• pp.384-389
• /
• 2004

Crystal structure and microwave dielectric properties of Ba(Mg1/3Nb2/3) $O_3$ (BMN) ceramics were investigated. Ba(Mg1/3Nb2/3) $O_3$ has the 1:2 ordered hexagonal structure. The 1:2 ordering and relative density of specimens increased with small Mg deficiency(x). The variation of Q${\times}$ $f_{0}$ with Mg deficiency is very similar to that of 1:2 ordering and relative density. The highest Q${\times}$ $f_{0}$ achieved in this investigation is about 96,000 for Ba(Mg1/3Nb2/3) $O_3$. The improvement of Q${\times}$ $f_{0}$ with Mg-deficiency is related to the increase of degree of ordering and relative density of the specimen.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
• /
• pp.46-50
• /
• 2003

Crystal structure and microwave dielectric properties of $Ba(Mg_{1/3-x}Nb_{2/3})O_3$ (BMN) ceramics were investigated. $Ba(Mg_{1/3}Nb_{2/3})O_3$ has the 1:2 ordered hexagonal structure. The 1:2 ordering and relative density of specimens increased with small Mg deficiency(x). The variation of Q-value with Mg deficiency is very similar to that of 1:2 ordering and relative density. The highest $Q{\times}f_0$ achieved in this investigation is about 96,000 for $Ba(Mg_{1/3-0.02}Nb_{2/3})O_3$. The improvement of Q-value with Mg-deficiency is related to the increase of degree of ordering and relative density of the specimen.

• 한국안전학회지
• /
• 제30권6호
• /
• pp.117-121
• /
• 2015

$O_2$-deficiency related accidents occur every year and the most effective way to prevent them is to measure $O_2$ concentration in air with a properly-calibrated $O_2$ monitoring device before entering low-$O_2$ areas. An electro-chemical sensor, Texas Instrument gas platform, and iPhone are used to construct a smartphone-based $O_2$ monitoring device. The smartphone based $O_2$ measuring approach offers advantages of small size, accessibility, internet-connectivity, and programmability in comparison to conventional $O_2$ measuring devices. Multiple gas sensors can be conveniently interfaced to single smartphone, allowing for creating a network of gas sensors distributed across workplaces and remote monitoring via existing mobile communication network. To check proper function of the $O_2$ monitoring device the sensor was exposed to shallow and deep human breaths. The readings decreased immediately after being exposed to exhalation and recovered during inhalation to a calibrated level of 20.9%. When readings decreased below a preset warning value of 19.5%, a low $O_2$ warning was successfully activated on the smartphone.

• 한방재활의학과학회지
• /
• 제18권2호
• /
• pp.97-109
• /
• 2008

Objectives : Effects of Kyungohkgo($Qi{\acute{o}}ng\;y{\grave{u}}\;g{\grave{a}}o$) on intellectual development and learning ability were investigated growth and intellectual impairment rat with insufficient nutrition diet. Methods : We divided male Sprague-Dawley rats into 4 groups(A, B, C, D). They were normal group(A), growth deficiency rat with insufficient nutrition diet group(B), growth deficiency rat with 0.1% Kyungohkgo($Qi{\acute{o}}ng\;y{\grave{u}}\;g{\grave{a}}o$) group(C) and growth deficiency rat with 0.2% Kyungohkgo($Qi{\acute{o}}ng\;y{\grave{u}}\;g{\grave{a}}o$) group(D). They were administered for 5 weeks. We measured body weight, serum growth hormone, insulin-like growth factor and thyroid stimulating hormone, RBC, concentration of Hb and PCV ratio, total WBC and its composition, the values of plasma glutamic oxaloacetic transaminase(GOT) and glutamic pyruvic transaminase(GPT) activities and morris water maze test in escape distance, escape time and escape speed. Results : 1. Body weight showed a tendency to increase in the Kyungohkgo($Qi{\acute{o}}ng\;y{\grave{u}}\;g{\grave{a}}o$) groups and 0.2% Kyungohkgo($Qi{\acute{o}}ng\;y{\grave{u}}\;g{\grave{a}}o$) group showed significantly different than control groups. 2. Serum growth hormone, insulin-like growth factor and thyroid stimulating hormone showed a tendency to increase in Kyungohkgo($Qi{\acute{o}}ng\;y{\grave{u}}\;g{\grave{a}}o$) groups, however these values showed no significantly different. 3. About the counts of RBC, 0.1% and 0.2% Kyungohkgo($Qi{\acute{o}}ng\;y{\grave{u}}\;g{\grave{a}}o$) groups showed significantly different than control groups. Concentration of Hb was higher than control group in Kyungohkgo($Qi{\acute{o}}ng\;y{\grave{u}}\;g{\grave{a}}o$) groups. And 0.2% Kyungohkgo($Qi{\acute{o}}ng\;y{\grave{u}}\;g{\grave{a}}o$) group showed significantly different than control groups in PCV ratio. 4. The counts of total WBC and its composition showed no significantly different in all treatment groups. 5. The values of plasma glutamic oxaloacetic transaminase(GOT) and glutamic pyruvic transaminase(GPT) activities showed no significantly different in all treatment groups. 6. In the morris water maze test, in escape distance and escape speed, Kyungohkgo($Qi{\acute{o}}ng\;y{\grave{u}}\;g{\grave{a}}o$) groups showed no significantly different than control group. But Kyungohkgo($Qi{\acute{o}}ng\;y{\grave{u}}\;g{\grave{a}}o$) groups showed the increasing tendency. Conclusions : So Kyungohkgo($Qi{\acute{o}}ng\;y{\grave{u}}\;g{\grave{a}}o$) have an effect of promoting growth of rats and might be effect to treat various kinds of growth delay in children.

• 혜화의학회지
• /
• 제18권2호
• /
• pp.95-104
• /
• 2009

This study was carried out through the investigation of Oriental and Western medical literature and we was discovered these conclusions about the etiology, treatment, prescription of habitual abortion. The result of this study were as follows : 1. The habitual abortion does agree with 'Hwaltae(滑胎)' and means that spontaneous abortion repeats three times or more. 2. The etiology of habitual abortion is divided 'Deficiency of kidney'(腎虛), 'Deficiency of vital energy and blood'(氣血虛弱), 'Deficiency of yin'(陰虛), 'Clotted blood'(瘀血). 3. By means of cause, the treatment of habitual abortion was mainly made use of 'Tonifying kidney and promoting spleen'(補腎健脾), 'Invigorating vital energy and nourishing blood'(補氣補血), 'Supplementing yin fluid and alleviating fever'(滋陰淸熱), 'Resuscitating blood and removing clotted blood'(活血祛瘀). 4. By means of cause, the prescription of habitual abortion was frequent made use of Bosingochunghwan(補腎固沖丸), Bosingotae$\breve{u}$m(補腎固胎飮), Taesanbans$\breve{o}$ksan(泰山磐石散), $Ch\breve{o}ng\breve{u}mboinghwan$(千金保孕丸), Agyotang(阿膠湯), Gungguibojungtang(芎歸補中湯), Taewon$\breve{u}$m(胎元飮), Gotaej$\breve{o}$n(固胎煎), Baekchulj$\breve{o}$n(白朮煎), Sas$\breve{o}$ngsan(四聖散), Gyegibokryonghwan(桂枝茯苓丸), $Dangguich\breve{o}ng\breve{u}mtang$(當歸千金湯). 5. The Western medical etiology of habitual abortion(recurrent spontaneous early pregnancy loss) is divided Genetic factor(Chromosome aberration), Anatomical deformity, Endocrinologic disorder, Infection, Immunologic factor, Unknown factor(Others).

• 한국분말재료학회지
• /
• 제13권6호
• /
• pp.401-407
• /
• 2006

Effects of oxygen deficiency on the room temperature ferromagnetism in Fe-doped reduced $TiO_2$ have been investigated by comparing the air-annealed $Ti_{0.97}Fe_{0.03}O_2$ compound with secondly post-annealed one in vacuum ambience. The air-annealed sample showed a paramagnetic behavior at room temperature. However, when the sample was further annealed in vacuum, a strongly enhanced ferromagnetic behavior was observed at same temperature. $M{\"{o}}ssbauer$ spectra of air-annealed sample at 295K showed a single doublet of $Fe^{3+}$, suggesting that the Fe ions are paramagnetic. On the other hand, the absorption spectra after vacuum-annealing exhibited two doublets, in which one is the same component with air-annealed sample and the other is new doublet corresponding to $Fe^{2+}$ state. This result suggests that the occurrence of ferromagnetism in reduced sample may be interpreted as the contribution of unquenched orbital moment of $Fe^{2+}$ ions.

• 전기화학회지
• /
• 제8권2호
• /
• pp.82-87
• /
• 2005

고전압 용 양극산화물 $LiNi_{0.5}Mn_{1.5}O_4$는 고온에서 합성 시, 입자 내에 산소결함에 의한 불순물상을 만들게 된다. 불순물상은 불완전한 스피넬 구조를 형성하며 리튬이온의 삽입$\cdot$탈리를 방해하여 전극의 성능을 감소시킨다. 본 연구에서는 고온 열처리 시 생성되는 이러한 불순물상의 거동을 파악하기 위해 크롬을 치환한 $LiNi_{0.5-x}Mn_{1.5}Cr_xO_4(0{\leq}x{\leq}0.05)$를 졸$\cdot$겔법을 이용하여 합성하여 고온 열분석을 실시하였다. 열분석 결과 크롬이 치환되지 않은 양극활물질은 산소결함에 의한 $2\%$의 무게 감소를 보였으나, 크롬이 치환된 경우 무게 감소분이 줄어들어 불순물 생성이 억제됨을 알 수 있었다. XRD 분석에서도 크롬이 치환된 경우 불순물 상이 억제됨을 나타내었으며 불순물상의 감소로 인해 크롬을 첨가한 양극활물질 $LiNi_{0.5-x}Mn_{1.5}Cr_xO_4$를 사용한 경우 충·방전 실험 시 가역 용량과 싸이클 안정성이 향상됨을 볼 수 있었다.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
• /
• pp.299-299
• /
• 2016

SiC는 넓은 에너지갭 (Eg=~3.4 eV)을 갖는 반도체로써, 고전압, 고온에서 동작이 가능하여 기존의 Si기반의 파워디바이스를 대체하기 위한 물질로 많은 연구가 이루어지고 있다. 파워 디바이스의 성능 향상을 위해서는 기판과 절연체 사이의 계면에 생성되는 계면 결함을 감소시켜야 한다. 따라서 본 연구에서는 SiC 기판에 high-k 물질인 HfO2를 증착하여 HfO2/SiC 계면에 유도된 결함을 분석하고 이를 감소시킬 수 있는 방법에 대한 연구를 수행하였다. HfO2 박막은 atomic-layer-deposition (ALD) 방법을 이용하여 SiC 기판 위에 $200^{\circ}C$에서 증착하였다. HfO2 박막 증착 후 NH3 분위기에서 rapid thermal annealing 방법을 이용하여 $600^{\circ}C$에서 1분 동안 열처리 진행하였다. Current-voltage (I-V) 측정을 통해 열처리 전 HfO2/SiC의 절연파괴 전압이 약 8.3 V 임을 확인하였다. NH3 열처리 후 HfO2/SiC의 절연파괴 전압이 10 V로 증가하였으며 누설 전류가 크게 감소하는 것을 확인하였다. 또한 capacitance-voltage (C-V) 측정을 통해 열처리 후 flat band voltage가 negative 방향에서 positive 방향으로 이동함을 확인하였고, 이를 통해 NH3 열처리 방법이 HfO2/SiC 계면에 존재하는 결함을 감소시킬 수 있음을 확인하였다. 전자 구조상의 conduction band edge에 존재하는 결함 준위를 분석하기 위해 x-ray absorption spectroscopy (XAS) 분석을 실시하였고, 열처리 전 HfO2/SiC 계면에 많은 결함 준위가 존재함을 확인하였으며, x-ray photoelectron spectroscopy (XPS) 분석을 통해 이 결함 준위가 oxygen deficiency state과 관련됨을 알 수 있었다. NH3 열처리 후 결과와 비교해보면, oxygen deficiency state가 감소함을 확인하였으며 이로 인해 conduction band edge에 존재하는 결함 준위가 감소함을 알 수 있었다. 따라서, NH3 열처리 방법을 이용하여 HfO2/SiC 계면에 존재하는 결함을 감소시킬 수 있으며, HfO2/SiC의 물리적, 전기적 특성을 향상시킬 수 있다는 결과를 도출하였다.