• Proceedings of the KAIS Fall Conference
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• 2003.06a
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• pp.91-94
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• 2003

하소온도에 따른 (Zn/sub 0.8.Mg/sub 0.2/)TiO₃ 마이크로파 유전체 세라믹스의 소결거동과 마이크로파 유전특성의 변화를 연구하였다. 저온소결을 위하여 0.45 wt.％Bi₂O₃와 0.55wt.％V₂O/sub 5/를 첨가하였으며, 1000℃이하의 온도에서 소결하여 치밀한 소결체를 얻을 수 있었다. 800℃～1000℃의 범위의 여러 온도에서 하소를 하고 소결 전ㆍ후의 존재상과 미세구조의 분석을 통하여, 하소한 분말에 존재하는 미반응상 및 이차상이 최소화 될 때 높은 Q×f/sub o/값을 갖는 것을 알 수 있었다. 1000℃에서 하소한 후 900℃에서 소결했을 때, 주상이 Hexagonal이고 미세구조가 균일하였으며, 이때 Q×f/sub o/ = 42,000㎓, ε/sub r/ = 22를 나타냈다.

• PNF and Movement
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• v.8 no.2
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• pp.47-55
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• 2010

Purpose : The purpose of present study was to determine effects of a task-oriented circuit training(TOCT) for lower limb on walking ability after stroke. Methods : Twenty one chronic stroke patients participated. Participants were randomly divided into either TOCT group or control group(11 experimental, 10 control). All of participants were in-patients at local rehabilitation centre and had been receiving a traditional rehabilitation program, five days a week. TOCT group have additionally undergone for four weeks, three days a week, the TOCT program but control group was not received any additional program except the traditional rehabilitation program. The 10 m walking test (10MWT), the 2 min walking test (2MWT), the step test (ST) and the figure-8 walking test (F8WT) to measure a walking ability were carried out twice before and after training. Results : After participation in the program, subjects of TOCT demonstrated a significant improvement in the scores of the 10MWT, 2MWT, the ST, the F8WT. The control group had no change on the any tests. After the training, the results to improve significantly in TOCT group compared to post-test of control group were the time of 10MWT and the time and the step of curved walking of F8WT. Conclusion : The present study suggests that the TOCT program may become a useful strategy for enhancing walking ability in the rehabilitation of stroke patients.

• Korean Journal of Materials Research
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• v.7 no.11
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• pp.934-941
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• 1997

C $r_{3}$ $C_{2}$-20wt% NiCr 이 크래드된 분말을 이용하여 HVOF 용사층의 특성(미세조직, 결정상, 경도 그리고 erosion rate)에 미치는 연료/산소 비(=3.2,3.0,2.8,2.6)의 영향을 조사했다. 실험범위 내에서 F/O=3.0의 경우가 C $r_{3}$ $C_{2}$-20wt%(NiCr)크래드 분말의 최적용사조건 이었다. XRD분석결과 F/O비에 관계없이 카바이드분해는 일어 났다. C $r_{3}$ $C_{2}$에서C $r_{7}$ $C_{3}$로의 상변화는 F/O비가 감소함에 따라 증가했다. 열처리 온도가 높아짐에 따라 C $r_{7}$ $C_{3}$분율은 증가 하였으며, 100$0^{\circ}C$에서 50시간 열처리후 용사층의 주된상은 C $r_{7}$ $C_{3}$이였다. 용사상태에서 경도값은 F/O=3.0조건으로 용사된 코팅층이 $H_{v300}$-1040으로 가장 높았으며, 공기중에서 $600^{\circ}C$, 50시간 열처리한 후, 경도값은 1340으로 증가하였다. 그리고 80$0^{\circ}C$열처리 후 경도값은 약간 감소하였다. 그러나 100$0^{\circ}C$ 열처리 후에도 1060정도로 용사상태의 경우 보다는 높은 경도값을 유지하였다. 이와같이 경도값이 증가하는 이유는 열처리에 따라 용사층이 치밀하게 되고 또한 C $r_{2}$ $O_{3}$의 산화물이 C $r_{3}$ $C_{2}$/C $r_{7}$ $C_{3}$ 내에 생성되어 탄화물/산화물 복합체를 이루기 때문으로 생각된다. 용사상태에서 drosion rate는 F/O비에 따라 2.6-3.05x$10^{-4}$mg/g까지 변화하였다. 또한 $600^{\circ}C$열처리 후에는 2.15-2.3 x $10^{-4}$mg/g이였으며, 80$0^{\circ}C$에서 열처리한 후에는 2.3-2.4x$10^{-4}$mg/g으로 $600^{\circ}C$열처리후 보다 약간 높은 결과를 보였다.결과를 보였다.

• Korean Chemical Engineering Research
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• v.58 no.1
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• pp.52-58
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• 2020

Electrochemical characterization and thermal stability were investigated for MgF₂ coated LiNi_0.8Co_0.15Al_0.05O₂ cathode. The ratio of MgF₂ was controlled by 0.5, 1, 3 wt%. Cyclic voltammetry, charge-discharge profiles, rate capability, cycle life were measured for electrochemical properties. DSC analysis was measured for thermal stability. The first discharge capacities of MgF₂ coated LiNi_0.8Co_0.15Al_0.05O₂ were decreased at 0.1C-rate compared to pristine LiNi_0.8Co_0.15Al_0.05O₂. But the rate capability and cycle life of MgF₂ coated LiNi_0.8Co_0.15Al_0.05O₂ were improved at 2C-rate. In DSC analysis result, the exothermic temperature of MgF₂ coated LiNi_0.8Co_0.15Al_0.05O₂ was increased and peak height was decreased.

• Korean Journal of Food Science and Technology
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• v.6 no.2
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• pp.86-90
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• 1974

Quantitative analysis of the fatty acids contained in Amorpha-fruticosa seeds was carried out by means of gas chromatography with F.I.D. The general components and chemical constants have been performed with A.O.A.C methods. The results are summarized as follow: 1. General components of Amorpha-fruticosa seeds come out to be 17.65% moisture, 21.02% crude protein, 12.04% crude lipid and 5.37% ash. 2. Extraction of crude lipids were performed by soxhlet extractor for 14 hour. Amounts of the crude lipids were extracted 80.25% in ether, 80.00% in methanol, 77.34% in benzene and 69.96% in hexane. 3. Chemical constants of Amorpha-fruticosa seed oil were saponification number 178.67, acid number 3.11 and iodine number 54.27. 4. The fatty acid components of Amorpha-fruticosa seeds were quantitatively determined by gas chromatography to give 78.73wt% linoleic, 5.8wt% oleic, 5.68wt% palmitic, 4.8wt% stearic and 3.40wt% linolenic acid in ether solvent and to give 77.86wt% linoleic, 7.77wt% palmitic, 5.84wt oleic and 4.97wt% stearic acid in methanol solvent. The peak of capric acid was not found. Myristic, arachidic and lauric acids were very small.

• Journal of the Korean Society of Physical Medicine
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• v.11 no.2
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• pp.63-70
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• 2016

PURPOSE: The aim of this study was to conduct an Otago exercise program with stroke patients in a clinical setting and ascertain its effects on balance and walking ability. METHODS: The participating subjects were 45 people who had been diagnosed with stroke. They were assigned to two groups (Otago exercise; OE, n=22; balance exercise; BE, n=23), and the exercises were conducted for three sessions per week for eight weeks. The main balance outcomes were evaluated using the timed up and go test (TUG) and the four step square test (FSST), while walking ability was evaluated using the 10 m walk test (10MWT), direction change ability was measured using the figure 8 of walk test (F8WT), and the decrease of fear was evaluated using the modified falls efficacy scale (MFES). RESULTS: In the analysis results, the Otago exercise group showed significant increases in TUG, FSST, 10MWT, and F8WT within the both groups. There were significant differences in all variables between the OE group and the BE group at the post-intervention evaluation, but there was no significant difference between the groups with respect to the 10MWT. This study showed that conducting Otago exercise in stroke patients increased the main outcomes for TUG, FSST, F8WT scores, but not for 10MWT. CONCLUSION: The results of this study demonstrated that Otago exercise would be useful to improve balance and gait for stroke patients who want to improve their abilities and activities of daily living.

• BMB Reports
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• v.34 no.1
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• pp.90-94
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• 2001

The mutagenic activity of chitosan oligosaccharide and its antimutagenic effect against 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) were investigated using the Salmonella/Ames test. No mutagenic activity was found in the Salmonella typhimurium strains TA 98 and TA 100, either with or without S9 activation. In contrast, chitosan oligosaccharide showed an inhibitory effect on the mutagenic activity of the cooked food mutagen, MeIQx, in the presence of S9. The influence of chitosan oligosaccharide on the genotoxicity of MeIQx was examined using a host-mediated assay in mice. The oligosaccharide was administered for 14 consecutive days (intragastric application at doses of 0.1 or 0.5 g/kg body wt) to mice. S. typhimurium TA 98 was given intravenously before an oral dose of MeIQx (4.5 mg/kg body wt.). The number of $his^+$ revertants were determined from the Ever of mice. The intragastric application of oligosaccharide led to a 47% reduction in the number of mutants induced by MeIQx (p<0.05). These results suggested that chitosan oligosaccharide had antimutagenic properties against MeIQx in vitro and in vivo.

• Polymer(Korea)
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• v.24 no.2
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• pp.259-267
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• 2000

Gel polymer electrolytes were prepared from poly(vinylidene fluoride-co-hexafluoro propylene)[P(VdF-co-HFP)] that had higher mechanical properties as well as higher dielectric constant ($\varepsilon$=8~13) than other polymeric matrix. Mechanical properties and ionic conductivities have been investigated as a function of blend ratio of electrolyte solution and polymer matrix. Ethylene carbonate (EC)/${\gamma}$-butyrolactone (${\gamma}$-BL) and lithium triflate (LiCF$_3$SO$_3$) were used as solvent and salt, respectively. The mechanical properties such as tensile strength, tensile modulus, compression modulus, and dynamic shear modulus were evaluated. The highest ionic conductivity was 1.09$\times$10$^{-3}$ S/cm for PVH40 containing 28.6 wt% of P(VdF-co-HFP) at $25^{\circ}C$. Tensile strength, tensile modulus and compression modulus were increased with P(VdF-co-HFP) content and abruptly changed between PVH70 and PVH80. Dynamic shear moduli showed a typical gel behavior and changed with shear strain.

• Journal of the Korean Society for Heat Treatment
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• v.13 no.4
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• pp.265-271
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• 2000

The microstructural change and transformation characteristics with cooling rate i.e. wheel speed were investigated in 82.8wt%Cu-12.8wt%Al-4.3wt%Ni SMA ribbons fabricated by melt-spinning. The thickness and width of ribbon were decreased with increasing wheel speed, while the uniformity of it was improved. At same wheel speed, the grain size of the contact surface of ribbon was smaller than that of free surface. The mean grain size was decreased with increasing wheel speed, resulted in obtaining grains with $3{\mu}m$ in mean diameter in the wheel speed of 30 m/s. However, micro-voids and cracks at grain boundary could be observed at higher wheel speed. $M_s$ and $A_s$ temperatures were decreased, and $M_s{\sim}M_f$ and $A_s{\sim}A_f$ temperature ranges were broadened with increasing wheel speed. All the ribbons were retained the ordered $D0_3$ due to rapid cooling, the volume fraction of it was increased with increasing wheel speed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.331-334
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• 2001

In this study, the magnetic properties for Ni-Zn ferrite were investigated as the function of $Co_3$ $O_4$ additive contents which was predicted to improve the resonance frequency. Toroid specimens with the composition of N $i_{0.8-x}$Z $n_{0.2+x}$F $e_2$ $O_4$(x = 0, 0.05, 0.1, 0.15) ferrites were preparation by conventional ceramic processing technique. The maximum resonance frequency of 19.905 MHz and the permeability of 90.88 in 10 MHz were attained to the N $i_{0.8}$Z $n_{0.2}$F $e_2$ $O_4$with $Co_3$ $O_4$0.3 wt%. Both of the permeability in 10 MHz and the resonance increased to 107.11 and 19.005 MHz respectively for the N $i_{0.8}$Z $n_{0.2}$F $e_2$ $O_4$with $Co_3$ $O_4$wt% than the N $i_{0.8}$Z $n_{0.2}$F $e_2$ $O_4$/ with the free $Co_3$ $O_4$composition.composition.