• Journal of Periodontal and Implant Science
• /
• 제25권3호
• /
• pp.668-678
• /
• 1995

In order to evaluate the therapeutic effect of argon laser irradiation on hypersensitive root, 60 mandibular premolars that had been extracted due to periodontal disease were treated by thorough scaling, root planing and root conditioning with tetracycline HCI(100mg/ml, 5 min.) for induction of hypersensitive root. Within middle one third of root mesial surface(30) or distal surface(30) was randomly irradiated by 0.5W-, 0.75W- and 1.0W-power for 2 minutes argon laser(HGM Inc., USA) with or without topical application of 1.23% acidulated phosphate fluoride gel(Pascal, USA). After all teeth were maintained in 2% methylene blue solution for 48 hours and cross-sectioned through irradiated surface of dried roots, methylene blue stained area was compared between irradiated side and nonirradiated side. Following results were obtained : 1. Methylene blue stained area was significantly less in the laser irradiated group than control group(p<0.05). 2. There was no significant difference in methylene blue stained area between 0.5W-power and 0.75W-power group(p>0.1) and between 0.75W-power and 1.0W-power group(p>0.1), but there was significant difference between 0.5W-power and 1.0W-power group(p<0.05). 3. There was no significant difference in methylene blue stained area between two groups with and without topical application of 0.12% acidulated phosphate fluoride gel(p>0.1). The results suggest that argon laser irradiation on hypersensitive root may reduce the hypersensitivity by obstruction of dentinal tubules.

• Korean Journal of Chemical Engineering
• /
• 제35권12호
• /
• pp.2452-2463
• /
• 2018

Surface treatment of sol-gel bioglass is required to increase its biomedical applications. In this study, a dielectric barrier discharge (DBD) plasma treatment in atmospheric pressure was performed on the surface of [$SiO_2-CaO-P_2O_5-B_2O_3$] sol-gel derived glass. The obtained bioglass was treated by plasma using discharge current 12 mA with an exposure period for 30 min. The type of discharge can be characterized by measuring the discharge current and applied potential waveform and the power dissipation. Apatite formation on the surface of the DBD-treated and untreated samples after soaking in simulated body fluid (SBF) at $37^{\circ}C$ is characterized by Fourier transform infrared spectroscopy (FTIR), X-Ray diffraction (XRD), inductively coupled plasma (ICP-OES) and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS). We observed a marked increase in the amount of apatite deposited on the surface of the treated plasma samples than those of the untreated ones, indicating that DBD plasma treatment is an efficient method and capable of modifying the surface of glass beside effectively transforming it into highly bioactive materials.

• 한국재료학회지
• /
• 제31권11호
• /
• pp.649-656
• /
• 2021

K_0.5Bi_0.5TiO₃ (KBT) thin films were prepared by sol-gel processing for future use in piezoelectric generators. It is believed that the annealing temperature of films plays an important role in the output performance of piezoelectric generators. KBT films prepared on Ni substrates were annealed at 500 ~ 700 ℃. Tetragonal KBT films were formed after annealing process. As the annealing temperature increased, the grain size of KBT films increased. KBT thin films show piezoelectric constant (d₃₃) from 23 to 41 pC/N. The increase of grain size in KBT films brought about output voltage and current in the KBT generators. Also, the increase in the displacement of specimens during bending test resulted in increases in output voltage and current. Although KBT generators showed lower output power than those of generators prepared using NBT films, as reported previously, the KBT films prepared by sol-gel method show applicability as piezoelectric thin films for lead-free nano-generators, along with NBT films.

• 대한미생물학회지
• /
• 제35권4호
• /
• pp.289-297
• /
• 2000

Background: Staphylococcus aureus (s. aureus) and Escherichia coli (E. coli) are major pathogens in community and hospital. And they sometimes cause the outbreak in hospital in the immunocompromised patients. Pulsed-field gel electrophoresis (PFGE) has been regarded as a standard method for genotyping in epidemiologic studies, but it is laborious and time-consuming. Infrequent restriction site-polymerase chain reaction (IRS-PCR), a new genotyping methods, was performed to compare the applicability with PFGE. Methods: We performed PFGE and IRS-PCR on S. aurues (n=120) and E. coli (n=117) which were collected clinically in 4 different hospitals. We assessed each method in terms of discriminatory power, quality, and efficiency. Results: In E. coli, the discriminatory power of IRS-PCR was $46.7{\sim}86.7%$, and that of PFGE was $88.9{\sim}96.7%$ according to hospital. But in S. aurues, the discriminatory power of IRS-PCR was $20{\sim}56.7%$, and that of PFGE was $40{\sim}90%$ according to hospital. The typablity and reproducibility of IRS-PCR were 100% of each. PFGE needed four days to complete the procedure, but IRS-PCR could be performed within one day, IRS-PCR showed better resolution than PFGE. Conclusion: In case of gram negative bacteria (like E. coli), IRS-PCR could be a reliable alternative for epidemiologic typing due to better efficiency and comparable discriminatory power. But in the case of gram positive bacteria (like S. aureus), IRS-PCR does not seem to be suitable for the strain-to-strain differentiation. More trials and changes of restriction enzymes or primers could reveal the efficacy of IRS-PCR in the field of molecular typing.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2011년도 제40회 동계학술대회 초록집
• /
• pp.465-465
• /
• 2011

In recent years, electrochemical supercapacitors have attracted much attention due to their high power density, long life cycles, and high efficiency. Some supercapacitors using CNTs have been reported, but there are several issues to be resolved for further development of CNT based supercapacitors. One issue is time consuming procedures to prepare CNT films, which may provide poor control of CNT uniformity over the large area of the substrates. Another is new electrolytes replacing the conventional liquid electrolytes in supercapacitors. In this work, We have successfully demonstrated that spray deposition method of multiwalled CNT films using gel electroytes could be promising for CNT-based supercapacitors on ITO substrates. Specific capacitances using gel electrolyte reached up to 1.5 F/g and 9 mF/$cm^2$, and internal resistance was 28 ${\Omega}$. Specific capacitances and internal resistance of supercapacitors with gel electrolyte were better than or comparable to those with liquid electrolytes($KNO_3$, $Na_2SO_4$), indicating that gel electrolytes could replace liquid counterparts in CNT-based supercapacitors. Combined with gel electrolyte, spray deposition method could provide low cost and easily scalable process for high performance supercapacitors using CNT films on ITO for applications in display devices.

• 동아시아식생활학회지
• /
• 제23권5호
• /
• pp.613-619
• /
• 2013

본 연구는 저칼로리 식품으로 알려져 있는 곤약과 약리작용이 뛰어난 쑥을 첨가한 곤약국수를 제조하고자 쑥의 건조방법에 따른 색도 변화와 곤약분말 농도, pH, 응고제의 종류에 따른 곤약 겔의 제조조건과 쑥의 첨가량에 따른 최적의 곤약국수의 제조방법을 조사하였다. 곤약국수에 사용할 쑥의 건조방법별 색도 변화 조사 결과, 1% $NaHCO_3$ 용액에 데친 후 건조한 방법(HADB, FDB)은 데치지 않은 방법(HAD, FD)에 비하여 쑥의 녹색유지에 효과적이었고 데친 후 동결건조한 방법(FDB)은 데친 후 열풍건조한 방법(HADB)에 비하여 선명한 녹색을 띄고 있었다. 따라서 쑥 가공처리에 있어서 1% $NaHCO_3$ 알칼리 용액에 데친 후, 동결건조방법이 쑥의 녹색을 유지하는데 가장 효과적이었다. 곤약 겔의 최적의 제조조건을 조사하고자 곤약분말의 농도, pH, 응고제의 종류에 따른 곤약 겔의 물성(견고성, 탄력성, 응집성, 점착성)을 측정하였으며, 그 결과, 분말농도는 9%, pH는 12, 응고제는 $Na_3PO_4$를 사용했을 때 물성치가 우수하게 나타났다. 쑥의 첨가량의 영향을 분석한 결과, 곤약분말에 대하여 1.5% 첨가가 색, 향, 맛 등 전반적인 기호도가 높게 나타나, 1.5% 첨가하는 것이 바람직할 것으로 판단되었다. 이상의 결과로부터 제시한 곤약의 제조 방법과 적절한 농도의 쑥을 첨가한 곤약국수를 제조하여 영양적, 물성적, 관능적으로 소비자들에게 긍정적인 반응을 보일 수 있는 제품이 제조될 수 있는 기초자료로 활용될 수 있다고 사료된다.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
• /
• pp.484.2-484.2
• /
• 2014

There are many efforts to improving the power conversion efficiencies (PCEs) of dye-sensitized solar cells (DSCs). Although DSCs have a low production cost, their low PCE and low thermal stability have limited commercial applications. This study describes the preparation of a novel multifunctional polymer gel electrolyte in which a cross-linking polymerization reaction is used to encapsulate $TiO_2$ nanoparticles toward improving the power conversion efficiency and long-term stability of a quasi-solid state DSC. A series of liquid junction dye-sensitized solar cells (DSCs) was fabricated based on polymer membrane encapsulated dye-sensitized $TiO_2$ nanoparticles, prepared using a surface-induced cross-linking polymerization reaction, to investigate the dependence of the solar cell performance on the encapsulating membrane layer thickness. The ion conductivity decreased as the membrane thickness increased; however, the long term-stability of the devices improved with increasing membrane thickness. Nanoparticles encapsulated in a thick membrane (ca. 37 nm), obtained using a 90 min polymerization time, exhibited excellent pore filling among $TiO_2$ particles. This nanoparticle layer was used to fabricate a thin-layered, quasi-solid state DSC. The thick membrane prevented short-circuit paths from forming between the counter and the $TiO_2$ electrode, thereby reducing the minimum necessary electrode separation distance. The quasi-solid state DSC yielded a high power conversion efficiency (7.6/8.1%) and excellent stability during heating at $65^{\circ}C$ over 30 days. These performance characteristics were superior to those obtained from a conventional DSC (7.5/3.5%) prepared using a $TiO_2$ active layer with the same thickness. The reduced electrode separation distance shortened the charge transport pathways, which compensated for the reduced ion conductivity in the polymer gel electrolyte. Excellent pore filling on the $TiO_2$ particles minimized the exposure of the dye to the liquid and reduced dye detachment.

• 대한가정학회지
• /
• 제27권1호
• /
• pp.39-46
• /
• 1989

Mung bean starch gel (Mook) and gel made from starch of cowpea are similar properties in texture. In order to elucidate the similarity between these two starch gels, some physicochemical properties of cowpea starch were compared with those of mung bean starch. Water bildings capacity of cowpea starch (183.6%) was a little low than that of mung bean starch (184.2%). The solobility, swelling power and optical transmitance of the cowpea starch showed a smiliar pattern to mung bean starch, but cowpea starch had a little lower solubility than mung bean starch. Amylogram of mung bean strach (4, 5, 6, 7%) shoved no peak viscosity but cowpea starch (4, 5, 6%) showed peak viscosity and both starches showed high viscosities when cooling. Cowpea and mung bean starches had the blue value of 0.41 and 0.47, the alkali number of 8.4 and 8.0, the amylose content of 30.5 and 32.1%, the molecular weight of amylose of 30,000 adn 29,258 and glucose unit per segment of amylopectin of 27.6 and 26.8 respectively. The shape of cowpea and mung bean strach granules were round and elliptical, and the mean vlalue of major axis, minor axis and the ratio of these were 20.7 and 21.8 ${\mu}{\textrm}{m}$, 14.6 and 14.4 ${\mu}{\textrm}{m}$ and 1.42 and 1.51, respectively. The extent of retrogradation determined by the glucoamylase digestion method and syneresis showed that cowpea starch gel was larger than that syneresis showed than cowpea starch gel was larger than that of mung bean starch gel. The redults of X-ray diffraction studies showed A pattern for two starches, Diffraction peak of gels disappeared with gelatinization of starches but that of two starch gels storaged for 2 days at 5$^{\circ}C$ showed a similar patterm.

• 한국산학기술학회논문지
• /
• 제13권11호
• /
• pp.5637-5645
• /
• 2012

폐기되는 홍어껍질을 기능성 식품원으로 재이용하고자 홍어껍질 물 추출물의 추출특성과 세 종류의 식용유에 대한 산화억제 효과를 측정하였으며, 추출 콜라겐의 겔화를 위한 최적조건 및 겔화제 선정, 겔의 저장성, 강도와 관능평가를 실시하였다. $50^{\circ}C$ 추출물의 방향족화합물 함량과 페놀성 화합물 함량은 $25^{\circ}C$ 추출물에 비하여 각각 49.4%와 32.7% 높았으며, $50^{\circ}C$ 추출물의 환원력은 $25^{\circ}C$ 추출물 보다 52.74% 높았으나 ascorbic acid의 14.9%, BHT의 27.8%였다. 추출물의 전자공여능은 방향족 화합물과 페놀성 화합물의 함량이 높을수록 높게 측정되었다. 식용유에 대한 $50^{\circ}C$ 추출물의 산화억제 효과는 옥수수 배아유, 대두유 및 올리브유 순이었으며, 식용유 종류에 따라 ascorbic acid의 38.27~96.83%, BHT의 49.53~75.31%였다. 홍어껍질 추출물로부터 콜라겐 겔화의 최적 추출조건은 2.5배의 가수비에서 $100^{\circ}C$, 2시간이었으며, 조미하지 않은 경우에 비해 10% 조미한 경우 겔의 강도를 50%이상 저하시킬 수 있었고, 5개항에 걸친 관능평가 결과 상당한 개선을 보여 식품으로서의 제품화가 가능한 것으로 평가되었다.

• 한국식품과학회지
• /
• 제23권5호
• /
• pp.633-641
• /
• 1991

전분의 어떤 성질이 묵 형성을 영향을 주는가를 알기위해 도토리, 메밀, 녹두 전분(묵전분)과 옥수수, 쌀, 밀 전분(비묵전분)의 이화학적, 분자구조적 성질과 전분지방질의 함량을 조사하여 겔 강도와 비교하였다. 전분의 아밀로오스 함량은 녹두, 도토리, 메밀, 밀, 옥수수, 쌀 순이었으며 겔 강도 역시 같은 순서로 나타나 이들 사이에서 가장 좋은 상관관계를 보였다(r=0.95). 묵전분의 아밀로오스의 특성을 보면 비묵전분보다 분자크기가 켰고(${\overline}D.P._{n}=1,800{\sim}1,580\;vs\;670{\sim}1,120$), 평균 가지수가 많았으나(${\overline}N.C.=2.9{\sim}5.4\;vs\;1.7{\sim}2.5$), 평균 가지 길이는 작았다(${\overline}C.L.=290{\sim}390\;vs\;390{\sim}450$). 묵전분의 아필로펙틴의 ${\overline}C.L.$은 비묵전분보다 컸으며 ($22.2{\sim}22.6\;vs\;18.9{\sim}21.3$), 전분지방질의 함량은 비묵전분보다 더 작았다($0.12{\sim}0.49\;vs\;0.68{\sim}1.26%$), 이들 분획물의 성질과 지방질함량은 겔 강도와 좋은 상관관계($r=0.76{\sim}0.84$)를 보였다. 따라서, 묵전분의 겔 형성능력은 아밀로오스 함량과 전분의 여러 특성이 종합적으로 작용해 나타내는 것으로 보인다.