• Journal of the Korean Electrochemical Society
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• v.3 no.2
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• pp.90-95
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• 2000

Cycle life test was carried out to evaluate the failure modes of the gel type nth batteries at $C_5$ currents and $100\%$ DOD. When the batteries were charged at constant voltage of 2.40 V and 2.50 Vi respectively, cycle lift was over 1,000 cycles. The batteries lost 426.4 g and 391.2 g of electrolyte far each case after the weight measurement. The battery charged at 2.50 V was shown to have a better cyclic performance than charged at 2.40 V, and the amounts of electrolyte loss was proportional to charge factor. After cycle test, the micro-structure of positive active material was completely changed and the corrosion layer of positive grid was about $50{\mu}m$. Failure mode of the positive plate of the gel type battery was a shedding of the positive active material, and the cause of discharge capacity decrease was found to be a electrolyte loss.

• Journal of Periodontal and Implant Science
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• v.25 no.2
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• pp.341-356
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• 1995

The purpose of this study was to evaluate the effect of demineralized freeze dried bone and demineralized bone gel with guided tissue regeneration treatment around titanium implants with dehisced bony defects and also evaluate space maintaining capacity of demineralized bone gel type and DFDB powder type under e-PTFE membrane. In 3 Beagle dogs, mandibular premolar was extracted and four peri-implant osteotomies were formed for dehiscence. After insertion of implants, the four peri-implant defects were treated as follows. 1) In control group. no graft material and barrier membrane were applied. 2) In experimental group.1, the site was covered only with the e-PTFE membrane. 3) In experimental group 2,received DFDB powder and covered by the e-PTFE membrane. 4) In experimental group 3, demineralized bone gel and e-PTFE membrane were used. By random selection, animals were sacrificed at 4, 8, 12 weeks. The block sectioned specimens were prepared for decalcified histologic evaluation(hematoxylin and eosin staining) and undecalcified histologic evahiation(Von Kossa's and toluidine blue staining) with light microscopy. The results of this study were as follows. 1) In control group, there was a little new bone formation and connective tissue was completely filled in the defect area. 2) Experimental group 1 showed lesser quantity of bone formation as compared to the bone grafted group. Thin vertical growth of new bone formation around implant fixture was shown. 3) Experimental group 2 showed thick bucco-lingual growth of new bone formation and grafted bone particles were almost resorbed in 12 week group. 4) In experimental group 3, most grafted bone particles were not resorbed in 12 week group and thick bucco-lingual bone formation was shown in dehisced defect base area. 5) There was no remarkable differences in space making capacity and new bone formation procedure between demineralized freeze-dried bone powder type and demineralized bone gel type.

• Journal of the Korean Home Economics Association
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• v.23 no.1
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• pp.33-47
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• 1985

The rheological properties of acorn starch gel were investigated in region of small and large deformation. The properties were compared with those of potato and wheat starch gel. On the physical characteristics and the effect of tannin contents of acorn starch were examined. RESULTS : 1. X-ray diffractogram of acorn starch showed C-type and its granules swelled gradully with heating. 2. Hardness, brittleness and both small and large deformation of the acorn starch gel were remarkably large, also the concentration dependence of the acorn starch gel could be recognized in small deformation and hardness. 3. The Young's modulus of Hookean body in small deformation and the rupture stress in large deformation differed obviously from the parameters of rheological properties in various gels. 4. It was found that the selling power, viscosity and rhelogical properties were affected obviously by the tannin.

• Journal of ILASS-Korea
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• v.24 no.2
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• pp.82-88
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• 2019

Shear coaxial injectors were commonly used in rocket engine combustor. They showed good combustion performance. However it is not easy to control the thrust. Pintle injectors were not as popular as the coaxial injectors so far, they have a great advantage over the coaxial injectors. That is, it is relatively easy to control the thrust. Spray characteristics of gel type propellant from movable sleeve pintle injector were investigated. Water with 0.05% of Carbopol 940 was used as gel simulant instead of kerosene gel combined with Thixarol ST for academic purpose. Experiments were performed in various temperature, pressure and pintle opening condition. The results were compared with neat liquid spray. It is also verified that the capabilites of the injector by adjusting the pintle opening.

• Electrical & Electronic Materials
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• v.9 no.2
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• pp.132-137
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• 1996

Pb(Zr$_{x}$Ti$_{1-x}$ )O$_{3}$ solutions prepared by sol-gel processing with different Zr/Ti ratio were coated on Pt/SiO$_{2}$/Si substrates using spin coating method. Coated films were annealed by rapid thermal annealing at 650.deg. C for 20sec to fabricate Pb(Zr, Ti)O$_{3}$ ferroelectric thin films. Electrical properties of the films such as dielectric constant and loss, ferroelectric hysteresis, fatigue, switching time, and leakage current were measured. Hysteresis of the films with different Zr/Ti ratio yield Pr ranging 10-21.mu.C/cm$^{2}$, E$_{c}$ ranging 37.5-137.5kV/cm. Hysteresis curve was changed from square-type to slim type according to increasing Zr contents. Switching time was faster than 180ns, and leakage current was about 20.mu.A/cm$^{2}$. The film underwent above 10$^{8}$ cycles of reversed polarization showed fatigue with increased coercive field and decreased remnant polarization.tion.

• Proceedings of the SAREK Conference
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• 2005.11a
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• pp.341-346
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• 2005

Nowadays, adsorption chillers have been receiving considerable attentions as they are energy-saving and environmental1y benign systems. A Fin & tube type heat exchanger in which adsorption/desorption take place is required more compact size. The adsorption chiller is expected to have high energy-efficiency in utilizing the waste heat exhausted from a process. The objectives of this paper are to investigate the effect of fin pitch of fin & tube on the adsorption performance and to develop an optimal design fin & tube heat exchanger in the silica gel/water adsorption chiller. Previous study concluded that optimal particle size selected 0.5mm, type HO silica gel, and fundamental heat transfer & mass transfer experiments carried out. From the numerical results, the adsorption rate for the fin pitch 2.5mm is the highest than that for the fin pitch 5mm, 7.5mm and 10mm. Also cooling water & hot water temperature affect the adsorption rate.

• Korean Journal of Food Science and Technology
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• v.20 no.6
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• pp.856-861
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• 1988

A new method developed for simultaneous purification of enterotoxin A and C from Staphylococcus aureus strain L 350/1 consisted of chromatography on carboxymethyl (CM)-cellulose using a buffer of variable pH, gel filtration on Ultro gel, and fast protein liquid chromatography(FPLC) using a buffer of variable pH. The enterotoxin A and C were purified by three steps: batchwise adsorption from culture supernatant on Amberlite CG-50; chromatography on CM-cellulose using a buffer of constant pH and molarity; and gel filtration on Sephadex G-75. The purified enterotoxin appeared homogeneous by gel diffusion and polyacrylamide gel electrophoresis. Upon treatment with CM-cellulose using a elution of variable pH, enterotoxin A and C were so close that they were not separated completely. After elution from gels, the enterotoxins appeared as a single peak at the same position. Gel filtration gave a reaction of complete identity to enterotoxin A and C in Ouchterlony immunodiffusion. In FPLC using a CM-cellulose, enterotoxin A and C were simultaneously separated at pH 8.6 and 6.8. When each fraction was performed to gel immunodiffusion, at peak of enterotoxin A and C were not detected each other. In a method of elution by pH-gradient was to be more efficient as a simultaneous separation method in terms of speed, yields and simplicity. The purified toxin A and C were identical to type A and C reference enterotoxin on both disc electrophoresis and Ouchterlony gel diffusion.

• Journal of Microbiology and Biotechnology
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• v.7 no.4
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• pp.267-271
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• 1997

We developed a dermal equivalent (DE) which was engineered using human dermal fibroblasts and a matrix of collagen gel. The in vitro construction of the DE was accomplished by casting a porcine collagen type I solution plus concentrated medium with isolated and cultured fibroblasts. These constructs were attached to culture dishes or left floating in culture medium. Contraction of attached gels results in decreased gel thickness without a change in gel diameter, and contraction of floating gels results in decreased gel thickness and diameter. After contraction, there was no increase in cell number in floating gels, but cells in attached gels began to increase after about 4 days of the lag phase in cell growth curve. At this lag phase, addition of fibroblast growth factor (FGF) at a concentration of $0.1{\mu}$/ml promoted cell proliferation in the attached collagen gels, but no effect in floating gels. These results indicate that the method of contraction had an influence on the extracellular matrix (ECM) organization, and this influenced not only cell growth but also fibroblast responsiveness to FGF. This suggests that attached collagen gel is more suitable as a dermal equivalent than the floating gel. And the final contracted area of attached gel is much larger than that of the floating gel since floating gel is contracted in all directions but attached gel is contracted only vertically.

• Journal of Embryo Transfer
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• v.9 no.1
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• pp.73-83
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• 1994

The objective of this study was to develop an effective in vitro production system capable of obtaining more porcine embryos from immature oocytes. These experiments were thus conducted to examine the effect of oocytes type and maturation time on the in vitro maturation(IVM) and fertilization(IVF) of oocytes and the in vitro development (IVD)of IVF embryos. 1. The degree of oocyte maturation based on cumulus expansion index(GEI) did not differ for A- and B-typed oocytes but the index of oocyte type C was lower(P<0.05) than that of other oocyte types. 2. When the oocytes of type A and B were matured for 36, 42 and 48hrs, the GEl was not different between the 36- and 42-h maturation but the GEl after 48hrs was greatly lower(P<0.05) than that of other maturation times. 3. The highest cleavage rate(48.6%) of IVF oocytes was obtained from A typed oocytes and 42-h maturation but the developmental potential based on cleavage index was the highest when B-typed oocytes were matured for 42hrs.

• Structural Engineering and Mechanics
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• v.50 no.5
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• pp.605-616
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• 2014

When the periodic cellular structure is loaded or swelling beyond the critical value, the structure may undergo a pattern transformation owing to the local elastic instabilities, thus leading to structural collapse and the structure changing to a new configuration. Based on this deformation-triggered pattern, we have proposed the novel composite gel materials. This designed material is a type of architectural material possessing special mechanical properties. In this study, the mechanical behavior of the composite gel periodic structure with various gel inclusions is studied further through numerical simulations. When pattern transformation occurs, it results in a different elastic relationship compared with the material at untransformed state. Based on the obtained nominal stress versus nominal strain behavior, the Poisson's ratio and corresponding deformed structure patterns, we investigate the performance of designed composite materials and the effects of the uniformly distributed gel inclusions on composite materials. A better understanding of the characteristics of these composite gel materials is a key to develop its potential applications on new soft machines.