• Journal of Electrochemical Science and Technology
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• v.14 no.4
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• pp.361-368
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• 2023

In lithium-sulfur (Li-S) batteries, encapsulation of sulfur in activated carbon (AC) materials is a promising strategy for preventing the dissolution of lithium polysulfide into electrolytes and enhancing cycle life, because instead of solid-liquid-solid reactions, quasi-solid-state (QSS) reactions occur in the AC micropores. While a high weight fraction of sulfur in S/AC composites is essential for achieving a high energy density of Li-S cells, the deterioration mechanisms under such conditions are still unclear. In this study, we report the deterioration mechanisms during charge-discharge cycling when the discharge products overflow from the AC. Analysis using scanning electron microscopy and energy-dispersive X-ray spectrometry confirms that the sulfur in the S/AC composites migrates outside the AC as cycling progresses, and it is barely present in the AC after 20 cycles, which corresponds to the capacity decay of the cell. Impedance analysis clearly shows that the electrical resistance of the S/AC composite and the charge-transfer resistance of QSS reactions significantly increase as a result of sulfur migration. On the other hand, the charge-discharge cycling performance under limited-capacity conditions, where the discharge products are encapsulated inside the AC, is extremely stable. These results reveal the degradation mechanism of a Li-S cell with micro-porous carbon and provide crucial insights into the design of a S/AC composite cathode and its operating conditions needed to achieve stable cycling performance.

• Journal of Animal Environmental Science
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• v.8 no.1
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• pp.9-16
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• 2002

This study was conducted to develope the new solid separating system which can be efficiently and economically removed the solid parts in high pollutants concentration of pig slurry. The pollutants concentration, BOD$_{5}$ , COD and SS of the slurry used in this study was 15,990($\pm$2,389)mg/l, 20,004($\pm$5,512)mg/l and 26,486($\pm$5,935)mg/l, respectively. After removal of solid part in slurry, the pollutants concentration, BOD$_{5}$, COD and SS was change into 5,617($\pm$690)mg/l, 5,553($\pm$633)mg/land 1,456($\pm$341)mg/l, respectively in the Fixed biological membrane tank. The reduction of the pollutants concentration of suspend liquid through membrane will be allowed to greatly improve the water purification by an Activated sludge method. This separating system consisted of a temporary storage, a circulating tank and a Fixed Biological membrane tank. A temporary storage which has a draining system of screw type and an aeration device played a tremendous role in draining the solid by filled an aeration of 0.3 l/min. A Fixed Biological membrane tank of which a styrofoam filled in a 2/3 volume as a Biological media was fixed by a stainless steel net (pore size : 0.5mm) to separate the liquid layer of influx in them. The separating system efficiency factors were the speed of screw motor, cycle number of slurries in a circulating tank and moisture contents of solid effluent through the screw path. Although the pollutants concentration was very variable in temporary storage, the final concentration of $BOD_5$ and SS, except COD of the suspended liquid in a Fixed biological membrane were not different regardless of cycle number of a circulating tank. Moisture contents of effluent from temporary storage was 73% under the speed 1 ppm of screw motor and 62% under the 1/4rpm of it.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.455-458
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• 2001

Spinel $LiMn_{2-y}$$M_{y}$ $O_4$powder was prepared solid-state method by calcining the mixture of LiOH - $H_2O$, Mn $O_2$, ZnO and MgO at 80$0^{\circ}C$ for 36h. To investigate the effect of substitution with Mg, Zn cation, charge-discharge experiments and initial impedance spectroscopy performed. The structure of $LiMn_{2-y}$$M_{y}$ $O_4$crystallites was analyzed from powder X-ray diffraction data as a cubic spinel, space group Fd3m. all cathode material showed spinel phase based on cubic phase in X-ray diffraction. Ununiform which calculated by (111) face and (222) face was constant in spite of the change of y value, except PUf\ulcorner LiM $n_2$ $O_4$. The discharge capacities of the cathode for the cation subbstitUtes $LiMn_{2-y}$$M_{y}$ $O_4$/Li cell at the 1st cycle and at the 40th cycle were about 120~124 and 108~112mAh/g except LiM $n_{1.9}$Z $n_{0.1}$ $O_4$/Li cell, respectively. This cell capacity is retained by 93% after 40th cycle. AC impedance of $LiMn_{2-y}$$M_{y}$ $O_4$/Li cells revealed the similar resistance of about 65~110$\Omega$ before cycling. before cycling.g.g.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.3
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• pp.1117-1122
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• 2015

Background: Cisplatin is still used as a first-line medication for solid tumors. Nephrotoxicity is a serious side effect that can decrease renal function and restrict applicable doses. This research aimed to obtain the profile of cisplatin-induced nephrotoxicity and its associated factors in adult cancer patients at Dharmais National Cancer Hospital (DNCH). Materials and Methods: The design was cross-sectional with data obtained from patient medical records. We retrospectively reviewed adult cancer patients treated with cisplatin ${\geq}60mg/m^2$ for at least four consecutive chemotherapy cycles from August 2011 to November 2013. The nephrotoxicity criterion was renal function decline characterized by creatinine clearance <60 ml/min using the Cockroft-Gault (CG) equation. Results: Eighty-eight subjects received at least four chemotherapy cycles of cisplatin. The prevalence of cisplatin nephrotoxicity was 34.1%. Symptoms could be observed after the first cycle of chemotherapy, and the degree of renal impairment was higher with increased numbers of cycles (r=-0.946, $r^2=89.5%$). Factors that affected the decline of renal function were patient age (p=0.008, OR=3.433, 95%CI= 1.363-8.645) and hypertension (p=0.026, OR=2.931, 95%CI=1.120-7.670). Conclusions: Cisplatin nephrotoxicity occurred in more than one-third of patients after the fourth cycle of chemotherapy and worsened after each cycle despite preventive strategies such as hydration. The decline of renal function induced by cisplatin ${\geq}60mg/m^2$ was affected by age and hypertension.

• Journal of Hydrogen and New Energy
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• v.12 no.1
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• pp.39-50
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• 2001

Vanadium based solid solution alloys have been studied as a potential negative electrode of Ni/MH battery due to their high hydrogen storage capacity. In order to improve the kinetic property of V-Ti alloy in KOH electrolyte, the ball-milling process with Ni, which has a catalytic effect of hydrogen absorption/desorption, was carried out to modify the surface properties of V-Ti-Cr alloys with high hydrogen storage capacity. Moreover, to overcome the problem of poor cycle life, V-Ti alloy substituted by Cr, V0.68 Ti0.20 Cr0.12, has been developed showing a good cycle performance (keeping about 80 % of initial discharge capacity after 200 cycles). The cycle life of surface-modified V0.68 Ti0.20 Cr0.12 alloy was improved by suppressing the formation of TiO2 layer on the alloy surface while decreasing the amount of dissolved vanadium in the KOH electrolyte. In order to promote the effect of Ni coating on the surface property of V0.68 Ti 0.20 Cr 0.12 alloy by ball-milling, filamentary-typed Ni, which has higher surface coverage area than sphere-typed Ni was used as a surface modifier. Consequently, the surface-modified V0.68 Ti0.20 Cr0.12 alloy electrode showed a improved discharge capacity of 460 mAh/g.

• Journal of Veterinary Clinics
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• v.17 no.2
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• pp.403-410
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• 2000

The Ultrasonographic method alas been widely applied to evaluating gastric motility with safety and reproducibility ill human medicine but few reference to its use in veterinary medicine is appeared. Therefore, in this study, the gastric motility was evaluated with ultrasonography by the cri-terion of mean cycle lime, short and lony axis and the area of pyloric antrum in dogs, fed with liquid of semisolid meals. Furthermore, the animals were evaluated for the effect of metoclopramide on the motility of pyloric antrum. Healthy 5 mongrel male dogs were fed with either 400 ml of milk a: a liquid meal or a mixed meal of 200 ml of milk with two pieces of bread as a semisolid meal. Mean cycle time of pyloric antrum of dogs was significantly delayed after feeding either of liquid and , semi- solid meals(P<0.05), alls it was returned to the fasting state at 60 min. after feeding of liquid meal and 160 min. after feeding of semisolid meal. Mean area of pyloric antrum of dogs was gradually decreased and was returned to the lasting state at 80 min. in doss fed liquid meal. but 1600 min. in dog\ulcorner fed semisolid meal. The administration of metoclopramide (1.0 mg/kg of of B.W.) accelerated the mean cycle time of pyloric antrum from 20 mill. to 60 min. after feeding of liquid meal and from 40 min. to 120 min. after feeding of semisolid meal. From this study, the ultrasonography was confirmed as a valuable diagnostic method leer evaluating the gastric motility and gastric area in dogs. It is non-invasive, safe and reproducible, and provides a method for the study of the effect of drugs and diseases states on gastric motility.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.9
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• pp.983-989
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• 2011

A numerical algorithm for predicting fretting wear was developed using the boundary element method (BEM). A contact analysis was performed numerically using the relation between the elastic displacement and uniformly distributed loading of a rectangular patch on a semi-infinite solid. Geometrical updating based on nodal wear depths was performed. The wear depths were computed using the Archard's equation for sliding wear. In order to investigate the efficiency of BEM for predicting fretting wear, a problem involving a two-dimensional cylinder on a flat contact was analyzed, comparing it with the simulation model proposed by McColl et al. that was based on the finite element method. The developed method was then applied to the analysis of a spherical contact and it was shown that the developed simulation technique could efficiently predict fretting wear. Moreover, the effect of a step cycle on the solution obtained by the developed method was investigated.

• Journal of Energy Engineering
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• v.20 no.2
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• pp.103-108
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• 2011

$Li_2MnSiO_4$/C was synthesized by solid state reaction and solution synthesis with sucrose for carbon source. The X-ray diffraction patterns of solid state reaction indicates small amount of impurities. By FE-SEM and HR-TEM, solution synthesis comprised several tens of nanometer comparing to 500~600 nm of $Li_2MnSiO_4$/C prepared by solid state reaction. The $Li_2MnSiO_4$/C prepared by solution synthesis show better electrochemical performance than solid state reaction. The first charge-discharge capacity are 236, 189 mAh/g respectively by solution synthesis. But its cycle performance was poor as yet and its capacity retention was 62% after 10 cycles.

• The KIPS Transactions:PartA
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• v.18A no.4
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• pp.135-142
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• 2011

This research is to design an effective buffer structure and its management for flash memory based high performance SSDs (Solid State Disks). Specifically conventional SSDs tend to show asymmetrical performance in read and /write operations, in addition to a limited number of erase operations. To minimize the number of erase operations and write latency, the degree of interleaving levels over multiple flash memory chips should be maximized. Thus, to increase the interleaving effect, an effective buffer structure is proposed for the SSD with a hybrid address mapping scheme and super-block management. The proposed buffer operation is designed to provide performance improvement and enhanced flash memory life cycle. Also its management is based on a new selection scheme to determine random and sequential accesses, depending on execution characteristics, and a method to enhance the size of sequential access unit by aggressive merging. Experiments show that a newly developed mapping table under the MBA is more efficient than the basic simple management in terms of maintenance and performance. The overall performance is increased by around 35% in comparison with the basic simple management.

• Archives of design research
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• v.19 no.5 s.67
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• pp.335-350
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• 2006

Due to the development in industrial technology, changes in consumer behavior and aggravating competition within the industry, it is growing only harder every day to build up a strong brand power. Besides, a brand is supposed to age as time goes by, following a brand life cycle, as it is not a solid, immutable asset but something of a living creature. Therefore, self-renovation and revitalization efforts are needed, in order to incessantly confirm the self existence through the relationship with the consumer. In sum, revitalization operation is needed to renew a brand that has grown trite in the passage of time or due to the change in market condition, so as to bring it back anew to the consumers. This study did not stop at measuring the effect of a design renewal as a short-term assignment, but focused on the long-term brand management following the brand life cycle and aimed to define the effective timing and method of revitalization by comprehending the analysis results of consumer consciousness by analyzing the successful cases of brand revitalization and selecting the research analysis targets. As a result, this study proved that a properly-timed brand revitalization efforts in order to cope in advance with predictable changes in environment, can significantly prevent any drop of brand equity from occurring and then extend the brand life cycle. Also, this study could find that a brand revitalization is not a mere concept of a strategy for a short-term sales increase, but should be a long-term strategy to manage a brand, which must be practiced continuously in the time when the brand life cycle curve starts to fall. This research could also confirm that a superficial design renewal, which changes only the packaging of a brand, peformed in short-term haste, is not of help at all.