• Journal of the Korean Society of Industry Convergence
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• v.23 no.5
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• pp.853-863
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• 2020

As the battery ages, the internal resistance of the battery increases, so the loss due to the internal resistance increases at the same charging current, causing the battery temperature to rise, which further accelerates battery aging. Therefore, it is necessary to optimize the charging conditions according to the aging of the battery or the current charge amount, and to accurately estimate this, estimation of the parameters of the equivalent circuit is most important. This paper proposes a new measurement technique that can measure the internal resistance of a battery by analyzing a specific high frequency voltage and current applied to the battery. In addition, in order to test the validity of the proposed measurement technique, the current charging amount was estimated based on the measured internal resistance, and the terminal voltage of the constant current charging mode was automatically set and operated. As a result, good results were obtained regardless of the battery voltage. If this equipment is installed in the charging device, it is believed that it will be of great help in the stability management of the aging reusable battery.

• Journal of Biomedical Engineering Research
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• v.39 no.5
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• pp.220-228
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• 2018

The internal resistance of microbial fuel cell (MFC) using stainless steel skein for oxidizing electrode was investigated and the factors affecting the voltage generation were identified. We also investigated the effect of power management system (PMS) on the usability for MFC and the removal efficiency of organic pollutants. The performance of a stack microbial fuel cell connected with (PMS) or PMS+LED was analyzed by the voltage generation and organic matter reduction. The maximum power density of the unit cells was found to be $5.82W/m^3$ at $200{\Omega}$. The maximum current density was $47.53A/m^3$ without power overshoot even under $1{\Omega}$. The ohmic resistance ($R_s$) and the charge transfer resistance ($R_{ct}$) of the oxidation electrode using stainless steel skein electrode, were $0.56{\Omega}$ and $0.02{\Omega}$, respectively. However, the sum of internal resistance for reduction electrode using graphite felts loaded Pt/C catalyst was $6.64{\Omega}$. Also, in order to understand the internal resistance, the current interruption method was used by changing the external resistance as $50{\Omega}$, $300{\Omega}$, $5k{\Omega}$. It has been shown that the ohm resistance ($R_s$) decreased with the external resistance. In the case of a series-connected microbial fuel cell, the reversal phenomenon occurred even though two cells having the similar performance. However, the output of the PMS constantly remained for 20 hours even when voltage reversal occurred. Also the removal ability of organic pollutants (SCOD) was not reduced. As a result of this study, it was found that buffering effect for a certain period of time when the voltage reversal occurred during the operation of the microbial fuel cell did not have a serious effect on the energy loss or the operation of the microbial fuel cell.

• Tuberculosis and Respiratory Diseases
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• v.72 no.4
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• pp.360-366
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• 2012

Background: Carbapenem-resistance is rapidly evolving among the pathogenic microbes in intensive care units (ICUs). This study aimed to determine annual trend of carbapenem-resistance in the ICU for 4 years, since the opening of a university-affiliated hospital in South Korea. Methods: From 2005 to 2008, microbial samples from consecutive 6,772 patients were screened in the ICU. Three hundred and ninety-seven patients (5.9%) and their first isolates of carbapenem-resistant pathogens were analyzed. Results: The percentage of patients infected with carbapenem-resistant organisms increased constantly during the initial three years (2.3% in 2005, 6.2% in 2006, 7.8% in 2007), then it declined to 6.5% in 2008. Acute Physiology and Chronic Health Evaluation (APACHE) III score at admission was $58.0{\pm}23.5$, the median length of the ICU stay was 37 days, and the mortality rate was 37.5%. The sampling sites were endotracheal suction (67%), catheterized urine (17%), wound (6%) and others (10%). Bacteria with carbapenem-resistance were Pseudomonas aeruginosa (247 isolates, 62%), Acinetobacter baumannii (117 isolates, 30%), Enterobacteriaceae (12 isolates, 3%), and others (21, 5%). Of note, peak isolation of carbapenem-resistant microorganisms in medical ICU was followed by the same epidemic at surgical ICU. Conclusion: Taken together, carbapenem-resistant pathogens are of growing concern in the ICU.

• Journal of Biosystems Engineering
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• v.23 no.5
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• pp.445-456
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• 1998

This study was carried out to evaluate the performance of a medium scale rice polisher of 2.5 t/h and to improve its performance for producing the clean rice with high quality. The maximum internal pressure, broken rice ratio. whiteness in the rice polisher were investigated, and the effects of outlet resistance, water spraying rate, shaft revolution speed and rice moisture content on the polishing performance were analyzed to find out proper operating conditions. The conclusions of this study were as follows: 1. In the performance evaluation of the polisher, the broken rice ratio increment of 0.1%, the max. internal pressure of about 11 N/${cm}^2$, and whiteness increment of 2.2~3.7 resulted at the conditions of 20 PS driving power, 950 rpm, 150 cc/min water spraying rate, 44.1 Nㆍcm outlet resistance and about 15% rice moisture content. 2. Though max. internal pressure and whiteness at the 17% rice moisture content were higher than those at the 15% moisture content under the same operating conditions of the polisher, but the broken rice rate at the 17% moisture content was absolutely low compared with that at 15% moisture content. The water spraying effect to reduce broken rice and to increase whiteness was much significant at the 15% moisture content not significant at 17% moisture content. 3. The main parameter of the performance was outlet resistance, and low resistance of about 44.1 Nㆍcm was recommended at the polisher. 4. The proper water spraying rate in the polisher was about 150 cc/min. 5. As the shaft revolution speed decreased from 950 rpm and 800 rpm to 650 rpm, the broken rice ratio increased and whiteness decreased. 6. As the driving power of the polisher increased from 20 PS to 30 PS, the max. internal pressure decreased by about 1~2.5 N/${cm}^2$ and whiteness increased by about 1~2, but the broken rice rate was not changed. 7. The proper operating conditions of the polisher seemed to be the revolution speed of 800-950 rpm, the water spraying rate of about 150 cc/min, the oulet resistance of about 44.1 N.cm and 30 PS driving power.

• The Journal of Internal Korean Medicine
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• v.35 no.2
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• pp.195-207
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• 2014

Objectives : The purpose of this study was to investigate how Rhei Radix et Rhizoma affects on insulin resistance and adipose tissue inflammatory response in high fat diet induced obese C57BL/6 mice. Methods : Obesity was induced in C57BL/6 mice by high fat diet for 12 weeks. Models were divided into 3 groups (n=6) of normal diet, high fat diet (HFD), and high fat diet with Rhei Radix et Rhizoma and investigated for 12 weeks. We measured body weight, FBS and oral glucose tolerance test (OGTT), serum insulin, homeostatic model assessment-insulin resistance (HOMA-IR), weight of liver and epididymal fat pad. Inflammatory markers such as adipose tissue macrophage (ATM), tumor necrosis factor-${\alpha}$ and interlukin-10 and CD68 of epididymal adipocyte were determined to evaluate the effect of Rhei Radix et Rhizoma on adipose tissue inflammation. Results : Compared with the HFD group, we observed loss of body weight and epididymal fat pad weight, improvement of glucose level and HOMA-IR, reduction of ATM and gene expression of TNF-${\alpha}$, CD68 in the high fat diet with Rhei Radix et Rhizoma group. Conclusions : This study suggests that Rhei Radix et Rhizoma has effects on insulin resistance and adipose tissue inflammatory response in high fat diet induced obese mice.

• Journal of IKEEE
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• v.28 no.1
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• pp.14-19
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• 2024

To determine the performance of recycled cells for application to residential BESS, cells used over the past 5 years were selected. The basic specifications of the cell used in the test are nominal voltage of 3.7[V], nominal capacity of 2,200[mAh], charging voltage of 4.05[V], continuous discharge current of 1[C](2,200[mA]), continuous charging current of 0.5[C](1,100[mA]). For new cells, the internal resistance was 21.3±1[mΩ], but for recycled cells, the average internal resistance was 25.38[mΩ], an increase of about 19.1[%]. The charge·discharge capacity was approximately 18.9~19.3[%] lower than that of a new cell. Because internal resistance and charge·discharge capacity are closely related to cell aging, cells to be applied to BESS need to use products with an initial internal resistance of 1.5 times or less and a charge·discharge capacity performance of 70[%] or more.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.493-497
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• 2000

A battery is the device that transforms the chemical energy into the direct-current electrical energy without a mechanical process. Unit cells are connected in series to obtain the required voltage while being connected in parallel to organize capacity for load current. Because the voltage drop down in one set of battery is faster than in two one it may result in the low efficiency of power converter with the voltage drop and cause the system shutdown. However when the system being shutdown. However when the system being driven in parallel a circular-current can be generated,. It is shown that as a result the new batteries are heated by over-charge and over-discharge and the over charge current increases rust of the positive grid and consequently shortens the lifetime of the new batteries. The difference between the new batteries and old ones is the amount of internal resistance. In this paper we can detect the unbalance current using the microprocessor and achieve the balance current by adjusting resistance of each set, The internal resistance of each set becomes constant and the current of charge and discharge comes to be balanced by inserting the external resistance into the system and calculating the change of internal resistance.

• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.1
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• pp.34-42
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• 2001

A battery is the device that transforms the chemical energy into the direct-current electrical energy directly without a mechanical process. Unit cells are connected in series to obtain the required voltage, while being connected in parallel to organize capacity for load current and to decrease the internal resistance for corresponding the sudden shift of the load current. Because the voltage droop down in one set of battery is faster than in tow one, it amy result in the low efficiency of power converter with the voltage drop and cause the system shutdown. However, when the system being driven in parallel, a circular-current can be generated. The changing current differs in each set of battery because the system including batteries, rectifiers and loads is connected in parallel and it makes the charge voltage constant. It is shown that, as a result the new batteries are heated by over-charge and over-discharge, and the over charge current increases rust of the positive grid and consequently shortens the lifetime of the new batteries. The difference between the new batteries and old ones is the amount of internal resistance. In this paper, we can detect the unbalance current using the micro-processor and achieve the balance current by adjusting resistance of each set. The internal resistance of each set becomes constant and the current of charge and discharge comes to be balanced by inserting the external resistance into the system and calculating the change of internal resistance.

• The Korean journal of helicobacter and upper gastrointestinal research
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• v.18 no.4
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• pp.242-246
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• 2018

Background/Aims: Helicobacter pylori eradication rates using first-line treatment have decreased due to clarithromycin resistance. The aim of this study was to investigate optimal eradication regimens for patients with clarithromycin resistance in Korea. Materials and Methods: A total of 72 patients with confirmed clarithromycin resistance were enrolled from August 2015 to July 2017. Patients were randomized to a 7-day bismuth quadruple therapy (BQT) regimen or a 7-day metronidazole triple therapy (MTT) regimen. Eradication was confirmed using the $^{13}C$-urea breath test. Results: There were no differences in baseline characteristics between the groups. Intention-to-treat eradication rates were 77.8% for the BQT group and 66.7% for the MTT group (P=0.293). Per protocol eradication rates were 87.5% for the BQT group and 77.4% for the MTT group (P=0.292). Adverse events were more frequent in the BQT group. Conclusions: Eradication rates using MTT were comparable to those using BQT, and adverse events were less frequent in the MTT group. Thus, MTT may be considered as a first-line regimen for patients with clarithromycin resistance. Since this was a pilot study, a study with a large group is required.

• Journal of the korean academy of Pediatric Dentistry
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• v.11 no.1
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• pp.159-167
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• 1984

In this experiments, the fracture loads were measured and analysed by using of Instron universal testing machine (Model 1132). With 80 upper and lower deciduous molars that were free of dental caries. Isthmus of teeth were prepared to 1/3 and 1/4 of intercuspal width, and internal line angles with round and sharp shape, and then amalgam restoration were performed. The results of this study were as follows; 1. Resistance to fracture loads were greater with isthmus of 1/3 intercuspal width than of 1/4 intercuspal width, especially, statistically significant difference on upper and lower second deciduous molars. 2. Resistance to fracture loads were greater with rounded internal line angle than sharp internal line angle. The above results were as follows, the fracture loads had greater resistance on isthmus of 1/3 intercuspal width, and rounded internal line angle, but normal physiological occlusal forces could permit isthmus of 1/4 intercuspal width and rounded internal line angle.