• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.11B no.3
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• pp.112-118
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• 2001

In the near future, the voltage of power system for passenger vehicle will be changed to 42V from existing 14V./ Because of increasing power and voltage ratings used in the vehicle the motor drive system has high switching dv/dt and it generates electromagnetic interference (EMI) To solve these problems multi-level inverter system may be used The feature of multi-level inverter is the output voltage to be synthesized from several levels of voltage Because of this feature high switching dv/dt and EMI can be reduced in the multi-level inverter system But as the number of level is increased manufacturing cost is getting expensive and system size is getting large. Because of these disadvantages the application of multi-level inverter has been restricted only to high power drives. The method to reduce manufacturing cost and system size is to integrate circuit of multi-level inverter into a few chips But isolated power supply and signal isolation circuit using transformer or opto-coupler for drive circuit are obstacles to implement the integrated circuit (IC) In this paper a drive circuit of 4-level inverter suitable for integration to hybrid or one chip is proposed In the proposed drive circuit DC link voltage is used directly as the power source of each gate drive circuit NPN transistors and PNP transistors are used to isolate to transfer the control signals. So the proposed drive circuit needs no transformers and opto-couplers for electrical isolation of drive circuit and is constructed only using components to be implemented on a silicon wafer With th e proposed drive circuit 4- level inverter system will be possible to be implemented through integrated circuit technology Using the proposed drive circuit 4- level inverter system is constructed and the validity and characteristics of the proposed drive circuit are proved through the experiments.

• Applied Chemistry for Engineering
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• v.9 no.3
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• pp.388-393
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• 1998

The effects of surface area of $UO_2$ pellets($s:0.034{\sim}0.282cm^2/g-UO_2$), concentration of nitric acid(1.5~10N) and temperature($40{\sim}105^{\circ}C$) on the dissolution rate were investigated in this experiment. The results showed that dissolution rate of $UO_2$ pellets was in direct proportion to effective surface area(s) and well fit to linear plot in high surface area. The dissolution rate was expressed as dc/dt = 10.6s at $90^{\circ}C$, [$HNO_3$]=8N, and proportioned to the power 1.42 of $HNO_3$ concentration. And also, the results showed that dissolution rate was sharply increased according to temperature increase in temperature below $90^{\circ}C$, but decreased in temperature above $90^{\circ}C$. Activation energy(E) was evaluated to be 36.3KJ/mol.

• Environmental Engineering Research
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• v.25 no.2
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• pp.222-229
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• 2020

Membrane assisted condenser is an innovative membrane operation that exploits the hydrophobic nature of microporous membranes to promote water vapor condensation and recovery. It can be used for water and chemicals recovery from waste gaseous streams. In this work, the testing of membrane condenser for water and ammonia recovery from synthetic streams (i.e., a saturated air stream with ammonia) simulating the plume of cooling tower is illustrated. The modeling of the process was carried out for predicting the membrane-based process performance and for identifying the minimum operating conditions for effectively recovering liquid water. The experimental data were compared with the results achieved through the simulations showing good agreement and confirming the validity of the model. It was found that the recovery of water can be increased growing the temperature difference between the plume and the membrane module (DT), the relative humidity of the plume (RH^plume) and the feed flow rate on membrane area ratio. Moreover, the concentration of NH₃ in the recovered liquid water increased with the growing DT, at increasing NH₃ concentration in the fed gaseous stream and at growing relative humidity of the feed.

• Ocean and Polar Research
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• v.24 no.3
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• pp.227-236
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• 2002

For ten firn cores, from both the eastern and the western side of Lambert Glacier basin (LGB), snow accumulation rate and isotopic temperature were measured far the recent 50 years. Results show that snow accumulation for five cores over the eastern side of LGB (GC30, GD03, GD15, DT001, and DT085) at Wilks Land and Princess Elizabeth Land increases, whereas it decreases at the western side (Core E, DML05, W200, LGB 16, and MGA) at Dronning Maud Land, Mizuho Plateau and Kamp Land. For the past decades, the increasing rate was $0.34-2.36kg\;m^{-2}a^{-1}$ at the eastern side and the decreasing rate was $-0.01\;-\;-2.36kg\;m^{-2}\;a^{-1}$ at the western side. Temperatures at the eastern LGB were also increased with the rate of $0.02%o\;a^{-l}$. At the western LGB it was difficult to see clear trends, which were confirmed by Instrumental temperature records at coastal stations. Although statistic analysis and modeling results display that both surface temperature and accumulation rate has increased trends in Antarctic ice sheet during 1950-2000, the regional distributions were much more different for different geographic areas. We believe that ice-core records at Wilks Land and Princess Elizabeth Land reflect the real variations of SST and moisture change in the southern India Ocean. For the Kamp Land and Dronning Maud Land, however circulation pattern was different, by which the climate was more complicated. The International Trans-Antarctic Scientific Expedition (ITASE) aimed to reveal an overall spatial pattern of climate change over Antarctic ice sheet for the past 200 years. This study points the importance of continental to regional circulation to annual-decadal scale climate change in Antarctica.

• 한국해양학회지
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• v.26 no.2
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• pp.108-116
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• 1991

A production model was constructed by combining the production rate and biomass of Sargassum confusum measured at monthly intervals on the coast of Ohori, Korea, to estimate the algal production for a given period. The production for a certain period, e.g., for a year (P/SUB yr/), was calculated from the equation: P/SUB yr/ = .int.P/SUB t/$.$B/SUB t/dt, where pl and Bl are the production rate and biomass at time t. P/SUB l/ was considered as a function of temperature and light. Photosynthesis-Irradiance curves obtained from the in situ experiments were applied for P/SUB l/ Temperature and light intensity can be expressed as periodic functions of time (T, L=f(t)). Diurnal values of water temperature and light intensity at 3 m depth where S. confusum mainly found were substituted into the equation of P/SUB l/. Simulations using our models show that temperature was one of the most sensitive factors operating on the primary production. Thirty percent decrease of light intensity by cloud cover was estimated to decrease the annual production by 5%.

• Journal of The Geomorphological Association of Korea
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• v.24 no.2
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• pp.65-78
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• 2017

In this study, stable carbon isotopic analysis (22 specimens) and magnetic susceptibility analysis (23 specimens) were conducted out on the specimens collected from two points (trench DT1, DT2) in the floodplain of Jemincheon(hereinafter the Jemin plain) to reconstruct the Holocene Environments (Period I, Period II, Period III) of the Jemin plain in Gongju, Chungnam. The results were as follows: In Period I (approximately 7,480~4,940 yrs B.P.) and especially around 7,480~7,320 yrs B.P., it was cool-dry and there were two minor climate fluctuations. This period received a continuous flow of sediments, rather than massive amounts of sediments due to abrupt flooding, and therefore, there was almost no soilization process. Period II(approximately 4,940~2,600 yrs B.P.) was also relatively cool-dry. However, in Period II b, unlike I, the minor climate fluctuations were less pronounced. In this period, flooding and desiccation repeated, inducing soilization processes especially around 3,160 yrs B.P. In Stage III (~360 yrs B.P.), it was warm and humid compared to II b. However, in III a, there was no inflow of sediments due to irregular flooding, and in fact, soilization process was more manifested than during II b due to the impact of the desiccation environment. However, there were some mass movements from Bonghwang Mt. (a.s.l. 147m) caused by heavy rains and typhoon during III b (approximately 360 yrs B.P.), thus moving a large amount of debris (i.e. gravel), which resulted in sedimentation.

• Journal of Chest Surgery
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• v.32 no.3
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• pp.224-236
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• 1999

Background: To evaluate the short-term effect of dynamic cardiomyoplasty on circulatory function and detect the related factors that can affect it, experimental cardiomyoplasties were performed under the state of normal cardiac function and heart failure. Material and Method: A total of 10 mongrel dogs weighing 20 to 30kg were divided arbitrarily into two groups. Five dogs of group A underwent cardiomyoplasty with latissimus dorsi(LD) muscle mobilization followed by a 2-week vascular delay and 6-week muscle training. Then, hemodynamic studies were conducted. In group B, doxorubicin was given to 5 dogs in an IV dose of 1 mg/kg once a week for 8 weeks to induce chronic heart failure, and simultaneous muscle training was given for preconditioning during this period. Then, cardiomyoplasties were performed and hemodynamic studies were conducted immediately after these cardiomyoplasties in group B. Result: In group A, under the state of normal cardiac function, only mean right atrial pressure significantly increased with the pacer-on(p<0.05) and the left ventricular hemodynamic parameters did not change significantly. However, with pacer-on in group B, cardiac output(CO), rate of left ventricular pressure development(dp/dt), stroke volume(SV), and left ventricular stroke work(SW) increased by 16.7${\pm}$7.2%, 9.3${\pm}$3.2%, 16.8${\pm}$8.6%, and 23.1${\pm}$9.7%, respectively, whereas left ventricular end-diastole pressure(LVEDP) and mean pulmonary capillary wedge pressure(mPCWP) decreased by 32.1${\pm}$4.6% and 17.7${\pm}$9.1%, respectively(p<0.05). In group A, imipramine was infused at the rate of 7.5mg/kg/hour for 34${\pm}$2.6 minutes to induce acute heart failure, which resulted in the reduction of cardiac output by 17.5${\pm}$2.7%, systolic left ventricular pressure by 15.8${\pm}$2.5% and the elevation of left ventricular end-diastole pressure by 54.3${\pm}$15.2%(p<0.05). With pacer-on under this state of acute heart failu e, CO, dp/dt, SV, and SW increased by 4.5${\pm}$1.8% and 3.1${\pm}$1.1%, 5.7${\pm}$3.6%, and 6.9${\pm}$4.4%, respectively, whereas LVEDP decreased by 11.7${\pm}$4.7%(p<0.05). Comparing CO, dp/dt, SV, SW and LVEDP that changed significantly with pacer-on, both under the state of acute and chronic heart failure, augmentation widths of these left ventricular hemodynamic parameters were significantly larger under the state of chronic heart failure(group B) than acute heart failure(group A)(p<0.05). On gross inspection, variable degrees of adhesion and inflammation were present in all 5 dogs of group A, including 2 dogs that showed no muscle contraction. No adhesion and inflammation were, however, present in all 5 dogs of group B, which showed vivid muscle contractions. Considering these differences in gross findings along with the following premise that the acute heart failure state was not statistically different from the chronic one in terms of left ventricular parameters(p>0.05), the larger augmentation effect seen in group B is presumed to be mainly attributed to the viability and contractility of the LD muscle. Conclusion: These results indicate that the positive circulatory augmentation effect of cardiomyoplasty is apparent only under the state of heart failure and the preservation of muscle contractility is important to maximize this effect.

• Nuclear Engineering and Technology
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• v.52 no.3
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• pp.568-574
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• 2020

The feasibility of the particle-in-cell (PIC) method is assessed to simulate the non-collective phenomena like non-collective Thomson scattering (TS). The non-collective TS in the laser-plasma interaction, which is related to the single-particle behavior, is simulated through a 2D relativistic PIC code (XOOPIC). For this simulation, a non-collective TS is emitted from a 50-50 DT plasma with electron density and temperature of n_e = 3.00 × 10¹³ cm^-3 and T_e = 1000 eV, typical for the edge plasma at ITER measured by ETS system, respectively. The wavelength, intensity, and FWHM of the laser applied in the ETS system are λ_i,0 = 1.064 × 10^-4 cm, I_i = 2.24 × 10¹⁷ erg=s·㎠, and 12.00 ns, respectively. The electron density and temperature predicted by the PIC simulation, obtained from the TS scattered wave, are n_e,TS = 2.91 × 10¹³ cm^-3 and T_e,TS = 1089 eV, respectively, which are in accordance with the input values of the simulated plasma. The obtained results indicate that the ambiguities rising due to the contradiction between the PIC statistical collective mechanism caused by the super-particle concept and the non-collective nature of TS are resolved. The ability and validity to use PIC method to study the non-collective regimes are verified.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.1
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• pp.90-98
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• 2009

The aim of this study was to evaluate the effect of a milling by-product diet and two sugar cane diets on the local Creole pig breed (CR). A total of 48 CR pigs (24 females and 24 castrated males) were randomly assigned to four different groups of 12 animals. Pigs were allotted to one of 4 dietary treatments: fed with a control soya-bean meal-corn diet containing 19.1% crude protein (CP) and 15.4 MJ DE/kg (diet 1), with an experimental milling by-product diet (soya-bean meal and wheat by-products) containing 19.4% CP and 13.0 MJ DE/kg (diet 2), with ground cane stalks (GCS) or with fresh sugar cane juice (SCJ). Both GCS and SCJ were supplemented with soya-bean meal complement (400 g/d of a 48.7% CP and 16.1 MJ DE/kg diet) in order to obtain diets 3 and 4, respectively. Pigs were fed close to ad libitum level and had free access to water. All the pigs were slaughtered at 65 kg BW. Between 30 and 65 kg BW, growth performance was significantly (p<0.001) affected by dietary treatments: average daily BW gain was 657, 530, 546 and 200 g/d for diets 1, 2, 4, and 3, respectively. Average daily DM intake was 1.8, 1.9, 2.5 and 1.4 kg/d for diets 1, 2, 4, and 3, respectively. Fat cuts (backfat+leaf fat) and backfat thickness were significantly lower on diet 3 than for other treatments (127 vs. 192, 166 g/kg of left half-carcass weight and 24.6 vs. 39.0, 35.3 mm for diet 3 vs. diets 1 and 4, and diet 2, respectively; p<0.001). The dressing weight was significantly lower on diets 2 (82.7 vs. 84.0%; p<0.001). The entire empty digestive tract (DT) weight was higher on diet 2 (73.1 vs. 66.7 g/kg empty BW). However, stomach and large intestine were more developed on diet 3: 12.8 vs. 9.3 g/100 g empty DT (p<0.001) and 26.4 vs. 23.8 g/100 g empty DT (p<0.05), respectively. In conclusion, this study suggests the CR pig has the ability to reach rather good growth and carcass performance with a well-formulated sugar cane meal and/or with a milling by-product diet refined according to its low requirements.

• The Korean Journal of Ecology
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• v.17 no.3
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• pp.367-378
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• 1994

The germination responses of Echinochloa crus-galli (L.) Beauv. seeds to temperature were examined under the various thermal conditions. While almost all the seeds tested did not germinate immediately after collection, almost of the seeds which were stored for 7, 10, and 17 months showed very high germination percentages (85-95%) at their own constant temperatures between $16^{\circ}C\;and\;40^{\circ}C$. The total thermal time which was required for germination(10-70%) of Echinochloa crus-galli seeds ranged from 539Kh(degree Kelvin X hour) to 1,279Kh in accordance with the distribution function of thermal time, $F({\Theta})=1-[3D^{-3}({\Theta}-m+D)+1]^{-1/2}$, where m is 935Kh and D is 555Kh. Moist chilling treatment at $2^{\circ}C$ for 20 days increased the final germination percentage as well as the germination rate. In the increasing temperature(IT1 regime, E. crus-galli seeds started to germinate at $12^{\circ}C$. and showed greater germination rate with increasing temperatures, with the final germination percentage of 80%. On the other hand, in the decreasing temperature(DT1 regime, the seeds began to germinate at $12^{\circ}C$(10% germination) with the final germination percentage of 20%. An induced dormancy occurred at $4^{\circ}C$ in the DT regime.