• Asian-Australasian Journal of Animal Sciences
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• v.14 no.5
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• pp.651-654
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• 2001

A study was made of the efficiency of ammonia N retention by Jowar kadbi (sorghum straw), initially 6.41% crude protein (CP), treated with 4% urea solution. After 30 days the CP in straw that was unchaffed and had been left uncovered was 10.02, and in chaffed straw that had been covered with a polythene sheet was 10.9%. The two treated straws were each fed to six crossbred (HF$\times$Deoni) calves, initially $12{\pm}2$ months old and $86.7{\pm}3.2kg$ bodyweight. They were also given two isocaloric (70% TDN) and isonitrogenous (20% CP) concentrate mixtures differing in calculated Rumen Degradable to Undegradable Dietary Protein ratio (RDP:UDP). Those fed the unchaffed uncovered treated straw (treatment C) received 65 RDP:35UDP and the other group (T1) received concentrate with a 55:45 ratio. The T1 group had the higher DM intake (p<0.01) in total (306 vs 268 kg), per day (4.1 vs 3.6 kg) and per unit bodyweight. Digestibility of DM, OM, CP and NDF, but not ADF, was higher in T1 and that group had the higher daily gain (517 vs 333 g) and higher total gain (38.8 vs 25.0 kg) over the 75 d of the feeding trial. It is concluded that chaffing and covering of Jowar kadbi treated with urea, not likely to be adopted by farmers because of financial constraints, does not confer important benefits. A concentrate supplement (estimated 45% of the CP as UDP) to calves given the treated straw has a beneficial effect on their growth and development.

• Journal of Sericultural and Entomological Science
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• v.34 no.1
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• pp.15-20
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• 1992

Effects of starvation, ligation, refeeding and methoprene treatment in the feeding phase of the fifth instar larvae of Bombyx mori on the regulation of juvenile hormone esterase(JHE) activity were investigated. Starvation and ligation contributed to the reduction of JHE activity, however, JHE levels in starved larvae were slightly higher than in legated larvae. Haemolymph JEH activity of starved larvae was increased by refeeding, and duration of increasing time of JHE activity after starvation was related to duration of starvation. When starved larvae were applied methoprene topically, JHE activity were not changed at day 0 and 1, but were increased by 1.3-1.4 times between day 2 and 5. When ligated larvae were applied methoprene topically, JHE activity was not changed at day 0, but were increased by 1.9-2.3 times between day 1 and 5. These results suggest that head factor, juvenile hormone(JH) and nutrient are major factors in the regulation of JHE in the feeding phase of the fifth instar larvae of Bombyx mori. Especially JHE might be regulated by the co-operative action of head factor and JH. However, head factor plays important role in the early stage, while JH plays important role thereafter.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.283-286
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• 2003

The electric traction load is quite differ from general power system load which is single-phase, high-speed heavy load receiving power from 3-phase power system and also has variable load characteristics over time and space. Therefore, there are inevitably power quality problems such as steady state or transient voltage drop, voltage imbalance and harmonic distortion. In addition, it is expected that transient voltage sag could affect the safety of feeding system. Thus, in this paper transient analysis and voltage sag compensation of AT(Auto Transformer) feeding system are studied. The fault study of traction network is analysed by using PSCAD/SMTDC simulation tool. In addition, application of DVR in electric traction system is proposed to compensate the voltage sag of traction network which is occurred by the fault of utility source. The results of fault study will be a useful research works for operation and setting of electric traction relay. Also, it can be shown that application of the DVR in electric system is very useful to compensate the voltage sag from the result of related simulated work. The results of study will be a useful research works for management and planning of power quality in electric traction system.

• ETRI Journal
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• v.35 no.6
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• pp.1156-1159
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• 2013

We investigate the characteristics of $Cu_2O$ thin films deposited through the addition of $N_2$ gas. The addition of $N_2$ gas has remarkable effects on the phase changes, resulting in improved electrical and optical properties. An intermediate phase ($6CuO{\cdot}Cu_2O$) appears at a $N_2$ flow rate of 1 sccm, and a $Cu_2O$ (200) phase is then preferentially grown at a higher feeding amount of $N_2$. The optical and electrical properties of $Cu_2O$ thin films are improved with a sufficient $N_2$ flow rate of more than 15 sccm, as confirmed through various analyses. Under this condition, a high bandgap energy of 2.58 eV and a conductivity of $1.5{\times}10^{-2}$ S/cm are obtained. These high-quality $Cu_2O$ thin films are expected to be applied to $Cu_2O$-based heterojunction solar cells and optical functional films.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.699-704
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• 2001

The purpose of this study is to present the atomization characteristics of 2-phase internal mixing nozzle. The obtained results are considered as the essential information of understanding the spray characteristics from the nozzle exit of an aerated nozzle. In this study, SMD and AMD are mainly measured at the distance of Z=10, 20, 50, 80, 120 and 170mm from the nozzle tip. The liquid flow rate was kept at 1.8g/s and the air feeding pressure was changed from 10kpa to 100kpa increasingly. The analysis of the acquired data was performed by 2-D PDPA system and in order to get the realibility, the number of data used in calculating the SMD & AMD were 10,000 samples.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.250-254
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• 2007

As photovoltaic(PV) power generation systems become more common, it will be necessary to investigate islanding detection method for PV systems. Islanding of PV systems can cause a variety of problems and must be prevented. However, if the real and reactive powers of the load and PV system are closely matched, islanding detection by passive methods becomes difficult. Also, most active methods lose effectiveness when there are several PV systems feeding the same island. The active frequency drift positive feedback method(AFDPF) enables islanding detection by forcing the frequency of the voltage in the island to drift up or down. In this paper the research for the minimum value of chopping fraction gain applied digital phase-locked-loop (DPLL) to AFDPF considering output power quality and islanding prevention performance are performed by simulation and experiment according to IEEE Std 929-2000 islanding test.

• Journal of the Korean Solar Energy Society
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• v.27 no.2
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• pp.37-44
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• 2007

As photovoltaic(PV) power generation system becomes more common, it will be necessary to investigate islanding detection method for PV systems. Islanding of PV systems can cause a variety of problems and must be prevented. However, if the real and reactive power of the load and PV system are closely matched, islanding detection by Passive methods becomes difficult. Also, most active methods lose effectiveness when there are several PV systems feeding the same island. The active frequency drift positive feedback method(AFDPF) enables islanding detection by forcing the frequency of the voltage in the island to drift up or down. In this paper the research for the minimum value of chopping fraction gain applied digital phase-locked-loop (DPLL) to AFDPF considering output power quality and islanding prevention performance are performed by simulation and experiment according to IEEE Std 929-2000 islanding test.

• Bulletin of the Korean Chemical Society
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• v.19 no.9
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• pp.927-933
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• 1998

Polycrystalline powder of vanadium-doped forsterite (Vδ $Mg_2SiO_4$) was synthesized by the $H_2O_2$-assisted sol-gel method. The vanadium dopant, which was added as VO$(OMe)_3$ in methanol, went through several redox reactions as the sol-gel reaction proceeded. Upon adding VO$(OMe)_3$ to a mixture of $Mg(OMe)_2$ and Si$(OEt)_4$ in methanol, V(V) reduced to V(IV). As hydrolysis reaction proceeded, the V(IV) oxidized all back to V(V). Apparently, some of the V(V) reduced to V(IV) during subsequent gelation by condensation reaction. The V(IV) remained even after heat treatment of the gel in highly oxidizing atmosphere. The crystallization of the xerogel around 880 ℃ readily produced single phase forsterite without any minor phase. Using the polycrystalline powder as feeding stock, single crystals of vanadium-doped forsterite were grown by the floating zone method in oxidizing or reducing atmosphere. The doping was limited in low level because of the high partitioning of the vanadium in liquid phase during melting. The greenish single crystal absorbed visible light of 700∼1100 nm. But, no emission was obtained in near infrared range.

• KSBB Journal
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• v.14 no.3
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• pp.309-314
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• 1999

In order to produce high concentration of sodium gluconate, optimization of the fermentation conditions, such as glucose concentration, inoculum size, dissolved oxygen concentration and glucose feeding method, was examined. When the glucose concentration was maintained in the range of 30∼50 g/L during the batch fermentation, glucose conversion yield and productivity were 92.2% and 6.0 g/L/hr, respectively. In the case of the low concentration below 30 g/L, the yield decreased by about 25%. As the inoculum size increased above 20%(w/v), lag phase was shortened but the productivity decreased. The dissolved oxygen level of 60∼70% was shown to be the threshold point for 75% of increase in the productivity of sodium gluconate. Finally, optimal glucose feeding rate was determined using various feeding methods such as exponential feeding, feeding based on the average glucose consumption rate and was determined using various feeding methods such as exponential feeding, feeding based on the average glucose consumption rate and on the oxygen uptake rate and etc. Our result shows that glucose feeding, based on the oxygen uptake rate is a very simple, efficient and robust method, especially when oxygen is consumed as a substrate for the bioconversion. Using the above glucose feeding strategy under the optimized condition, 255 g/L of sodium gluconate concentration, 12 g/L/hr of productivity and 95% of glucose conversion yield were achieved with A. niger ACM53.

• Korean Journal of Poultry Science
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• v.25 no.4
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• pp.169-175
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• 1998

A feeding trial was carried out to evaluate optimum feeding system to Korean Native Chicken (KNC) with various feeding programs for 64 weeks. Eight hundreds and ten KNC＇one day birds were assigned to three feeding systems, NRC(T1), Japanese Feeding Standard(T2), Korean Feeding Standard(T3). Each treatment had three replicates of 90 birds a replicate. Data were obtained growing performance to 20 week of age and laying performance from twenty one to sixty four week. Viability to 20 week of age was similar to treatments. Growth characteristics by feeding systems were not significantly difference on body weight, feed intake and 50％ egg production days. However, body weight was less about 100g in T2. There were no different on egg production, egg weight, and egg mass during laying period. Feed intake of T1 was 104g daily and showed lower than other treatments, but was not different significantly. Feed conversion was significantly improved in T2(P <0.05) compared to other treatments(P<0.05). Egg production of all treatments was the highest between 27 to 30 week of age. ME intake of T1 was significantly maximized, whereas CP intake was the lowest of all treatments(P < 0.05). Nutrient requirements for egg mass tended to depend on nutrients intake. Interior egg and eggshell characteristics were not different among treatments except yolk color. Fertility and hatchability were similar to treatments, and the results at 39 week of age were higher than at 62 week in all treatments. In conclusion, treatments fed three or four phase feeding would be superior to other treatments during the growing period and suggest 2,800 ㎉/kg ME, 15％ CP for Korean native laying hen.