• Journal of Embryo Transfer
• /
• v.30 no.3
• /
• pp.189-193
• /
• 2015

Calculating break-even price of calf production is closely associated with reproductive efficiency. To determine the price, we need data from reproduction records including number of claves weaned, number of cows exposed for breeding, and annual cash coast per cow, and average weaning or market weight of claves sold and retained. Unfortunately, the data were not available in Korea native cow (Hanwoo). To evaluate the performance and the price, we collected calving interval from about 60,000 cows for last 10 years and estimated reproductive performance. Calving interval was increased 4.3% and pregnancy rate was decreased about 1.4~2.8% year-on-year. Increases in growth rates of number of cow and semen per calf supported the low reproductive performance. Finally, break-even price was calculated using estimated percent calf crop and demonstrated that growth rate of break-even price is larger than that of annual cash per cow, suggesting cow-calf profitability and financial efficiency in Korea native cow (Hanwoo) is getting worse.

• Bulletin of the Korean Chemical Society
• /
• v.22 no.1
• /
• pp.46-52
• /
• 2001

To evaluate the non-ionic polymer, poly(ethylene glycol) (PEG), as a component in cationic copolymers for non-viral gene delivery systems, PEG was coupled to polyethylenimine (PEI). We present the effects of different degrees and shapes of pegylation of PEI on cytotoxicity, water solubility and transfection efficiency. This work reports the synthesis and characterization of a series of cationic copolymers on the basis of the conjugates of PEI with PEG. The modified molecules were significantly less toxic than the original polymer. Moreover, the chemical modification led to enhancement of their solubility. The comparison of pegylated PEIs with different degrees of derivation showed that all the polymers tested reached comparable levels of transgene expression to that of native PEI. As assessed by agarose gel electrophoresis, even highly substituted PEI derivatives were still able to form polyionic complexes with DNA. However, aside from an increase in solubility and retention of the ability to condense DNA, methoxy-PEG-modified PEIs resulted in a significant decrease in the transfection activity of the DNA complexes. In fact, the efficiency of the copolymer was compromised even at a low degree of modification suggesting that the PEG action resulting from its shape is important for efficient gene transfer. The mode of PEG grafting and the degree of modification influenced the transfection efficiency of PEI.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.40 no.3
• /
• pp.139-148
• /
• 2016

Thermodynamic analysis is conducted on the first-order approximation model for turbines and compressors. It is shown that the adiabatic efficiency could be greater than unity, depending on the entropic mean temperature, entropy generation, thermal reservoir temperature, and heat transfer. Therefore, adiabatic efficiency applied to a diabatic control volume results in an error overestimating its performance. To resolve this overestimation, it is suggested that a reversible diabatic process be referred to as an ideal process to evaluate diabatic efficiency. The diabatic efficiency suggested in this work is proven to always be less than unity and it is smaller than the exergy efficiency in most cases. The diabatic efficiency could be used as a more general definition of efficiency, which would include adiabatic efficiency.

• Proceedings of the KIPE Conference
• /
• 2017.11a
• /
• pp.49-50
• /
• 2017

In a two-dimensional wireless power transfer system, the mutual inductance angle is the most important parameter for determining the power transmission efficiency. This paper presents a technique to estimate the mutual inductance angle from the voltage and current information of the transmitting (Tx) coils. The equation to estimate the mutual inductance angle is derived, and the validity of the proposed method is verified through simulation and experiment.

• Proceedings of the Korean Society of Embryo Transfer Conference
• /
• 2005.10a
• /
• pp.125-125
• /
• 2005

• Proceedings of the Polymer Society of Korea Conference
• /
• 2006.10a
• /
• pp.35-36
• /
• 2006

Excited-state intramolecular proton transfer (ESIPT) is a phototautomerization occurring in the excited states of the molecules possessing a cyclic intramolecular or solvent-bridged hydrogen bond. Recently, we have developed novel ESIPT chromophores, molecules, dendrimers and polymers which show very high fluorescence quantum efficiency combined with the characteristic features of optical switching, fluorescence patterining, lasing, and electroluminescence. Broad overview of these topics will be given in this talk.

• Journal of information and communication convergence engineering
• /
• v.7 no.2
• /
• pp.113-118
• /
• 2009

This paper is about design broadband impedance matching circuit for Coupler to improve power transfer efficiency in the power line communication (PLC) system. The Tchebycheff gain function algorithm is represented to design broadband matching circuit. A practical PLC Coupler impedance matching circuit is designed, and the characteristics for S11 and S21 of PLC coupler are enhanced comparing with unmatched one. This is done by maximizing the power transfer gain from modem to the load.

• Journal of information and communication convergence engineering
• /
• v.8 no.3
• /
• pp.258-262
• /
• 2010

This paper represents design broadband impedance matching circuit for Coupler to improve power transfer efficiency in the broadband power line communication(BPLC) systems. The Butterworth gain function equalizer is used to design broadband matching circuit. A practical PLC Coupler impedance matching circuit is designed, and the characteristics for S11 and S21 of PLC Coupler are enhanced comparing with unmatched one. This is done by maximizing the power transfer gain from modem to the load.

• Journal of the Korean Institute of Telematics and Electronics C
• /
• v.35C no.5
• /
• pp.17-24
• /
• 1998

In this paper, we suggested and verified the effective traffic information transfer methods using the GPS (Global positioning system) and voice broadcasting. We suggested four traffic information selection methods with their testing algorithms. A traffic information transfer simulation system is developed for testing the recommended methods. In the result, we compared and analyzed efficiency of suggested methods.

• Bulletin of the Korean Chemical Society
• /
• v.28 no.3
• /
• pp.408-412
• /
• 2007

Combining the analytical transfer matrix method with supersymmetry algebra, a new quantization condition is suggested. To demonstrate the efficiency of the new quantization condition, the eigenenergies of the Coulomb potential are analytically derived. The scattering-led phase shifts are also determined and they are the same for all Coulomb potential states. It is found that the new quantization condition is mathematically simple and exact.