• Bulletin of the Korean Chemical Society
• /
• v.24 no.11
• /
• pp.1575-1578
• /
• 2003

An environmentally benign approach for the synthesis of 2-substituted-4,6-diaryl pyrimidines using inorganic solid supports for its catalytic role as well as an energy transfer medium is described. The methodology eliminates the usage of solvent during the reaction. The reaction time is brought down from hours to minutes along with yield enhancement. The rate enhancement and high yield is attributed to the coupling of solvent free conditions with microwaves. Further, the role of base is studied in the reaction and it is concluded that microwave assisted basic alumina catalysed reaction is the best in terms of catalysis as well as reaction time and yield.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2000.07a
• /
• pp.293-298
• /
• 2000

• Proceedings of the Korea Society for Simulation Conference
• /
• 2003.11a
• /
• pp.147-151
• /
• 2003

Yield enhancement in semiconductor fabrication is important. Even though DRAM yield loss may be attributed to many problems, the existence of defects on the wafer is one of the main causes. When the defects on the wafer form patterns, it is usually an indication for the identification of equipment problems or process variations. In this paper describes the techniques to automatically classify a failure pattern using a fail bit map.

• Journal of Magnetics
• /
• v.21 no.2
• /
• pp.244-248
• /
• 2016

Aiming to improve the shear yield stress of magnetorheological fluid, magnetorheological fluids with different particle characteristics are prepared, and the influence rules of particle mass fraction, particle size, nanoparticles content and application temperature on shear yield stress are investigated. Experimental results indicate that shear yield stress increases approximate linearly with the enhancement of particle mass fraction. Particle size and the nanoparticles within 10% mass fraction can improve the shear yield stress effectively. When the application temperature is higher than $100^{\circ}C$, the shear yield stress decreases rapidly because of thermal expansion and thermal magnetization effect.

• Proceedings of the Acoustical Society of Korea Conference
• /
• 1985.10a
• /
• pp.87-94
• /
• 1985

In this paper, enhancement of speech corrupted by additive white or colored noise is stuided. The nuconstrained frequency-domain block least-mean-square (UFBLMS) adaptation algorithm and its frequency-weighted version are newly applied to speech enhancement. For enhancement of speech degraded by white noise, the performance of the UFBLMS algorithm is superior to the spectral subtraction method or Wiener filtering technique by more than 3 dB in segmented frequency-weighted signal-to-noise ratio(FWSNERSEG) when SNR of speech is in the range of 0 to 10 dB. As for enhancement of noisy speech corrupted by colored noise, the UFBLMS algorithm is superior to that of the spectral subtraction method by about 3 to 5 dB in FWSNRSEG. Also, it yields better performance by about 2 dB in FWSNR and FWSNRSEG than that of time-domain least-mean-square (TLMS) adaptive prediction filter(APF). In view of the computational complexity and performance improvement in speech quality and intelligibility, the frequency-weighted UFBLMS algorithm appears to yield the best performance among various algorithms in enhancing noisy speech corrupted by white or colored noise.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.10 no.2
• /
• pp.837-856
• /
• 2016

Underwater image enhancement has received considerable attention in last decades, due to the nature of poor visibility and low contrast of underwater images. In this paper, we propose a new automatic underwater image enhancement algorithm, which combines nonsubsampled contourlet transform (NSCT) domain enhancement techniques with the mechanism of the human visual system (HVS). We apply the multiscale retinex algorithm based on the HVS into NSCT domain in order to eliminate the non-uniform illumination, and adopt the threshold denoising technique to suppress underwater noise. Our proposed algorithm incorporates the luminance masking and contrast masking characteristics of the HVS into NSCT domain to yield the new HVS-based NSCT. Moreover, we define two nonlinear mapping functions. The first one is used to manipulate the HVS-based NSCT contrast coefficients to enhance the edges. The second one is a gain function which modifies the lowpass subband coefficients to adjust the global dynamic range. As a result, our algorithm can achieve contrast enhancement, image denoising and edge sharpening automatically and simultaneously. Experimental results illustrate that our proposed algorithm has better enhancement performance than state-of-the-art algorithms both in subjective evaluation and quantitative assessment. In addition, our algorithm can automatically achieve underwater image enhancement without any parameter tuning.

• Carbon letters
• /
• v.19
• /
• pp.57-65
• /
• 2016

Isroaniso matrix precursor synthesized from commercially available petroleum pitch was stabilized in air. The influence of oxygen mass gain during stabilization on the yield of matrix precursor was studied. Additionally, the influence of pressure on the yield of the stabilized matrix precursor in a real system was studied. The fourier transform infrared spectrometry (FTIR), thermogravimetric analysis (TGA), yield, yield rate, and yield impact were used to check the effect of stabilization and pressure on the yield of the matrix precursor and the end properties of the composite thereafter. The results showed that the yield increased with stabilization duration up to 20 h whereas it decreased for stabilization duration beyond 20 h. Further results showed that the stabilized matrix precursor for a duration of 5 h could withstand almost two-fold greater hot-pressing pressure without resulting in exudation as compared to that of a 1 h stabilized matrix precursor. The enhanced hot-pressing pressure significantly improved the yield of the matrix precursor. As a consequence, the densification and mechanical properties were increased significantly. Further, the matrix precursor stabilized for a duration of 20 h or more failed to provide proper and uniform binding of the reinforcement.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2009.10a
• /
• pp.855-863
• /
• 2009

In this study, a beam-column junction type damper is proposed which saves the inner and outer space for the installation of damping devices and allows easy adjustment of control performance The result of the numerical analysis indicated that the displacement response and base shear of a single degree of freedom system by seismic load, El Centro 1940 was reduced with yield moment of the joint hinge and the specific yield moment ratio $\delta$ of the joint hinge existed for the optimal seismic performance. In addition, the dynamic nonlinear characteristics, effects of yielding and dependence of natural period of bi-linear system with the junction type damper is identified. The analysis of multi-degree of freedom system showed that responses of the controlled structures was reduced significantly as the number of a story increases and yield moment ratio decreases when the system is excited by seismic load and sine wave. On top of that, it was also observed that energy dissipation at the joint connected with the dampers was remarkable during excitation.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.44 no.6
• /
• pp.118-123
• /
• 2007

In this paper, we propose an improved global soft decision for speech enhancement in noise environments. From an examination of statistical model-based speech enhancement, it is shown that the global soft decision has a fundamental drawback at the offset region of speech signals. To overcome the drawback, we apply a new speech enhancement method based on a smoothed Global likelihood ratio to the global soft decision. Performances of the proposed method are evaluated by subjective tests under various environments and yield better results compared with the reported speech enhancement method.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.51 no.6
• /
• pp.519-522
• /
• 2006

Randomized field experiments were conducted to study the interactive effect of sulphur (S) and nitrogen (N) on seed, oil and protein yield of two cultivars of groundnut {Arachis hypogea: cv Amber $(V_{1})$: cv Kaushal, $(V_{2})$.} Two dosage levels of sulphur ($0\;and\;20kg\;ha^{-1}$) and two dosage levels of N ($23.5\;and\;43.5kg\;ha^{-1}$) in various combinations were tested as micronutrient treatments, $T_{1},\;T_{2},\;and\;T_{3}$. Results indicated significant enhancement of the yield components namely seed and oil yield as well as seed protein. Maximum response was observed with treatment $T_{3}$(having 20kg S and 43.5kg N $ha^{-1})$. Increase in seed and oil yields of 90% and 103% in $V_{1}$, and 79 and 90% in $V_{2}$, respectively were recorded as compared to the control treatment $T_{1}$(having 0kg S and 23.5kg N $ha^{-1}$). Effect of S and N interaction was observed on protein, N and S content in seeds. The results obtained by these experiments clearly suggest that judicious balanced application of N and S could improve the yield.