• Transactions on Electrical and Electronic Materials
• /
• v.1 no.1
• /
• pp.32-39
• /
• 2000

Langmuir probe measurements of electron density, electron temperature and potential are mad in the early stage (<5${\mu}$s) of a laser ablated plasma plume, in which a positive current form positive ions and a electron current are overlapped. The plasma wes produced by focusing the second harmonic, 532 nm, of Q-switched Nd:YAG laser on a high purity carbon target. Then the laser intensity on the target of ~1.6${\times}$10$\^$15/ W/$\textrm{cm}^2$. The measured electron desities and temperatures are ~2${\times}$10/sip 11/ cm$\^$-3/ and -3 eV. In particluar , the phenomenon that the electron temperature decreased and then increased was observed,. It could be well explained that this phenomenon occurred in the process of inverse Bremsstrahlung of free electrons in plasma. Additionally, the plasma potential(>11V) was higher than the published values.

• Journal of Technologic Dentistry
• /
• v.15 no.1
• /
• pp.27-41
• /
• 1993

Degree of noise by personal dental laboratory working process and degree of noise by complex dental laboratory working process were measured separtely. The time of exposure to noise greater than 70dB was analyzed. Then, the whole degree of noise in dental laboratory was estimated on the basis of afore-mentioned information. Questionaire were employed to investigate the mental, emotional and physiological effects of noise in dental technicians, The purpose of this study was to provide basic information on keeping dental techneicans who are exposed to noise pollution in good working condition and good health. Results obtained are as follows ; 1. Polishing process in each working part showed high degree of noise greater than 70dB in terms of degree of noise by personal working. 2. Degree of noise by complex working process in each working part was greater than that of personal working process. 3. Time of exposure to noise complex working process the part of porcelain 150min, partial denture 120 min, crown and bridge 100 min, full denture 80 min. 4. Degree of noise by time in dental laboratory was 80dB in general for polishing process and below 75dB for waxing process. 5. Effects of noise on mental and emotional state of dental technicians showed that they felt irritated every day(14%), irritated once in a while(29%) and easily ger mad(19%). 6. Effects of noise on heart and stomach were hyper-gastric acid(38%), gastric ulcer(11%), gastritis(5%), deuodenal ulcer(3%) and weak heart function(32%). 7. Effects of noise in the hearing ability were weak(39%), moderate(33%) and normal(14%) Data presented in this study demonstrated that noise in the dental laboratory exerts profound effect on dental technicians mentally, physiologically and emotionally, in light of the above results, therefore, it appears advisable to devots substantial on the management of working condition and put further(continuing) efforts in the investigation for reducing noise problem.

• Asian-Australasian Journal of Animal Sciences
• /
• v.29 no.6
• /
• pp.845-854
• /
• 2016

Characteristics and properties of gelatin from goat skin pretreated with NaOH solutions (0.50 and 0.75 M) for various times (1 to 4 days) were investigated. All gelatins contained ${\alpha}$-chains as the predominant component, followed by ${\beta}$-chain. Gelling and melting temperatures of those gelatins were $23.02^{\circ}C$ to $24.16^{\circ}C$ and $33.07^{\circ}C$ to $34.51^{\circ}C$, respectively. Gel strength of gelatins increased as NaOH concentration and pretreatment time increased (p<0.05). Pretreatment for a longer time yielded gelatin with a decrease in $L^*$-value but an increase in $b^*$-value. Pretreatment of goat skin using 0.75 M NaOH for 2 days rendered the highest yield (15.95%, wet weight basis) as well as high gel strength (222.42 g), which was higher than bovine gelatin (199.15 g). Gelatin obtained had the imino acid content of 226 residues/1,000 residues and the gelatin gel had a fine and ordered structure. Therefore, goat skin gelatin could be used as a potential replacer of commercial gelatin.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.44 no.1
• /
• pp.26-39
• /
• 2007

In recent years, rate control is an important technique in real time video communication applications using H.264/AVC. Many existing rate control algorithms employ the quadratic rate-distortion model, which is determine the target bits for each P frame. In this paper, a new rate control algorithm for transmission of H.264/AVC video bit stream through CBR(Constant Bit Rate) channel is proposed. The proposed algorithm predicts an adaptive QP(Quantization Parameter) for improving video distortion, due to high motion and abruptly scene change, which target bit rate and MAD(Mean of Absolute Difference) for current frame considering image complexity variance between previous and current frames. Additionally, it uses frame skip technique to maintain bit stream within a manageable range and protect buffer from overflow or underflow. Experimental results show that the proposed method gives a quality improvement of about 0.5dB when compared to previous rate control algorithm. Also our proposed algorithm encodes the video sequences with less frame skipping compared to the existing rate control for H.264/AVC.