• 한국분무공학회지
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• 제9권4호
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• pp.67-76
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• 2004

Diode laser absorption sensors are advantageous because they may provide fast, sensitive, absolute, and selective measurements of species concentration. These systems are very attractive for practical applications owing to its compactness, reasonable cost, robustness, and ease of use. In addition, diode lasers we fiber-optic compatible and thus enable simultaneous measurements of multiple species along a line-of-sight. Recent advances of room-temperature, near-IR and visible diode laser sources for telecommunication, optical data storage applications make it possible to be applied for combustion diagnostics based on diode laser absorption spectroscopy. Therefore, combined with fiber-optics and high sensitive detection strategies, compact and portable sensor systems are now appearing for variety of applications. The objectives of this research are to develop new gas sensing system and to verify feasibility of this system. Wavelength modulation spectroscopy has been demonstrated in these experiments and has a bright prospect to this diode laser system.

• Journal of the Optical Society of Korea
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• 제14권1호
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• pp.49-54
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• 2010

In this study, the use of a continuous-wave (CW) supercontinuum (SC) seeded by an erbium-doped fiber's amplified spontaneous emission (ASE) for optical-coherence tomography imaging is experimentally demonstrated. It was shown, by taking an in-depth image of a human tooth sample, that due to the smooth, flat spectrum and long-term stability of the proposed CW SC, it can be readily applied to the spectral-domain optical-coherence tomography system. The relative-intensity noise level and spectral bandwidth of the CW SC are also experimentally analyzed as a function of the ASE beam power.

• Environmental Engineering Research
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• 제24권2호
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• pp.347-353
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• 2019

Although membrane distillation (MD) has great promise for desalination of saline water sources, it is crucial to improve its thermal efficiency to reduce the operating cost. Accordingly, this study intended to examine the thermal energy efficiency of MD modules in a pilot scale system. Two different modules of hollow fiber membranes were compared in direct contact MD mode. One of them was made of polypropylene with the effective membrane area of $2.6m^2$ and the other was made of polyvinylidene fluoride with the effective membrane area of $7.6m^2$. The influence of operation parameters, including the temperatures of feed and distillate, feed flow rate, and distillate flow rate on the flux, recovery, and performance ratio (PR), was investigated. Results showed that the two MD membranes showed different flux and PR values even under similar conditions. Moreover, both flow rate and temperature difference between feed and distillate significantly affect the PR values. These results suggest that the operating conditions for MD should be determined by considering the module properties.

• 대한의용생체공학회:의공학회지
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• 제26권4호
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• pp.199-205
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• 2005

When recording single-unit responses from neural systems, a common problem is the accurate detection of spikes (action potentials) in the presence of competing unwanted (noise) signals. While some sources of noise can be readily dealt with through filtering or 'template subtraction' techniques, other sources present a more difficult problem. In particular, noise components introduced by power supplies, which contain harmonics of the power-line frequency, can be particularly troublesome in that they can mimic the shape of the desired spikes. Thus, standard 'template subtraction' techniques or notch-filtering approaches are not appropriate. In this study, we propose the use of a novel template-subtraction scheme that involves estimating the power-line noise waveform and using cross-correlation techniques to subtract them from the recordings. This technique requires two key steps: (1) cross-correlation analysis of each recorded waveform extracts a robust representation of the power-line noise waveform and (2) a second level of cross-correlation to successfully subtract that representation from each recorded waveform. This paper describes this algorithm and provides examples of its implementation using actual recorded waveforms that are contaminated with these noise signals. An improvement (reduction) in the noise level is reported, as are suggestions for future implementation of this strategy.

• 한국식품조리과학회지
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• 제24권1호
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• pp.121-131
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• 2008

This study was performed to examine the food behavior and dietary fiber intakes of high school girls using questionnaires and 24-hr recall method. Collected sample were 263 girls from 4 different high schools. The dietary intakes were analyzed by the DS24 WIN program. The average height and weight of the respondents were $161.0{\pm}5.0$ cm and $51.8{\pm}6.3$ kg. The average BMI was $20.2{\pm}2.2$ which was within the normal range. The breakfast skipping rate was 39.2% and the reason of breakfast skipping were lack of time(50.0%), irregular meal time due to eating between meals(17.0%) and poor appetite(13.7%). The average daily energy intake of the respondents was 1741kcal. Beside protein, phosphorus, iron, niacin, vitamin A, and B1, all other nutrients intake level were below the recommended intake(RI). Average calcium and folate intakes were below the EAR as of $59.5{\sim}89.7%$ and $63{\sim}83%$ respectively. The average dietary fiber intake of the subjects was $15.6{\pm}5.2$ g, between 3.4g-35.2 g, and the respondents coumed $9.2{\pm}2.6$ g/kcal of dietary fiber. The main sources of dietary fiber were rice and kimchi which supplied 14.75% and 13.66% of total dietary fiber respectively. Also the major food groups supplying dietary fiber were vegetables and cereals, 36.90% and 31.06% of total dietary fiber respectively.

• Asian-Australasian Journal of Animal Sciences
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• 제30권7호
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• pp.999-1005
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• 2017

Objective: Two experiments were conducted to determine the content of digestible energy (DE) and metabolizable energy (ME) as well as the apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of crude protein (CP) and amino acids (AA) in barley grains obtained from Australia, France or Canada. Methods: In Exp. 1, 18 growing barrows ($Duroc{\times}Landrace{\times}Yorkshire$; $31.5{\pm}3.2kg$) were individually placed in stainless-steel metabolism crates ($1.4{\times}0.7{\times}0.6m$) and randomly allotted to 1 of 3 test diets. In Exp. 2, eight crossbred pigs ($30.9{\pm}1.8kg$) were allotted to a replicate $3{\times}4$ Youden Square designed experiment with three periods and four diets. Two pigs received each diet during each test period. The diets included one nitrogen-free diet and three test diets. Results: The relative amounts of gross energy (GE), CP, and all AA in the Canadian barley were higher than those in Australian and French barley while higher concentrations of neutral detergent fiber, acid detergent fiber, total dietary fiber, insoluble dietary fiber and ${\beta}-glucan$ as well as lower concentrations of GE and ether extract were observed in the French barley compared with the other two barley sources. The DE and ME as well as the SID of histidine, isoleucine, leucine and phenylalanine in Canadian barley were higher (p<0.05) than those in French barley but did not differ from Australian barley. Conclusion: Differences in the chemical composition, energy content and the SID and AID of AA were observed among barley sources obtained from three countries. The feeding value of barley from Canada and Australia was superior to barley obtained from France which is important information in developing feeding systems for growing pigs where imported grains are used.

• Journal of Nutrition and Health
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• 제30권7호
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• pp.770-780
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• 1997

This study was performed to investigate the effect of chitosan and NOCC from different sources and of different molecular weights on lipid metabolism. Sprague-Dawley rats were blocked into 26 groups according to body weight, and were raised for 4 weeks. Cadmium chloride was given at the level of 0 or 400 ppm in diet. Various chitosan and NOCC sources were given at the level of 0%(w/w) of diet. Total serum cholesterol and serum triglyceride concentrations were little affected by chitosan and NOCC supplements. However, HDL-cholesterol concentration and HDL : total cholesterol ratio were increased , and liver lipid, cholesterol , and triglyceride concentration were decreased by chitosan and NOCC supplements. The cholesterol and lipid lowering activity depends on fiber sources(crab and shrimp); type (chitosan and NOCC); and molecular weight(low , medium , and high). Among cadmium-free groups, chitosan-fed groups showed greater activity than NOCC -fed groups in lowering cholesterol and lipid levels, and greater fecal excretion of lipids and bile acids. Crab chitosans were more effective in cholesterol and lipid lowering activity than shrimp chitosans. The group fed high molecular weight crab chitosan showed the highest fecal excretion of lipids and bile acids. This indicated that high molecular weight crab chitosan was most effective in interfering with cholesterol and lipid absorption.

• 농업과학연구
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• 제47권4호
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• pp.941-949
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• 2020

This study evaluated the nutritional value of Italian ryegrass (IRG) as a forage source for Hanwoo. The nutritional value of IRG was assessed and compared to that of rice straw, oat hay, and timothy hay using two different methods: 1) in vitro ruminal fermentation 2) in vivo total tract digestibility. In vitro DM digestibility was lower in rice straw compared to the other three forage sources after both 24 and 48 h of incubation (p < 0.01). Among the four forage sources, IRG had a higher NH3-N concentration after both 24 and 48 h of incubation (p < 0.01). In the in vivo digestibility trials, four different substrates were used: 1) 80% concentrate with 20% rice straw, 2) 80% concentrate with 20% oat hay, 3) 80% concentrate with 20% IRG, and 4) 80% concentrate with 20% timothy hay. The dry matter, crude protein, non-fiber carbohydrate, and detergent fiber digestibility were the greatest in the C80-IRG20 among the four forage groups. In summary, IRG had a similar level of energy efficiency compared to oat hay and timothy hay. Furthermore, the result of the chemical composition analysis showing a higher ammonia concentration in the in vitro fermentation experiment and the high protein digestibility in the in vivo experiment indicate that IRG is a good source of protein compared to oat hay and timothy hay.

• Asian-Australasian Journal of Animal Sciences
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• 제27권5호
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• pp.667-673
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• 2014

Eight multiparous Holstein cows ($632{\pm}12$ kg BW; $135{\pm}16$ DIM) were used in a replicated $4{\times}4$ Latin square design to evaluate the effects of forage sources on rumen fermentation characteristics, performance, and microbial protein (MCP) synthesis. The forage portion of the diets contained alfalfa hay (AH), oat hay (OH), Leymus chinensis (LC), or rice straw (RS) as the primary source of fiber. Diets were isonitrogenous and isocaloric, and cows were fed four corn silages based total mixed rations with equivalent nonfiber carbohydrate (NFC) and forage neutral detergent fiber (NDF). Dry matter intake was not affected by the source of dietary forages, ranging from 18.83 to 19.20 kg/d, consequently, milk yield was similar among diets. Because of the numerical differences in milk fat and milk protein concentrations, 4% FCM and ECM yields were unchanged (p>0.05). Mean rumen pH, NH3-N content, and concentrations of volatile fatty acids in the rumen fluid were not affected by the treatments (p>0.05). Dietary treatments did not affect the total tract apparent digestibility of dry matter, organic matter, and crude protein (p>0.05); however, digestibility of NDF and acid detergent fiber in RS diet was higher compared with AH, OH, and LC diets (p<0.05). Total purine derivative excretion was higher in cows fed AH, OH, and LC diets compared with those fed RS diet (p<0.05), consequently, estimated MCP synthesis was 124.35 g/d higher in cows fed AH diet compared with those fed RS diet (p<0.05). The results indicated that cows fed AH, OH, LC, and RS diets with an equivalent forage NDF and NFC have no unfavourable effect on the ruminal fermentation and productive parameters.

• Asian-Australasian Journal of Animal Sciences
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• 제16권5호
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• pp.660-664
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• 2003

An attempt was made to evaluate the effects of total mixed rations (TMR) containing 17.5% forage neutral detergent fiber (NDF) from paragrass, paragrass+cassava chips and corn silages on the performance of dairy cows in the tropics. Experimental dietary treatments contained a similar content of total NDF, total non-fiber carbohydrates, crude protein and energy. Maximum and minimum temperature humidity index during the experimental period were 79.1-80.6 and 66.8-68.6, respectively. Among silage sources, there were no differences (p>0.05) in concentrations of acetic and propionic acids and butyric acid was undetectable. Concentration of lactic acid was higher (p<0.01) in corn silage but its pH was lower (p<0.01) than in paragrass and paragrass+cassava silages. Dairy cows on TMR containing corn silage not only gained more weight (161 and 46 vs. -189 g/d) but also consumed more feed (18.47, 15.84 and 14.49 kg/d), and produced more milk (23.89, 22.03 and 20.83 kg/d), 4% fat corrected milk (25.47, 24.05 and 22.02 kg/d), solids-not-fat (1.99, 18.3 and 1.73 kg/d) and total solid (3.10, 2.85 and 2.64 kg/d) compared with those on TMR containing paragrass+cassava and paragrass silages, respectively (p<0.01). Dairy cows on TMR containing paragrass+cassava silage were better in these respects (p<0.01). These results suggest that in formulating diets on an equal NDF basis for different forage qualities, diets higher in forage quality can stimulate higher DMI for dairy cows in the tropics and thus improve productivity.