• Applied Biological Chemistry
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• v.17 no.1
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• pp.42-48
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• 1974

Hot air thin layer drying method was studied for red pepper, Capsicum annum var. longum as the whole and cut pod states, at various temperature and air velocities. Drying curve of whole pod showed a settling down period followed by the first and second falling rate periods. By lowering the drying temperature, the first falling rate period approached to a constant rate one. Cut drying curve had simple falling rate period and also cut drying method could effectively shorten the drying time. Drying rate constant, k, was varied with time for both the drying methods and the plots of k vs. time in two methods sugested the different drying mechanisms. When an average k was taken as a constant value, the following equations; $M-M_e/M_o-M_e=e^{-0.118t}$ and $M-M_e/M_o-M_e=e(-0.342t^{0.128})$ were applicable for whole and cut drying, respectively.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.6
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• pp.678-686
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• 2019

In this study, marine heat waves on coastal waters of Republic of Korea were detected using satellite-based Sea Surface Temperature Anomaly (SSTA). The detected results were compared with the warm water issues reported by the National Institute of Fisheries Science (NIFS). Marine heat waves detection algorithm using SSTA based on a threshold has proposed. The threshold value was defined as 2℃ for caution and 3℃ for warning issues, respectively. Daily averaged SST data from July to September of 2017-2018 were used to generate SSTA. The satellite-based detection results were classified into nine areas according to the place names used in the NIFS warm water issues. In the comparison of frequency of marine heat waves occurrence to each area with the warm water issue, most areas in the southern coast showed a similar pattern, that is probably NIFS uses spatially well distributed buoys. On the other hand, other sea areas had about two times more satellite detection results. This result seems to be because NIFS only considers the water temperature data measured at limited points. The results of this study are expected to contribute to the development of a satellite-based warm/cold water monitoring system in coastal waters.

• Journal of the Korean Chemical Society
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• v.62 no.1
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• pp.24-29
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• 2018

Despite the great potential for the versatile applications in food industry and medical area, chitosan as a biocompatible cationic polysaccharide has suffered from the limited solubility under physiological condition. Herein, we demonstrated the electrostatic formation of chitosan-based polyplex particles, counterbalanced by polyacrylate as an anionic polyelectrolyte. The resulting polyplex exhibited pH- and composition-dependent changes in their surface charges as measured by zeta potential, which can be employed to provide the interparticle repulsive forces for enhanced colloidal stability in homogeneous solution. Subsequently, amide coupling between the acrylates and glucosamine residues of chitosan inside the polyplex further generated the hydrogel particles, which showed the temperature-sensitive swelling property. This aspect can be attributed to the partial formation of acryl amide residues, which have been generally known to possess the lower critical solution temperature (LCST).

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.4
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• pp.296-301
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• 2017

In various industrial places such as power generation plants, petrochemical and unit factories, the demands of systems that produce hot water by utilizing wasted or surplus steam have been increased. Compact steam unit(CSU) is a system that can meet these demands and produce hot water by using surplus or wasted steam, and it is also one of the good solutions in view of energy reuse. The new CSU with a capacity of 1,600 kW was developed with a hybrid plate heat exchanger of which thermal performances are better than a conventional plate heat exchanger, an improved temperature control valve, a user-friendly control system, and other components in this study. The purpose of this study was to obtain performance data of the new CSU through various experiments and utilize them for the CSU commercialization. The experimental results show that heat balances between the hot side(steam) and the cold side(cold water) were within ${\pm}0.77%$, and the fluctuations of outlet temperature of the secondary side which are one of the most important evaluation factors in the CSU were $(0{\sim}0.3)^{\circ}C$.

• Korean Journal of Food Science and Technology
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• v.17 no.2
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• pp.107-112
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• 1985

Viscometric properties of japonica(Olchal) and japonica${\times}$indica(Hankang and Suwon 317) waxy rice starches were investigated. Light transmittance of starch suspension increased from $50^{\circ}{\sim}55^{\circ}C$ and remained constant after $75^{\circ}C$. Swelling power was in the order of Hankang, Suwon 317 and Olchal. Amylograph data revealed that Hankang had the highest viscosity at all reference points. The apparent viscosity of 5% starch suspension indicated that the j${\times}$indica starches were completely gelatinized after 30 min cooking at $65^{\circ}C$ whereas japonica starch at $70^{\circ}C$. The apparent viscosity of gelatinized starch at $121^{\circ}C$(15 psig) was higher compared to that of gelatinized one at $95^{\circ}C$. Hankang was the most susceptable to alkali gelatinization followed by Suwon 317 and Olchal.

• Journal of the Korean Chemical Society
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• v.38 no.8
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• pp.539-546
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• 1994

The critical micelle concentration(CMC) and the counterion binding $constant(\beta)$ at the CMC of cetyltrimethylammonium bromide(CTAB) in a series of aqueous solutions containing medium chain-length n-alcohols(Propanol, Butanol, Pentanol and Hexanol) have been determined from the concentration dependence of electrical conductance at serveral temperature from $17^{\circ}C\;to\;41^{\circ}C.$ Thermodynamic parameters $({\Delta}G^o_m,\;{\Delta}H^o_m,\;{\Delta}S^o_m,\;and\;{\Delta}C_p)$ associated with micelle formation of CTAB have been also estimated from the temperature dependence of CMC and $\beta$ values, and the significance of these parameters and their relation to the theory of micelle formation have been considered. The results show that an enthalpy-entropy compensation effect is usually observed for the micellization of CTAB. The effects of n-alcohols on the micellar properties (CMC and $\beta$) of CTAB solutions have been also investigated. The addition of n-alcohol to the CTAB solution in a small quantity decreases the CMC value and the counterion binding constant $(\beta)$ at the CMC, but the addition of n-alcohol in an excessive quantity increases the CMC values on the conterary. These results have been explained in terms of the effect of the micelle-solubilized alcohol on the micellar surface charge density.

• Korean journal of applied entomology
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• v.53 no.3
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• pp.311-315
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• 2014

Lantern fly(Lycorma delicatula) is a major invasive pest that causes withering symptom of agricultural crops by sucking tree sap and sooty mold symptom by producing honeydew. This study was conducted to investigate the occurrence pattern of lantern fly in grape orchards in Gyeonggi area and the effect of winter temperature on L. delicatula egg survival during 2010 to 2013. In Gyeonggi areas, overwintered L. delicatula eggs began to hatch from early May and nymphs peaked in mid May. Adults emerged from late July and laid eggs until early November. The survival of L. delicatula eggs during overwintering was largely affected by winter temperatures. The relationship between the number of days below a threshold temperature (x) in January and the survival rate of overwintering L. delicatula eggs (y) was using linear regression model. The best model selected by the lowest RSS (residual sum of square) between predicted and actual survival was y = -1.0486 x + 94.496 ($R^2=0.7067$) with $-11^{\circ}C$ of threshold temperature. These results should be helpful to conduct L. delicatula management programs, since the results provided relivable prediction for the winter survival of L. delicatula eggs and the phenology of egg hatch in the spring.

• Korean Journal of Food Science and Technology
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• v.29 no.6
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• pp.1175-1183
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• 1997

Lethal effects of high voltage pulsed electric fields (PEF) on suspensions of Lactobacillus plantarum cells in phosphate buffer solution were examined by using continuous recycle treatment system. Critical electric field strength and treatment time needed for inactivation of L. plantarum were 13.6 kV/cm and $16.1\;{\mu}s$ at room temperature, respectively. As decrease in frequency (decreasing pulse number), the degree of inactivation of L. plantarum was increased. A 2.5 log reduction in microbial population could be achieved with an electric field strength of 80 kV/cm, 300 Hz frequency and $2000\;{\mu}s$ treatment time. Survivability was decreased with increase in total treatment time (cycle number) and frequency at the same cycle number. As sterilization model of continuous recycle PEF treatment, $logS=-N_m\;log\;m+B$ and $N_m=k_1\;P_n+k_2$ were established. This model was very well fitted to tile empirical data. The rate of inactivation increased with increase in the processing temperature. The maximum reduction in survivability (5.6 log reduction) was obtained with 80 kV/cm electric field strength at $50^{\circ}C$ for $1000\;{\mu}s$ treatment.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2001.11a
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• pp.28-28
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• 2001

$TiCl_44,{\;}AICl_3,{\;}H_2,{\;}Ar,{\;}NH_3$ 기체를 사용하여 플라즈마 화학 증착법으로 $(Ti_{1-x}AI_x)N$ 피막을 증착한 후 진공열처리 실험을 통해 열처리 전후에 나타나는 피막의 가계적 특성 변화 및 상변화 양상에 대해 연구하였다. 기판으로는 M2 고속도강과 알루미나(${\alpha}-Al_2O_3$)를 사용하였으며, 열처리 실험은 진공 열처리로를 이용하여 $800$ ~ $1100^{\circ}C$ 에서 진행하였다. M2 고속도강 위에 증착한 $(Ti_{1-x}AI_x)N$ 피막은 모두 (200) 우선 방위를 갖고 있었으며, AI의 함량이 높아짐에 따라 입자의 크기가 미세해져 $(Ti_{0.2}AI_{0.8})N$ 의 경우 수 nm의 업자들로 이루어져 있었다. 열처리 시간을 일정하게 하고, 그 온도를 증가시킬 경우 비교적 낮은 온도 영역($~900^{\circ}C$)에서는 경도 증가를 나타내지만, 열처리가 더욱 진행됨에 따라 다시 경도가 감소하는 양상을 나타내었으며, 열처리 온도를 일정하게 하고 열처리 시간을 변화 시킬 경우에도 초기에 경도가 증가하다가 열처리가 진행됨에 따라 경도가 다시 감소하는 현상을 관찰 하였다. 이때 경도증가 정도는 Al 함량이 높을 수록 뚜렷하고 오래 지속되었으며, $(Ti_{0.2}AI_{0.8})N$ 피막의 경우 열처리 전 $2000HK_{0.01}$에서 열처리 후 $4500HK_{0.01}$로, 매우 큰 경도 증가를 나타내었다. 이와 같은 열처리 전후의 기계적 특성 변화는 준 안정상의 $(Ti_{1-x}AI_{x})N$ 피막에서, 열처리가 진행됨에 따라 미세한 AlN 업자가 석출되면서 나타나는 현상으로, 고분해능 전자현미경(HRTEM) 분석을 통해 경도가 증가한 시편의 경우 석출상의 크기가 5nm 이하로 매우 작고 대체로 기지와 연속적인 계면을 형성하나, 열처리가 진행될수록 석 출상의 크기가 커지고 임계크기 이상에 이르면 연속적인 계면은 거의 발견되지 않고, 대부 분 불연속적이고 확연한 계면을 형성함을 관찰 할 수 있었다. 알루미나(${\alpha}-Al_2O_3$) 기판 위에 증착한 $(Ti_{1-x}AI_{x})N$ 피막은 마찬가지로 (200) 우선 방위를 나타내었으나, 그 입자의 크기가 수십 nm로 고속도강위에 증착한 피막에 비해 상당히 크게 형성되었다. 또한 열처리 후에 AIN의 석출이 진행됨에도 불구하고 경도 증가는 나타나지 않고, 열처리가 진행됨에 따라 경도가 감소하는 양상만을 나타내었다. 결국 $(Ti_{1-x}AI_{x})N$ 피막이 열처리 전후에 보아는 기계적 특성의 변화 양상은 열역학적으로 안정한 Wurzite-AlN의 석출에 따른 것으로 AlN 석출상의 크기에 의존하며, 또한 이러한 영향은 $(Ti_{1-x}AI_{x})N$ 피막에 존재하는 AI의 함량이 높고, 초기에 증착된 막의 업자 크기가 작을 수록 클 것으로 여겨진다.

• Journal of the Korean Applied Science and Technology
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• v.38 no.4
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• pp.994-1002
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• 2021

The solubilization constants (K_s) of 4-halogenated aniline derivatives by cationic surfactants (DTAB, TTAB, and CTAB) were measured by the UV-Vis method. As a result, the K_s values decreased as the temperature increased for all the aniline derivatives and showed a tendency to increase as the radius of the halogen substituent and the hydrophobic length of surfactant increased. The calculated values of ΔG^o and ΔH^o for these solubilizations all showed negative values within the measured range, but all the ΔS^o values showed positive values. For all the 4-halogenated anilines, the ΔG^o values all tended to decrease as the temperature increased, but both values of ΔH^o and ΔS^o showed a tendency to increase. In addition, as the radius of the halogen substituent increased, the values of ΔH^o and ΔS^o tended to decrease in general. However, when the hydrophobic group length of the surfactant was increased, the values of these thermodynamic functions showed a tendency to increase in general, although it differed depending on the type of aniline derivative. From the changes of such functions, it was possible to estimate the type and strength of interactions between 4-halogenated aniline and micelle, and the location at which they were solubilized in the micelle.