• Title/Summary/Keyword: Temperature fluctuation

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Comparison of the Real-time Measurements for PM2.5 and Quality Control Method (PM2.5 자동측정장비 비교 및 정도관리 방안)

  • Park, Mikyung;Park, Jin Su;Jo, Mira;Lee, Yong Hwan;Kim, Hyun Jae;Oh, Jun;Choi, Jin Soo;Ahn, Joon Young;Hong, You Deog
    • Journal of Korean Society for Atmospheric Environment
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    • v.33 no.6
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    • pp.616-625
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    • 2017
  • Measurements using five real-time particle samplers were compared to measurements using three NRM (National Reference Method system) filter-based samplers(Gravimetric method) at Incheon, Korea, between May and August, 2014. The purpose of this study was to suggest the quality assurance/quality control (QA/QC) method of each instrument for use in a real-time continuous particle sampler to measure the mass of airborne particles with an aerodynamic diameter less than $2.5{\mu}m$ ($PM_{2.5}$). Five real-time particle samplers of BAM1020, FH62C_14, TEOM, PM-711 and SPM-613 were evaluated by comparing its measured 23 hr average $PM_{2.5}$ concentrations with those measured with NRM filter-based samplers simultaneously. The parameters(e.g. Inlet heating condition, Slope factor, Film response, Intercept, Background, Span value) of the real-time samplers were optimized respectively by conducting test performance evaluation during 7 days in field sampling. For example, inlet heating temperature of TEOM sampler controls $35{\sim}40^{\circ}C$ to minimize the fluctuation of the real-time measurement data and background value of BAM1020 is the key factor affecting the accuracy of $PM_{2.5}$ mass concentration. We classified the $PM_{2.5}$ concentration according to relative humidity (80%) to identify water absorbed in aerosols by measuring the ${\beta}$-ray samplers(BAM1020, FH62C_14) and TEOM. ${\beta}$-ray samplers were not strongly affected by relative humidity that the difference of the average $PM_{2.5}$ concentration was about 5%. On the other hand, The TEOM sampler overestimated $PM_{2.5}$ mass concentration about 15% at low relative humidity (<80%).

Optical Current Sensors with Improved Reliability using an Integrated-Optic Reflective Interferometer (반사형 간섭계를 이용하여 신뢰성을 향상시킨 광전류센서)

  • Kim, Sung-Moon;Chu, Woo-Sung;Oh, Min-Cheol
    • Journal of the Institute of Electronics and Information Engineers
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    • v.54 no.5
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    • pp.17-23
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    • 2017
  • Optical current sensors are suitable for operation in high voltage and high current environments such as power plants due to they are not affected by electromagnetic interference and have excellent insulation characteristics. However, as they operate in a harsh environment such as large temperature fluctuation and mechanical vibration, high reliability of the sensor is required. Therefore, many groups have been working on enhancing the reliability. In this work, an integrated optical current sensor incorporating polarization-rotated reflection interferometer is proposed. By integrating various optical components on a single chip, the sensor exhibits enhanced stability as well as the solution for low-cost optical sensors. Using this, we performed the characterization for the actual field application. By using a large power source, the current of 0.3 kA~36 kA was applied to the photosensor and the linear operation characteristics were observed. The error of the sensor was within $0{\pm}.5%$. Even when operating for a long time, the error range of the sensor was kept within $0{\pm}.5%$. In addition, the measurement of the frequency response over the range of 60 Hz to 10 kHz has confirmed that the 3-dB frequency band of the proposed OCT is well over 10 kHz.

Fabrication and Transmission Experiment of the Distributed Feedback Laser Diode(DFB-LD) Module for 2.5Gbps Optical Telecommunication System (2.5Gbps 광통신용 distrbuted feedback laser diode(DFB-LD) 모듈 제작 및 광송신 실험)

  • 박경현;강승구;송민규;이중기;조호성;장동훈;박찬용;김정수;김홍만
    • Korean Journal of Optics and Photonics
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    • v.5 no.3
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    • pp.423-430
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    • 1994
  • We designed and fabricated the single mode fiber pigtailed DFB-LD module for 2.5 Gbps optical communication system. In the design of the DFB-LD module, we made the module divided into two parts of inner sub-module and outer 14-pin butterfly package and cylindrical shaped sub-module contain quasi confocal 2 lens system including optical isolator and electrical connection between these parts via hybrid substrate of bias T circuit. Laser welding was used to assemble the sub-module which requires accurate fixing between optical elements. The fabricated DFB-LD module showed optical coupling efficiency of 20% and - 3 dB small signal response of more than 2.6 GHz. We confirmed mechanical reliability of the module by temperature cycle test where the tested module exhibit optical power fluctuation of less than 10%. Finally we evaluated the performance of the fabricated DFB-LD module as light source of 2.5 Gbps optical communication system, sensitivity of - 30.2 dBm was obtained through 47 km optical fiber transmission under the criterion of $1\times10^{-10}$ BER and transmission penalties were 1.5 dB caused by extinction ratio and 1.0 dB caused by chromatic dispersion of normal single mode fiber. fiber.

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The Relationship between the Fishing Grounds and Oceanographic Condition Associated with Fluctuation of Mackerals Catches in the East China Sea (고등어 어획량 변동에 따른 동지나해의 어장과 해황)

  • Jo, Gyu-Dae;Hong, Cheol-Hun;Kim, Yong-Mun
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.20 no.2
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    • pp.83-90
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    • 1984
  • The secular fluctuations of catches and fishing grounds of mackerals and the oceanographic conditions for the fishing grounds are examined by using the data of catches of mackerals by middle and large class purse-seiner during 1951 to 1981 and those of oceanographic observation carried out by Japan Meteorological Agency. The results are as follows; The fishing grounds of mackerals are respectively distributed at northeastern and southwestern areas from the central part of the East China Sea through every season of the studied years: 1968, 1974 and 1980. The narrow belt type of fishing grounds were formed inside of the Kuroshio in spring and winter of the three years. In summer mackeral species move northward and the fishing grounds are formed in the southern sea of Korea. In winter, however, mackeral species move southward and the fishing grounds are appeared in the Tsushima Current region. The dispersion of fishing grounds is generally larger in summer and smaller in spring, and especially it is the largest in summer in 1980. It seems that the concentration and dispersion of fishing grounds are related to the depth of thermocline and the position of horizontal temperature gradient in this area.

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Estimation of Air-Sea Heat Exchange Using BUOY Data at the Yellow Sea, Korea (부이 관측자료를 이용한 서해 해역의 해양-대기 열교환량 산출)

  • kang, Yune-Jeung;Hwang, Seung-On;Kim, Tae-Hee;Nam, Jae-Cheol
    • Journal of the Korean earth science society
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    • v.22 no.1
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    • pp.40-46
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    • 2001
  • Heat exchange between the atmosphere and sea is produced using the data from two 3m discus buoy installed by KMA in 1996. The meteorological and oceanic characteristics at the Dukjukdo and Chilbaldo buoy for the period 1996 ${\sim}$ 2000 are discussed. Daily averaged sensible heat and latent heat flux at each site are estimated from bulk aerodynamic method using given data and analyzed. Quantitative analyses show SST indicates 1-year cycle like air temperature but has 1 month lag. Sea level pressure is lowest in July, humidity is higher from May to August, and wind speed has averaged value of 5 m/s and higher in autumn and winter. Sensible heat flux analyses present that strong heat loss from the sea occurs in autumn and winter and weak heat loss from atmosphere appears in spring and summer, and net sensible heat loss from the sea is found throughout the year. The ocean significantly releases latent heat into atmosphere from August to May but get a little latent heat from atmosphere in other months. Net latent heat loss from the sea is larger than net sensible heat loss except in January and February. Comparison with two sites suggests that the magnitude of heat flux and their fluctuation are generally stronger at Dukjukdo than at Chilbaldo. In case study, both sensible and latent heat flux is a little more at Chilbaldo in March 1998, but substantially stronger at Dukjukdo in November 1996.

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In vitro Effect of High Osmolality on Plasma Membrane Activities in the Spermatozoa (In Vitro 고삼투압이 정자 원형질막의 Protein Tyrosine Phosphorylation에 미치는 영향)

  • 오영근;장재호;최인호;정노팔;신형철;곽병주
    • Biomedical Science Letters
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    • v.6 no.4
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    • pp.237-244
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    • 2000
  • It has been reported that plasma membrane activity of the spermatozoa may be susceptible to be influenced by extracellular osmolality and such membranous changes involve infracellular molecular changes, special regard to the structure of membranous lipids, and the accompanying ion-channel of which are closely related with their fluidity of $Ca^{2+}$ and HCO$^{-}_{3}$. It is of common recognition that a certain kind of sterol acceptor player an important to induce lipid fluctuation of the sperm plasma membrane which have been influenced by BSA administration and came in effect to outflow of cholesterol from the spermatozoa and resulted in changes of ionic fluidity to facilitate adenylyl cyclase, and to induce protein tyrosine phosphorylation by increase of cAMP and activation of PKA. Thus it seems likely that an augmentation of the acrosomal reaction is closely related with protein tyrosine phosphorylation. The following experimental results were obtained in the present study; Under the high osmolality conditions, the spermatozoa motility declined significantly and the structural change of the plasma membrane diminished to confirm that the response degrees to the osmolality depended upon the water transfer volume through the plasma membrane and the changes of cellular volume. Those experimental results suggest that a physiological parameter such as low temperature condition played an important role for presentation of spermatozoa and that inducement of spermatozoa activation for reinforcement of protein tyrosine phosphorylation. On the other hand, it seemed likely that the BSA administration as one of sterol accepters might represent a key role also under the high osmolality condition and their result also suggests that osmolality change, special regard to high osmolality condition may play an important role also in the processes of signal transmission.

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Deterioration and Microclimate in the Shelter for the Gaetaesajiseokbulibsang (Standing Triad Buddha Statues in Gaetaesaji Temple Site), Nonsan, Korea (논산 개태사지석불입상의 손상도와 보호각 내부의 미기후 환경)

  • Kim, Ji-Young;Park, Sun-Mi;Lee, Chan-Hee
    • Journal of Conservation Science
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    • v.25 no.2
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    • pp.179-196
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    • 2009
  • The Gaetaesajiseokbulibsang (Treasure No. 219) consists of light gray and coarse to medium-grained granodiorite with feldspar phenocrysts in part. Magnetic susceptibility of the rock material was measured as 12.06(${\times}10^{-3}$ SI unit), being different from the granite($0.19{\times}10^{-3}$ SI unit) in the Mt. Cheonho. This indicates the raw material has been supplied from the outside. As a result of deterioration assessment, exfoliation of the Right Buddha, cement and dust of the Main Buddha were estimated as 35.2%, 21.1% and 25.0%. The ultrasonic velocity was measured as 2850.2m/s(Main Buddha), 2648.4m/s(Left Buddha) and 2644.5m/s(Right Buddha). The compressive strength calculated from the velocity showed low in the Right Buddha among three and the all pedestal parts which corresponds to the result of deterioration assessment. The indoor mean temperature and relative humidity of the shelter were $13.7^{\circ}C$ and 79.0%. It is evaluated that the indoor microclimate was stable and the shelter functioned to reduce climatic fluctuation of the outdoor. However, water condensation was occurred on the surface of the pedestal part during spring and summer, and freezing in winter season might also be done. These factors were probable to be a main cause of the surface exfoliation of the Triad Buddha Statues. Therefore, dehumidification and heating system in the shelter should be applied to prevent further deterioration.

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500-days Continuous Observation of Nutrients, Chlorophyll Suspended Solid and Salinity in the Keum Estuary, Korea (금강 하구역에서 영양염류, 엽록소, 부유물질과 염분변화에 대한 500일간의 연속관측)

  • Lee, Yong-Hyuk;Yang, Jae-Sam
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.2 no.1
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    • pp.1-7
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    • 1997
  • We have monitored nutrients, chlorophyll, suspended solids, and salinity in the Keum Estuary to understand the temporal fluctuation of oceanographic parameters and to illustrate any variation due to the gate operation of the Keum River Dike from June, 1995 to September, 1996, approximately for 500 days. Tidal range is used as the key factor to explain the fluctuations and atmospheric parameters such as air temperature, wind velocity and rainfall are also used supplementally. The fresh water discharge was selected as another major impact on the estuarine environment due to the gate operation of the Keum Dike. In addition, daily variation by tidal cycle was investigated twice in April and July, 1996. In diurnal variation, salinity was positively correlated with tidal elevation, whereas negatively correlated with nutrients. Relatively high suspended solid and chlorophyll contents were found in the period between high and low tide. In 500 days continuous observations, salinity was negatively correlated with the volume of fresh-water discharge, but positively correlated with nutrients. A major chlorophyll bloom occurred in spring. A similar pattern of variation was observed between suspended solid and the neap-spring tidal cycle. In comparison with the data of the Keurn Estuary before the gate operation of the Keum River dike, fresh-water discharge predominated other environmental factors during the rainy season. In addition, the velocity of tidal current and the concentration of suspended solid were decreased, while nutrients and chlorophyll contents were increased.

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Effect of Current Density on Nickel Surface Treatment Process (니켈 표면처리공정에서 전류밀도 효과분석)

  • Kim, Yong-Woon;Joeng, Koo-Hyung;Hong, In-Kwon
    • Applied Chemistry for Engineering
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    • v.19 no.2
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    • pp.228-235
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    • 2008
  • Nickel plating thickness increased with the electric current density, and the augmentation was more thick in $6{\sim}10A/dm^2$ than low current. Hull-cell analysis was tested to evaluate the current density. Optimum thickness was obtained at a temperature of $60^{\circ}C$, and the pH fluctuation of 3.5~4.0. Over the Nickel ion concentration of 300 g/L, plating thickness increased with the current density. The rate of decrease in nickel ion concentration was increased with the current density. The quantity of plating electro-deposition was increased at the anode surface, which was correlated with the increase of plating thickness. The plating thickness was increased because of the quick plating speed. However, the condition of the plating surface becomes irregular and the minuteness of nickel plating layer was reduced with the plating rate. After the corrosion test of 25 h, it was resulted in that maintaining low electric current density is desirable for the excellent corrosion resistance in lustered nickel plating. According to the program simulation, the thickness of diffusion layer was increased and the concentration of anode surface was lowered for the higher current densities. The concentration profile showed the regular distribution at low electric current density. The field plating process was controlled by the electric current density and the plating thickness instead of plating time for the productivity. The surface physical property of plating structure or corrosion resistance was excellent in the case of low electric current density.

The Growth of the Cultured Scallop, Patinopecten yessoensis (양식 가리비의 성장)

  • Yoo Sung Kyoo;Ryu Ho-Young;PARK Kyung-Yang
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.14 no.4
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    • pp.221-226
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    • 1981
  • The seedlings of the scallop, Patinopecten yessoensis, which were collected in April 1980, April 1981 and May 1981, and the grown-up scallops collected in the sea bottom in November 1979, were reared by hanging method up to the July 1981. The growth of the seedlings collected in April 1980 was greatly affected by the time of the seedling collection, manipulation of the net cage, density in the net cage and the annual water temperature fluctuation. The scallops reared from the spat collected in April 1980 reached the sizes of 0.33 mm, 1.23 mm, 29.34 mm and 59.59 mm in shell length in 40,75, 285 and 450 days respectively. Since then, growth rate was determined as follows based on the age estimated by the year rings on the shell:84.96mm in 19 months, 99.3mm in 31, 112.3mm in 37 and 113.64mm in 43 months. The meat and the adductor muscle weight increased with the shell length. The meat weight roached about 15g when the shell length was 60-70mm and about 94.13 g when 130-140mm, and the adductor muscle weight reached about 4.89 g when the shell length was 60-70 mm and about 39.59g when 120-130 mm. But the growths of the meat and the adductor muscle weight were in stagnancy after scallops reached 125 mm in shell length.

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