• Journal of Adhesion and Interface
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• v.3 no.4
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• pp.1-9
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• 2002

The main goal of this study was to analyze the effect of process additives, i.e. maleated polypropylene (MAPP), and nucleating agent on the viscoelastic properties of different types of extruded polypropylene-wood plastic composites manufactured from either PP homopolymer, high crystallinity PP or PP impact copolymer using dynamic mechanical thermal analysis. And also, the esterification reaction between wood flour and maleated polypropylene, and its role in determining the mechanical properties of wood flour-polypropylene composites was investigated. The wood plastic composites were manufactured using 60% pine wood flour and 40% polypropylene on a Davis-Standard $Woodtruder^{TM}$. Dynamic mechanical thermal properties, polymer damping peaks(than ${\delta}$), storage modulus (E') and loss modulus (E") were measured using a dynamic mechanical thermal analyzer. XPS (X-ray Photoelectron Spectroscopy), also known as ESCA (Electron Spectroscopy for Chemical Analysis) study of wood flour treated with MAPP was performed to obtain information on the chemical nature of wood fiber before and after treatment. To analyze the effect of frequency on the dynamic mechanical properties of the various composites, DMA tests were performed over a temperature range of -20 to $100^{\circ}C$, at four different frequencies (1, 5, 10 and 25 Hz), and at a heating rate of $5^{\circ}C/min$. From these results, the activation energy of the various composite was measured using an Arrhenius relationship to investigate the effect of maleated PP and nucleating agent on the measurement of the interphase between the wood and plastic of the extruded polypropylene wood plastic composites.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.139-139
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• 2010

금속 실리사이드 나노입자는 열적 및 화학적 안정성이 뛰어나고, 절연막내에 일함수 차이에 따라 깊은 양자 우물구조가 형성되어 비휘발성 메모리 소자를 제작할 수 있다. 그러나 단일 $SiO_2$ 절연막을 사용하였을 경우 저장된 전하의 정보 저장능력 및 쓰기/지우기 시간을 향상시키는 데 물리적 두께에 따른 제한이 따른다. 본 연구에서는 터널장벽 엔지니어링을 통하여 물리적인 두께는 단일 $SiO_2$ 보다는 두꺼우나 쓰기/지우기 동작을 위하여 인가되는 전기장에 의하여 상대적으로 전자가 느끼는 상대적인 터널 절연막 두께를 감소시키는 방법으로 동작속도를 향상 시킨 $SiO_2/Si_3N_4/SiO_2$ 및 $Si_3N_4/SiO_2/Si_3N_4$ 터널 절연막을 사용한 금속 실리사이드 나노입자 비휘발성 메모리를 제조하였다. 제조방법은 우선 p-type 실리콘 웨이퍼 위에 100 nm 두께로 증착된 Poly-Si 층을 형성 한 이후 소스와 드레인 영역을 리소그래피 방법으로 형성시켜 트랜지스터의 채널을 형성한 이후 그 상부에 $SiO_2/Si_3N_4/SiO_2$ (2 nm/ 2 nm/ 3 nm) 및 $Si_3N_4/SiO_2/Si_3N_4$ (2 nm/ 3 nm/ 3 nm)를 화학적 증기 증착(chemical vapor deposition)방법으로 형성 시킨 이후, direct current magnetron sputtering 방법을 이용하여 2~5 nm 두께의 $WSi_2$ 및 $TiSi_2$ 박막을 증착하였으며, 나노입자 형성을 위하여 rapid thermal annealing(RTA) system을 이용하여 $800{\sim}1000^{\circ}C$에서 질소($N_2$) 분위기로 1~5분 동안 열처리를 하였다. 이후 radio frequency magnetron sputtering을 이용하여 $SiO_2$ control oxide layer를 30 nm로 증착한 후, RTA system을 이용하여 $900^{\circ}C$에서 30초 동안 $N_2$ 분위기에서 후 열처리를 하였다. 마지막으로 thermal evaporator system을 이용하여 Al 전극을 200 nm 증착한 이후 리소그래피와 식각 공정을 통하여 채널 폭/길이 $2{\sim}5{\mu}m$인 비휘발성 메모리 소자를 제작하였다. 제작된 비휘발성 메모리 소자는 HP 4156A semiconductor parameter analyzer와 Agilent 81101A pulse generator를 이용하여 전기적 특성을 확인 하였으며, 측정 온도를 $25^{\circ}C$, $85^{\circ}C$, $125^{\circ}C$로 변화시켜가며 제작된 비휘발성 메모리 소자의 열적 안정성에 관하여 연구하였다.

• Korean Journal of Food Science and Technology
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• v.46 no.5
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• pp.593-600
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• 2014

Normal rice starch (NRS) possesses high gelling and retrogradation tendencies, with poor freeze-thaw stability. This study investigated the effects of partial replacement of waxy rice starch (WRS) with gums on the pasting and viscoelastic properties as well as the freeze-thaw stability of the WRS paste. Xanthan gum (XAT), locust bean gum (LBG), and their mixtures were individually mixed with WRS at a ratio of 1:19 (w/w). WRS-gum mixtures were pasted using a rapid visco-analyzer at 5% total solid content, and analyzed with respect to the pasting and viscoelastic characteristics, and freeze-thaw stability. Pasting properties of WRS were retarded in pasting temperature and enhanced in pasting viscosity (although peak viscosity was varied) by partial replacement with gum and gum mixtures. Storage moduli of WRS-XAT:LBG pastes became similar to those of NRS paste with increasing angular frequency from 1 to 10 rad/s. Finally, WRS-XAT and WRS-XAT:LBG possessed more enhanced freeze-thaw stability than NRS.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.9 no.6
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• pp.711-718
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• 2019

Spectrum analyzer and electromagnetic field meter were used to investigate the EM generation behaviour in different types of home electrical appliances. During microwave oven operation, the EM power measured at a point 30cm apart was measured in the range of 8~11mW/㎡, the strength of the low frequency magnetic field was 60~80mG and the electric field strength was measured at 150~160V/m. For smart phone wireless charging pad, it was measured at an electromagnetic power of 0.4mW/㎡, an electric field of 160 V/m and a magnetic field of 1mG at a point 10cm away. For microwave oven and wireless charging pad, if used within 10cm, the size of the electric field has been measured at a large value that exceeds the human body protection standard and may be hazardous to humans. On the other hand, home appliances such as TVs, hairdryers and refrigerators all showed very low levels of electromagnetic waves, electric fields and magnetic fields, with no harmful effects seen. For electromagnetic shielding, the metal Cu fabric and metal foil had a high level of EM shielding, while polymer films had a low EM shielding characteristic.

• The Korea Journal of Herbology
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• v.24 no.2
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• pp.13-20
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• 2009

Objectives: To compare the contents of hazardous substances before/after a decoction. Methods : The heavy metal contents before/after a decoction were measured by Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES) and mercury analyzer. In order to analyze pesticides in 6 samples we used simultaneous multi-residue analysis of pesticides by GC/ECD, which was followed by GC/MSD analysis to confirm the identity of the detected pesticide in each sample. In addition, the contents of sulfur dioxide (S02) were performed by Monier-Williams distillation method. Results : 1. The mean values of heavy metal contents (mg/kg) for the samples were as follows: Socheongryong-tang (before decoction - Pb; 1.115, Cd; 0.179, As; 0.069 and Hg; 0.028, after decoction - Pb; 0.110, Cd; 0.011, As; 0.005 and Hg; 0.002), Insampaedok-san (before decoction - Pb; 1.207, Cd; 0.148, As; 0.171 and Hg; 0.026, after decoction - Pb; 0.075, Cd; 0.006, As; not detected and Hg; O.OOD, Oryung-san (before decoction - Pb; 1.955, Cd; 0.430, As; 0.063 and Hg; 0.027, after decoction - Pb; 0.083, Cd; 0.013, As; 0.006 and Hg; 0.002), Hwangryunhaedok-tang (before decoction - Pb; 1.825, Cd; 0.210, As; 0.050 and Hg; 0.009, after decoction - Pb; 0.107, Cd; 0.010, As; 0.005 and Hg; O.OOD, Bangpungtongseong-san (before decoction - Pb; 1.740, Cd; 0.162, As; 0.585 and Hg; 0.018, after decoction - Pb; 0.041, Cd; 0.006, As; 0.022 and Hg; not detected) and Oyaksungi-san (before decoction - Pb; 1.199, Cd; 0.183, As; 0.321 and Hg; 0.031, after decoction - Pb; 0.096, Cd; 0.008, As; 0.021 and Hg; 0.0004). 2. Contents (mg/kg) of sulfur dioxide (S0$_2$) before a decoction in Socheongryong-tang, Insampaedok-san, Oryung-san, Hwangryunhaedok-tang, Bangpungtongseong-san and Oyaksungi-san exhibited 3.2, 5.7, 4.5, 49.8, 7.8 and 22.4, respectively. However, contents of sulfur dioxide after a decoction in all samples were not detected. 3. Contents (mg/kg) of residual pesticides before/after a decoction in all samples were not detected. Conclusions : These results will be used to establish a criterion of heavy metals, residual pesticides and sulfur dioxide.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.23 no.2
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• pp.8-8
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• 1987

This paper describes on the distribution of the vibration and the noise produced on a skipjack pole and line training ship M/S Pusan 403 (243GT, 1,000ps) under the cruising or drifting condition. The vibration and the noise level were measured by use of protable vibration analyzer (B and K 3513) and sound level meter (B and K 2205), and so the vibration level was converted into dB unit. The check points were set through every decks and around important places of the ship. The results obtained can be summarized as follows: 1. The vibration and the noise level 1) On the main deck, both the vibration and the noise level were highest at the vertically above the main engine, whereas the vibration level was the lowest in the bow store and the noise level beneath the bridge. 2) Under cruising condition, the vibration level around the cylinder head of main engine, port side of the engine room, on the shaft tunnel was 80, 67, 65 dB and the noise level 104, 87, 86 dB, respectively. 3) The vibration level on the vertical line passing through the bridge was the highest at the orlop deck with 60 dB and the lowest on the bridge deck with 55 dB, whereas the noise level the highest at the compass deck with 75 dB and the lowest at the orlop deck with 53 dB. 4) The vibration and the noise level on the open decks were the highest with 65 dB and 84 dB on the boat deck, whereas the vibration level was the lowest at the lecture room with 51 dB and the noise level the lowest at the fore castle deck with 57 dB. 5) On the orlop decks, both the vibration and the noise level were the highest at the engine room with 65 dB and 85 dB, and the lowest at bow store with 54 dB and 52 dB, respectively. Comparing with the vibration level and the noise level, the vibration level was higher than the noise level in the bow part and it was contrary in the stern part of the ship. 2. Vibration analysis 1) The vibration displacement and the vibration velocity were the greatest at the cylinder head of main engine with 100μm and 11mm/sec, and were the smallest at the compass deck with 3μm and 0.07mm/sec. They were also attenuated rapidly around the frequency of 100Hz and over. 2) The vibration acceleration was the greatest at the cylinder head with the main frequency of 1KHz and the acceleration of 1.1mm/sec super(2), and the smallest at the compass deck with 30KHz and 0.05mm/sec super(2).

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.23 no.2
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• pp.54-60
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• 1987

This paper describes on the distribution of the vibration and the noise produced on a skipjack pole and line training ship M/S Pusan 403 (243GT, 1,000ps) under the cruising or drifting condition. The vibration and the noise level were measured by use of protable vibration analyzer (B and K 3513) and sound level meter (B and K 2205), and so the vibration level was converted into dB unit. The check points were set through every decks and around important places of the ship. The results obtained can be summarized as follows: 1. The vibration and the noise level 1) On the main deck, both the vibration and the noise level were highest at the vertically above the main engine, whereas the vibration level was the lowest in the bow store and the noise level beneath the bridge. 2) Under cruising condition, the vibration level around the cylinder head of main engine, port side of the engine room, on the shaft tunnel was 80, 67, 65 dB and the noise level 104, 87, 86 dB, respectively. 3) The vibration level on the vertical line passing through the bridge was the highest at the orlop deck with 60 dB and the lowest on the bridge deck with 55 dB, whereas the noise level the highest at the compass deck with 75 dB and the lowest at the orlop deck with 53 dB. 4) The vibration and the noise level on the open decks were the highest with 65 dB and 84 dB on the boat deck, whereas the vibration level was the lowest at the lecture room with 51 dB and the noise level the lowest at the fore castle deck with 57 dB. 5) On the orlop decks, both the vibration and the noise level were the highest at the engine room with 65 dB and 85 dB, and the lowest at bow store with 54 dB and 52 dB, respectively. Comparing with the vibration level and the noise level, the vibration level was higher than the noise level in the bow part and it was contrary in the stern part of the ship. 2. Vibration analysis 1) The vibration displacement and the vibration velocity were the greatest at the cylinder head of main engine with 100$\mu$m and 11mm/sec, and were the smallest at the compass deck with 3$\mu$m and 0.07mm/sec. They were also attenuated rapidly around the frequency of 100Hz and over. 2) The vibration acceleration was the greatest at the cylinder head with the main frequency of 1KHz and the acceleration of 1.1mm/sec super(2), and the smallest at the compass deck with 30KHz and 0.05mm/sec super(2).

• Korean Journal of Remote Sensing
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• v.27 no.2
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• pp.191-201
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• 2011

Soybean has widely grown for its edible bean which has numerous uses. Microwave remote sensing has a great potential over the conventional remote sensing with the visible and infrared spectra due to its all-weather day-and-night imaging capabilities. In this investigation, a ground-based polarimetric scatterometer operating at multiple frequencies was used to continuously monitor the crop conditions of a soybean field. Polarimetric backscatter data at L, C, and X-bands were acquired every 10 minutes on the microwave observations at various soybean stages. The polarimetric scatterometer consists of a vector network analyzer, a microwave switch, radio frequency cables, power unit and a personal computer. The polarimetric scatterometer components were installed inside an air-conditioned shelter to maintain constant temperature and humidity during the data acquisition period. The backscattering coefficients were calculated from the measured data at incidence angle $40^{\circ}$ and full polarization (HH, VV, HV, VH) by applying the radar equation. The soybean growth data such as leaf area index (LAI), plant height, fresh and dry weight, vegetation water content and pod weight were measured periodically throughout the growth season. We measured the temporal variations of backscattering coefficients of the soybean crop at L, C, and X-bands during a soybean growth period. In the three bands, VV-polarized backscattering coefficients were higher than HH-polarized backscattering coefficients until mid-June, and thereafter HH-polarized backscattering coefficients were higher than VV-, HV-polarized back scattering coefficients. However, the cross-over stage (HH > VV) was different for each frequency: DOY 200 for L-band and DOY 210 for both C and X-bands. The temporal trend of the backscattering coefficients for all bands agreed with the soybean growth data such as LAI, dry weight and plant height; i.e., increased until about DOY 271 and decreased afterward. We plotted the relationship between the backscattering coefficients with three bands and soybean growth parameters. The growth parameters were highly correlated with HH-polarization at L-band (over r=0.92).

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.7
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• pp.711-719
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• 2011

A study of miniaturization of an L-band orthomode transducer(OMT) for field experiments of radar backscatter is presented in this paper. The proposed OMT is not required the additional waveguide taper structures to connect with a standard adaptor by the newly designed junction structure which bases on a waveguide taper. Total length of the OMT for L-band is about 1.2 ${\lambda}_o$(310 mm) and it's a size of 60 % of the existing OMTs. And, to increase the matching and isolation performances of each polarization, two conducting posts are inserted. The bandwidth of 420 MHz and the isolation level of about 40 dB are measured in the operating frequency. The L-band scatterometer consisting of the manufactured OMT, a horn-antenna and network analyzer(Agilent 8753E) was used STCT and 2DTST to analysis the measurement accuracy of radar backscatter. The full-polarimetric RCSs of test-target, 55 cm trihedral corner reflector, measured by the calibrated scatterometer have errors of -0.2 dB and 0.25 dB for vv-/hh-polarization, respectively. The effective isolation level is about 35.8 dB in the operating frequency. Then, the horn-antenna used to measure has the length of 300 mm, the aperture size of $450{\times}450\;mm^2$, and HPBWs of $29.5^{\circ}$ and $36.5^{\circ}$ on the principle E-/H-planes.

• Korean Journal of Remote Sensing
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• v.23 no.2
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• pp.145-152
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• 2007

The polarimetric backscattering coefficients of a wet-land rice field which is an experimental plot belong to National Institute of Agricultural Science and Technology in Suwon are measured using ground-based polarimetric scatterometers at 1.8 and 5.3 GHz throughout a growth year from transplanting period to harvest period (May to October in 2006). The polarimetric scatterometers consist of a vector network analyzer with time-gating function and polarimetric antenna set, and are well calibrated to get VV-, HV-, VH-, HH-polarized backscattering coefficients from the measurements, based on single target calibration technique using a trihedral corner reflector. The polarimetric backscattering coefficients are measured at $30^{\circ},\;40^{\circ},\;50^{\circ}\;and\;60^{\circ}$ with 30 independent samples for each incidence angle at each frequency. In the measurement periods the ground truth data including fresh and dry biomass, plant height, stem density, leaf area, specific leaf area, and moisture contents are also collected for each measurement. The temporal variations of the measured backscattering coefficients as well as the measured plant height, LAI (leaf area index) and biomass are analyzed. Then, the measured polarimetric backscattering coefficients are compared with the rice growth parameters. The measured plant height increases monotonically while the measured LAI increases only till the ripening period and decreases after the ripening period. The measured backscattering coefficientsare fitted with polynomial expressions as functions of growth age, plant LAI and plant height for each polarization, frequency, and incidence angle. As the incidence angle is bigger, correlations of L band signature to the rice growth was higher than that of C band signatures. It is found that the HH-polarized backscattering coefficients are more sensitive than the VV-polarized backscattering coefficients to growth age and other input parameters. It is necessary to divide the data according to the growth period which shows the qualitative changes of growth such as panicale initiation, flowering or heading to derive functions to estimate rice growth.