• Korean Journal of Digital Imaging in Medicine
• /
• v.14 no.2
• /
• pp.57-61
• /
• 2012

To compare the accuracy of breath-hold magnetic resonance imaging sequences to establish the most effective superparamagnetic iron oxide-enhanced sequence for detection of hepatic metastases. A total of 100 patients(50men and 50women, mean age: 60years) with liver disease(including malignant and benign liver lesions) were investigated at 3.0T machine (GE, General Electric Medical System, Excite HD) with 8Ch body coil. Pulse sequence for MR imaging decided to the FS-T2-FSE-RT(TR/TE/Thick./Freq./Phase=12857ms/100ms/7mm/512/384), MGRE(TR/TE/Thick./Freq./Phase=100ms/9.7ms/7mm/384/288), in-out of phase echo(TR/$TE_1$, $TE_2$/Thick./Freq./Phase=140ms/2.4, 5.8ms/7mm/352/300), Images obtained before the injection of SPIO. Six sequences were optimized for lesion detection: FS-T2-FSE-RT, multigradient recalled echo data image(MGRE), T2-weighted MGRE with an 9.7msec echo time. Images were reviewed independently by five blinded observers. The accuracy of each sequence was measured by using picture archiving communication system analysis. All results were correlated with findings at multidectator computed tomography examination. Differences between the mean results of the six observers were measured by using paired student t-test analysis. Postcontrast T2-weighted MGRE sequences were the most accurate and were significantly superior to postcontrast FS-T2-FSE-RT, T2-weighted MGRE, in-out of phase MR sequences(p < .05). For all lesions that were malignant or smaller than 1 cm, respectively, contrast to noise ratio of pre and postcontrast sequences were -1and -0.3 for T2-weighted FSE, 0.53 and 4.5 in-out of phase, 7, 7.08, 5.08, 3.32, 1.7, 1.16, 0.79, 0.68 for GRE with 2.9, 7.5, 12.1, 16.6, 21.2, 25.8, 30.4, 35.0 TE values. Breath-hold various TE precontrast sequences offer improvement in sensitivity compared with fixed multigradient recalled echo sequences alone.

• Journal of Adhesion and Interface
• /
• v.5 no.2
• /
• pp.22-36
• /
• 2004

Several in-situ testing methods of adhesively bonded joints under static short-time tensile loading are critically analyzed in terms of experimental procedure and data evaluation. Due to its rather homogeneous stress state across the glue line, the tensile-shear test with thick single-lap specimens, according to ISO 11003-2, has become the most important test process for the determination of realistic materials parameters. This basic method, which was improved in both, the experimental part by stepped adherends and easily attachable extensometers and the evaluation procedure by numeric substrate deformation correction and test simulation based on the finite element method (FEM), is therefore demonstrated by application to several kinds of adhesives and metallic adherends. Multi-axial load decreases the strength of a joint. This effect, which is illustrated by an experimental comparison, impedes the derivation of realistic mechanical characteristics from measured force-displacement curves. It is shown by numeric modeling that tensile-shear tests with thin plate substrates according to ISO 4587, which are widely used for quick industrial quality assurance, reveal an inhomogeneous stress state, especially because of relatively large adherend deformation. Complete experimental determination of the elastic properties of bonded joints requires independent measurement of at least two characteristics. As the thick-adherend tensile-shear test directly yields the shear modulus, the tensile butt-joint test according to ISO 6922 represents the most obvious complement of the test programme. Thus, validity of analytical correction formulae proposed in literature for the derivation of realistic materials characteristics is verified by numeric simulation. Moreover, the influence of the substrate deformation is examined and a FEM correction method introduced.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.27 no.3_4
• /
• pp.429-440
• /
• 2003

The purpose of this study is to classify the types of men's shoulders through the criteria which represent the characteristic of men's shoulders. In addition, we introduce new bodice patterns depending on our classification. We have the fo11owing conclusions based on our sample size of 200 men's shoulders: 1. The result of factor analysis indicates that six factors are extracted and they consist of 62.3% of total variance. We then choose three factors as standard items for our classification of the shape of men's shoulders. 2. We divide the shape of shoulders into three categories: bent, slopeness, and thickness. Each category is divided into three subcategories. (a) Bent: If one's shoulders are bent forward or backward, then we call them front or back-bent type. Otherwise, they are called standard-bent type. (b) Slopeness: If one's shoulders have an easy or steep slope, then we call them easy or steep slope type. Or else, they are called standard slope type. (c) Thickness: If one's shoulders are thick or thin, then we call them thick or thin type. Otherwise, we call them standard thick type. 3. According to the frequency based on our data entries of 200 men's shoulders, we introduce five new types of men's shoulders. 76.5% of examined men's shoulders belong to one of these five types: (a) 8.0% of standard slope and back-bent type: (b) 9.5% of easy slope and standard-bent type; (c) 45.5% of standard slope and standard-bent type; (d) 5.5% of steep slope and standard-bent type; (e) 8.0% of standard slope and back-bent type. 4. The suitability of new basic bodice patterns based on the types of men's shoulders are demonstrated by the high approval rate of the subjects who participate in testing.

• Korean Journal of Optics and Photonics
• /
• v.14 no.3
• /
• pp.266-271
• /
• 2003

The reflectance spectrum of optical films thicker than a few microns shows an intensity oscillation due to interference. Since the spectral period of the oscillation is inversely related to film thickness, the thickness of an optical film can be determined from the spectral frequency of the oscillation. For rapid data processing, the spectral frequency is obtained by use of a Fast Fourier Transformation technique. The conventional method of applying a Fast Fourier Transformation to the reflectance spectrum versus photon energy is modified so as to clear the ambiguity in choosing the proper effective refractive index value and to prevent the broadening of the Fourier transformed peak due to the refractive index dispersion. This technique of modified Fast Fourier Transformation is suggested by the authors for the first time to their knowledge. From the analysis of the calculated reflectance spectrum of a 30-${\mu}{\textrm}{m}$-thick dielectric film. it is shown to improve the accuracy in determining film thickness by a great amount. The improved accuracy of the modified Fast Fourier Transformation is also confirmed from the analysis of the reflectance spectra of a sample with 80-${\mu}{\textrm}{m}$-thick cover layer and 13-${\mu}{\textrm}{m}$-thick spacer layer on a PC substrate.

• Proceedings of the Korean Society of Medical Physics Conference
• /
• 2002.09a
• /
• pp.119-120
• /
• 2002

The aim is to urge the need of elaborate commissioning of 3D RTP system from the firsthand experience. A 3D RTP system requires so much data such as beam data and patient data. Most data of radiation beam are directly transferred from a 3D dose scanning system, and some other data are input by editing. In the process inputting parameters and/or data, no error should occur. For RTP system using algorithm-bas ed-on beam-modeling, careless beam-data processing could also cause the treatment error. Beam data of 3 different qualities of photon from two linear accelerators, patient data and calculated results were commissioned. For PDD, the doses by Clarkson, convolution, superposition and fast superposition methods at 10 cm for 10${\times}$10 cm field, 100 cm SSD were compared with the measured. An error in the SCD for one quality was input by the service engineer. Whole SCD defined by a physicist is SAD plus d$\sub$max/, the value was just SAD. That resulted in increase of MU by 100${\times}$((1_d$\sub$max//SAD)$^2$-1)%. For 10${\times}$10 cm open field, 1 m SSD and at 10 cm depth in uniform medium of relative electron density (RED) 1, PDDs for 4 algorithms of dose calculation, Clarkson, convolution, superposition and fast-superposition, were compared with the measured. The calculated PDD were similar to the measured. For 10${\times}$10 cm open field, 1 m SSD and at 10 cm depth with 5 cm thick inhomogeneity of RED 0.2 under 2 cm thick RED 1 medium, PDDs for 4 algorithms were compared. PDDs ranged from 72.2% to 77.0% for 4 MV X-ray and from 90.9% to 95.6% for 6 MV X-ray. PDDs were of maximum for convolution and of minimum for superposition. For 15${\times}$15 cm symmetric wedged field, wedge factor was not constant for calculation mode, even though same geometry. The reason is that their wedge factor is considering beam hardness and ray path. Their definition requires their users to change the concept of wedge factor. RTP user should elaborately review beam data and calculation algorithm in commissioning.

• Journal of the Korean Society of Costume
• /
• v.37
• /
• pp.181-190
• /
• 1998

The purpose of this study was to provide basic information for women's women's head type for mil-inary. The subjects were 141 college women aged from 19∼23. Data were collected from the real anthropometric measurements and 4 index. Correlation coefficientss, factor analysis, cluster analysis and analysis of variance in SAS package. The results were as follows : 4 factors were extracted from 20 anthrometric measurements and in index data, which explain 60.0% of variance. The subjectss were classified into 4 clusters by 11 measurement and 4 index data. Each charicteristics of cluster by the measurements was flat, big, thick, small types in women's head. Each charicteristics of cluster by the index data was mostly flat in head thickness and wide, midium, narrow, very wide type in face.

• Journal of the Korean Geophysical Society
• /
• v.7 no.1
• /
• pp.1-10
• /
• 2004

Gravity, magnetic and high-resolution seismic surveys were carried out in the Powell Basin to examine tectonic structure and recent sedimentation on Dec. 2002. The trend of negative gravity anomalies along the spreading axis of the Powell Basin changes from northwest to east-west toward south. Both boundaries of the basin with the Antarctic Peninsula and the South Orkey micro-continent show negative magnetic anomalies, which indicates that the boundaries were continental rift areas in the initial stage of spreading. Magnitude of the magnetic anomalies corresponding to the axis of the basin is rather small compared to those of normal spreading axises in other regions. Such small anomalies would be caused by reduction of magnetic strength of oceanic crust below thick sediments due to thermal alternation. High-resolution (3.5 kHz) seismic profiles reveal that top of the South Scotia Ridge is a flat terrain coverd with thin coarse sediments by glacial erosion. Thick oceanic sediments are deposited in the central part of the basin. Little deformation in the oceanic sediments indicates that the Powell Basin has been in stable tectonic environment after spreading of the basin stopped.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.19 no.1
• /
• pp.71-74
• /
• 2006

In this paper, we investigated the characterization of silicon oxide(SiOx) thin film on Ethylene Terephthalate(PET) substrates by e-beam deposition for transparent barrier application. The temperature of chamber increases from $30^{\circ}C$ to $110^{\circ}C$, the roughness increase while the Water vapor transmission rate (WVTR) decreases. Under these conditions, the WVTR for PET can be reduced from a level of $0.57 g/m^2/day$ (bare subtrate) to $0.05 g/m^2/day$ after application of a 200-nm-thick $SiO_2$ coating at 110 C. A more efficient way to improve permeation of PET was carried out by using a double side coating of a 5-${\mu}m$-thick parylene film. It was found that the WVTR can be reduced to a level of $-0.2 g/m^2/day$. The double side parylene coating on PET could contribute to the lower stress of oxide film, which greatly improves the WVTR data. These results indicates that the $SiO_2$ /Parylene/PET barrier coatings have high potential for flexible organic light-emitting diode(OLED) applications.

• International Journal of Precision Engineering and Manufacturing
• /
• v.8 no.3
• /
• pp.64-70
• /
• 2007

Of all the rapid tooling (RT) methods currently available, thick-layer laminated tooling is the most suitable for large-scale, low-cost dies and molds. Currently, the determination of a lamina's contour or profile and the associated slicing algorithms are based on existing rapid prototyping (RP) data manipulation technology. This paper presents a new adaptive slicing algorithm developed exclusively for profiled edge laminae (PEL) tooling PEL tooling is a thick-layer RT technique that involves the assembly of an array of laminae, whose top edges are simultaneously profiled and beveled using a line-of-sight cutting method based on a CAD model of the intended tool surface. The cutting profiles are based on the intersection curve obtained directly from the CAD model to ensure geometrical accuracy. The slicing algorithm determines the lamina thicknesses that minimize the dimensional error using a new tool shape error index. At the same time, the algorithm considers the available lamination thicknesses and desired lamina interface locations. We demonstrate the new slicing algorithm by developing a simple industrial PEL tool based on a CAD part shape.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2005.05a
• /
• pp.92-95
• /
• 2005

The silver photodoping effect in amorphous AsGeSeS chalcogenide thin films for holographic recording has been investigated using a HeNe laser ($\lambda$=632.8 nm). The chalcogenide films prepared in this work were thinner in comparison with the penetration depth of recording light ($d_p$=1.66 mm). The variation of the diffraction efficiency $(\eta)$ in amorphous chalcogende films exhibits a tendency, independently of the Ag photodoping. That is, n increases relatively rapidly at the beginning of the recording process, reaches the maximum $({\eta}_{max})$ and slowly decreases. In addition, the value of ${\eta}_{max}$ depends strongly on chalcogenide film thickness(d) and its peak among the films with d = 40, 80, 150, 300, and 633 nm is observed at d = 150 nm (approximately 1/2n), where n is refractive index of the chalcogenide (n=2.0). The ${\eta}$ is largely enhanced by Ag photodoping into the chalcogenides. In particular, the value of hmax in a bilayer of 10-nm-thick Ag/150-nm-thick AsGeSeS film is about 1.6%, which corresponds to ~20 times in comparison with that of the AsGeSeS film (without Ag).