• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.302-304
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• 1998

Self magnetic field in a Bus bar usually degrades the critical current in it. Actually the total critical current of a Bus bar is not the same as the sum of total critical current of each stacked HTS tape. This is due to the self field effects in a bus bar. To reduce the degradations of critical current in a bus bar, we need to analyze the self field distributions in a bus bar. Conceptually, by rearranging the each stacked tapes, the self field effects can be minimized. In this paper, we calculate the self magnetic field distributions across a bus bar analytically, with the variations of the relative angle of the two conductors in a go-and-return pair. As a result, we suggest that the optimum relative angle exist which minimize the self field effect in a bus bar.

• Progress in Superconductivity
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• v.2 no.2
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• pp.81-85
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• 2001

Uniformity of critical currents of YBa$_2$Cu$_3$O$_{7}$ step-edge Josephson junctions on SrTiO$_3$(100) substrates have been studied at various step-line angles. 15 identical junctions were made in series on each substrate that has a long straight step-edge line. Step-line angles studied were 0$^{\circ}$, 15$^{\circ}$, 30$^{\circ}$, and 45$^{\circ}$with respect to the crystal major axes of the substrate. Scattering of junction critical currents among the junctions on the same substrate increased with the step-line angle. Current-voltage curves showed standard resistively-shunted-junction (RSJ) characteristics in most of the 0$^{\circ}$junctions. However, the number of junctions showing RSJ behavior decreased with increasing step-line angle. Variations of detailed microstructure of the step-edge among junctions, which are coupled with the d-wave symmetry of YBa$_2$Cu$_3$O$_{7}$, are believed to be the main cause for the nonuniformity in the critical current.ent.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.1
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• pp.178-189
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• 1989

An experimental study has been performed to study the effect of the base slant angle of a 1/10 scale two-dimensional vehicle-like body on its wake flow including the recirculating region, where the simplified shape of the body has been originated from a profile of a domestic passenger car. In the case of a Reynolds number based on the length of the model R=7.96*10$^{5}$ , the surface pressure coefficient, the mean velocity and the turbulent stresses have been measured, while the flow visualization technique using wool tuft has been adopted as well. When the base slant angle of the model is 15.deg., the free stream flowing parallel to the slant is observed to be separated from the lower edge of the slant, thus forming the smallest recirculating region. When the base slant angles are 30.deg. and 45.deg., the free streams are separated from the upper edge of the slant and the sizes of the recirculating zones are observed to be almost the same as when the base slant angle is 0.deg. From these observations, it is conjectured that between the base slant angles of 15.deg. and 30.deg. there exists a critical angle at which the size of the recirculating region becomes minimum and as the slant angle becomes larger than this critical angle the separation line moves along the slant towards the rear edge of the roof. Through the flow visualization technique, the existence of the two counter-rotating bubbles in the recirculating region has been clearly observed and verified.

• Korean Journal of Materials Research
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• v.25 no.1
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• pp.54-59
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• 2015

Glancing angle deposition (GLAD) is a powerful technique to control the morphology and microstructure of thin film prepared by physical vapor deposition. Chromium (Cr) thin films were deposited on a polymer substrate by a sputtering technique using GLAD. The change in thickness and Vickers microhardness for the samples was observed with a change in the glancing angle. The adhesion properties of the critical load (Lc) by a scratch tester for the samples were also measured with varying the glancing angle. The critical load, thickness and Vickers microhardness for the samples decreased with an increase in the glancing angle. However, the thickness of the Cr thin film prepared at a $90^{\circ}$ glancing angle showed a relatively large value of 50 % compared to that of the sample prepared at $0^{\circ}$. The results of X-ray diffraction and scanning electron microscopy demonstrated that the effect of GLAD on the microstructure of samples prepared by sputter technique was not as remarkable as the samples prepared by evaporation technique. The relatively small change in thickness and microstructure of the Cr thin film is due to the superior step-coverage properties of the sputter technique.

• Journal of the Korean Geotechnical Society
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• v.32 no.6
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• pp.5-16
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• 2016

In the geosynthetics-reinforced piled embankment the effects of soft soil stiffness, friction angle of the fill material, tensile stiffness of geosynthetics, and height of the embankment on the load transfer soil arch measured by the critical height were numerically investigated. Results from parametric studies show that the magnitude of the soft soil stiffness is the most influencing factor on the critical height. The contour charts of the critical height with respect to the combination of the soft soil stiffness and other parameters were presented. The charts show that the critical height sensitively varies with the combination of the soft soil stiffness and the height of embankment. Under the sufficiently low stiffness of soft soil, the critical height sensitively varies with the friction angle of the fill material. Once the geosynthetic layer is placed, however, the magnitude of the tensile stiffness of the geosynthetic layer hardly influences the critical height of the soil arch.

• The Journal of Engineering Geology
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• v.25 no.2
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• pp.299-304
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• 2015

Slope stability analysis of unsaturated soil slopes due to rainfall infiltration is an important issue in evaluating landslide analysis and stability assessment. The purpose of this study is to establish the critical depth considering weathered soil of parent rock and rainfall intensity at main scarp in national landslide. Based on the analytical results, it is found that as rainfall duration and Slope angle increased, the critical depth of gneiss-weathered soil increased from 3.00 m to 3.77 m, the critical depth of granite weathered-soil increased from 1.75 m to 2.40 m, and the critical depth of mudstone-weathered soil increased from 3.00 m to 4.15 m, respectively. The critical depth of granite-weathered soil with low cohesion and high internal friction angle is much lower than those of other soils. It is interestingly shown that a decrease in the safety factor is highly significant, much affected by the slope increase rather than the rainfall intensity.

• Geomechanics and Engineering
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• v.23 no.1
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• pp.39-50
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• 2020

In order to understand the shear mechanical properties of the interface between clay and structure and better serve the practical engineering projects, it is critical to conduct shear tests on the clay-structure interface. In this work, the direct shear test of clay-concrete slab with different joint roughness coefficient (JRC) of the interface and different normal stress is performed in the laboratory. Our experimental results show that (1) shear strength of the interface between clay and structure is greatly affected by the change of normal stress under the same condition of JRC and shear stress of the interface gradually increases with increasing normal stress; (2) there is a critical value JRC_cr in the roughness coefficient of the interface; (3) the relationship between shear strength and normal stress can be described by the Mohr Coulomb failure criterion, and the cohesion and friction angle of the interface under different roughness conditions can be calculated accordingly. We find that there also exists a critical value JRC_cr for cohesion and the cohesion of the interface increases first and then decreases as JRC increases. Moreover, the friction angle of the interface fluctuates with the change of JRC and it is always smaller than the internal friction angle of clay used in this experiment; (4) the failure type of the interface of the clay-concrete slab is type I sliding failure and does not change with varying JRC when the normal stress is small enough. When the normal stress increases to a certain extent, the failure type of the interface will gradually change from shear failure to type II sliding failure with the increment of JRC.

• Clinics in Shoulder and Elbow
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• v.27 no.1
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• pp.26-31
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• 2024

Background: The coracoacromial ligament (CAL) is frequently observed to be damaged during arthroscopy and it is unclear how demographic, anatomic, and radiographic factors are related to CAL degeneration in full-thickness rotator cuff tears. Methods: A prospective study was conducted of patients at a single institution undergoing shoulder arthroscopy for first-time, full-thickness rotator cuff tears. We evaluated preoperative anteroposterior radiographs to obtain critical shoulder angle, glenoid inclination, acromial index, acromiohumeral distance, lateral acromial angle, and acromial morphology. We documented CAL quality, rotator cuff tear size and pattern during arthroscopy. Multiple logistic regression was used to identify predictive factors for encountering severe CAL fraying during arthroscopy. Results: Shoulders had mild CAL degeneration in 58.1% of cases, whereas severe CAL degeneration was present in 41.9% of shoulders. Patients with severe CAL attrition were significantly older (62.0 years vs. 58.0 years, P=0.042). Shoulders with severe CAL attrition had large rotator cuff tears in 54.1% of cases (P<0.001), and tears involving the infraspinatus (63.2% vs. 29.6%, P=0.003). The severe degeneration group was more likely to have a larger critical shoulder angle measurement on preoperative radiographs than those in the mild attrition group (36.1°±3.6° [range, 30°-45°] vs. 34.1°±3.8° [range, 26°-45°], P=0.037). Conclusions: While the clinical impact of CAL degeneration remains uncertain, increased severity of CAL degeneration is associated with older age, larger rotator cuff tear size, presence of infraspinatus tearing, and increased preoperative critical shoulder angle. Level of evidence: III.

• Proceedings of the Korean Nuclear Society Conference
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• 1999.05a
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• pp.155-155
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• 1999

Pool boiling critical heat flux (CHF) have been investigated using plate type test sections with different widths (3 cm & 4 cm) and lengths (10 cm, IS cm & 20 cm) under various incli- nation angles. As the inclination angle increases from $0^{\circ}$ (horizontally facing downward plate) to $30^{\circ}$, CHF sharply increases. After that angle, CHF gradually increases with the increase of the inclination angle. There must be a transition angle between $0^{\circ}$ and $30^{\circ}$, at which the CHF increase rate remarkably changes. According to the comparison of present and previous ex- periments, the transition angle may be affected by heater size and increase with the increase of heater size. The size effect of heated surface on CHF is noticeable in the L15 & L20 series and W4 series; however, it seems to be difficult to find the size effect in L10 series and W3 series.

• Journal of Veterinary Clinics
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• v.40 no.3
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• pp.221-224
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• 2023

A two-year-old spayed female Maltipoo dog was presented with a two-month duration of glaucoma in the right eye. On the first presentation, menace response and dazzle reflex were absent in the right eye, but it was present in the left eye. Slit-lamp biomicroscopy showed buphthalmia, mild corneal edema, and conjunctival and episcleral hyperemia in the right eye. The intraocular pressures were 70 mmHg and 30 mmHg in the right and left eyes, respectively. On the gonioscopic and high-resolution ultrasound examinations, both the iridocorneal angle and ciliary cleft were completely closed in the right eye. However, gonioscopy revealed an opened iridocorneal angle even with some broader base of pectinate ligament fiber, but high-resolution ultrasound showed a narrowed ciliary cleft and increased contact of the iris base with the limbal cornea in the left eye. Based on these results, a diagnosis of primary angle-closure glaucoma was made in both eyes. This case report highlighted the importance of evaluating the ciliary cleft with high-resolution ultrasound as a critical diagnostic and prognostic role in canine glaucoma.