• Journal of Korean Ophthalmic Optics Society
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• v.11 no.3
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• pp.249-258
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• 2006

There are many functions of glasses. Not only as a medical instrument but also for decorative purpose and individuality as a mean of expression. The concept of glasses applied according to various purposes and use. Following the designers' point of view, the most important research task is to make products substantial and convenient rather than external beauty after analysis problems and the needs of customers. Because customers ask for the best quality of design all the time. The best design of glass includes essential conditions like; creativity, satisfaction, convenience of use, identity. These conditions are common elements of glasses in both domestic and foreign markets. Also they can be a catalyst to stimulate glasses industry in Korea. First of all to study tho parts of glasses "End Piece", it is essential to consider for a better design. Because it adjusts the center of glasses weight balance for user's comfort. Since many brands are imitated, the significance of "End piece" is of a great importance resulting in a more successful competitiveness.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.4
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• pp.417-424
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• 2011

A fuel assembly consists of five major components, i.e., a top end piece (TEP), a bottom end piece (BEP), spacer grids (SGs), guide tubes (GTs) and an instrumentation tube (IT); in addition, it also includes fuel rods (FRs). The TEP/BEP should satisfy stress intensity limits according to the conditions A and B of ASME, Section III, Division 1-Subsection NB. In a dual-cooled fuel assembly, the array and position of fuel rods are different from those in a conventional PWR fuel assembly; these changes are necessary for achieving power uprating. The flow plates of the TEP and BEP have to be modified accordingly. The pattern and shape of the flow holes were newly designed. To verify the strength compatibility, the Tresca stress limit according to the ASME code was investigated in the case of an axial load of 22.241 kN. In this paper, the stress linearization procedure for strength evaluation of a newly designed TEP is presented.

• Journal of the Korean Society of Safety
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• v.14 no.3
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• pp.3-11
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• 1999

The atomic fuel rods between top and bottom end pieces of reactor need to be extended for high combustion rate of future-type fuel to increase the irradiation in the axial direction. For allowing axial extension of the fuel rods, the space between top and bottom end pieces should be expanded. Thus the thickness reduction of the flow plate is necessary. This study was carried out the mechanical strength test by using strain gages as a function of flow plate thickness, the existence of skirt and loading condition for the Korean Fuel Assembly(KOFA). The experimental apparatus was designed for load conditions, uniformly distributed load and displacement. Test method using whiffle tree of uniformly distributed load has been comparatively conservative. The test results were compared with those of finite element analysis and the test method on bottom end piece was established.

• Nuclear Engineering and Technology
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• v.21 no.3
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• pp.186-192
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• 1989

As a part of the design of the top end piece(TEP) for the 14$\times$14 reload fuel, various models of top end piece structure were analysed, using the ANSYS code, under fuel assembly shipping and handling load conditions. The 3-dimensional isoparametric elements were used in each model. By rearrangement of slots and holes on the adapter plate, without violating the design requirements, and also by changing the enclosure attachment method used on the adapter plate from pin joints to through-weld, the load carving capacity of the adapter plate was greatly strengthened. These concepts were adopted for the design of the 14$\times$14 reload fuel.

• Applied Microscopy
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• v.41 no.2
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• pp.99-107
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• 2011

Light microscope, and scanning and transmission electron microscopy were used to investigate the fine structure of sperm of the Korea squirrel, Tamias sibiricus. The sperm head of T. sibiricus was paddle in shape. The total length of T. sibiricus sperm was 67.8 ${\mu}m$. The length of sperm head was 7.8 ${\mu}m$, and the tail (60.0 ${\mu}m$) was consisted of four major segments: the neck (1.0 ${\mu}m$), middle (8.0 ${\mu}m$), principal (48.5 ${\mu}m$) and end piece (2.5 ${\mu}m$), respectively. Especially, the length of the middle piece is short, and end piece was very shorter than those of other rodents. The post-nuclear cap was occupied about a fifth of nucleus. The equatorial segment is located between the post-nuclear cap segment and acrosomal cap on the nuclear surface. Nine segmented columns were surrounded by the mitochondria, and numbers of gyres of mitochondria were 26. One segmented column was consisted ten to twelve knobs, and each of segmented column in the neck region connected with the nine outer dense fiber in the middle piece. Numerous satellite-like fibers were scattered around the segmented columns. Nos. 1, 5 and 6 of the outer dense fibers in the middle piece were larger than the others. A fibrous sheath and longitudinal column of the principal piece were in evidence, but the fibrous sheath and longitudinal column was not seen at the end piece. In conclusion, the structural features of sperm head and tail may be useful information to patterns of sperm evolution and classification of species.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.4
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• pp.52-60
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• 1999

In this study the effect of roundness error with respect to the cutting conditions using the external cylindrical work piece by end mill cutting in a machining center was studied. the end mill used in this study is HSS coated with Ti-N which is of Ø 12-4 flutes. The material of workpiece is SM20C and cutting oil is used as a cooling flued The cutting experiments were carried out for the several cutting conditions(depth of cut height of end mill feed rate revolution per minute and cutting direction) and their roundness effects were compared using the least squares circle measuring method. The experimental results are summarized as follows : 1) The cutting depth is dominant for the roundness of a cylindrical work piece and the cutting speed must be determined precisely when the cutting depth is large 2) When the cutting direction in circular manufacturing is the same with the spindle rotation i.e up-cutting condition the surface roundness is also improved.

• Parasites, Hosts and Diseases
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• v.22 no.1
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• pp.30-36
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• 1984

An ultrastructural study on the mature spermatoBoa oi Cloptorchis sineitsis was carried out. For this study, the liver cukes were collected from the livers of rabbits and rats artificially infected with the metacercariae obtained from the fresh water fish, Pseudorasbora parve. Six-month old worms were used. The collected liver fiukes were washed with 0.85% saline solution and then immediately moved to cold 2% glutaraldehyde buffered with 0.1M Millonig's phosphate buffier (pH 7.4) . The materials were dissected into appropriate pieces in the fixative about 30 minutes after beginning of the fixation. Two hours later the materials containing the seminal receptacle were rinsed several times with the buffier and were secondarily fixed with cold, bugeyed 1% osmium tetroxide(OsO4) for 2 hours. The fully mixed tissue blocks Ivere dehydrated in a series of graded concentrations of acetone and were embedded in Epon 812 mixture. Thin sections obtained from LKB-5 ultramicrotome were stained with uranyl acetate and Reynold's lead citrate. Observations of the sections were carried out with JEM-100CX II electron microscope, In general, the mature sperm was long thread-like form with a sickle-shaped head. According to the longitudinal sectioned view of the sperm tail, the nucleus seemed to be spirally coiled and run a little far along the tail. The acrosome was not observed. The cytoplasm of the tail was biflagellated as usual in trematodes. Unlike other platyhelminth spermatozoa, the sperm tail of Clenorchis sinensis showed the ${\ulcorner}9+2{\lrcorner}$ in the microtubular arrangement. The mitochondria with poorly developed cristae were observed throughout the middle piece. The middle piece of the tail showed dull ladder or triangular shapes with the two flagella at the bottom. But, the principal piece of the tail was slightly flattened cylindrical shape with two aagella within the cytoplasm. The end piece was uniflagellated. It was not clearly identised whether the end piece was subdivided into two by aagellum or the lengths of the two aagella were different. The glycogen granules were rich in the cytoplasm throughout the lenght of the spermatozoa. These granules might be the energy source for the movement of the spermatosoa.

• Proceedings of the Korean Nuclear Society Conference
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• 1999.05a
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• pp.281-281
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• 1999

• Animal cells and systems
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• v.1 no.2
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• pp.371-379
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• 1997

To investigate the movement of sperm head and the role of sperm neck in forward sperm motility in the Korean striped field mouse, Apodemus agrarius coreae, the morphological characteristics of the cauda epididymal spermatozoa were examined by light microscopy and scanning and transmission electron microscopy. Spermatozoa of A. agrarius coreae were characterized by the conspicuous shape of the acrosome and the long tail compared with those of other rodents. Total length of the sperm was $133\mu{m}$. The sperm head had a curved falciform shape. The head was 8.0${\mu}$m in length, and about 4.0 ${\mu}$m in width. The shape of acrosome had an openerlike form. The sperm tail (125 ${\mu}$m) consisted of four major segments: neck (0.5 ${\mu}$m), middle piece (29.5 ${\mu}$m), and principal piece plus the end piece (95 ${\mu}$m). The outer dense fibers were arranged in a horseshoe fashion, and No. 1, 5, 6, and 9 of the outer dense fibers were larger than the others. The mitochondrial bundles of middle piece were composed of a pair of arms, which surrounded the axone of the middle piece by the 45 0 angled helical structure. The total number of mitochondrial gyres was 188. In particular, the microfilament structures existed in plasma membrane of the sperm, which was adjacent to the acrosomal region on the nuclear membrane. The segmented columns were surrounded by microfilament structures, and the microfilament bundles were adjacent to the outer membrane of the first mitochondria of middle piece. This study presents for the first time the existence of microfilament structures within the plasma membrane of sperm which is located from the adjacent acrosome region to the connecting piece in sperm neck of Korean striped field mouse, Apodemus agrarius coreae. The present result suggests that the constriction and extension of microfilament in sperm neck as well as the wave-movement of sperm tail may play a role in the movement of sperm head.

• Applied Microscopy
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• v.41 no.1
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• pp.31-35
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• 2011

The fine structures of the sperm morphology in the Myotis daubentonii ussuriensis were observed by transmission electron microscope. The results showed that the sperm head revealed bullet shaped, the width was showed a slender more than toward the posterior region to anterior region of nucleus. The sperm head was about $4.5{\mu}m$ in length, being about $2.0{\mu}m$ in width. The nuclear length was $4.3{\mu}m$, occupied most of the sperm head. The nucleus and acrosome were separated by the apical body. The neck region was composed the basal plate, capitulum and segmented columns. The segmented columns were about 12 to 14 in number and connected with the outer dense fibers of the middle piece. The mitochondria sheath were arranged like the thread of a screw, and the total number of mitochondrial gyres were 57. The satellite fibers were observed irregularly among the outer dense fibers in the middle piece. Except the middle piece they are not observed in the principal and end pieces of the tail. In general, the tail show axoneme composed of a 9+2 microtubular pattern, and microtubules of the end piece were arranged irregularly.