• Natural Product Sciences
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• v.10 no.4
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• pp.168-172
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• 2004

In India, Gymnema sylvestre due to the unique property of the plant to antagonize the sweet taste is known as 'Gur-mar'. It has several ethnomedicinal values as various tribals/traditional communities and rural peoples of India find diverse medicinal uses viz. antidiabetic, stomachic, diuretic, and is useful in cough and throat troubles. Besides, it has strong effect on reducing blood sugar. The present communication deals with the detailed pharmacognostical evaluation of the aerial parts of G. sylvestre collected from three places of the country-Varanasi (U.P), Panchmarhi (M.P), Salem (Tami Nadu) and commercial sample procured from local market. The botanical and physico-chemical parameters of all the samples were quite similar though little variations were observed in foaming index, alcohol and water soluble extractives of local sample. The microscopic characteristics of the drug are horse shoe shaped petiole with 3 amphicribal vascular bundles, sieve tubes well developed; anomocytic stomata only on the abaxial surface of the leaf, the fan shaped amphicribal vascular bundle, presence of intraxylary phloem. The TLC fingerprint profile of all the samples was more or less similar only the quantity of some of the compounds varied.

• Korean Journal of Veterinary Research
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• v.30 no.4
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• pp.465-471
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• 1990

The fine structure of the inoculated Theileria sergenti on the splenectomized Korean native cattle was observed to delineate the morphological. characteristics with transmission and scanning electron microscope. The cattle was inoculated with 1.5ml cryopreserved stabilate ($5.63{\times}10^6/{\mu}l$, PE 3%). At peak parasitemia (40%), infected blood was collected, washed and then T sergenti was observed. Scanning electron micrograph of the erythrocytes infected with T sergenti appeared various irregular from involving specific swelling, and abnormal projections like acantocyte, echinocyte and knizocyte. Transmission electron microscopic studies of T sergenti showed that piroplasm possess intracytoplasmic food vacuole, rhoptries and tubule. Merozoite, $0.6{\sim}1.81{\mu}m$ to $0.4{\sim}1.21{\mu}m$ in length, surrounded by 10~15nm thickness of pellicula. which is surrounded by a single unit membrane. Various size of veil which was observed in stroma of erythrocytes infected with T sergenti, located at the proximate part of the merozoite. The merozoite multiplied by means of binary fission so that two and more oval-like merozoites in the stroma of infected erythrocyte could be observed.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.6
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• pp.1441-1455
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• 1993

Under unlubricated condition, the friction and wear tests of silicon nitride and zirconia manufactured by HIP were carried out at room temperature. The wear resistance of silicon nitride was superior to that of zirconia under low load, whereas the wear resistance of zirconia was superior to that of silicon nitride under high load. Wear model of ceramic was suggested by the microscopic SEM observation of worn surfaces and debris. Theoretical analysis and discussions based on linear fracture mechanics were made out about this ceramic wear model. From the theoretical analysis, a new nondimensional parameter, Scf, was introduced to estimate wear rate of ceramics. This new nondimentional parameter consists of contact pressure, surface defect of contact material, frictional coefficient and fracture toughness.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.26 no.1
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• pp.8-13
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• 1990

The microscopic relaxation parameters for the single crystal were measured by using thermally stimulated depolarization (TSD). Initial rise method, various heating rate method and total glow peak method were used for the determination of the activation energy and Debye relaxation time from TSD glow curves. Activation energy, pre-exponential factor and relaxation time for impurity-vacancy dipole reorientation were 0.55eV, 1.97$\times$10 super(-12) sec and 12.19sec in average, respectively. Dielectric dissipation factor for the crystal was calculated from the measured TSD glow curve, its value being about 3$\times$10 super(-2).

• Korean journal of food and cookery science
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• v.15 no.6
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• pp.639-644
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• 1999

The objective of this study was to compare the quality characteristics of cultured and red sea bream. The color of dorsal muscle was different between wild and cultured red sea bream. Lipid content of the dorsal muscle was higher in cultured fish than in wild one. The contents of moisture and crude protein in cultured fish muscle were almost same as those of wild one. Sensory evaluation of raw fish meat showed that cultured fish had lower preference in appearance, taste and texture than wild one. Especially the texture of cultured raw fish meat had lower preference than wild meat. For cooked fish meat, cultured fish were harder and less juicy than wild fish. These textural differences between wild and cultured meats were confirmed by objective evaluation including the measurements of hardness, springiness, and cohesiveness. Light microscopic observation showed that cultured red sea bream had more lipid in the surface layer near epidermis than wild one. Also more lipid droplet between muscle fibers were observed in cultured red sea bream by SEM.

• Journal of the Korean Society of Visualization
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• v.8 no.1
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• pp.46-52
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• 2010

In the present study, we employed the confocal laser scanning microscopy (CLSM) system to visualize the blood flow field with $1{\times}1{\mu}m^2$ spatial resolution. Based on the confocal microscopic image of red blood cells (RBCs), we performed the velocity vector field measurement and evaluated characteristics of cell migration from the cell depleted layer thickness calculation. The rat and mouse's blood were supplied into a micro glass tubes in vitro. The line scanning rate of confocal microscopy was 15 kHz for a $500{\times}500$ pixels image. As a result, the red blood cell itself can be used as a tracer directly without any kind of invasive tracer particle to get the velocity vector field of blood flow by performing particle image velocimetry (PIV) technique.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.9-9
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• 2011

There has been strong demand for novel nonvolatile memory technology for low-cost, large-area, and low-power flexible electronics applications. Resistive memories based on metal oxide thin films have been extensively studied for application as next-generation nonvolatile memory devices. However, although the metal oxide-based resistive memories have several advantages, such as good scalability, low-power consumption, and fast switching speed, their application to large-area flexible substrates has been limited due to their material characteristics and necessity of a high-temperature fabrication process. As a promising nonvolatile memory technology for large-area flexible applications, we present a graphene oxide-based memory that can be easily fabricated using a room temperature spin-casting method on flexible substrates and has reliable memory performance in terms of retention and endurance. The microscopic origin of the bipolar resistive switching behaviour was elucidated and is attributed to rupture and formation of conducting filaments at the top amorphous interface layer formed between the graphene oxide film and the top Al metal electrode, via high-resolution transmission electron microscopy and in situ x-ray photoemission spectroscopy. This work provides an important step for developing understanding of the fundamental physics of bipolar resistive switching in graphene oxide films, for the application to future flexible electronics.

• Korean Journal of Materials Research
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• v.14 no.12
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• pp.840-845
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• 2004

Tin dioxide ($SnO_2$) thin films were prepared on Si(100) substrate by PE-ALD using the $DBDTA((CH_{3}CO_2)_{2}Sn[(CH_2)_{3}CH_3]_2)$ Precursor. The properties were studied as a function of source temperature, substrate temperature, and purging time. Scanning probe microscopic images at the source temperature $50^{\circ}C$ and the substrate temperature $300^{\circ}C$ shows lower roughness than those $40/60^{\circ}C$ source and $200/400^{\circ}C$ substrate temperature samples. The purging time for optimum process was 8sec and the deposition rate was about 1 nm per 10 cycles. The conductance of $SnO_2$ thin film showed a constant region in the range of $200^{\circ}C\;to\;500^{\circ}C$. The thin films deposited for 200 cycle show a better sensitivity to CO gas.

• Analytical Science and Technology
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• v.23 no.2
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• pp.103-108
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• 2010

Single crystals of $ZnWO_4$ with [100], [010] and [001] directions were successfully grown by the Czochralski method. The seed crystals for the single crystal growth of $ZnWO_4$ could be induced by the crystal growth using platinum wires applied by the capillary action from the melt. The growth conditions in each direction were investigated in terms of the variations of rotation speed, pulling rate and diameter of the grown crystals. The formation of cracking in the grown crystals during the cooling process could be prevented by annealing effect. The growth directions of the grown crystals were determined using Laue back reflection. The microscopic characteristics of the grown crystals in each direction were discussed, and their physical properties were evaluated for hardness, thermal expansion coefficients and dielectric constants.

• Applied Microscopy
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• v.44 no.1
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• pp.1-7
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• 2014

The spermatogenesis of Siamese fighting fish, Betta splendens, belongs to Osphronemidae was investigated by light and electron microscopic observations. In primary spermatocyte stage, the nucleus was comparatively large ellipsoidal, and mitochondria showed a marked development in cytoplasm. In secondary spermatocyte stage, the germ cells were smaller than that of primary spermatocytes. The nucleus was a spherical shape and intercellular space was formed between germ cells. In spermatid stage, the early spermatids were not much different from a secondary spermatocyte. But, the chromatin condensation was occurred from the outside to the inside. The nucleus was more condensed. Intracellular space was larger than early spermatid. The mitochondria were rearranged in a middle piece, and occupied about half of the head part in early sperm. In sperm stage, the head of mature sperm was a spherical shape and had no acrosome. The flagellum was showed the typical 9+2 array of microtubules. Also, the tail of sperm had no lateral fins and outer coarse fibers. These ultrastructural characteristics can be used in classification of species.