• Korean Journal of Environmental Biology
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• v.37 no.3
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• pp.293-298
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• 2019

A marine ulvalean species (Chlorophyta) was collected from the eastern coast of Korea. This species is morphologically characterized by a distromatic, dark to medium green and mostly irregularly orbicular or irregularly expanded thallus with entire or undulate margin without serrations. Vegetative cells are irregularly polygonal with distinctly rounded corners in shape, and have chloroplast completely covering the outer cell wall and one to two pyrenoids per cell. In a phylogenetic tree based on ITS (Internal Transcribed Spacer) sequences, this Korean alga nests in the same clade with Ulva sublittoralis, as a sister clade of U. californica, U. flexuosa and U. tanneri, which share the irregularly orbicular or expanded thallus normally without teeth cells. The genetic divergence between them is intraspecific within Ulva. Accordingly, it is identified as U. sublittoralis based on the morphological and molecular data. This is the first record of Ulva sublittoralis in the Korean marine algal flora.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.2
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• pp.271-275
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• 1997

We have successfully grown Cl-doped ZnSe epitaxial layers on GaAs(100) sub-strates by HWE using $ZnCl_2$ as a doping source. The Cl-doped ZnSe layers showed mirrorlike morphology and good crystallinity. It has been found that the layer exhibited an n-type conduction with low resistivity. The carrier concentration is, obtained about $10^{16}\textrm {cm}^{-3}$, where a resistivity reached 10 $\Omega \textrm {cm}$. The layer with an appropriate doping level exhibited blue photoluminescence at room temperature. The strong blue PL was obtained at the hall mobility of $100^2\textrm {cm}$/Vㆍsec.

• Journal of Plant Biology
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• v.38 no.2
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• pp.181-193
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• 1995

Cuticle micromorphology of four families of Korean gymnosperms, Cycadaceae, Ginkgoaceae, Taxaceae, and Cephalotaxaceae, were studied with scanning electron microscopy. The outer and inner features of abaxial and adaxial cuticles were described in details; the absent or present of Florin ring, orifice, trichome, and plug and their shape, the shape and periclinal and anticlinal wall sculpture of epidermal cells, the shape of cuticular flange of epidermal cell, guard cell, and subsidiary cell, the number of stomatal bands and rows, and stomatal apparatus including the shape of polar extension, number of subsidiary cells, the sculpture of guard cell and subsidiary cell. Most of these features have not been sufficiently substantiated by the previous reprots. Furthermore, all the species investigated showed distinctive cuticle morphology with morphological and taxonomical informations.

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.5
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• pp.391-395
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• 2006

Microcapsules containing fragrant oils as a core material were prepared by in situ polymerization, using melamine-formaldehyde prepolymer as the wall material. The several parameters, such as stirring times, stirring rates, emulsifier types, emulsifier concentrations, and the viscosity of the core materials, affect the characteristics of the microcapsules. These parameters were investigated by the analyses of microcapsule size, particle size distribution, and morphology. The average microcapsule size decreased with an increase in stirring time, stirring rate, emulsifier concentration, and viscosity of the core material. It was also found that poly(vinyl alcohol) as a protective colloid could enhance the stability of the melamine-formaldehyde microcapsules.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1333-1335
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• 1997

We have made disperse diazo black D(DBD) thin films using Langmuir-Blodgett(LB) and vacuum-evaporation technique. Physical and optical properties of the films were investigated. Solution was made with a concentration of $10^{-3}mol/{\ell}$ using chloroform. Moving wall apparatus, (NL-LB140S-MWC) was employed to make the LB films. X,Y and Z-type LB films were manufactured and studied UV/visible absorbance spectra and morphology of surface using atomic force microscopy(AFM). Vacuum-evaporated DB D thin films were made at a pressure of $10^{-5}$ torr. The absorption peaks were observed at 200 and 400 nm in the LB films and vacuum-deposited films. We have also studied photoluminescence spectrum of the DBD films.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.493-496
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• 1997

We have made disperse diazo black D(DB-D) ultrathin films using Langmur-Blodgett(LB) and vacuum-evaporation technique. Physical and electrical properties of the films were investigated. Solution was made with a concentration of 10$^{-3}$ mol/$\ell$ using chloroform. Moving wall apparatus (NL-LB140 S-MWC) was employed to make the LB films. X,Y and Z-type LB films were manufactured and studied by UV/visible absorbance spectra and morphology of surface using atomic force microscopy. Vacuum-evaporated DB-D think films were made at a pressure of 10$^{-5}$ torrr. The absorption peaks appear at 200 and 40nm in the LB films and vacuum-deposited films. And we have studied photoluminescence spectrum of the DB-D films. Also TGA and DSC properties of the DB-D have been observed and current -voltage characteristics of the DB-D LB films have been measured along the perpendicular direction.

• ALGAE
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• v.24 no.2
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• pp.57-60
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• 2009

We described a freshwater filamentous zygnematacean species, Zygnema cruciatum (Vaucher) Agardh in Korea,based on light microscopy and scanning electron microscopy. Zygnema cruciatum is characterized by unbranched fil-amcnts of short cylindrical cells, two stellate chloroplasts per cell, a pyrenoid in each chloroplast. Cells are 32-39 $\mu$m in width and 35-50 $\mu$m in length, Conjugation is scalariform and female gametangia are cylindrical or slightlyenlarged. Zygospores are yellow-brown, spherical or broadly ovoid, 35-44 $\mu$m wide and 40-47 $\mu$m long. Under SEM, wall of zygospore has pitted mesospore and pits are 1.4-1.8 $\mu$m in diameter and 3-4 $\mu$m apart from each other.

• International Journal of Industrial Entomology and Biomaterials
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• v.3 no.1
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• pp.63-67
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• 2001

Surface morphology of perithecia of the powdery mildew fungus of mulberry, Phyllactinia corylea is described under scanning electron microscope. The perithecia have penicellate cells on the upper surface and at an average 17 acicular appendages towards the lower surface each emerging from a bulbous base. Many perithecial walls towards the base have shrunken walls. When the perithecia dry out they are pushed above the leaf surface by the acicular append-ages which then bend at the base. The bending of the appendages may be attributed to the shrinkage of lower wall cells due to loss of water.

• Korean Journal of Radiology
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• v.24 no.10
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• pp.960-973
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• 2023

The bicuspid aortic valve (BAV) is the most common congenital cardiovascular malformation. Patients with BAV are at higher risk of other congenital cardiovascular malformations and valvular dysfunction, including aortic stenosis/regurgitation and infective endocarditis. BAV may also be related to aortic wall abnormalities such as aortic dilatation, aneurysm, and dissection. The morphology of the BAV varies with the presence and position of the raphe and is associated with the type of valvular dysfunction and aortopathy. Therefore, accurate diagnosis and effective treatment at an early stage are essential to prevent complications in patients with BAV. This pictorial essay highlights the characteristics of BAV and its related congenital cardiovascular malformations, valvular dysfunction, aortopathy, and other rare cardiac complications using multimodal imaging.

• Journal of Biomedical Engineering Research
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• v.19 no.6
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• pp.571-575
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• 1998

One of the most significant features of diagnostic ultrasonic instruments is to provide real time information of the soft tissues movements. Echocardiogram has been widely used for diagnosis of heart diseases since it is able to show real time images of heart valves and walls. However, the currently used ultrasonic images are deteriorated due to presence of speckle noises and image dropout. Therefore, it is very important to develop a new technique which can enhance ultrasonic images. In this study, a technique which extracts enhanced binary images in echocardiograms was proposed. For this purpose, a digital moving image file was made from analog echocardiogram, then it was stored as 8-bit gray-level for each frame. For an efficient image processing, the region containing the heat septum and tricuspid valve was selected as the region of interest(ROI). Image enhancement filters and morphology filters were used to reduce speckle noises in the images. The proposed procedure in this paper resulted in binary images with enhanced contour compared to those form the conventional threshold technique and original image processing technique which can be further implemented for the quantitative analysis of the left ventricular wall motion in echocardiogram by easy detection of the heart wall contours.