• ETRI Journal
• /
• v.21 no.1
• /
• pp.1-27
• /
• 1999

We present a new description of envelope-function equation of the superlattice (SL). The SL wave function and corresponding effective-mass equation are formulated in terms of a linear combination of Bloch states of the constituent material with smaller band gap. In this envelope-function formalism, we review the fundamental concept on the motion of a wave packet in the SL structure subjected to steady and uniform electric fields F. The review confirms that the average of SL crystal momentums K = ($k_x,k_y,q$), where ($K_x,k_y$) are bulk inplane wave vectors and q SL wave vector, included in a wave packet satisfies the equation of motion = $_0+Ft/h$; and that the velocity and acceleration theorems provide the same type of group velocity and definition of the effective mass tensor, respectively, as in the Bulk. Finally, Schlosser and Marcus's method for the band theory of metals has been by Altarelli to include the interface-matching condition in the variational calculation for the SL structure in the multi-band envelope-function approximation. We re-examine this procedure more thoroughly and present variational equations in both general and reduced forms for SLs, which agrees in form with the proposed envelope-function formalism. As an illustration of the application of the present work and also for a brief investigation of effects of band-parameter difference on the subband energy structure, we calculate by the proposed variational method energies of non-strained $GaAs/Al_{0.32}Ga_{0.68}As$ and strained $In_{0.63}Ga_{0.37}As/In_{0.73}Ga_{0.27}As_{0.58}P_{0.42}SLs$ with well/barrier widths of $60{\AA}/500{\AA}$ and 30${\AA}/30{\AA}$, respectively.

• Korean Journal of Ichthyology
• /
• v.25 no.4
• /
• pp.239-243
• /
• 2013

Two specimens of the syngnathid Syngnathoides biaculeatus were collected from the coastal waters of Geoje Ialand and Tongyeong, Korea, represent first record of the species and the genus from Korea. This species is characterized by the following combination of characters: caudal fin absent; opercle without keel; superior and inferior trunk ridges continuous with their respective tail ridges; lateral trunk ridge deflected dorsal behind anal ring. Tail shorter than head and body hexagonal in its subdorsal part, posterior quadrangular, rapidly tapering, without caudal fin, prehensile. Head essentially in line with longitudinal axis of body or bent very little. New Korean names are proposed, "Jal-pi-sil-go-gi-sok" for the genus Syngnathoides, and "Jal-pi-sil-go-gi" for S. biaculeatus.

• Journal of the Korean Magnetics Society
• /
• v.14 no.4
• /
• pp.120-126
• /
• 2004

In order to understand the temperature dependence of magnetic properties of $F_{84}Nb_{16}$(wt.%) thin films, ferromagnetic resonance experiments have been carried out. The ferromagnetic resonance spectra for all temperatures consist of several volume modes and one (or two) surface modes. It is suggested that both surface of the film have a perpendicular hard axis to the film plane (negative surface magnetic anisotropy). Saturation magnetization coincides with the Block's T$\^$2/3/ and spectroscopic splitting factor is almost constant in the temperature range from 113 K to 293 K. The surface magnetic anisotropy constant K$\_$s2/ of the film-substrate interface increased with decreasing temperature in the temperature range from 233 K to 293 K. The surface magnetic anisotropy constant K$\_$s1/ of the air-substrate interface decreased from -0.322 erg/$\textrm{cm}^2$ to -0.394 erg/$\textrm{cm}^2$ as the temperature decreased to 253 K and was almost constant below 233 K.233 K.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.1C
• /
• pp.79-85
• /
• 2008

Dirty Paper Coding(DPC) can achieve the sum capacity of a multiuser multiple-input multiple-output(MU MIMO) broadcast channels. However, due to the high computational complexity of the successive encoding and decoding, deploying DPC in real systems is impractical. As one of practical alternatives to DPC, Block Diagonalization(BD) was researched. BD is an extension of the zero-forcing preceding technique that eliminates interuser interference(IUI) in downlink MIMO systems. Though BD has lower complexity than DPC, BD shows poor sum capacity performance. We show that sum capacity performance of BD is degraded due to no IUI constraint. Then, we modify BD to improve its sum capacity performance with relaxing the constraint and sub optimal channel set searching. With simulation results, it can be verified that our modification in BD induces some improvement in sum capacity performance.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.22 no.6
• /
• pp.793-803
• /
• 1998

Since most clothing research has still centered around buying behavior, the importance of consumer behavior which exists outside the purchase context has been neglected. This orientation focusing solely on purchase-related processes is deficient as it cannot account for consumer behavior that is recreational or that occurs without a recognized consumption need. In this vein, clothing browsing behavior can be a significant variable that has effects on clothing purchase-related variables. So to speak, browsers do make purchases at times; delayed-action purchases, impulse purchases and browsers may provide other less informed people with product information. In this study, we used definition proposed by Bloch and Richins(1983), which defines non purchase shopping(browsing) as 1,he examination of merchandises of a store for recreational or informational purposes without a current intention to buy. The specific objectives of the study were to identify the dimensions of clothing non -purchase shopping and to determine the causal relationship among clothing involvement, non-purchase shopping, impulse buying, purchase quantity, opinion leadership. The questionnaire method was used and 366 questionnaires were analyzed. Results can be summarized as follows. First, the non-purchase shopping was divided into two dimensions such as recreational non-purchase shopping and informational non-purchase shopping Of the two dimensions, recreational dimension explained the greater part than informational one. Second, it was revealed that clothing involvement was strongly positively related to non-purchase shopping, which influenced considerably on impulse buying, purchase quantity, and opinion leadership. In other words, clothing non-purchase shopping behaivor is very significant concept of clothing product category and has considerable effects on clothing buying though it occurs independently of purchase, so it seems that much more concern will be needed on this concept.

• The Journal of Korea Assosiation for Disability and Oral Health
• /
• v.14 no.2
• /
• pp.88-91
• /
• 2018

Incontinentia pigmenti(IP), or Block-Sulzberger syndrome is a rare X-linked dominant genodermatosis that affects almost in female infant and is usually lethal for males in utero. IP is characterized by four cutaneous stages and is frequently associated with dental, ocular, central nervous system and structural anomalies. Dental problems are congenital missing of teeth, delayed eruption, abnormal crown shape. We reported a case of 5 year-old female with IP. She had congenital missing of multiple primary and permanent teeth, accessory cusp and cone-shaped crowns. Systemically, she had a problem of retina and hyperpigmented macules on her trunk and extremities as typical character of IP. As the syndrome involves many different medical problems and needs comprehensive consideration. Dental care should be performed in a multidisciplinary consultation system.

• The Korean Journal of Zoology
• /
• v.15 no.3
• /
• pp.133-147
• /
• 1972

Ultrastructures of spermiogeneis in other invertebrates were investigated by several workes (Anderson, et al., 1967; Bloch, et al., 1964; Christen, 1961; Gatenby, et al., 1959; Paik, et al., 1968; Silveira, 1964; Yasuzumi, 1957) but spermiogenesis of dragonfly has not been reported previously. Testes and vass deferentia of the Korean dragonfly, Crocothemis servilia, were used for electron microscopic study of spermiogenesis. Materials were prefixed for 1-2 hours at $3^{\circ}C$ in 1.25% glutaraldehyde buffered to pH 7.2 with 0.2M sodium cacodylate buffer. Fixed tissue was washed twice in 0.2M cacodylate buffer and was subsequently postfixed for 2 hours at $3^{\circ}C$ in 1% osmium tetroxide buffered to pH 7.2 with 0.4M sodium cacodylate buffer solution. Specimens were dehydrated in graded ethyl alcohol, and finally embedded in epoxy Epon resin. Thin sections prepared from all the blocks were doubly stained; first in uranyl acetate and then in lead citrate. All thin sectios were examined with a Hitachi HS-7S electron microscope. The results of this study were summarized as follows. 1. Along the condensation of chromatin in nucleus, the shpae of nucleus was changed from spherical shpae to ellipse and cone cell type. 2. During the elongation of nucleus and the migration of cytoplasm, the nucleus removed to the one side of spermatid and began to invaginate from the posterior portion of nucleus. 3. There are ring centrioles in invaginated portion and axial filaments derived from centriole extend to the tail through the tailward half of spermatid. 4. In the cross sections the axial filament consisted of a central sheath, a central fibril, and 9 peripheral doublets.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.6 no.3
• /
• pp.147-175
• /
• 2011

The purpose of this study is to examine the effects of store choice criteria on customer satisfaction and store loyalty, and the moderating effects of customer emotions on the causal relationship between store choice criteria and customer satisfaction. In this regard, this study tries to identify the effects of store choice criteria on customer satisfaction and store loyalty in case of mass merchandisers, and to analyze the moderating effects of customer emotions on the causal relationship between store choice criteria and customer satisfaction. For this purpose, 300 customers, who have ever shopped at mass merchandisers, were surveyed and 246 valid responses were finally used for the data analysis. The results of this study are as follows. First, out of six store choice criteria, product factors, store reputation and physical environment turn out to have statistically significant effects on customer satisfaction. This result confirms those of the previous studies. On the other hand, store accessibility, subsidiary facilities and store atmosphere are not found to have statistically significant effects on customer satisfaction. This result is somewhat different from those of previous studies, and so further research on the subject needs to be carried out. Secondly, it turns out that customer satisfaction has a statistically significant effect on store loyalty, which is in line with the results of previous studies that perceived emotions affect customers' store attitudes which in turn influence their revisit intentions. Thirdly, as for the moderating effects of customer emotions on the relationship between store choice criteria and customer satisfaction, pleasure moderates the effects of store accessibility, subsidiary facilities and store atmosphere on customer satisfaction, arousal moderates the effects of product factors, subsidiary facilities and store reputation on customer satisfaction, and finally dominance moderates the effects of product factors and subsidiary facilities on customer satisfaction. These findings partially support the results of previous studies that customers' in-store emotional experiences such as feeling good or bad enhance their store loyalty.

• Journal of Life Science
• /
• v.17 no.10
• /
• pp.1309-1314
• /
• 2007

Investigation on health conditions of Thai koi (Anabas testudineus) were carried out through clinical and histopathological observations from different farms of Mymensingh district for seven months during August 2006 to February 2007. Fish sampling and water quality parameters (temperature, dissolved oxygen and pH) were monitored on a monthly basis. Clinical examination of fishes was also carried out for any kind of abnormalities at monthly intervals. Samples of skin, muscle, gill, liver and kidney were observed by histological technique. Among the water quality parameters the values of water temperature, dissolved oxygen were found to be at unfavorable level for fish during the colder months in the farms. Clinically it was observed that fishes were more affected from December to January and almost normal in appearance during August to September and February. Different clinical symptoms like scale loss, dermal lesion, ulcer and loss of caudal fin were noticed in December and January. In histopathological study, structures of fish organs were normal from August to September. In the months of October and November, minor pathologies were found to be started. Marked pathological changes like necrosis, pyknosis, inflammation, hemorrhage, hypertrophy, hyperplasia, missing of primary and secondary gill lamellae were observed in the months of December and January. Whereas, in the month of February the pathological condition of fish gradually reduced. Again when considered individual fish farm, fishes of Reliance Aqua Farm were more affected than Sotota Matshya Hatchery. The study showed that severity of clinical and pathological changes were increased in December and January. During the period EUS and protozoan diseases were noticed in A. testudineus of the investigated farms.

• Fisheries and Aquatic Sciences
• /
• v.23 no.1
• /
• pp.1.1-1.14
• /
• 2020

Background: Dietary protein requirements are dependent on a variety of factors and water temperature is one of the most important abiotic factors affecting protein requirement of fish. This study was, therefore, conducted to investigate effects of water temperature on dietary protein requirement of fry Heteropneustes fossilis which has high demand in most of the Asian markets. Methods: Quadruplicate groups of 30 fish per treatment (2.97 ± 0.65 cm; 5.11 ± 0.34 g) were fed seven isoenergetic diets (17.9 kJ g^-1 gross energy; 14.99 kJ g^-1 digestible energy) containing dietary protein levels ranging from 28 to 52% at two water temperatures (18 and 26 ℃). Experimental diets were fed to apparent satiation as semi-moist cakes thrice daily at 17:00, 12:00, and 17:30 h for 12 weeks. For precise information, various growth parameters, protein deposition, hematological parameters, metabolic enzymes, and stress response were analyzed, and effects of water temperature on dietary protein requirement was recommended on the basis of response from above parameters. Results: Groups held at 26 ℃ attained best growth, feed conversion, and protein deposition at 44% dietary protein indicating that temperature affected dietary protein requirement for optimum growth of H. fossilis fry and protein requirement seems to be satisfied with 44% dietary protein. Interestingly, interactive effects of both dietary protein levels and temperature were not found (P > 0.05). Fish reared at 18 ℃ had comparatively higher values for aspartate and alanine transferases than those reared at 26 ℃ water temperature which exhibited normal physiological value for these enzymes indicating that body metabolism was normal at this temperature. Hematological parameters also followed same pattern. Furthermore, fish reared at 26 ℃ water temperature exhibited more resistant to thermal stress (P < 0.05). The 95% maximum plateau of protein deposition data using second-degree polynomial regression analyses exhibited dietary protein requirement of fry H. fossilis between 40.8 and 41.8% of diet at 26 ℃ water temperature. The recommended range of dietary protein level and protein/digestible energy ratio for fry H. fossilis is 40.8-41.8% and 27.21-27.88 mg protein kJ^-1 digestible energy, respectively. Conclusions: Information developed is of high significance for optimizing growth potential by making better utilization of nutrient at 26 ℃ and, to develop effective management strategies for mass culture of this highly preferred fish species.