Showing papers by "Seoul National University published in 1986"
TL;DR: In this paper, the authors proposed a set of curves for the improvement factor as a function of cost for maintenance type 1P and age of the system and formulated the cost rate for a system as a ratio of an average cost for a cycle (time between replacements) to an average cycle length.
Abstract: Simple preventive maintenance (Maintenance type 1P) and preventive replacement (maintenance type 2P) are scheduled in such a way that the system does not drop below a minimum reliability. Failure rate after maintenance type 1P lies between "good as new" and "bad as old". The degree of improvement in failure rate after maintenance type 1P is cailed the improvement factor. A set of curves for the improvement factor as a function of cost for maintenance type 1P and age of the system is proposed. The cost rate for a system is formulated as a ratio of an average cost for a cycle (time between replacements) to an average cycle length. An optimum number of type 1P maintenance actions before type 2P maintenance is obtained by minimizing the cost rate when the failure times are Weibull distributed. The optimum solutions are a function of improvement factors and predetermined upper limit of failure rate.
211 citations
TL;DR: A total of 624 of 699 vasovasostomy patients was followed during the last 20 years and results were obtained when there was shorter duration of obstruction, bilateral straight vas-to-straight was anastomosis and bilateral presence of sperm in the vas fluid during vasovAsostomy.
95 citations
TL;DR: A pathologic study was done on four cases of ovarian sex cord tumor with annular tubules that occurred in young women and were not associated with the Peutz‐Jeghers syndrome, finding tumors that were solid, yellowish, and unilateral, with varying degrees of cystic degeneration.
Abstract: A pathologic study was done on four cases of ovarian sex cord tumor with annular tubules. All for tumors occurred in young women (11–24 years of age) and were not associated with the Peutz-Jeghers syndrome. Two patients had evidence of hyperestrinism. One patient who had metastasis to the retroperitoneum, left supraclavicular lymph node, and liver confirmed the malignant potential of this tumor. Gross examination revealed tumors that were solid, yellowish, and unilateral, with varying degrees of cystic degeneration. Microscopic examination showed simple or complex annular tubules with prominent basement membranes. Many tumor cells contained lipid in the cytoplasm. Ultrastructural study showed Charcot-Botteher filaments in all four cases, indicating Sertoli cell differentiation. True lumens and microvilli were identified in one case. The classification of the sex cord tumor with annular tubules as a Sertoli cell tumor, annnular tubular type was proposed on the basis of ultrastructural findings.
94 citations
TL;DR: In this article, a characterization of the whole class of nonlinear decoupling control laws for real analytic nonlinear systems is obtained and several examples which illustrate its generality are presented.
Abstract: In the past decade, conditions for feedback decoupling of nonlinear systems have been studied extensively; the class of control laws which decouple has received relatively little attention. In this paper, a characterization of the whole class of nonlinear decoupling control laws for real analytic nonlinear systems is obtained. This result is important from both mathematical and engineering viewpoints. For instance, we present an example where former results do not allow stable decoupling, while our result does. The main result is proved and several examples which illustrate its generality are presented.
68 citations
TL;DR: In this article, the authors used 3He/4He ratio anomalies coupled with deviations from ambient T-S relationships on the Galapagos spreading centre to search for effluent plumes in back-arc basins, which are also thought to be active regions of seafloor spreading where new oceanic crust is formed.
Abstract: Submarine hydrothermal vents were first unequivocally detected by measurement of 3He/4He ratio anomalies coupled with deviations from ambient T–S relationships on the Galapagos spreading centre1,2. Since then the existence of hydrothermal vents along the entire length of the East Pacific Rise has been demonstrated by shipboard observations of 3He, methane, and manganese in the effluent plumes3–5. We have extended our studies of vent fields at mid-ocean-ridge spreading centres to search for effluent plumes in back-arc basins, which are also thought to be active regions of seafloor spreading where new oceanic crust is formed6, and thus where rifting and Assuring along the axis of extension should provide similar opportunities for the downward penetration of sea water and the development of active hydrothermal systems. We have detected large plumes of methane-enriched water in the Mariana Trough back-arc basin7 and also in the summit crater of Loihi Seamount7 at the present site of the Hawaiian hotspot, thus establishing the widespread existence of ‘off-ridge’ hydro-thermal vents in the ocean. However, although the Loihi vents produce plumes enriched in both 3He and methane7, we find that, surprisingly, the Mariana vents are enriched in methane without a corresponding enrichment in 3He. This is the first time such a ‘decoupling’ of these two effluent plume tracers has been observed.
64 citations
TL;DR: In this paper, the synthesis of a γ-lactam analogue of the penems, which showed antibacterial activity, was described, and a method to synthesize a lactam analog of penems was proposed.
63 citations
TL;DR: An adequate cross-linguistic account of relative clause comprehension must be based upon an integrated view of multiple universal processing strategies, whose application will depend upon language-specific structural properties of relative clauses and upon the developmental stage of the child.
57 citations
TL;DR: In this paper, satellite-derived sea surface temperatures illustrate the variability of the path of the Tsushima Current in the Sea of Japan, which is contrary to the historical concept of branching.
49 citations
TL;DR: In this article, the low-energy dynamics of the axion is considered, taking into account the effects of the nine SU(3) singlet pseudo-scalar meson and of the instanton physics.
47 citations
TL;DR: In this article, 14 volatile components including eight allypyrocatechol analgos were isolated and identified from the essential oil and ether soluble fraction of PhilippinePiper betle leaves (Piperaceae).
Abstract: Fourteen volatile components including eight allypyrocatechol analgos were isolated and identified from the essential oil and ether soluble fraction of PhilippinePiper betle leaves (Piperaceae). The major constituents of PhilippinePiper betle oil were chavibetol and chavibetol acetate. Capillary GC analysis of the oil showed chavibetol (53.1%), chavibetol acetate (15.5%), caryophyllene (3.79%), allypyroacatechol diacetate (0.71%), campene (0.48%), chavibetol methyl ether (=methyl eugenol, 0.48%), eugenol (0.32%), α-pinene (0.21%), β-pinene (0.21%), α-limonene (0,14%), safrole (0.11%), 1,8-cineol (0.04%), and allylpyrocatechol monoacetate. The major component of the ether soluble fraction was allylpyrocatechol (2.38% of the leaves).
43 citations
TL;DR: Ten soldiers of the Korean Army found to have F. seoulensis ova in their faeces had eaten raw or undercooked snake meat or frogs during survival training and were egg-negative 2-6 months after treatment.
Abstract: Ten soldiers of the Korean Army were found to have F. seoulensis ova in their faeces. These men were treated with praziquantel and the worms passed after purging were successfully collected in one case: 59 F. seoulensis, 68 Metagonimus and 2 Stellantchasmus falcatus were collected. 2 men were also infected with Clonorchis sinensis. All the cases of fibricoliasis had eaten raw or undercooked snake meat or frogs during survival training. All were egg-negative 2-6 months after treatment.
TL;DR: For dielectric rectangular waveguides an approximate analysis by the modified effective index method is presented in this paper, where the results are generally in good agreement with results of other rigorous approximate analyses.
Abstract: For dielectric rectangular waveguides an approximate analysis by the modified effective-index method is presented. The results of this method are compared with those of the effective-index method. Our results are generally in good agreement with results of other rigorous approximate analyses.
TL;DR: The flavonoids isolated from the leaves ofRhododendron brachycarpum, were identified as quercetin, avicularin, quercitrin and hyperin this article.
Abstract: The flavonoids isolated from the leaves ofRhododendron brachycarpum, were identified as quercetin, avicularin, quercitrin and hyperin.
TL;DR: Larval anisakids found in the yellow corvina (Pseudosciaena manchurica), a marine fish caught in the Yellow Sea, were classified by their morphological types.
Abstract: Larval anisakids found in the yellow corvina (Pseudosciaena manchurica), a marine fish caught in the Yellow Sea, were classified by their morphological types. Total 1,068 anisakid larvae were collected from 30 fish examined, with the average number per fish of 35.6. They were classified into Anisakis type I larvae of Berland (859 in number, 80.4%), Contracaecum type A of Koyama et al. (13, 1.2%), Contracaecum type C'(new type) (55, 5.1%), Contracaecum type D of Koyama et al.(18, 1.7%), Contracaecum type D'(new type) (77, 7.2%), Contracaecum type V of Yamaguti(3, 0.28%), Raphidascaris sp. of Koyama et al. (1, 0.09%) and unidentified (42, 3.9%). Contracaecum type C' and D' were considered new in the literature.
TL;DR: In this paper, an experimental determination is made of the extinction states of droplet combustion, which are relevant to spray combustion processes, and an overall activation energy can be extracted from the experimental data obtained in a way similar to that for the stagnation flame.
TL;DR: In this article, a study of suspended particulate matter in the Keum estuary and the adjacent continental shelf, southeastern Yellow Sea, showed that most of the suspended matter (average amount of 2.7 × 104 tons in October 1980) is derived from Keum River and the major dispersal directions are westward and southwestward.
TL;DR: Chromatographic separation of the alkaloid fraction of the methanol extract from the stem bark of Pseuduvaria macrophylla resulted in the isolation of 1,2,3-trimethoxy-4,5-dioxo-6a,7-dehydroaporphine, together with possibly the known O -methylmoschatoline.
23 Jun 1986
TL;DR: In this paper, the authors deal with the realization technique that optimizes the flux level to improve the efficiency of an induction motor, when harmonics and saturation effects are considered, the slip of minimum loss, or optimal slip, depends both on the speed and on the load torque.
Abstract: This paper deals with the realization technique that optimizes the flux level to improve the efficiency of an induction motor. When harmonics and saturation effects are considered, the slip of minimum loss, or optimal slip, depends both on the speed and on the load torque. The measurements of speed and torque are achieved with motor terminal quantities dispensing with conventional torque and speed sensors. The control strategy is divided into two stages. Firstly, the optimal slip is searched by trial and error and the results are tabulated in microprocessor memory. Then the motor is made to be operated at optimal efficiency condition by simply tracking the optimal slip given in the table. Experimental results show good performance in energy saving and dynamic responses.
TL;DR: It is of interest that the worms persisted in a patient although he had been back in Korea for 14 months, the first report on imported heterophyiasis in Korea, and human infection by H. dispar is the first record in the literature.
Abstract: Two human cases of Heterophyes heterophyes and H. dispar infections were proven by the recovery of their adult worms. The cases were 38-year and 40-year old Korean workers who had been in Saudi Arabia for 4-6 years and returned home in 1983 or 1984 with gastrointestinal troubles. In Saudi Arabia they had eaten raw brackish water fishes such as the mullet. After the treatment with 10 mg/kg praziquantel and purgation with magnesium salt, a total of 19 specimens of H.heterophyes and 140 of H. dispar were collected. It is of interest that the worms persisted in a patient although he had been back in Korea for 14 months. This is the first report on imported heterophyiasis in Korea. Human infection by H. dispar is the first record in the literature.
TL;DR: Contrary to previous conclusions from more indirect experiments, inhibition of poly(ADP-ribose) synthesis by 3-aminobenzamide actually facilitates rapid ligation.
TL;DR: In this article, the effect of a small variation of the equilibrium compositions on the fluctuation in the calculated free energy curves was investigated, and it was recommended that the widest possible tie line or tie lines located in the central region of a phase diagram be used to calculate the interaction parameters.
Abstract: The interaction parameters for various phases were calculated using binary phase diagram data. Since two equilibrium compositions of a binary tie line have some errors in their measurements, a particular attention was paid to the effect of a small variation of the equilibrium compositions on the fluctuation in the calculated free energy curves. From this investigation, it was recommended that the widest possible tie line or tie lines located in the central region of a phase diagram be used to calculate the interaction parameters. Based on these facts, the interaction parameters for various phases in the Ti-W, Pd-W, Zr-W and Hf-W systems were estimated, which were subsequently used to calculate the phase diagrams of the above systems.
TL;DR: Two new aristolactams named as enterocarpam-I and enterocarambam-II have been isolated and characterized from the stem bark of Orophea enterocalarpa as discussed by the authors.
TL;DR: Examination of the hydrolysis, of the substrate to phenylglycine with cell free extracts, and the supernatant fraction and the particulate fraction both of which were obtained after ultracentrifugation of the cell free extract, indicated that the nitrile group hydrolyzing enzymes, nitrilase existed not only in cytoplasm, but in microsome fractions.
Abstract: Phenylglycine was obtained as the sole metabolite when α-aminophenylacetonitrile was ted to the culture broth ofAspergillus furmigatus. The isolated phenylglycine showed L-configuration with 80% optical purity. Examination of the hydrolysis, of the substrate to phenylglycine with cell free extracts, and the supernatant fraction and the particulate fraction both of which were obtained after ultracentrifugation of the cell free extract at 100,000g, indicated that the nitrile group hydrolyzing enzymes, nitrilase existed not only in cytoplasm, but in microsome fractions.
TL;DR: The results indicated that the affinity-purified A-Ag had the higher specificity but the lower sensitivity as a diagnostic antigen in cysticercosis, probably because it only detected a single or limited numbers of monospecific antibodies among the diverse polyclonal antibodies produced in the patients with neurocysticercotic diseases.
Abstract: This study was undertaken to purify cystic fluid (CF) antigen of Taenia solium metacestodes by affinity chromatography using specific monoclonal antibody (McAb) and to characterize the antigenicity of the purified antigen. The hybridoma cell lines, prepared by fusion between mouse plasmacytoma and spleen cells from BALB/c mice immunized with CF, secrected antibodies reacting to various helminthic antigens. Majority of cell lines reacted to CF only but some also reacted to parenchymal antigen of T. solium metacestodes, adult T. saginata, sparganum, hydatid cystic fluid, Paragonimus westermani and Clonorchis sinensis, either in combination with CF, other antigens or independently. Cloned cells derived from monoclonal lines also produced antibodies reacting either to CF only or to other helminthes in combination or independently. These results indicated that CF of T. solium metacestodes contained proteins which possessed antigenic determinants not only specific to CF but also cross reactive with the afore-mentioned helminthes. CF of T. solium metacestodes was purified by affinity chromatography using the McAb which reacted to CF and parenchymal antigens. The affinity-purified antigen(A-Ag) and unbound pool(U-Ag) were separated. A-Ag showed 2 protein bands by disc-PAGE whereas CF exhibited 6 bands and U-Ag consisted of all bands CF had. The diagnostic significance of A-Ag was evaluated by ELISA in human neurocysticercosis and other helminthic and neurologic diseases. By A-Ag, the levels of the specific IgG antibody, as shown by absorbance in sera and CSF, were lower than those of CF and U-Ag. Accordingly, the sensitiviy was about 70 % of CF and U-Ag. However, the nonspecific positive reactions to CF and U-Ag, observed in sparganosis, T. saginata infection and paragonimiasis did not occur when A-Ag was used. These results indicated that the affinity-purified A-Ag had the higher specificity but the lower sensitivity as a diagnostic antigen in cysticercosis, probably because it only detected a single or limited numbers of monospecific antibodies among the diverse polyclonal antibodies produced in the patients with neurocysticercosis.
TL;DR: In this article, a conservative lower confidence bound on the probability of a correct selection is derived when the probability density function has the monotone likelihood ratio property under the location parameter setting.
Abstract: In the problem of selecting the best of k populations, a natural rule is to select the population corresponding to the largest sample value of an appropriate statistic. As a retrospective analysis, a conservative lower confidence bound on the probability of a correct selection is derived when the probability density function has the monotone likelihood ratio property under the location parameter setting. The result is applied to the normal populations with both known and unknown common variance. Tables to implement the confidence bound are provided.
TL;DR: Highly diastereoselective intramolecular alkylation of acyclic ester system was developed based upon allylic strain concept as an approach to trans-hydrindane system as mentioned in this paper.
TL;DR: Meyer as discussed by the authors identified N9-formylharman, ethyl β-carboline-1-carboxylate and perlolyrine on the basis of spectroscopic studies.
Abstract: Over twelve alkaloids were delected in the roots ofPanax ginseng C.A. Meyer. Among them three alkaloids were isolated and were identified as N9-formylharman, ethyl β-carboline-1-carboxylate and perlolyrine on the basis of spectroscopic studies.
TL;DR: The results suggest that the tegument of E. hortense is similar to that of other echinostomes especially E. revolutum, but the number and arrangement of collar spines, and/or the type and distribution of sensory papillae seem characteristic features of E., which differed from other e Chinostomes.
Abstract: The tegumental ultrastructures of Echinostoma hortense adults were observed by scanning electron microscopy. The worms of 4 weeks of age were harvested from albino rats experimentally infected with the metacercariae obtained from the loach. The results were as follows: The worms were leaf-like and their anterior end portion, including oral sucker and head crown, ventrally curved to face posteriorly. The tegument of whole body was wrinkled transversely and covered with cobblestone-like cytoplasmic processes. The oral sucker had roundly swollen (type II) sensory papillae on the ventral half of its lip and uni-ciliated knob-like (type I) sensory papillae, arranged in 2-3 rows, on the dorsal outer surface. Aspinous ventral sucker had many of type I papillae arranged in a circular band on its outer surface. The tegument around the genital opening was of similar feature to the ventral sucker, but sensory papillae were hardly found around the former. Scale-like spines with broad base and round tip were distributed densely on the tegument anterior to the ventral sucker but they became sparse in posterior half of the ventral surface, finally to disappear at posterior extremity. A few number of type I papillae were observed on the ventral surface. The results suggest that the tegument of E. hortense is similar to that of other echinostomes especially E. revolutum. But the number and arrangement of collar spines, and/or the type and distribution of sensory papillae seem characteristic features of E. hortense differed from other echinostomes.
TL;DR: In this article, the pseudografted PET unit was found to be pseudografted to the PET chain end as a result of the aminolysis reaction of the ester bond of PET by the primary amine radical of PEG-diamine.
Abstract: PET film treated with PEG–diamine at 130°C was investigated for the aminolysis reaction and the pseudografted PEG content was measured with FTNMR. The hydrophilic properties of the PET film and fabric treated with PEG–diamine were estimated by their surface free energies, water-wicking time, oily soil releasing, and static electricity. Results obtained indicated that the PEG unit was pseudografted to the PET chain end as a result of the aminolysis reaction of the ester bond of PET by the primary amine radical of PEG–diamine. The pseudografted PET content increased with the aminolysis time [PEG wt % = 2.1147 × t (h)0.4593]. γSP increased very much, γSd decreased a little, and consequently γS, ISWn, and the work of adhesion of water Wa increased with the increasing PEG content. γFW decreased very much, γFO increased a little, and consequently the difference between adhesion tensions of oily soil and water to the specimen (AFO–AFW) increased as the PEG content increased. The contact angle of oily soil to the specimen θO immersed in water increased and consequently θW and WFO/W decreased. Therefore, the PET fabric treated with PEG–diamine had very good water-wicking, oily soil releasing, and antistatic properties.