Showing papers by "Yonsei University published in 1982"

Zinc-lead skarns of the Yeonhwa-Ulchin District, South Korea

Abstract: The Yeonhwa I, Yeonhwa II, and Ulchin mines, producing 13.5 million metric tons of ore in the period 1962 to 1981, account for 80 percent of South Korea's Zn and Pb production. These skarn deposits occur in basal Cambrian limestone (locally dolomitic) overlying slate, quartzite, and Precambrian granitic basement, and they are the result of hydrothermal activity associated with felsic calc-alkaline plutonism of Late Cretaceous to early Tertiary age.Skarn at Yeonhwa I consists of pipes of pyroxene (+ or - garnet) at depth branching to veins of rhodocrosite-pyrite near the surface in an area of sparse quartz-porphyry dikes. In contrast, skarns at Yeonhwa II and Ulchin display higher garnet/pyroxene ratios and occur as stratabound lenses and irregular masses at or near contacts with larger bodies of quartz monzonite. Exoskarns are zoned in the sequence garnet-pyroxene-(pyroxenoid)-marble relative to slate-limestone contacts or fissures in limestone. The lack of zoning relative to igneous contacts and the presence of porphyry-limestone contacts without skarn indicate that skarn-forming fluids did not originate from magma at the present level of exposure.Electron microprobe analyses reveal that calc-silicates are notably enriched in Mn and Fe. Garnets are intermediate grandite-andradite with 1 to 5 mole percent spessartine. Calcic rhodonite is characteristic of endoskarns and garnet zones, whereas a more calcic pyroxenoid, manganoan bustamite, occurs in pyroxene skarn. Pyroxenes are manganoan salite-ferrosalite; average Fe/Mn ratio (and mole % hedenbergite) in pyroxene decreases from 5.7 (65%) at Ulchin, to 3.5 (59%) at Yeonhwa II, to 1.6 (30%) at Yeonhwa I. This ratio also decreases with distance from garnet zones and correlates with an increase in Mg, suggesting a progressive depletion of Fe in solution due to precipitation of iron-rich garnet near channelways, and a progressive enrichment in Mg in the fluid as it approached equilibrium with dolomitic wall rocks. Based on this and the geologic setting, Ulchin is the most proximal and Yeonhwa II the most distal skarn in terms of distance from their sources of fluids.Pyrrhotite, accompanied by sphalerite, lesser galena, and minor chalcopyrite, are concentrated in pyroxene zones variably altered to chlorite, Mn-rich clays, calcite, quartz, and fluorite. Pyroxene compositions indicate that the maximum oxidation-sulfidation state that could have been imposed on the ore fluid by early skarn was located near the pyrrhotite-pyrite-magnetite buffer. Only the hedenbergitic skarn at Ulchin lay below this buffer and could have controlled the precipitation of pyrrhotite rather than pyrite. Ulchin also contains the district's highest grades of Pb + Zn in skarn, suggesting that reduction of aqueous sulfate by ferrous iron was an important factor in ore deposition. Later ore fluids, and fluids that reached beyond skarn in the most distal deposit, envolved to higher sulfidation states, as demonstrated by pyrite-rhodochrosite veins that cut skarn and pyrrhotite ore, and by the near-surface pyrite-sphalerite-galena-rhodocrosite veins in limestone overlying skarn pipes at Yeonhwa I.

The cluster expansion for classical and quantum lattice systems

Abstract: We develop a high-temperature expansion for general lattice systems which can be applied to classical as well as quantum systems. Applying the expansion we prove analyticity of correlation functions, uniqueness of equilibrium states, and cluster properties for classical and quantum lattice systems in the high-temperature region.

Sperm Storage in the Oviduct of the Japanese Greater Horseshoe Bat, Rhinolophus ferrumequinum nippon

Abstract: In the Japanese greater horseshoe bat, Kizi~~hph~~~ fcrruwzequim~~ nippm, copu la t ion took place in midor late October and ovulation was induced early in April. The principal site of sperm storage was the caudal isthmus of the oviduct, lined with non-ciliated cpithelium, although moderate or small numbers of spermatozoa were found a l so in the in t ramura l pa r t o f the u te ro tuba l junc t ion . The in tac t sper matozoa in contact with the microvilli of epithelial cells in folds in the storage sites appeared normal, while some degenerated spermatozoa were eliminated by extensive epithelial engulfment throughout the period of storage; leucocytic phagocytosis rarely occurred and was confined to the period just before or after ovulation.

A Case Of Human Thelaziasis In Korea

Abstract: The 15th case of human thelaziasis is reported from Korea. The patient was a 15-year-old girl from Seoul. Both of the worms which were removed from her eye were female and were identified by the number of transverse cuticular striations (281, 172 and 162/mm in the oesophageal, middle and posterior portions, respectively), as Thelazia callipaeda. The patient owned a pet dog ADDITIONAL ABSTRACT: The 15-year-old patient had herself removed a worm from one eye. Two worms were identified morphologically as Thelazia callipaeda. The source of infection was uncertain, but the patient was known to have close contact with a dog. The authors refer to 14 previously reported cases of thelaziasis in Korea.

Analysis of13C(γ,π+)13Bg.s. and13C(e,é)13C* (15.11 MeV)

Abstract: The DWIA calculation of the differential cross section for photoproduction of π+ from13C was carried out with the photon multipole expansion. It is shown that the Cohen-Kurath wave function can reproduce the data quite well. We also calculated the ratio of theM1 transition to theE2 transition to be 1.9. The transverse form factor for13C(e, e)13C* was evaluated consistently with the same wave function as used forl3C(γ, π+)13B.

On the motion of a particle with the shadow of vacuum fluctuation

Abstract: From the concept that effects of the vacuum fluctuation cannot completely be removed from the motion of a microscopic particle, we derive a restriction imposed on the energy-momentum of the microscopic particle. As an application, the electron self-energy duo to the electromagnetic interaction was calculated. The result is δm 0 = 0.18m 0, wherem 0 is the electron bare mass containing effects of fluctuation.

Cutaneous leishmaniasis in Korea: a case report with electron microscopic studies.

Abstract: Cutaneous leishmaniasis developed in a 41-year-old Korean man who returned from the Middle East. Light microscopy showed the lesion consisted of a heavy, chronic ill-defined granulomatous inflammation involving the entire thickness of the dermis. Numerous Leishman bodies were seen extracellulary and histiocytes also contained many Leishman bodies. Electronmicroscope studies revealed organisms with a relatively thick pellicle, a complete intracellular flagellum, a distinct kinetoplast, Golgi apparatus, many free ribosomes, and partial degenerative changes.

Lorentz transformation in indeterministic space-time

Abstract: A generalized Lorentz transformation is derived on the basis of statistical characters of observable quantities. Fluctuation of the space-time is of an order of 10-27, with which all particles are fluctuating. It is suggested that the restless motion of photons may be due to the fluctuation. The energy of a single photon is kept finite in the framework of the present theory. The fundamental length is shown to be Lorentz invariant in our scheme.

Anti‐Hegemonism and US‐PRC‐Japan security cooperation

Abstract: (1982). Anti‐Hegemonism and US‐PRC‐Japan security cooperation. Journal of East and West Studies: Vol. 11, No. 2, pp. 21-34.