Fog and rain water chemistry at Mt. Fuji: A case study during the September 2002 campaign   总被引：2，自引：0，他引：2  

Koichi Watanabe  Yusaku Takebe  Nobuhiro Sode  Yasuhito Igarashi  Hiroshi Takahashi  Yukiko Dokiya 《Atmospheric Research》2006,82(3-4):652

Measurements of fog and rain water chemistry at the summit of Mt. Fuji, the highest peak in Japan, as well as at Tarobo, the ESE slope of Mt. Fuji in September 2002. The pH of fog and rain water sampled at Mt. Fuji varied over a range of 4.0–6.8. Acidic fogs (pH < 5.0) were observed at the summit when the air mass came from the industrial regions on the Asian continent. The ratio of [SO₄²⁻]/[NO₃⁻] in the fog water was lower at Tarobo than at the summit. High concentrations of Na⁺ and Cl⁻ were determined in the rain water sampled at the summit, possibly because of the long-range transport of sea-salt particles raised by a typhoon through the middle troposphere. The vertical transport of sea-salt particles would influence the cloud microphysical properties in the middle troposphere. Significant loss of Mg²⁺ was seen in the rain water at the summit. The concentrations of peroxides in the fog and rain water were relatively large (10–105 μM). The potential capacity for SO₂ oxidation seems to be strong from summer to early autumn at Mt. Fuji. The fog water peroxide concentrations displayed diurnal variability. The peroxide concentrations in the nighttime were significantly higher than those in the daytime.  相似文献   

Stray-Light Effect on Magnetograph Observations     

Chae  Jongchul  Yun  Hong Sik  Sakurai  Takashi  Ichimoto  Kiyoshi 《Solar physics》1998,183(2):229-244

To examine the stray-light effect in magnetograph observations, we have determined the point spread functions of the vector magnetograph mounted on the Japanese Solar Flare Telescope based on two indirect methods, one analyzing the solar limb intensity profile, and the other using the Fourier power spectra of photospheric intensity distributions. Point spread functions consist of two parts: a blurring part which describes seeing and small-spread-angle stray light, and a scattering part which describes large-spread-angle stray light. The FWHM spatial resolution is typically 3.0, and the amount of scattered light is about 15% on clear days. We find that the blurring part is well described by a Moffat function whose Fourier transform is given by an exponential function. Our results indicate that polarization measurements of low-intensity magnetic elements like sunspots may be significantly underestimated due to the large-spread-angle stray light, and polarization measurements of magnetic elements which are smaller than 5–7 appear to be disturbed by small-spread-angle stray light.  相似文献   

Performance of a lithium fluoride bolometer for Tokyo dark matter search experiment     

Wataru Ootani  Makoto Minowa  Takayuki Watanabe  Yutaka Ito  Yasuhiro Kishimoto  Kentaro Miuchi  Yoshizumi Inoue  Youiti Ootuka 《Astroparticle Physics》1998,9(4):325-329

The performance of a 21-g lithium fluoride bolometer is presented. The background spectrum was measured in the surface laboratory. We derive an exclusion plot for the spin-dependent coupled Weakly Interacting Massive Particles (WIMPs) cross section.  相似文献   

Instabilities in the consumption and production for cobalt     

Takashi Nishiyama  Hideki Fujii 《Natural Resources Research》1998,7(4):281-285

Cobalt is obtained mainly as a byproduct of the mining and metallurgical processing of copper and nickel. The amount of minable cobalt has a characteristic supply limit, which is dependent upon demand for copper and nickel. It is considered that cobalt consumption will be affected by the amount mined in the near future, because world demand has been gradually increasing, while the production from copper sulfide ores in Zaire and Zambia, major producing countries, has decreased for political, economical and technological reasons. The world demand for cobalt has surpassed the world mine production, and cobalt sales from the National Defense Stockpile of the United States and exports from Russia and cobalt recovered from stockpiled intermediates contributed to the supply in 1994. It is concluded, from a statistical point of view, that this trend of shortage and high prices for cobalt will continue in the near future.  相似文献   

“Extreme boiling” model for variable salinity of the Hokko low-sulfidation epithermal Au prospect, southwestern Hokkaido, Japan   总被引：1，自引：0，他引：1  

A.-M. Scott  Y. Watanabe 《Mineralium Deposita》1998,33(6):568-578

The Hokko prospect is located in the Minamikayabe area southwestern Hokkaido, Japan, where gold-bearing quartz veins of Pliocene age are exposed at the surface. The alteration mineral assemblage is typical of low-sulfidation epithermal systems, with the quartz veins associated with adularia alteration overprinted on Late Miocene propylitic alteration. Fluid inclusion studies of the vein quartz reveal mean homogenization temperatures of approximately 220 °C, and the co-existence of low-salinity (<2 wt.% NaCl equivalent) and moderate salinity (2 to 12 wt.% NaCl equivalent) fluid inclusions within the same veins. The moderate salinity fluid inclusions (2–12 wt.% NaCl equivalent) typically have relatively low homogenization temperatures between 150° to 200 °C. The results obtained from stable isotope analysis of  δ¹⁸O in quartz vein material showed a gradual decrease in  δ¹⁸O signatures with increasing depth. The majority of the samples have calculated fluid source signatures (δ¹⁸O_H2O) between −8.0 and −10.0‰, but there is a significant change in the composition above 185 m drill depth. The shallower samples in particular show a wide range of oxygen isotope signatures that are associated with the moderate salinity fluid inclusions. We interpret that low-salinity inclusions within the Hokko system represent the composition of the liquid phase of the fluid, before boiling, and that the moderate-salinity inclusions are representative of the residual liquid phase, after extensive non-adiabatic boiling and vapor loss in an open system. This mechanism resulted in the entrapment of fluids with variable salinities at the same time, and in close proximity to each other. This is also reflected in the  δ¹⁸O_H2O values which become more variable and heavier where the moderate-salinity inclusions occur. Deposition of ore minerals within the Hokko vein system also occurred at this time as a result of boiling and gas loss. Received: 30 May 1997 / Accepted: 6 January 1998  相似文献   

Rare-earth and trace elements in the Quaternary volcanic rocks of Hokkaido,Japan     

Yasuyuki Masuda  Susumu Nishimura  Takashi Ikeda  Yoshio Katsui 《Chemical Geology》1975,15(4):251-271

Seven rare-earth elements (La, Ce, Sm, Eu, Tb, Yb, Lu) and Co, Cr, Sc, Ba, Hf and Th have been determined by non-destructive neutron activation analysis on the Quaternary volcanic rocks in Hokkaido, Japan. The trace-element abundances are discussed in terms of the petrological problems, particularly the origin of calc-alkali magma. On the basis of the La/Sm ratio and the contents of K, Ba, Th and La, lateral variations in the contents of trace elements exist across the Kurile and the northern Honshū arcs. The calc-alkali rocks can be classified into three types which correspond to Kuno's three basalt-magma types. There is no essential difference in the rare-earth patterns between the basaltic rocks and the associated calc-alkali rocks in each petrographic province. This suggests that the calcalkali rocks may be derived from the basaltic magmas by fractional crystallization under certain conditions.  相似文献   

Jointing of two tunnel shields using artificial underground freezing     

Tsutomu Takashi  Shiro Kiriyama  Tetsuji Kato 《Engineering Geology》1979,13(1-4):519-529

Freezing was used in the jointing section of two shields (diameter 3.14 m) which ran across at right angles and at 25-m depth under the crossing of main roads for the construction of a 2.4-m diameter sewer tunnel. The object of freezing was to create a frozen barrier to prevent the inflow of water and fine sand into the area to be excavated.

Thirty-five freeze pipes (length about 7 m) were placed from one shield conically in the direction of the flank of another shield with freeze pipes attached to its inside wall. The cooling unit was placed on unoccupied land at about 60 m distant from the jointing section and the freeze pipes were connected with the cooling unit by supply and return pipelines.

The cooling unit had a cooling capacity of 79,000 kcal/h at an evaporation temperature of −27°C and a condensation temperature of +40°C. Freezing was continued for 180 days and the CaCl₂ brine temperature was −25 to −30°C. These works were accomplished without the sinking of shaft and the use of injection, in complete safety with no traffic restriction on the road surface.  相似文献   

Water saturated phase relations of some andesites with application to the estimation of the initial temperature and water pressure at the time of eruption     

Toshimori Sekine  Takashi Katsura  Shigeo Aramaki 《Geochimica et cosmochimica acta》1979,43(8):1367-1376

Near-liquidus phase relations in one-atmosphere dry and water-saturated high pressure conditions were experimentally determined on products of three historic andesitic eruptions. Run conditions ranged from 900 to 1100°C, at pressures up to 1500 bars with fO₂ controlled close to the nickel-nickel oxide (NNO) buffer. In order to represent the compositions of the true liquid parts of the erupting magmas, groundmass portions were mechanically separated from the porphyritic andesites. Such groundmass materials should lie exactly on the liquidus field boundary between the phases precipitating from the magma just prior to eruption under the prevailing P-T condition.All the samples showed a crossing of the plagioclase and orthopyroxene liquidi in the pressure-temperature range from 1 to 800 bar and 950–1090°C. The crossing condition approximates the magmatic condition immediately prior to eruption. In the case of the 1970 eruption of Akita-komagatake, the crossing point is at 150 bar and 1090°C, matching closely the observed explosive gas pressure and the temperature. In both cases of the 1783 eruption of Asama and the 1914–1915 eruption of Sakurajima volcanoes, the crossing point shift from higher water pressure and lower temperature for the earlier erupting magmas to lower pressure and higher temperature for the later magmas. This regularity may be explained by a vertical gradient of the temperature and water content within the magma column prior to eruption.  相似文献   

地闪回击的微秒级辐射场特征及近地面连接过程分析   总被引：14，自引：6，他引：8  

郄秀书  郭昌明 《高原气象》1998,17(1):44-54

利用１μｓ时间分辨率的慢天线电场变化仪在甘肃中川地区雷暴过程中测量得到的大量地闪辐射波形地地闪回击辐射场特征及回击的慢前沿过程进行分析,发现１８次正地闪和８５次负地闪产在周前沿过程上升时间为１９．２μｓ和９．４μｓ,８４次负地闪继后回击的前沿过程为４．３ μｓ。ＹＹ ＵＤＡ Ｏ ３．１μ;  相似文献   

中国内陆高原正极性雷电的观测实验研究   总被引：20，自引：7，他引：13  

刘欣生  郭昌明 《高原气象》1998,17(1):1-9

叙述了１９９７年夏季中日两国科学家在甘肃平凉地区合作进行的有关正极性雷电的综合观测实验情况,包括地布局,所采用的技术手 取得的主要结果。实验中采用人工引发雷电技术并取得了两次成功,其中一次是利用“空中解发”方式,即火箭拖带的细钢丝下端不直接接地,而是通过一段绝缘尼龙线与接地的另一段细钢丝相连。用这种方式可以更真实地再现自然雷电的初始过程。实验中观测到了空中导线两端先导的双向传输现象;电流、电场变化  相似文献