An improved numerical approach in surrounding rock incorporating rockbolt effectiveness and seepage force     

Jinfeng Zou  Kaifu Chen  Qiujing Pan 《Acta Geotechnica》2018,13(3):707-727

The solutions of stress and displacement of a circular opening excavated in brittle and strain-softening rock mass incorporating rockbolts effectiveness and seepage force are presented in this study. The evolution equation is reconstructed for the strength parameters that incorporate these factors. Based on the evolution equation, an improved numerical method and stepwise procedure are presented which are compatible with the Mohr–Coulomb (M–C) and the generalized Hoek–Brown (H–B) failure criteria, respectively. Then given three interaction mechanisms between rockbolts and surrounding rock, solutions for stress and displacement are proposed in line with the improved numerical method and numerical stepwise procedure. The proposed approach can be reduced to Fahimifar and Soroush’s (Tunn Undergr Space Technol 20:333–343, 2005) solutions for special cases. The proposed method was validated by field monitoring data and FLAC results of Yanzidong tunnel. Examples under the M–C and generalized H–B failure criteria for rock mass are generated through MATLAB programming. Moreover, parametric studies are conducted to highlight the influence of rockbolts effectiveness in combination with seepage force on the stress and displacement of very good, average, and very poor surrounding rock. Results show that in this case, stress confinement is higher and tunnel convergences are lower than the corresponding stresses and displacements obtained in non-reinforced tunnels. Displacement and plastic radius are also higher than those without considering seepage force.  相似文献   

Effects of pH and temperature on dimerization rate of glycine: Evaluation of favorable environmental conditions for chemical evolution of life     

Kasumi Sakata  Norio Kitadai 《Geochimica et cosmochimica acta》2010,74(23):6841-6851

To evaluate favorable environmental conditions for the chemical evolution of life, we studied the effects of pH and temperature on the dimerization rate of glycine (Gly: NH₂-CH₂-COOH), one of the simplest amino acids. Gly dimerizes to form glycylglycine (GlyGly), and GlyGly further reacts to form diketopiperazine (DKP). Gly solutions with pH ranging from 3.1 to 10.9 were heated for 1-14 days at 140 °C, and changes in concentrations of Gly, GlyGly, and DKP were evaluated. At pH 9.8, the experiments were conducted at 120, 140, 160, and 180 °C. The dimerization rate of Gly was nearly constant at pH 3-7 and increased with increasing pH from 7 to 9.8 and then decreased with further increases in pH. To elucidate the reason for this pH dependency, we evaluated the role of the three dissociation states of Gly (cationic state: Gly⁺, zwitterionic state: Gly^±, and anionic state: Gly⁻). For pH >6, the dominant forms are Gly^± and Gly⁻, and the molar fraction of Gly^± decreases and that of Gly⁻ increases with increasing pH. The dimerization rate was determined for each dissociation state. The reaction between Gly^± and Gly⁻ was found to be the fastest; the rate constant of the reaction between Gly^± and Gly⁻ was 10 times the size of that between Gly⁻ and Gly⁻ and 98 times that between Gly^± and Gly^±. The dimerization rate became greatest at pH 9.8 because the molar fractions of Gly^± and Gly⁻ are approximately equal at this pH. The dimerization rate increased with temperature, and an activation energy of 88 kJ mol⁻¹ was obtained. Based on these results and previous reports on the stability of amino acids under hydrothermal conditions, we determined that Gly dimerizes most efficiently under alkaline pH (∼9.8) at about 150 °C.  相似文献   

Radio astronomy and very large telescopes     

Norio Kaifu 《Astrophysics and Space Science》1989,160(1-2):27-29

The current achievements of the observational abilities of radio astronomy is briefly reviewed putting emphasis on the imaging capability. The new projects in radio astronomy are discussed in connection with the new generation of optical/IR telescope projects.Paper presented at the Symposium on the JNLT and Related Engineering Developments, Tokyo, November 29–December 1988.  相似文献   

A new interstellar polyatomic molecule: detection of propynal in the cold cloud TMC-1     

Irvine WM  Brown RD  Cragg DM  Friberg P  Godfrey PD  Kaifu N  Matthews HE  Ohishi M  Suzuki H  Takeo H 《The Astrophysical journal》1988,335(2):L89-L93

We report the detection of the acetylene derivative propynal (HC triple bond CCHO) in the cold cloud TMC-1, with an abundance that is very close to that for the related species tricarbon monoxide (C3O). Propadienone, an isomer of propynal with the formula H2C=C=C=O, was not detected and is hence less abundant than either C3O or HC2CHO.  相似文献   

Behaviour of proteinaceous substances in the estuary of the Tama River     

Norio Ogura  Yoshiharu Tanaka  Jun-ichi Itoh  Katsufumi Takahashi 《Journal of Oceanography》1984,40(3):184-191

Behaviour of dissolved and particulate proteinaceous substances in the estuary of the Tama River was investigated through field observations and laboratory experiments. Concentrations of dissolved proteinaceous substances in estuarine water were determined at eight stations between the mouth of the Tama River (TA-15) and a point 16km upstream (TA-8), using the colorimetric method of Lowryet al. (1951) that employs Folin phenol reagent. The results were expressed in terms of Folin phenol active substances (FPAS). It was found that FPAS decreased with increasing salinity and that the proportion of high molecular weight FPAS (molecular weight greater than 100,000) decreased rapidly in the estuary.The shapes, sizes and numbers of amorphous particulate substances stained by Amido Black 10B, called Amido Black active substances (ABAS), were determined under a microscope. The numbers of ABAS retained on Millipore HA filters (mean diameter: 10–80µm) amounted to 450ml^–1 in the estuarine water about 6km from the mouth of the estuary (Station TA-12M). Some of these aggregates are considered to be producedin situ by flocculation of high molecular weight FPAS during estuarine mixing. ABAS were also produced in experiments by mixing filtered river water with sea water.  相似文献   

MIS11–19 pollen stratigraphy from the 250-m Choshi core, northeast Boso Peninsula, central Japan: Implications for the early/mid-Brunhes (400–780 ka) climate signals     

Masaaki  Okuda  Hiroomi  Nakazato  Norio  Miyoshi  Takeshi  Nakagawa  Hiroko  Okazaki  Saneatsu  Saito  Asahiko  Taira 《Island Arc》2006,15(3):338-354

Abstract   The 250-m Choshi core (CHOSHI-1), drilled from hemipelagic muds of the Inubo Group, has been physically, geochemically and tephrochronologically analyzed back to 1 Ma. We provide pollen results for the 19–169 m section of the core (400–780 ka) bracketed by the marker tephra Ty1 (equivalent to J4) and the Brunhes–Matuyama paleomagnetic boundary. The results show good agreement with the corresponding oxygen isotope (δ¹⁸O) profile, with high δ¹⁸O intervals dominated by boreal conifers Picea , Abies , Pinus (subgen. Haploxylon ) and Tsuga ( diversifolia ), whereas low δ¹⁸O intervals are dominated by temperate conifers Cryptomeria , Taxaceae-Cephalotaxaceae-Cupressaceae and Sciadopitys . In order to confirm pollen-climate relations for the relevant taxa, a modern surface pollen dataset for the Japanese archipelago was consulted. In this analysis, the ratios of Cryptomeria / Picea and temperate/boreal conifers serve as proxies for the 100-kyr glacial/interglacial cycle during the Middle Pleistocene. Distinct signals for marine isotope stages (MIS) 11, 12, 13–15, 16, 17 and 18–19 are recognized in accordance with the tephrochronology and δ¹⁸O of the same core. Application of the criteria to an independent pollen record from Lake Biwa provides an integrated pollen stratigraphy for mid-latitude Japan during the past 800 ky. Some degree of uncertainty remains in the chronology of the MIS13–15 interval, relating to the uncertainty in the eruption age of widespread tephra Ks11.  相似文献   

High Ash Content in Net-Plankton Samples from Shallow Coastal Water: Possible Source of Error in Dry Weight Measurement of Zooplankton Biomass   总被引：2，自引：0，他引：2  

Norio Nagao  Tatsuki Toda  Kazutaka Takahashi  Koji Hamasaki  Tomohiko Kikuchi  Satoru Taguchi 《Journal of Oceanography》2001,57(1):105-107

Annual examination of net-plankton biomass in dry weight, ash-free dry weight, organic carbon, and nitrogen weight at the Manazuru harbor, central Japan revealed that net-plankton samples from shallow coastal water contained considerable amount of ash (53±13% of dry weight) which would be caused by contamination of inorganic materials from re-suspendion of sediments, terrestrial runoff and chain-forming diatoms. Therefore, in coastal water, dry weight is inadequate fro determination of zooplankton biomass in volving the possibility of over-estimation. Practical estimation of net-plankton biomass in shallow coastal waters, ash-free dry weight, organic carbon, and/or nitrogen are more adequate.  相似文献   

Physical factors influencing immature-fish communities in the surf zones of sandy beaches in northwestern Kyushu Island,Japan     

Ryutei Inui  Takashi Nishida  Norio Onikura  Katsuhisa Eguchi  Motoyoshi Kawagishi  Masaya Nakatani  Shin Oikawa 《Estuarine, Coastal and Shelf Science》2010,86(3):467-476

We aim to understand the relationships between physical conditions and characteristics of the immature-fish community in surf zones of sandy beaches. Therefore, we obtained fish samples between March 2007 and February 2008 and analyzed certain physical conditions in the surf zones of 21 sandy beaches on the coastline of the northwestern Kyushu Island, Japan. We collected a total of 83 species and 6458 immature individuals. In a BIO-ENV analysis, the highest correlation was observed between fish assemblage and S20 (i.e., the slope from the shoreline to the sites where the depth was 20 m) and current velocity (CV) values. Stepwise multiple linear regression analyses revealed that the number of species and individuals decrease with an increase in the S20 and CV values. These results show that species richness and the abundance of immature-fish increase under shelving and calm conditions. Thus, immature-fish assemblages are strongly influenced by the prevailing physical conditions. Moreover, in six of the 10 dominant species, a negative correlation was observed between CV and abundance. On the other hand, S20 was found to be the explanatory variable only in the case of the most dominant species, i.e., Gymnogobius breunigii. Furthermore, a positive correlation was observed between S1 (i.e., the slope from the shoreline to the sites where the depth was 1.0 m at the mean tidal level) and median particle size (i.e., MPS of the sediments) and the abundances of Sillago japonica and Favonigobius gymnauchen, respectively, and a negative correlation with salinity, in the case of Acanthogobius lactipes. We conclude that the characteristics of the fish community in surf zones on sandy beaches are determined by not only the shelving and calm conditions, which influence fish assemblages and abundances, but also the habitat diversity, which influences the diversity of fish species.  相似文献   

基于格网数据的洪水灾害风险评估方法——以日本新川洪灾为例   总被引：13，自引：1，他引：12  

张超万庆  张继权NorioOkada 励惠国 《地球信息科学学报》2003,5(4):69-73

本文对日本格网统计数据的历史、体系以及结构进行了介绍 ,并应用地理信息技术给出了各级格网的自动生成方法。同时以 2 0 0 0年日本新川洪水灾害为案例 ,建立了二维洪水演进水动力学模型 ,并采用地理信息系统与水动力学模型结合的方法对新川破堤洪水泛滥进行了模拟 ,同时对洪泛区灾害损失进行了评估 ,得到的结果为进一步评估洪水灾害风险以及确定合理的洪灾保险费率奠定了基础 ,对于格网统计数据在城市规划以及城市减灾等领域的应用也有一定的借鉴意义。  相似文献   

Evaluation of the resistance of coastal Pinus thunbergii Parlat. forests to the tsunami fluid force in Japan     

Torita  Hiroyuki  Tanaka  Norio 《Natural Hazards》2019,96(3):1141-1152

Natural Hazards - Coastal forests can protect coastal areas from the effects of tsunamis. However, the coastal forests of Tohoku were destroyed by the Great East Japan Tsunami, which was triggered...  相似文献