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511.
Modeling gross primary production of temperate deciduous broadleaf forest using satellite images and climate data 总被引:9,自引:0,他引:9
Xiangming Xiao Qingyuan Zhang Shawn Urbanski Steven Wofsy Dennis Ojima 《Remote sensing of environment》2004,91(2):256-270
Net ecosystem exchange (NEE) of CO2 between the atmosphere and forest ecosystems is determined by gross primary production (GPP) of vegetation and ecosystem respiration. CO2 flux measurements at individual CO2 eddy flux sites provide valuable information on the seasonal dynamics of GPP. In this paper, we developed and validated the satellite-based Vegetation Photosynthesis Model (VPM), using site-specific CO2 flux and climate data from a temperate deciduous broadleaf forest at Harvard Forest, Massachusetts, USA. The VPM model is built upon the conceptual partitioning of photosynthetically active vegetation and non-photosynthetic vegetation (NPV) within the leaf and canopy. It estimates GPP, using satellite-derived Enhanced Vegetation Index (EVI), Land Surface Water Index (LSWI), air temperature and photosynthetically active radiation (PAR). Multi-year (1998-2001) data analyses have shown that EVI had a stronger linear relationship with GPP than did the Normalized Difference Vegetation Index (NDVI). Two simulations of the VPM model were conducted, using vegetation indices from the VEGETATION (VGT) sensor onboard the SPOT-4 satellite and the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor onboard the Terra satellite. The predicted GPP values agreed reasonably well with observed GPP of the deciduous broadleaf forest at Harvard Forest, Massachusetts. This study highlighted the biophysical performance of improved vegetation indices in relation to GPP and demonstrated the potential of the VPM model for scaling-up of GPP of deciduous broadleaf forests. 相似文献
512.
Xiang Liu Tsuyoshi Yamada Yuji Yamauchi Yuko Hirohata Tomoaki Hino Nobuaki Noda 《Fusion Engineering and Design》2004,70(4):425-334
Helium irradiation experiments of V–4Ti alloy were conducted in an ECR ion irradiation apparatus by using helium ions with energy of 5 keV. The ion fluence was in the range from 1 × 1017 He/cm2 to 8 × 1017 He/cm2. After the helium ion irradiation, the helium retention was examined by using a technique of thermal desorption spectroscopy (TDS). After the irradiation, the blisters with a size of about 0.1 μm were observed at the surface, and the blister density increased with the ion fluence. Two desorption peaks were observed at approximately 500 and 1200 K in the thermal desorption spectrum. When the ion fluence was low, the retained helium desorbed mainly at the higher temperature regime. As increase of the ion fluence, the desorption at the lower temperature peak increased and the retained amount of helium saturated. The saturated amount was approximately 2.5 × 1017 He/cm2. This value was comparable with those of the other plasma facing materials such as graphite. 相似文献
513.
Taro Shimaoka Hiroyuki Kagi Makoto Natsuisaka Satoshi Adachi Yuko Inatomi 《Microgravity science and technology》2005,16(1-4):104-106
We carried out several analytical studies in order to determine the butanol distribution on a salol-butanol crystal. This work is required for a research using microgravity condition focused upon the in-situ observation with an interferometer of the temperature and concentration field for the organic transparent crystal (salol-butanol). In order to evaluate the concentration field for the liquid phase with an interferometer in case of crystal growth from solution in space, it is significant to determine the distribution of solute (butanol) on starting crystal before sample launching using a non-destructive analytical method. The Micro Raman Spectroscopy (MRS) was choice as the most appropriate analytical method among several analytical methods. We prepared a salol-butanol crystal enclosed into the 1mm thick quartz glass ampoule in order to verify the propriety for MRS. Obtained Raman spectrums for salol, butanol and salolbutanol crystal show that the butanol 2D-distribution on salolbutanol crystal can be determined by MRS. These results also demonstrate that there are no influences of thick glass cell upon measurements and that 3D-measurement is possible. In conclusion, we argue that MRS is the most appropriate method for determination of the 2D- and/or 3D- distribution of solute on the crystal among several non-destructive analytical methods. 相似文献
514.
Sauvarop Bualek Yuko Ikeda Shinzo Kohjiya Orapin Phaovibul Pranee Phinyocheep Krisda Suchiva Kazunori Utani Shinzo Yamashita 《应用聚合物科学杂志》1993,49(5):807-814
Blends of natural rubber (NR) and butadiene rubber (BR) have been studied with or without diblock copolymers of isoprene–butadiene (BIR). It was found that NR/BR blends displayed the optimal properties at about 4 wt % of BIR from the tensile measurements of NR/BR blends. Increase of molecular weight of BIR resulted in the decrease of tensile properties, but had no significant effect on their hardness. Abrasion resistance of rubber blends containing BIR was about 30% higher than that without BIR. The molecular weight of BIR did not show a remarkable effect on the abrasion index. Differential scanning calorimetry and dynamic mechanical analyses of rubber blends suggested a two-phase structure even in the presence of BIR. © 1993 John Wiley & Sons, Inc. 相似文献
515.
The nature of the high work‐hardening rate of nitrogen bearing steels was examined focusing on the stacking fault energy (SFE). The dislocation configuration and the width of dissociated dislocations were evaluated in various kinds of austenitic stainless steels with and without nitrogen, using the weak beam method. Nitrogen addition resulted in changing the dislocation configuration from tangled to planar. Nitrogen was, however, found to increase the SFE rather than decrease as reported previously and the SFE can be formulated as a function of chemical composition, SFE(mJ/m2) = 5.53 ‐ 0.16 (wt%Cr) + 1.40 (wt%Ni) + 17.10 (wt%%N). These results indicate that dislocation planarization by nitrogen addition is inadequately explained in terms of SFE. 相似文献
516.
H Yanagawa Y Nakamura T Ojima M Yashiro S Tanihara I Oki 《Canadian Metallurgical Quarterly》1999,18(1):64-66
Cholangiocarcinoma is the second most common primary tumor of the liver after hepatocellular carcinoma and accounts for 5 to 25% of primary hepatic malignancies. Patients with intrahepatic or peripheral cholangiocarcinoma (ICC) most often present at an advanced stage leading to a poor prognosis. A review of the literature has produced only 10 patients who have survived over five years. We review the case of a young woman with a large cholangiocarcinoma, who has been disease free for eight years. The patient was treated with a right hepatic lobectomy, and received 4 cycles of 5-fluorouracil and levamisole postoperatively. Known factors associated with longer survival in patients with ICC include lack of evidence of local invasion (i.e. capsular, lymphatic, or vascular), negative margins, mucoblia, and well differentiation of the tumor, as well as the absence of lymph node metastases. Our patient had negative margins and lymph nodes, and showed no local invasion. However, no mucobilia was noted, and the tumor was only moderately differentiated. Young age has never been associated with increased survival. ICC remains a relatively uncommon tumor with an insidious onset and late presentation contributing to poor survival. Surgical resection remains the only therapeutic option. Since few patients are potentially resectable at the time of presentation, efforts at early diagnosis and options for adjuvant therapy are imperative. 相似文献
517.
The paper is introducing an economic method (interindustry relations analysis) into studies of autopoietic systems and shows its application to scientometrics, which can also be regarded as the analysis of autopoietic systems. The merit of the application is discussed, and the outline of the proof of a related theorem is suggested in the appendix. 相似文献
518.
Effect of network-chain density (ν) on the strain-induced crystallization of peroxide-crosslinked natural rubber was studied by fast time-resolved synchrotron wide-angle X-ray diffraction. It was observed that the elongation ratio at the onset of strain-induced crystallization (αc) became smaller with the increase of ν. The difference of the entropy between the undeformed and deformed states at each αc was nearly equal in spite of the variation of ν. The calculated melting temperature at αc of the samples was also almost the same regardless of their ν. These observations mean that the strain-induced crystallization occurred when the deformation brought about a definite entropic state for peroxide-crosslinked natural rubber. They agreed with the prediction by Flory and were consistent with the classical theory of rubber elasticity. 相似文献
519.
Self-assembled fluorinated oligomeric aggregates formed by fluoroalkyl end-capped N-(1,1-dimethyl-3-oxobutyl)acrylamide oligomers, N,N-dimethylacrylamide oligomers, and acrylic acid oligomers in methanol could recognize selectively fluoresceins as guest molecules
to form a new class of fluorinated aggregates/fluoresceins nanocomposites. These fluorinated fluoresceins nanocomposites were
found to exhibit an extraordinarily enhanced light absorption (λmax: ca. 440 nm) compared to that (λmaxs: 452 and 480 nm) of the parent fluorescein in the absence of fluorinated aggregates. On the other hand, fluoroalkyl end-capped
2-carboxyethyl acrylate oligomers, which possess no aggregate characteristic in methanol solutions, could not afford such
an enhanced light absorption peak under similar conditions. Not only fluorescein but also fluorescein derivatives such fluoresceinamine,
carboxyfluorescein, and fluorescein isothiocyanate afforded similar enhanced narrow absorption peaks under similar conditions.
Naphthofluorescein was also encapsulated into these fluorinated oligomeric aggregate cores to afford fluorinated aggregates/naphthofluorescein
composites, and these fluorinated naphthofluorescein composites afforded an extremely enhanced narrow absorption peak around
520 nm. 相似文献
520.