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排序方式: 共有683条查询结果,搜索用时 15 毫秒
151.
The effects of bacterial activity on the degradation of estrone (E1), estradiol (E2), estriol (E3) and ethinylestradiol (EE2) in nitrifying activated sludge (NAS) were studied with different substrates and organic loading rates (OLRs) and low temperature conditions. Heterotroph was shown to have utilized glucose prior to E1 for metabolism. The co-metabolism of ammonia oxidizing bacteria (AOB) dominated the degradation of E1, E2 and EE2 in NAS. The higher the organic loading, the higher the rate of organic matter transformation, with less ammonia oxidation and less degradation of E1, E2 and EE2. The degradation of E3 in NAS was shown to be largely due to heterotroph metabolism. On the basis of the difference of apparent activity between heterotroph and AOB at 4 degrees C, the process of estrogen degradation via the co-metabolism of AOB was able to be identified. 相似文献
152.
153.
Ojima D Chiba T Shima K Hiramatsu H Hosono H Hayashi K 《The Review of scientific instruments》2012,83(2):023903
An atomic oxygen (AO) source has been redesigned to coordinate with a pulsed laser deposition system and used to grow nitrogen-doped TiO(2) films by deposition of TiN and simultaneous irradiation of the substrate with AO. The AO source uses an incandescently heated thin tube of zirconia as an oxygen permeation media to generate pure AO of low kinetic energy. The emission flux is calibrated using a silver-coated quartz crystal microbalance. The thin shape of the probe and transverse emission geometry of this emission device allow the emission area to be positioned close to the substrate surface, enhancing the irradiation flux at the substrate. AO irradiation is crucial for formation of TiO(2) phases via oxidation of the deposited TiN laser plume, and is effective for decrease of the substrate temperature for crystallization of anatase phase to as low as around 200 °C. 相似文献
154.
Hirata K Saitoh Y Chiba A Yamada K Takahashi Y Narumi K 《The Review of scientific instruments》2011,82(3):033101
We report suitable secondary ion (SI) counting for surface-sensitive chemical analysis of organic compounds using time-of-flight (TOF) SI mass spectroscopy, based on considerably higher emission yields of SIs induced by cluster ion impact ionization. A SI counting system for a TOF SI mass spectrometer was developed using a fast digital storage oscilloscope, which allows us to perform various types of analysis as all the signal pulses constituting TOF SI mass spectra can be recorded digitally in the system. Effects of the SI counting strategy on SI mass spectra were investigated for C(8) and C(60) cluster ion impacts on an organically contaminated silicon wafer and on polytetrafluoroethylene targets by comparing TOF SI mass spectra obtained from the same recorded signals with different SI counting procedures. Our results show that the use of a counting system, which can cope with high SI yields, is necessary for quantitative analysis of SI mass spectra obtained under high SI yield per impact conditions, including the case of cluster ion impacts on organic compounds. 相似文献
155.
Ondřej Mašek Nozomu Sonoyama Eiji Ohtsubo Sou Hosokai Chun-Zhu Li Tadatoshi Chiba Jun-ichiro Hayashi 《Fuel Processing Technology》2007
In-situ steam reforming of tar from the rapid pyrolysis of a Victorian brown coal was studied, employing a single-stage drop-tube reactor and a particular type of two-stage reactor, in which the nascent tar underwent steam reforming and thermal cracking in the presence and absence of nascent char particles, respectively. Na was the most abundant inherent metallic species contained in the coal, and a significant proportion of Na (60–80%) was volatilized during the pyrolysis. However, the Na dispersed in the vapor phase seemed to have no significant catalytic effect on the steam reforming. Na, and/or Ca remaining on the surface of char particles were responsible for rapid and extensive steam reforming of the nascent tar into gases, resulting in tar yield decrease by nearly 90%. The presence of steam alone was effective for suppressing soot formation from the tar vapor by approx. 80%, but in the absence of char particles containing metallic species, the addition of steam led to an increase in the yield of poly-nuclear aromatics. 相似文献
156.
Takahiro Chiba Kazuaki Takeda Kazuki Takeda Fumiyuki Adachi 《Wireless Personal Communications》2011,58(3):455-468
Multi-user single-carrier multiple-input multiple-output (MU SC-MIMO) multiplexing can increase the uplink capacity of a cellular system without expanding the signal bandwidth. It is practically important to make clear an extent to which the MU SC-MIMO multiplexing combined with frequency-domain equalization (FDE) and transmit power control (TPC) can increase the uplink capacity in the presence of the co-channel interference (CCI). Since the theoretical analysis is quite difficult, we resort to the computer simulation to investigate the uplink capacity. In this paper, frequency-domain zero-forcing detection (ZFD) and frequency-domain minimum mean square error detection (MMSED) are considered for MU signal detection. It is shown that ZFD and MMSED provide almost the same uplink capacity and that an advantage of fast TPC over slow TPC diminishes. As a result, MU SC-MIMO using computationally efficient ZFD can be used together with slow TPC instead of using MMSED. With 8 receive antennas and slow TPC, MU SC-MIMO multiplexing using ZFD can achieve about 1.5 times higher uplink capacity than SU SC-SIMO diversity. 相似文献
157.
Beamforming experiment with a DBF multibeam antenna in a mobilesatellite environment 总被引:1,自引:0,他引:1
Miura R. Tanaka T. Chiba I. Horie A. Karasawa Y. 《Antennas and Propagation, IEEE Transactions on》1997,45(4):707-714
This paper describes a digital beamforming (DBF) multibeam antenna that incorporates a compact digital signal processor (DSP) engine, and the results of using it in a beamforming experiment receiving a satellite signal in a land-mobile environment. A considerable reduction in the scale of the DSP engine has been achieved by using field programmable gate arrays (FPGAs). To capture a satellite signal arriving from an unknown direction, a two-dimensional (2-D) spatial FFT signal processing provides orthogonal multibeam patterns on the broad side of a planar array antenna. The experimental results demonstrated the features of coarse acquisition and tracking of a signal arrival by selecting the strongest of the beams without assistance from direction finding sensors or microwave phase shifters. The DBF multibeam antenna will provide high-quality communications and increase traffic capacity if it is applied to high-gain mobile antennas or multispot-beam base station antennas in cellular or satellite mobile communications 相似文献
158.
A new dual slot-coupled circular antenna for dual frequency or dual polarisation operation is proposed. By optimising the placement of the two slots, high isolation between two ports is achieved. Experimentally, an isolation of more than 35 dB is obtained at L-band.<> 相似文献
159.
Characterization of DLC films by EELS and electron holography 总被引:1,自引:0,他引:1
Shindo D Musashi T Ikematsu Y Murakami Y Nakamura N Chiba H 《Journal of electron microscopy》2005,54(1):11-17
Thickness measurements of diamond-like carbon (DLC) films by electron energy-loss spectroscopy (EELS) and electron holography are discussed. In order to evaluate the thickness by EELS and electron holography, the mean free path for inelastic scattering and mean inner potential of DLC films were determined precisely, respectively. It is found that both the mean free path for inelastic electron scattering and the mean inner potential are sensitive to the preparation methods, namely the density of DLC films. The present work has demonstrated that thickness measurement by EELS is available to DLC films thicker than 20 nm, while electron holography can be applied to thinner films ( approximately 5 nm). Furthermore, close relations are observed between the density of DLC films and the energy-loss spectra. 相似文献
160.
Tsechpenakis G Mukherjee P Kim MD Chiba A 《IEEE transactions on bio-medical engineering》2012,59(5):1253-1263
Type-specific dendritic arborization patterns dictate synaptic connectivity and are fundamental determinants of neuronal function. We exploit the morphological stereotypy and relative simplicity of the Drosophila nervous system to model the diverse neuronal morphologies of individual motor neurons (MNs) and understand underlying principles of synaptic connectivity in a motor circuit. Our computational approach aims at the reconstruction of the neuron morphology, namely the robust segmentation of the neuron volumes from their surroundings with the simultaneous partitioning into their compartments, namely the soma, axon, and dendrites. We use the idea of cosegmentation, where every image along the z -axis (depth) is segmented using information from "neighboring" depths. We use 3-D Haar-like features to model appearance. Because soma and axon are determined by their distinctive shapes, we define an implicit shape representation of the 2-D segmentation sets to drive cosegmentation and achieve the desired partitioning. We validate our method using image stacks depicting single neurons labeled with green fluorescent protein (GFP) and serially imaged with laser scanning confocal microscopy. 相似文献