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41.
42.
住宅区内的小尺度休憩空间 ,易于为居民把握并建立有效控制的空间 ,与居民日常活动有着密切的关系 .结合大量珠江三角洲商品住宅区的实例 ,着重探讨了住宅区室外、架空层、室内等三类小尺度公共休憩空间的设计和营造 相似文献
43.
Bioretention is a novel stormwater best-management practice that uses a mixture of soil/sand/mulch as adsorptive filtration media that can capture both urban particulates and dissolved pollutants while promoting infiltration. This study conducted a series of laboratory column experiments and field observations, which showed that: (1) bioretention media stratification occurs with runoff percolation due to particulate deposition; (2) bioretention filter media are clogging limited, instead of breakthrough limited; and (3) both depth filtration and cake filtration significantly contribute to urban particle capture. Because of the fine size of bioretention media, incoming suspended solids cannot significantly penetrate below 5–10?cm of the media in the column tests and approximately 20?cm in the monitored field facility. Bioretention filters under intermittent flow conditions exhibited higher solids loading capacity (in kg/m2) before clogging than under continuous flow conditions. The clay components in incoming total suspended solids assume critical responsibility for bioretention media clogging. The media resistance due to solids deposition was estimated through Darcy’s law. The hydraulic conductivity of two media types decreased from 54±23 and 72±46?cm/h to less than 10?cm/h due to particle capture. Experimental results suggest that a 20-cm media depth is sufficient for bioretention design and maintenance procedures (media replacement) for runoff particle capture. 相似文献
44.
Glass doped TiO2 (GTO) thin films were deposited by radio frequency (RF) magnetron sputter at room temperature and annealed in a reductive atmosphere containing 90 % N2 and 10 % H2. Highly dense TiO2 ceramic mixed with glass consisting of multi-metal oxides (as a sintering aid) was used as the sputtering target. This sintering aid allows low temperature densification of TiO2 target through a liquid phase wetting mechanism, and also works as a doping resource. XRD and FESEM were carried out to characterize the microstructure of the GTO films and the results reveal that the doping of multi-metal ions enhances the crystallization and increases the grain size of TiO2 films. TEM analysis also showed that these metal ions were dissolved into TiO2 lattices. The electrical and optical properties of TiO2 thin films at different glass concentrations were evaluated and compared to the films merely doped with MoO3. The electrical resistivity of the GTO films reaches 9.1 × 10–4 Ω·cm at 2 wt% glass doping, corresponding to a carrier density of 8.9 x 1020 cm-3 and a mobility of 7.1 cm2/Vs. Meanwhile, the electrical resistivity of the TiO2 film doped with glass was found to be lower than that of MoO3-doped film. This was mainly attributed to the increase in carrier concentration by double doping effect of glass. The optical band gap of the GTO films ranged from 3.34 to 3.42 eV, which is greater than that of the un-doped TiO2 film. This blue shift of approximately 0.18 eV was due to the Burstein-Moss effect. 相似文献
45.
Summary
Radical polymerization of the methacryloyl isocyanate containing 1-adamantanol (Ad-MAI) with AIBN in different solvents at
60°C was investigated. It is observed that polymerization is slower in polar solvents than in nonpolar ones. The rate of polymerization
for Ad-MAI was found to be slower than those of Adph-MAI and MMA both in photopolymerization and in thermal polymerization.
Copolymerization of Ad-MAI (M1) with styrene (M2) in benzene was studied at 60°C. The monomer reactivity ratio was calculated to be r1=1.53 and r2=0.76 according to the method of Fineman-Ross. The prominent glass transition temperature for poly(Ad-MAI) was observed at
142°C from global TSC spectrum.
Received: 20 November 1998/Revised version: 16 February 1999/Accepted: 25 February 1999 相似文献
46.
Chen HJ Huang TH Chang CS Chen LS Horng JH Wang YH Houng MP 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2006,53(11):2183-2187
In this paper, we present an effective technique to enhance stopband bandwidth for a bandpass filter by using an asymmetric, cross-shape defected ground structure (CSDGS). A single CSDGS can provide a higher attenuation rate near passband and broader stopband bandwidth. Moreover, with the asymmetric CSDGS, two different resonant frequencies can be excited and controlled independently, resulting in synthesizing a passband. The synthesized bandpass filter can be modeled by parallel LC resonant circuits in connection with T-networks. The bandwidth and insertion loss of this bandpass filter at 4.2 GHz is 28.6% and -1.44 dB, respectively, and 20 dB rejection in the stopband is up to four times the central frequency. All the synthesized bandpass filters have been measured and are in good agreement with simulated results. 相似文献
47.
Min-Chien Hsiao Ming-Yu Yen Shuo-Jen Lee Chih-Hung Hung Xiao-Feng Xie 《Journal of power sources》2010,195(2):509-2961
This study prepares novel metal mesh hybrid polymer composite bipolar plates for proton exchange membrane fuel cells (PEMFCs) via inserting a copper or aluminum mesh in polymer composites. The composition of polymer composites consists of 70 wt% graphite powder and 0-2 wt% modified multi-walled carbon nanotubes (m-MWCNTs). Results indicate that the in-plane electrical conductivity of m-MWCNTs/polymer composite bipolar plates increased from 156 S cm−1 (0 wt% MWCNT) to 643 S cm−1 (with 1 wt% MWCNT) (D.O.E. target >100 S cm−1). The bulk thermal conductivities of the copper and aluminum mesh hybrid polymer composite bipolar plates (abbreviated to Cu-HPBP and Al-HPBP) increase from 27.2 W m−1 K−1 to 30.0 W m−1 K−1 and 30.4 W m−1 K−1, respectively. The through-plane conductivities decrease from 37.8 S cm−1 to 36.7 S cm−1 for Cu-HPBP and 22.9 S cm−1 for Al-HPBP. Furthermore, the current and power densities of a single fuel cell using copper or aluminum mesh hybrid polymer composite bipolar plates are more stable than that of using neat polymer composite bipolar plates, especially in the ohmic overpotential region of the polarization curves of single fuel cell tests. The overall performance confirms that the metal mesh hybrid polymer composite bipolar plates prepared in this study are promising for PEMFC application. 相似文献
48.
Sui-Ying Hsu Chih-Hung Tsai Chun-Yang Lu Yu-Tang Tsai Tsung-Wei Huang Yuan-Hsuan Jhang Yan-Fang Chen Chung-Chih Wu Yen-Shan Chen 《Organic Electronics》2012,13(5):856-863
We report an effective way to produce nanoporous Pt counter electrodes of dye-sensitized solar cells by the glancing-angle deposition (GLAD) technique. By controlling the orientation of the substrate relative to the incident Pt vapor flux during the deposition, nanoporous films composed of inclined nm-scale columns were produced through the self-shadowing effect. Pt counter electrodes having varied nanoporous structures were characterized for their morphological and electrochemical properties, and were subjected to device studies to establish the correlation with DSSC characteristics/performances. The results suggest that the nanoporous GLAD Pt electrodes can effectively enhance active surface areas, the catalytic ability and charge exchange at the Pt/electrolyte interface of a DSSC. As a result, the quantum efficiency, short-circuit current, and power conversion efficiency of the DSSC can be enhanced by up to 12–13% with using the nanoporous GLAD Pt counter electrodes. 相似文献
49.
The piezoelectric, phase structure and ferroelectric properties of lead-free Na0.5K0.5Nb1−xSbxO3 piezoelectric ceramics were systematically investigated. (Na0.5K0.5)Nb1−xSbxO3 ceramics were synthesized using the conventional solid-state reaction method. The effect of B-site Sb5+ substitution for Nb5+ on the structural characteristics and piezoelectric properties of samples was determined. According to XRD patterns, the phase gradually changes from tetragonal to orthorhombic with increasing Sb content. At x = 0.03, the tetragonal and orthorhombic phases coexist and relatively high piezoelectric properties were obtained. The relatively high Qm value obtained after substitution with Sb5+ ions might be due to the increased electronegativity and decreased ionic radius at the morphotropic phase boundary (MPB) at x = 0.03. However, the Qm value decreases with further Sb addition. Relatively high piezoelectric properties at x = 0.03 of kp = 0.42, kt = 0.48, ?r = 446, Qm = 143, tan δ = 2.3%, and density = 4.31 g/cm3, d33 = 123 pC/N, were obtained. 相似文献
50.
Gu-Jiun Lin Shing-Hwa Huang Shyi-Jou Chen Chih-Hung Wang Deh-Ming Chang Huey-Kang Sytwu 《International journal of molecular sciences》2013,14(6):11742-11766
Melatonin is the major secretory product of the pineal gland during the night and has multiple activities including the regulation of circadian and seasonal rhythms, and antioxidant and anti-inflammatory effects. It also possesses the ability to modulate immune responses by regulation of the T helper 1/2 balance and cytokine production. Autoimmune diseases, which result from the activation of immune cells by autoantigens released from normal tissues, affect around 5% of the population. Activation of autoantigen-specific immune cells leads to subsequent damage of target tissues by these activated cells. Melatonin therapy has been investigated in several animal models of autoimmune disease, where it has a beneficial effect in a number of models excepting rheumatoid arthritis, and has been evaluated in clinical autoimmune diseases including rheumatoid arthritis and ulcerative colitis. This review summarizes and highlights the role and the modulatory effects of melatonin in several inflammatory autoimmune diseases including multiple sclerosis, systemic lupus erythematosus, rheumatoid arthritis, type 1 diabetes mellitus, and inflammatory bowel disease. 相似文献