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1.
Nano ZnSnO3 powders were prepared by the coprecipitation method, using ZnSO4·7H2O SnCl4·5H2O as the starting material. The ceramic powders were characterized by X ray diffraction and transmission electron microscopy. Pure and noble metal doped ZnSnO3 thick film gas sensors were fabricated by an indirect heating process and the gas sensing properties were tested. The reason for the above improvement was analyzed on a gas sensing mechanism and the basis of morphology observation of these thick film sensors. The results show that the sensitivities of these thick sensors to combustible gases, such as C2H5OH and H2, are greatly improved. Gas sensitivities of thick sensors with doping metallic irons, including Ag+ and Pd2+ to hydrogen gas, are fifteen times greater than that of pure ZnSnO3 thick film sensors. The grain size is inhibited and more gas holes cover the surface by doping metallic irons, the key reason for the improved gas sensing properties. 相似文献
2.
The conductivity of a TiO2 cathode in the FFC process was studied by sintering and electrolyzing experiments. Sintered TiO2 cathode and electrochemical reduction of TiO2 were measured using X ray diffraction. Results show that changing the energy band structure of TiO2 via high temperature sintering can cause electric conduction vacancy. An electric double layer can be formed in molten salt. Ionization of oxygen atoms leads to formation of TiO2 x ionic structures. The ions infiltrate to the electrode in molten salt, increasing the number of conduction ions. The electrolyzing process proceeds smoothly, based on the integrated mechanism of activating the TiO2 cathode. The activated TiO2 cathode can be obtained by forming electric conduction vacancy at high temperature sintering, the TiO2 x ionic structure by electric double layer, and ions infiltrating to the interior of the electrode. 相似文献
3.
Experimental study of recycling strontium chloride from strontium waste residues was conducted with ammonia chloride as the leaching solvent. The effects of the granule diameter of strontium waste residues, the extraction time, the mass ratio between liquid and solid and the n(NH4Cl)/n(Sr) on the conversation ratio was investigated using orthogonal and single factor experiments. The results show that the optimal strontium conversation condition includes strontium waste residues of 0.054 mm in size, a two hour extraction time, a 3.3 mass ratio between liquid and solid, and 3.8 n(NH4Cl)/n(Sr). Under these conditions, the highest strontium conversation ratio reached 96%. The kinetics of the conversion process is fractal. 相似文献
4.
The chromatographic fingerprint of Pinellia ternata was established by high performance liquid chromatography (HPLC) using an Agilent C18 (5 μm, 4.6×250 mm) column; CH3OH∶H2O as elution solvents; an ultraviolet detector at 254 nm; a flow rate of 1.0 mL/min. The guanosine peak was used as the reference and the relative retention value α and the relative area Sr as the parameters for the survey of the chromatographic fingerprint. Nine co possessing peaks were selected as the charaterizing fingerprint peaks to distinguish Pinellia ternata from false Pinellia ternata. The relative retention time of the 9 peaks were 1.00, 1.12, 1.50, 1.56, 1.60, 1.67, 1.71, 1.81 and 1.87, respectively. These peaks can be used to identify the quality of Pinellia ternata. 相似文献
5.
An improved structure of digital matched filter(DMF)is presented. Two same pseudorandom spread spectrum sequences with the length of N are used to spread the same baseband symbol at the transmitter, which is equal to spread the baseband symbol with a spread spectrum sequence with the length of 2N. At the receiver, only a spread spectrum sequence with the length of N is needed to de spread the data, and then cumulates the two correlation peaks and exports to the output. The detection probability(Pd)and the false alarm probability(Pf)are analyzed and simulated. The improved structure of DMF is implemented based on the recursive and folded principle. Experimental results show that, for the same spread gain, the improved structure has the same Pd and Pf as the basic DMF, while saves the hardware resources greatly compared with the recursive and folded structure. 相似文献
6.
FANG Liang PENG Liping YANG Xiaofei HUANG Qiuliu ZHOU Ke WU Fang LIU Gaobin MA Yong 《保鲜与加工》2009,(9):1002-1005
In doped ZnO thin films were prepared on glass substrate by RF magnetron sputtering. The result of XRD and AFM shows that the films are polycrystalline with high c axis orientation. The study of gas sensing reveals that the films are sensitive to NO2 and the best sensibility occurs at 273 ℃; the sensibility is concerned with the concentration of NO2 and the film thickness. The ZnO∶In films are more sensitive to the NO2 gas with higher concentration of NO2 and thinner films have a better sensitivity. Exposed to 2×10-5 NO2 at 273 ℃, the 90nm thick film has a sensibility of 16, indicating that ZnO∶In films can be used to measure NO2 with a low concentration. 相似文献
7.
Based on the strong poly role of phosphate on polymeric ferric sulfate (PFS), with PFS and Na 2HPO 4 as raw materials, a new type of composite flocculant polymeric phosphate ferric sulfate (PPFS) was developed. The structure of PPFS was characterized by IR and SEM, and the mechanism of flocculation was analyzed. The factors affecting phthalic acid esters (PAEs) removal were discussed, including dosage, nPO 43-/nFe3+and alkalization degree. The results indicate that PPFS has good removal effect to PAEs. When the dosage is 70 mg·L-1, nPO 43-/nFe3+ is 0.3 and alkalization degree is 30%, the removal rate of dimethyl phthalate, diethyl phthalate, dibutyl phthalate and bis (2 ethylhexyl) phthalate are 67.93%,84.55%,90.88%,88.69%, respectively. 相似文献
8.
The removal of oxytetracycline (OTC) in water by UV, UV/TiO2, UV/Zeolite, and UV/Composite photocatalyst with different ratio was investigated respectively with a 32W low voltage mercury lamp. The effects of composite photocatalyst concentration, initial OTC concentration and pH value on degradation were also investigated. It was shown that the UV/Composite photocatalyst with 10% TiO2 and 90% Zeolite was an effective one to remove OTC in water. And in a solution with 50 mg/L OTC in ultrapure water the OTC was removed by 99% within 120 min with the help of 300 mg/L composite photocatalyst. The degradation of OTC by UV/Composite photocatalyst was little influenced by its initial concentration, but influenced by its initial pH. In the environment with pH+2~10, the OTC was removed by more than 95% within 120 min with the help of UV/Composite photocatalyst, when the pH is above 10, the removal rate is rapidly decreased. 相似文献
9.
To discuss the optical properties of water body in Xiaojiang river backwater area for the early impounding stage of the Three Gorges Reservoir (TGR), the spatiotemporal variations of visible light attenuation coefficients (Kd) and Secchi Disc transparency (SD) are investigated during the period from January, 2008 to December, 2008. The correlations between Kd and SD, total particulate matters (TPM), dissolved organic carbon (DOC) and chlorophyll-a (Chla) are also analyzed according to the monitoring data. In the study area, there are no significant spatial variations in the mean Kd at five sampling stations, but the seasonal variations are obvious with the highest value of Kd in the winter and the lowest value in the summer. The range of Kd is 0.23~4.82 m-1, and the mean value is (1.03±0.07) m-1. Statistics analysis suggests that there are remarkable correlations between Kd and SD, TPM, TIM as revealed by the coefficient of determination R2=0.779 1, R2 =0.728 5 and R2=0.763 7, respectively. The relationship between Kd and DOC is less significant as shown by the low value of R2=0.128 9. However, the correlation between Kd and Chla is weak which can be seen from the value of R2=0.006. The analysis suggests that total inorganic particulate matters largely influenced the optical properties of water body in Xiaojiang river backwater area. 相似文献
10.
The arrival time of data received by a mobile station in IEEE 802.16e is stochastic. When the arrival rate is low, the shorter initial sleep time (Tmin) and the maximal sleep time (Tmax) will lead to the mobile station being awakened frequently, which increases the average listening times and consumes more energy. On the other hand, when the arrival rate is high, longer Tmin and Tmax lead to longer response times. To address these problems, a novel adaptive energy saving mechanism is proposed. Firstly, Tmin and its corresponding Tmax are initialized. The mumber of Tmax which the mobile station lasted in a sleep mode is denoted as J. The real time Tmin is defined as R(Tmin) when the mobile station is in a sleep mode. R(Tmin) is determined by J which representd the Tmax of the former sleep mode. As a result, Tmin is adjusted adaptively, and the average listening times are reduced. A Markov chain is adopted to analyze the above adaptive energy saving mechanism. The simulation results demonstrate the effectiveness of the proposed energy saving mechanism. 相似文献
11.
A method was developed for nonlinear analysis of laterally loaded long piles in cohesionless soil. It is considered that the modulus of horizontal subgrade reaction is related with groundline pile displacement by an attenuation power function based on the existing methods and it is assumed that both the modulus of horizontal subgrade reaction and the ultimate soil resistance increase linearly with depth . It is also considered that soil in front of the pile may change from elastic state into plastic state as pile displacement increase. Nonlinear differential equations of the fourth order were derived for both states and to solve the equations, the Gleser finite difference approach with iteration and the Reese Matlock approach were developed,respectively of propsed methed. It is validated by the test and numerical field calculation that the results respectively of proposed methed are more accurate than ‘m’method and simpler than ‘p y’method. And the results are in good agreement both when pile displacement is small and large,thus it can be applied to construction in place of ‘p y’ method especially when test parameters are unavailable. 相似文献
12.
Orthogonal experiments were carried out for high grade gray water treated by combinational technique of coagulation sedimentation and constructed wetland. With the orthogonal experiment of coagulation sedimentation pre treatment, it is shown that the regression equations relating to effluent BOD5, cubage loads(Nv), temperature(T) and PAC addition dosage(ρ) is BOD5=2.05Nv-0.41T-0.82ρ+38.9. For the orthogonal experiment of constructed wetland post treatment, it is shown that the regression equations relating to effluent BOD5, cubage loads(NA), and temperature(T) is BOD5=1 190 NA-0.32T+12.2. Based on the two orthogonal regression equations, combined with reclaimed water quantity requirements in different seasons in buildings, an investment optimization model of combinational technique was established. According to the model, the reasonable scale of the reclaimed water treatment systems can be determined and treatment efficacy can be well predicted. 相似文献
13.
A method is proposed to measure the thickness of nano-scale thin film. Based on the differences about mechanical property between the film and the base, a required scratching will be obtained with the proper tool scratching the film directly, which is through the film touching the base and without any effects to the surface of the base. Scanning the scratching area by using atomic force microscope, some data will be obtained and the average thickness of nano-scale thin film can be calculated in the scratching area. The thickness of the TiO2 nano-scale thin film was measured by this method, the experiment result showed that the average thickness of the film is 71.6 nm, which is consistent with the reported result of the reference. This method has high measuring precision, wider application area, more intuitive images, simpler calculation and operation. 相似文献
14.
Not only population densities of phytoplankton but also its community structure can be influenced by nitrite concentration.To investigate this effect,the growth and competition of Microcystis aeruginosa and Scendesmus quadricauda under different nitrite concentrations are studied by using batch cultures,and the competition relation is analyzed by the competition parameters.The results indicate that there is competition between M.aeruginosa and S.quadricauda in present experiment conditions,and S.quadricauda is dominant in competition.Meanwhile,the increase of nitrite concentration can strengthen S.quadricauda dominance,because under high nitrite concentration (20 mg/L,30 mg/L),M.aeruginosa is more damaged and the allelopathy between M.aeruginosa and S.quadricauda is intenser. 相似文献
15.
Both NO and N2O emission in fluidized bed reactor are studied by numerical simulation. The effects of excess air ratio, coal composition and co combustion of coal and biomass are researched. The results show that NO and N2O are the main products of the NOx in the fluidized bed reactor combustion, and the emission of NO and N2O increases with the excess air ratio increasing. The NOx production has strong relationship with coal composition. The nitrogen content of the coal plays an important role in the production of NO and N2O, as well as oxygen to nitrogen mass ratio and hydrogen to nitrogen mass ratio. In the co combustion process of coal and biomass, carboxyl group have remarkable effect on HCN production, which reduces the content of NO and NO2. The co combustion of coal and biomass can reduce the emission of NO and N2O. 相似文献
16.
WANG Wei liang 《保鲜与加工》2010,(3):138-144
The BAF for wastewater treatment loaded with new ceramic fillers was investigwed in comparison with the BAF loaded with biogenic ceramisite agitator.The feasibility and features of the new ceramic fillers had been analyzed by comparing the two fillers and the operational parameters had been analyzed and determined at the same time.It is shown are that when the average influent CODcr is 135.6 mg/L, NH4+-N 42.1 mg/L and TP 0.69 mg/L, the removal efficiencies of The BAF loaded with new ceramic fillers and ceramisite agitator are 81.2%, 99.8%, 68.1% and 80.8%, 99.5%, 66.7% respectively at the condition of the HRT=1.5 h.New ceramic fillers required less water to backwash and had better effect than biogenic ceramisite agitator at the same condition, what is more, the running costs of the BAF loaded with new ceramic fillers were less than that of the BAF loaded with ceramisite agitator. 相似文献
17.
HU Mei-long BAI Chen-guang XU Sheng-ming QIU Gui-bao LV Xue-wei ZHANG Sheng-fu 《保鲜与加工》2011,(5):53-58
Spherical titania (TiO2) with narrow size distribution and nice dispersibility has been obtained by hydrolysis in the mixed solvent of 1-propanol to de-ionized water using microwave as heat source. Parameters like precursor concentration, heating method, microwave power, and pH value have been investigated. The results show that the high quality TiO2 can be synthesized using PVP as surfactant when the volume ratio of 1-propanol to de-ionized water is 1DK〗∶1. The results display that size and size distribution of the particles are affected by heating method, precursor concentration and pH value. However, the effect of microwave power is comparatively less obvious. 相似文献
18.
Ni-Co-P/Si3N4 composite coating on Al alloy is prepared by electroless composite plating in order to improve the minohardness of Al alloy. The influence of electroless plating process parameters on the micro-hardness of Ni-Co-P/Si3N4 coating on a hyper-eutectic Al-Si casting alloy is studied by an orthogonal experiment. The effects of process parameters, such as pH and mole ratio of Co 2+/（Co 2+ +Ni2+）,Si3N4 concentration in electroless plating bath and plating temperature,on the micro-hardness of composite layer are obtained. It is indicated that the hardness of coatings can be increased by increasing pH, plating temperature,Si3N4 concentration and keeping mole ratio of Co2+/（Co 2+ +Ni2+）moderate. Moreover, the influence of heat treatment on the micro-hardness of coatings is also investigated. It is found that the hardness of films increases with the heat treatment temperature rising below 400 ℃ but decreases when temperature is over 400 ℃. 相似文献
19.
To improve the coating stain resistant performance using the photocatalytic activity of TiO2 is a hot research topic in recent years. In the article,hydrophilic TiO2 and hydrophobic TiO2 are prepared by hydrothermal method. The samples are characterized by X-ray diffraction(XRD) and transmission electron microscope(TEM). The results show that both the hydrophilic-TiO2 and hydrophobic-TiO2 are anatase,and the particle size of hydrophilic-TiO2 is 40 nm,while hydrophobic-TiO2 is only 7 nm. Moreover,the samples are employed for super-hydrophilic and super-hydrophobic coatings,respectively. The contact angle measurement is used to characterize the as-synthesized TiO2 coatings. The effect of the water contact angle on the contamination resistance is investigated. It is shown that the synthesized the hydrophilic TiO2 and hydrophobic TiO2 coatings both can remarkably improve the contamination resistance of the paint and the latter exhibited the better performance. 相似文献
20.
We used the variance analysis method to analyze the effects of the proportion of the actual operated load, the pulse on degree of guide baffles, the temperature of cold water of the outlet, and outdoor relative humidity on the coefficient of performance (COP) of centrifugal refrigerating units. When the confidence level is set as 95% and 99%, respectively, the results of single factor variance analysis of the above four parameters show that the test statisticF of the pulse on degree of guide baffles is higher than its critical value F0.01 (r-1,n-r), which establishes that its influence on the COP is quite remarkable. The test statistic F of the proportion of the actual operated load and the outlet temperature of cold water are higher than their own critical value F0.05 (r-1,n-r), which shows that their influence on the COP is remarkable. The test statistic F of outdoor relative humidity is lower than its critical value F0.05 (r-1,n-r), which demonstrates that its influence on the COP is unremarkable. The results of the two factor variance analysis of the cold water outlet temperature and outdoor relative humidity show that the test statistic F of their interaction is higher than its critical value F0.01 (r-1,n-r), which indicates that influence of their interaction on the COP is very remarkable. The actual COP value of centrifugal refrigerating units can increase by 6.885% in average on the condition of the invariable refrigerating capacity after adjustment according to the analytical results. 相似文献