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This study mainly reports on the preparation of Sn-imidazolates (Sn(Im)n) supported on boron and nitrogen-doped activated carbon (AC), which proved to be highly active catalysts for the acetylene h...

In the Fizeau imaging interferometer testbed we recently built, the optical path difference (OPD; i.e., piston error) among three sub-telescopes should be corrected for phased imaging to enhance the spatial resolution. This study presents the detection of the OPD via a dispersed fringe sensor (DFS) method and its closed-loop control. The retrieval of the OPD from a dispersed fringe map is a fast-Fourier-transform-based DFS method, which indicates in theory that the OPD has a linear relationship with the displacement of the secondary peaks in the Fourier spectrum of the dispersed fringe map. Then the design and alignment of the OPD detection module are presented, as well as the OPD compensation module with a two-level motion stage. A unique benefit of the fast-Fourier-transform-based DFS is high time efficiency for closed-loop control; for a window of 32 × 128 p i x e l s , a 932 Hz computation rate was achieved by dedicated electrical hardware, which is significant for the distributed satellite formation-flying platform. The experiments validated (1) that the detection range of the DFS is more than ± 160 µ m , (2) that the OPD has a fine-line relationship with the secondary peak displacement, (3) the feasibility of the DFS method used for closed-loop control, and (4) that an OPD control precision of 0.0593 µm RMS is achieved.

Organotin-based catalysts prepared by a facile and green synthesis route were used in the acetylene hydrochlorination reaction. In detail, organotin-based catalysts were directly synthesized by supporting both organotin and nitrogen compounds on a coal-based columnar activated carbon (AC) using both incipient wetness impregnation and calcination methods. Interestingly, upon addition of nitrogen compounds, the resultant (SnCl4 + C16H34Cl2Sn)/AC catalysts showed higher activity and stability when compared the its (SnCl4 + C16H34Cl2Sn + C2N4H4)/AC counterpart at 200 °C and a gas hourly space velocity (GHSV, C2H2 based) of 30 h−1. According to the results, organotin was demonstrated to be the active site, whereas the incorporation of nitrogen allowed partial mitigation of the loss of active components.

Intracrystal-mesoporous ZSM-5 zeolites of varying SiO 2 /Al 2 O 3 molar ratios with different morphologies have been synthesized by employing a novel organosiloxane (OSO) as mesopore-directing template. In comparison to the previously reported ZSM-5 zeolites with mesoporosity, the mesoporous ZSM-5 zeolites obtained in this paper have high hierarchical factor (HF, 0.13–0.18), meaning that little microporosity has been consumed with abundant mesopores introduced within zeolite frameworks. The effects of tetrapropylammonium hydroxide (TPAOH), SiO 2 /Al 2 O 3 molar ratios, crystallization temperature and crystallization time on the morphologies and textural properties of the products have been discussed in detail. The synthesized mesoporous ZSM-5 zeolites were characterized with X-ray diffraction (XRD), nitrogen sorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), nuclear magnetic resonance (NMR) spectroscopy, inductively coupled plasma (ICP) optical emission spectroscopy, the temperature-programmed desorption of NH 3 technique (NH 3 -TPD) and thermogravimetric (TG)/differential scanning calorimetry (DSC) techniques. The outstanding hydrothermal stability of mesoporous ZSM-5 zeolites have been demonstrated by the hydrothermal treatment test. The Na + ion-exchange test exhibits obvious superiority compared to traditional ZSM-5 zeolite. And the primary catalytic performance in reaction of cracking of 1, 3, 5-tri-isopropylbenzene also exhibits excellent conversion activity and products selectivity.

In this paper, a novel organosiloxane was prepared and employed as mesoporogen to synthesis mesoporous zeolite Beta successfully. With the increase of organosiloxane to synthesis mixture, the total BET (Brunauer–Emmett–Teller) surface areas of the as-obtained samples increased initially and then decreased. When the mesoporogen/SiO2 ratio was 0.0142, the prepared zeolite sample had the largest BET surface area up to 810 m2/g. The DFT pore size distribution shows that the resulting mesoporous zeolite Beta samples have mesopore size distributions of approximately 2–6 nm. SEM images exhibit the morphology of the samples comprised ellipsoidal particles of 400–500 nm, and its surface is similar to a cracked cauliflower. From the TEM images, large numbers of worm-like mesopores and the basic crystal structure of the mesoporous zeolite Beta are clearly presented.

The transition metal oxide, such as iron oxide and Fe2O3/Al2O3 is cheap and industrialized that are widely used to catalyze the reaction of chlorine and oxygen with hydrogen in mixture gas to remove hydrogen from tail chlorine at low temperature. The reaction gas was prepared by the same composition with industrial tail chlorine, namely Cl2 (65% ~ 80%), O2 (8% ~ 10%), N2 (6% ~16%) and H2 (1.5% ~ 4%). In this experiment, the fixed bed reactor and iron oxide or Fe2O3/Al2O3 were used as the reaction device and catalysts, respectively. The optimum conversion rate of hydrogen was 84.11% when the reaction temperature was at 70 °C with 3%wt. Fe2O3/Al2O3 and the calcination temperature was 500 °C. The results showed that the catalytic performance of Fe2O3/Al2O3 is superior to Fe2O3. The selectivity of the reaction of hydrogen and chloride was higher than that of hydrogen and oxygen. We also characterized the catalysts with XRD, XPS, SEM and N2 adsorption-desorption and the results showed that the iron oxide was dispersive uniformly on the support surface.

To increase the spatial resolution while circumventing the problems of increased mass and volume of monolithic telescopes, a Fizeau imaging interferometer testbed (FIIT) with three individual subtelescopes was designed and constructed for high resolution astronomical observation. FIIT is intended to be mounted on a distributed small-satellite constellation with a formation fly configuration; thus the extremely stable pointing of the subtelescopes is the prerequisite for phased imaging, which is because the satellite suffers from some extent of detrimental jitters and drifts needs to be corrected by FIIT itself. FIIT makes use of a shared tip/tilt detection module with a cross-correlation algorithm, three fast-steering mirrors, and closed-loop control technology for pointing correction of three subtelescopes, which can make sure the images are coaligned for a long period of time used to image some faint astronomical objects. This study gives a detailed description of the detection algorithm of image shifts, the hardware design, and data processing flow, followed by closed-loop experiments of a wide-band white light point source. The results of residual errors on the detection camera and the beam-combining camera demonstrate the performance of the pointing correction function, which is a significant milestone for FIIT.

Under the background of astronomical observation by a distributed small-satellites constellation, a Fizeau imaging interferometer testbed (FIIT) was designed and constructed at National Astronomical Observatories of the Chinese Academy of Sciences in the past four years that achieved wide-band white light (400–700 nm) phased imaging at laboratory with a field of view (FOV) ∼2 arcmin. This study presents the design of FIIT, which is mainly composed of a light source module for simulating infinite objects, three sub-telescopes in a Golay-3 distribution (i.e., equilateral triangle), three tip/tilt correction modules and optical path delay modules, as well as three detecting telescopes and one beam-combining telescope for phased imaging. The three detecting telescopes could determine the piston and tip/tilt errors, which could be compensated for by optical path delay modules and fast steering mirrors in a close-loop mode. The performance of FIIT is also derived analytically and simulated by a ray-tracing model. The tolerance analysis of the pupil geometry and magnification matching are also performed for achieving a better FOV. The optical test of each module could efficiently validate them to achieve diffraction limit imaging. The preliminary experimental results for both point source and extend scene could sufficiently demonstrate the phased mode imaging of FIIT, thus validating the good prospects of this technique in the future.

An ordered mesoporous LTA zeolites (MLTA) have been synthesized in presence of the bridged polysilsesquioxane monomer (BS-1) as mesoporogen. The relatively well-defined small-angle X-ray diffraction peaks and nitrogen sorption isotherms with narrow pore size distribution centered at around 2.2 nm both indicated the presence of uniformly mesopores in MLTA samples. The scanning electron microscopy and transmission electron microscopy observations further confirmed that the uniform and partially interconnected intracrystal mesopores were randomly distributed throughout the globular particles with rugged surfaces. Interestingly, removal of the BS-1 resulted in uniform mesopore diameters that are nearly consistent with the molecular size of BS-1 (1.8 nm). 29Si MAS NMR revealed that the BS-1 was linked to MLTA zeolite crystal surface through 2 Si–O bonds and 3 Si–O bonds before calcinations. Nitrogen sorption analysis showed that the mesoporosity in MLTA samples could be adjusted by adding different amounts of BS-1 in starting gels. Relative to conventional mesoporous materials, one obvious feature of MLTA is that the resultant mesopores were structured by the bridged polysilsesquioxane monomer instead of commercial polymers or micelles, which broad the routes in synthesizing of various mesoporous materials with controllable pore size distribution, adjustable mesopore volume, and large surface area.

A novel core–shell LTA zeolite (CSLTA) with uniform mesoporous core and compact microporous shell was hydrothermally synthesized with ultrasonic processing employing a bridged polysilsesquioxane monomer (BPM) as mesoporogen. The morphology of as-prepared CSLTA particles transformed from cubic to circular structure upon introduction of BPM to the synthesis mixture. The XRD patterns confirmed the synthesized CSLTA samples of well LTA-type crystal phase and TEM micrographs clearly showed the novel core–shell structure. The obvious difference of external surface area in nitrogen isotherms between Na + - and Ca 2+ -CSLTA samples further demonstrated that abundant mesopores were encapsulated within the particles. BET data indicated that the as-prepared CSLTA zeolite samples had large total BET surface area and external surface area. DFT pore size distribution illustrated that the mesopores formed in core mainly centered at around 2–8 nm. The exchange rate of Na + by Mg 2+ showed that CSLTA samples had faster initial exchange rate and more efficient Mg 2+ removal ability than conventional LTA zeolite.

This article reports on findings regarding the mechanism of chlorination process. In this experiment, propanoic acid was chlorinated to α-chloropropanoic acid in a lab-scale glass tube reactor operating at 130°C. Propanoic anhydride and concentrated sulfuric acid were, respectively, used as the catalyst and the promoter. This experiment adopted the DFT method to calculate the activation energy of routes for the synthesis α-chloropropanoic acid, β-chloropropanoic acid, α,α-dichloropropanoic acid, and α,β-dichloropropanoic acid. The results showed that the main route of α-chloropropanoic acid was formed through an ionic mechanism when propanoic anhydride was used as the catalytic agent. Activation energy of 1-propen-1-ol,1-chloro, which was formed from 1-prop-anol,1-chloro-, was the highest in the process of ionic mechanism. In addition, α,α-dichloropropanoic acid was formed via a consecutive ionic chlorination path from α-chloropropanoic acid. β-Chloropropanoic acid was produced from propanoic acid through a chlorination radical mechanism. α,β-Dichloropropanoic acid was formed via a consecutive radical chlorination path.

In this paper, the static load and dynamic load of light steel portal frame are simulated and analyzed by ABAQUS. The influences of these three factors on the mechanical behavior of the joint are considered, including the shape of the opening, whether the end plate of the joint provided with the stiffening ribs, end plate placement. On the one hand we simulate the influences of these three factors on the stress of beam flange, column flange stress under static loading; on the other hand, we simulate the influences of these three factors on the skeleton curve under the low cyclic loading test and the ultimate bearing capacity of each cellular node is further understood. The above simulation analysis has certain practical significance.

A space-qualified fast steering mirror (SQ-FSM) was designed, built, and tested at the National Astronomical Observatories of the Chinese Academy of Sciences for an image stabilization system of space astronomical telescopes, which is used for the tip-tilt correction of small jitter of the satellite platform; this achieved image stability in a closed-loop manner. Its design primarily faces four challenges involving (1) sustaining the specified sine and random vibration without launch lock, as well as shock response spectrum experiments; (2) surface form error of a clear aperture of ϕ120 mm less than 1/50λ root mean square (RMS, λ=632.8 nm) with a relatively rigid mirror support; (3) resonance frequency of at least 800 Hz and as high as possible; (4) minimum reaction force and torque in order to decrease its unfavorable influence on the satellite platform. To achieve these goals, the global optimizations and compromises have to be made throughout the design process. The study reviews the detailed design of the SQ-FSM with respect to the four challenges, mainly by keeping the mirror and its support lightweight, mirror bonding and solidification, actuator and its stiffness, flexure support of the mirror and its holder, material optimization for weight, stiffness, and coefficient of thermal expansion, as well as finite element analysis on statics and dynamics. The performances are also measured and expatiated, including the surface form, resonant frequency, tip-tilt stroke, vibration and shock response spectrum experiments, etc., which validate the performances of the SQ-FSM.

The effect of zeolite 5A on the crystalline behavior of polypropylene (PP) in PP/β-nucleating agent system was investigated with X-ray diffractometer (XRD), differential scanning calorimeter (DSC), and polarized light microscope (PLM) in this study. Zeolite 5A has less effect on crystalline phase of PP/β-nucleating agent than does n-CaCO3, which is ascribed to the stronger surficial polarity and better dispersibility of zeolite 5A. The data of DSC indicated that the crystallization peak temperature of PP increases by 8.3°C in the presence of zeolite 5A, and n-CaCO3 increases 5.7°C in PP/TMB-5 system, relative to pure PP. And the initial crystallization temperature (Tc0) and the relative crystallinity (Xc) of PP is much more dramatically raised in the presence of zeolite 5A than CaCO3. The efficiency of zeolite 5A in reducing the spherulites size of PP was seen clearly from the PLM photographs. The mechanical testing results showed that the flexural strength and impact strength of PP/β-nucleating agent system increased in the presence of zeolite 5A. POLYM. COMPOS., 2008. © Society of Plastics Engineers

Bacillus sp. TSH1 is a butanol-producing microorganism newly isolated in our laboratory; it can grow and ferment under facultative anaerobic conditions, while sharing similar fermentation pathways and products with Clostridium acetobutylicum. To illustrate the relationships between the products and the enzyme activities in Bacillus sp. TSH1, key butanol- and ethanol-forming enzymes were studied, including butyraldehyde dehydrogenase, butanol dehydrogenase and alcohol dehydrogenase. The activities of the three enzymes increased rapidly after the initiation of fermentation. Activities of three enzymes peaked before 21 h, and simultaneously, product concentrations also began to increase gradually. The maximum activity of alcohol dehydrogenase was 0.054 U/mg at 12 h, butyraldehyde dehydrogenase 0.035 U/mg at 21 h and butanol dehydrogenase 0.055 U/mg at 15 h. The enzyme activities then decreased, but remained constant at a low level after 24 h, while the concentrations of butanol, acetone, and ethanol continued increasing until the end of the fermentation. The results will attribute to the understanding of the butanol metabolic mechanism, and provide a reference for further study of a facultative Bacillus metabolic pathway.

The effects of reaction temperature, ethanol concentration and weight hourly space velocity (WHSV) on the ethylene production from ethanol dehydration using zinc, manganese and cobalt modified HZSM-5 catalyst were investigated by response surface methodology (RSM). The results showed that the most significant effect among factors was reaction temperature and the factors had interaction. The optimum conditions were found as 34.4% ethanol concentration, 261.3 0 degrees C of reaction temperature and 1.18 h(-1) of WHSV, under these conditions the yield of ethylene achieved 98.69%.

In this work, a series of PhnSnCl4-n (n = 1, 2, 3, and 4) based catalysts were prepared by incipient wetness impregnation using activated carbon (AC) as support and triphenyltin chloride (Ph3ClSn) and tin(IV) chloride (SnCl4) as Sn precursors. The obtained catalysts were systematically characterized by X-ray diffraction (XRD), N2 physisorption, Scanning electron microscope (SEM), Thermogravimetric analysis (TG-DTG), and Inductively coupled plasma (ICP) analytical techniques. The catalytic performance of the prepared PhnSnCl4-n samples was evaluated in the acetylene hydrochlorination reaction. When a gas hourly space velocity (GHSV, C2H2 based) and a reaction temperature of 30 h-1 and 200 ºC, respectively were used for the reaction performed over the 12% (1.0Ph3ClSn+3.5SnCl4)/AC-200 catalyst, an acetylene conversion of 98.0% with a selectivity to vinyl chloride of 98.5% were obtained. These results demonstrated that PhnSnCl4-n can effectively improve the catalytic activity and prolong the lifetime of SnCl4/AC catalysts. Moreover, by comparing with HgCl2/AC, PhnSnCl4-n-based catalysts exhibit much enhanced catalytic activity in the hydrochlorination of acetylene. It is assumed that the outstanding activity is due to trichlorophenylstannane (PhCl3Sn) active sites, resulted from the organotin redistribution reaction between Ph3ClSn and SnCl4. In addition, such sites also improved the SnCl4/AC catalyst stability during the reaction.

A series of alkylorganotin-based catalysts Sn-g-C$_{3}$N$_{4}$/AC was prepared by wet impregnation in ethanol using different g-C$_{3}$N$_{4}$ precursors and alkylorganotin compounds. The structure, texture, surface composition, and adsorption properties of the as-prepared catalysts were extensively characterized. Then, the obtained samples were evaluated for their catalytic performance in hydrochlorination of acetylene. The results provided by the X-ray photoelectron spectroscopy, acetylene temperature-programmed desorption, and HCl adsorption confirmed the nature of the active sites i.e. Sn-N$_{x}$ involved in the reactant adsorption, and hence in the improved catalytic performance. These active sites were also related to the improved lifetime of alkylorganotin-based catalysts in the hydrochlorination of acetylene. At a constant reaction temperature of 200 °C with an acetylene gas hourly space velocity C2H2-GHSV of 30 h$^{-1}$, Sn-g$_{1}$ -C$_{3}$N$_{4}$/AC-550 exhibited the highest acetylene conversion ~98.0% and selectivity toward the vinyl chloride monomer >98.0% . From the catalytic test results, it was reasonably concluded that the hexamethylenetetramine is the most suitable N precursor, as compared to the dicyandiamide and urea, to prepare high-performance catalysts. From the BET specific surface area of fresh and used catalysts, it was suggested that, in contrast to dicyandiamide and urea, hexamethylenetetramine could delay the deposition of coke on alkylorganotin-based catalysts, which is reflected by the extended lifetime.