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Conformational analysis was performed for 18-thiacrown-6 (18t6) using the CONFLEX method and the MMFF94s force field. Computations were performed for some of the low energy conformations at the HF, B3LYP, CAM-B3LYP, M06, M06L, M062x, M06HF and MP2 levels. The computations were also performed using the DFT-D3 method along with the TPSS and PBE functionals. The study predicted a new C2 conformation as the ground state conformation of 18t6. This new C2 conformation is more stable than the experimentally known solid state conformation by 4.7 kcal/mol at the MP2/6-311G** level. This conformation has all of the SCCS dihedral angles adopt exodentate structure. However, the experimentally known conformation of the solid phase has two of the SCCS dihedral angles violating this exodentate rule. It was concluded that for 18t6 stability a linear dihedral SCCS angle requirement is more important than a gauche CSCC dihedral angle requirement.  相似文献   
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In this work, native silicon nitride (Si3N4) nanoparticles were modified by macromolecular coupling agent (LMPB-g-MAH) which was designed and synthesized according to the chain structure of styrene butadiene rubber (SBR), and Si3N4/SBR nanocomposites were prepared by two-segment mixing process. The structure and surface properties of modified Si3N4 nanoparticles were characterized by Transmission Electron Microscope (TEM), Fourier Transform Infrared Spectroscopy (FTIR), size distribution analyzer, and contact angle measuring instrument. The effect of different dosage of nano-Si3N4 on Si3N4/SBR nanocomposites was also systematically studied. It can be got that LMPB-g-MAH can effectively inhibit the agglomeration and improve the hydrophobic property of Si3N4 nanoparticles. It also can be found that modified Si3N4 nanoparticles brings well physical and dynamic mechanical properties, aging resistance, oil resistance, wear resistance, and low rolling resistance to SBR, especially, when the dosage is 0.5–1.5 phr, the best overall performance of Si3N4/SBR nanocomposites can be achieved.  相似文献   
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A new type of entrained flow gasifier with membrane wall and two-stage oxygen supply is being developed in China. The fraction of the secondary oxygen in total oxygen (FSO) is an important parameter for this kind of gasifier. A dynamic reduced order model (ROM) based on a reactor network model (RNM) is developed for this gasifier, which is used to investigate the effects of FSO on the slag layer thickness profile on the wall and explore the potential of FSO in dynamic slag control. The ROM adopts a flexible RNM blocking method, which varies with FSO to account for the influence of FSO on the flow pattern in the gasifier. Available industrial data was used to validate the model and a detailed sensitivity analysis for the calculation of slag layer thickness was performed. Static analyses show that FSO has a marked effect on the slag thickness distribution and higher FSO leads to lower heat loss through the wall. Finally, a slag control system, which introduced FSO as an auxiliary regulator, is proposed. Dynamic simulation shows that the new control system offers an improved performance in slag control and can broaden the regulating range of operating temperature.  相似文献   
5.
29%甘蔗杀虫复混肥在甘蔗上的药肥效研究   总被引:1,自引:0,他引:1  
进行了施用29%三合一甘蔗杀虫复混肥的试验,在甘蔗全生育期,共施3000 kg/hm2。第1次为基肥,施1500kg/hm2,施肥后65天,对蔗龟等甘蔗害虫防效达76.33%。第2次为追肥,施1500 kg/hm2,施肥后45天,防效达73.08%。该药肥对苗期甘蔗株高、叶数、叶长都有较好效果,其最终产量比29%对照复混肥增产14.85 t/hm2,增产率为24.87%。增产的主要原因是甘蔗有效茎数、茎径和单茎重的增加。该药肥对甘蔗株高影响不大。  相似文献   
6.
The Ni/pillared-bentonite catalysts with high BET area were synthesized and used in dry reforming reaction. The effects of different parameters such as calcination temperature, OH/Al3+ ratio, temperature and time of pillaring process and the content of nickel on the textural and catalytic properties of the synthesized catalysts were studied. The results indicated that the 15 wt% Ni catalyst supported on pillared bentonite prepared under specified conditions (OH/Al3+ = 2.2, pillaring temperature of 40 °C and pillaring time of 3 h) possessed the highest BET area (90.80 m2/g). Also, this catalyst possessed higher catalytic activity and stability with lower amount of deposited carbon in comparison to other prepared catalysts in methane reforming with CO2.  相似文献   
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A oxamido-bridged binuclear complex, [Cu(L)Co(bpy)2](ClO4)2·0.5C2H5OH·H2O has been synthesized, and structurally and magnetically characterized, where L = 1,4,8,11- tetraazacyclotradecanne-2,3-dione and bpy = 2,2-bipyridine. In the complex, the copper atom from the macrocyclic oxamido-copper(II) precursor in a square-planar and cobalt atoms in a distorted octahedral environment is bridged by the oxamidate group, Cu⋯Co separation of 5.359 Å. The metal–metal separations are consistent with the sequence of decrease of the ion radius of the metal ion. The magnetic properties of the complex have been investigated. The χMT versus T plots is typical of antiferromagnetically coupled Cu(II)–Co(II).  相似文献   
9.
《Energy》1986,11(9):887-892
We use first-law and second-law efficiencies on 2 multi-process food processing plants. These efficiencies are 59.6 and 19.4% for a condensed milk plant and 43.0 and 15.5% for the bakery plant. Improvements in both first-law and second-law efficiencies for the bakery can be achieved by reducing the mass of dough moulds and recovery of energy in the bake-oven exhaust to heat the air in the proofing oven. Replacement of the flash-cooling process in the condensed-milk plant by a combination of boiling at 100 °C and cooling via a vapour-compression refrigerator would lead to significant improvements in plant efficiencies.  相似文献   
10.
《Ceramics International》2015,41(4):5525-5530
A series of single-phase Eu3+, Tb3+, Bi3+ co-doped LaPO4 phosphors were synthesized by solid-state reaction at 800 °C. Crystal structures of the phosphors were investigated by X-ray diffraction (XRD). A monoclinic phase was confirmed. The excitation (PLE) and emission (PL) spectra showed that the phosphors could emit red light centered at 591 nm under the 392 nm excitation, which is in good agreement with the emission wavelength from near-ultraviolet (n-UV) LED chip (370–410 nm). The results of PLE and PL indicated that the co-doped Tb3+ and Bi3+could enhance emission of Eu3+ and the fluorescent intensities of the phosphors excited at 392 nm could reach to a maximum value when the doping molar concentration of Tb3+ and Bi3+ is about 2.0% and 2.0%, respectively. The co-doping Tb3+ and Bi3+ ions can strengthen the absorption of near UV region. They can also be efficient to sensitize the emission of Eu3+, indicating that the energy transfer occurs from Tb3+ and Bi3+ to Eu3+ ions. From further investigation it can be found that co-doping Tb3+ and Bi3+ ions can also induce excitation energy reassignment between 5D07F1 and 5D07F2 in these phosphors, and result in more energy assignment to 5D07F2 emission in LaPO4:Eu3+, Tb3+, Bi3+. Our research results displayed that La0.94PO4:Eu3+0.02, Tb3+0.02, Bi3+0.02 could be a new one and could provide a potential red-emitting phosphor for UV-based white LED.  相似文献   
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