基于TTS的中英文语音软件设计与实现

本文提出了一种基于TTS语音合成技术,利用Microsoft Speech SDK语音开发包、TTS引擎,采用VB平台开发了一个中英文语音软件,实现了从文本文件到语音并能把文本文件保存为语音文件的功能。     

2,4-二氯苯甲醛的合成研究

2,4-二氯苯甲醛是一种白色或近似白色棱柱结晶,是农药、医药、染料和电镀等行业中一种重要的化工原料。研究了2,4-二氯苯甲醛的合成方法。以2,4-二氯甲苯为原料,经芳甲基二氯化和水解两步反应合成得到2,4-二氯苯甲醛,总收率为79.3%。合成路线中氯化反应温度控制在(140±2)℃,氯化单步收率为96.5%。工艺路线具有原料简单、收率高、操作条件易于控制、三废少的特点。     

合成堇青石研究现状及进展

堇青石具有低的热膨胀系数、较好的抗热震性能等优点,广泛应用于耐火材料,电子封装材料,多孔陶瓷,催化剂载体及红外辐射材料.目前,工业上主要通过人工合成的方法制备堇青石.人工合成堇青石所用原料已在天然矿物原料的基础上,扩大到固体废物等原料,并且已有很多成功的合成实例.与天然产出的堇青石相比,合成堇青石的性能更加优越.从堇青石的合成原料、合成方法及机理、添加剂改性等方面,就其研究进展进行了介绍,并认为加强对其他合成方法及低温合成的研究,加强对改性添加剂及从固体废物中寻找原料的研究是未来的发展趋势.     

电场作用下电流大小对Fe-V-C体系燃烧合成的影响

采用Gleeble-1500D热模拟机,探讨电场下电流大小(1.0×104~2.3×104 A)对Fe-V-C体系燃烧合成的影响。结果表明,在电场作用下,采用此体系可以在较低温度(632~740 ℃)下燃烧合成VC/Fe复合材料,其硬度为60～67 HRC。随电流增大,体系点火温度降低,点火延迟时间缩短,试样的致密性提高,硬度提高。在1.0×104~1.6×104 A电流范围内,产物颗粒尺寸相差不大;在1.6×104~2.3×104 A电流范围内,随电流增大,产物颗粒变大。     

Heat exchanger network synthesis with detailed exchanger designs: Part 1. A discretized differential algebraic equation model for shell and tube heat exchanger design

A new method for the detailed design of shell and tube heat exchangers is presented through the formulation of coupled differential heat equations, along with algebraic equations for design variables. Heat exchanger design components (tube passes, baffles, and shells) are used to discretize the differential equations and are solved simultaneously with the algebraic design equations. The coupled differential algebraic equation (DAE) system is suitable for numerical optimization as it replaces the nonsmooth log mean temperature difference (LMTD) term. Discrete decisions regarding the number of shells, fluid allocation, tube sizes, and number of baffles are determined by solving an LMTD-based method iteratively. The resulting heat exchanger topology is then used to discretize the detailed DAE model, which is solved as a nonlinear programming model to obtain the detailed exchanger design by minimizing an economic objective function through varying the tube length. The DAE model also provides the stream temperature profiles inside the exchanger simultaneously with the detailed design. It is observed that the DAE model results are almost equal to the LMTD-based design model for one-shell heat exchangers with constant stream properties but shows significant differences when streams properties are allowed to vary with temperature or the number of shells are increased. The accuracy of the solutions and the required computational costs show that the model is well suited for solving heat exchanger network synthesis problems combined with detailed exchanger designs, which is demonstrated in Part 2 of the paper.     

Hydrothermal microwave-assisted synthesis of LaFeO3 catalyst for N2O decomposition

Lanthanum orthoferrite powders were synthesized via one-step hydrothermal reactions under mild conditions using microwave and conventional heating. The use of microwave irradiation during the synthesis allows one to obtain nanocrystalline LaFeO₃ with a higher yield and reduced crystallite and particle size within a 16 times shorter duration (3 hours) at a lower temperature of 220°C as compared to the conventional heating. The catalytic decomposition of nitrous oxide was performed over both samples, it was shown that the sample obtained under microwave conditions demonstrates enhanced activity as a catalyst: N₂O decomposes completely at 700°C over the catalyst formed at microwave conditions, while the comparative catalyst prepared by conventional heating reaches a lower conversion of only 60% at the same temperature and catalytic reaction conditions.     

Tailorable thermal expansion in leucite-pollucite materials derived from geopolymers for environmental barrier coatings

The K[AlSi₂O₆]-Cs[AlSi₂O₆] pseudo-binary system was synthesized by geopolymer crystallization. The thermal expansion properties of these materials were studied by in situ high-temperature X-ray diffraction to characterize thermal expansion behavior for potential application as environmental barrier coatings. Tailorable thermal expansion through changing cation stoichiometry allowed reduced thermal expansion mismatch with SiC_f/SiC composites compared to rare-earth-based coatings.     

Synthesis method comparison of compositionally complex rare earth-based Ruddlesden–Popper n = 1 T′-type cuprates

The multicomponent approach has been successfully expanded to the Ruddlesden–Popper structure with the synthesis of two different high-entropy cuprate compositions: (La_0.2Nd_0.2Gd_0.2Tb_0.2Dy_0.2)₂CuO₄ and (La_0.2Pr_0.2Nd_0.2Sm_0.2Eu_0.2)₂CuO₄. The effect of synthesis method is explored using both solid-state reaction and polymeric steric entrapment (PSE) methods. It is found that PSE leads to more randomly distributed cation species, providing an advantageous method of synthesis for the growing field of high entropy oxides. In situ high-temperature x-ray diffraction tracks the amorphous to crystalline phase transformation in (La_0.2Nd_0.2Gd_0.2Tb_0.2Dy_0.2)₂CuO₄ powder, synthesized using the PSE method. Using the High-Temperature XRD data, a method for gaining information on the kinetic behavior is also applied. Magnetometry of both compositions indicates ferrimagnetic behavior at low temperatures.     

Fine TiC dispersed Al2O3 composites fabricated via in situ reaction synthesis and conventional process

To further improve the mechanical performance and reduce the percolation threshold by controlling microstructures, Al₂O₃-TiC composites containing 0-20 vol% TiC were fabricated via in situ reaction synthesis. Graphite (ATC) and carbon nanotubes (ATCT) were used as carbon sources. The composites were also fabricated via a conventional process using a TiC starting powder (AT). X-ray diffraction analysis and scanning electron microscopy observation results indicated successful fabrication of the composites with various microstructures. TiC particles in ATCT were completely dispersed at grain boundaries, whereas in ATC and AT, these particles were either intragranular or intergranular dispersed. The composites could be listed as follows, ATCT > ATC > AT, that is, in descending order of the reinforcing flexural strength and fracture toughness. The nanoindentation measurement indicated the optimum hardening effect of ATCT. The ATCT composite also exhibited the highest fracture toughness, which was 49% higher than that of the monolithic Al₂O₃. Crack deflection was considered as the main toughening mechanism while crack bridging behavior also occurred in ATCT. For a given TiC content, ATCT exhibited the lowest electrical resistivity, owing mainly to the complete grain-boundary dispersion of the relatively large TiC particles. The similarity of the Al₂O₃ grain size and TiC particle size of ATCT contributed to the lowest percolation threshold achieved (11.2%), which (to date) is the lowest value that has been reported for the Al₂O₃-TiC system.     

One pot synthesis of nano Ag in calcium alginate beads and its catalytic application in p‐Nitrophenol reduction with kinetic parameter estimation and model fitting

In this work, one step process of synthesis of silver nanoparticles (Agnp) embedded in insitu formed calcium alginate (CA) beads is stated. CA, formed from the reaction between sodium alginate and calcium hydroxide, acts as reducing and stabilizing agent as well as support for nanoparticles. The reaction mechanism for the formation and stabilization of Agnp is proposed where the vicinal dihydroxy groups of alginate are assumed to act as the reducing agent for Ag⁺ to Ag°. Transmission electron microscopy (TEM), x‐ray diffraction (XRD), UV‐vis spectroscopy, field emission scanning electron microscopy (FESEM), and atomic absorption spectroscopy (AAS) were used to characterize the Agnp. The formation of spherical nanoparticles with average size range of 4‐5 nm was confirmed by TEM. Catalytic activity of this nano silver‐calcium alginate (Agnp‐CA) composite was evaluated in the reduction of p‐nitrophenol. Concentrations of sodium alginate, calcium hydroxide, and AgNO₃ are found to be the parameters that critically affect the synthesis of Agnp. The efficacy of the catalyst is expressed on the basis of suitable reaction parameters. Both pseudo‐homogeneous and heterogeneous kinetic models are proposed for the reaction to find the best model and the Eley‐Riedel model is found to fit well with the experimental data. The novelty of this work is that the tandem process of CA bead formation, Agnp formation, and Agnp entrapment in CA have been transformed into a single‐step process. Moreover, elaborations of each step of the ionic mechanisms of Agnp formation and p‐NP reduction with Agnp and the establishment of a heterogeneous kinetic model for the reaction are reported for the first time here.