基于基音同步帧叠接的吴语语音合成

吴语语音和普通话一样,也是由声母、韵母和声调这三个要素构成。语音的平稳段存在于韵母中,波形具有周期性,周期的变化趋势决定语音的声调;非平稳段包括声母、过渡音和鼻音。根据这些特点,提出了一种利用基音同步帧和声调曲线来合成语音的新方法PSFC,并用该方法合成吴方言。实验表明,该方法简单实用,合成语音有较好的自然度和可懂度。     

Generation of Technology-Independent Retargetable Analog Blocks

This paper introduces a complete methodology for retargeting of analog cells to different sets of specifications. This methodology is technology-independent, thus allowing the migration, from one technology to another, of the circuit under retargeting. Careful integration of the device sizing and layout generation tasks via the incorporation of layout constraints during the sizing process allows to generate fully functional designs in a few minutes. The methodology is illustrated via the retargeting of a fully-differential Miller-compensated two-stage operational amplifier for a new set of specifications and two different technological processes.An erratum to this article can be found at     

HgCl2/I2复合催化剂协同催化合成异丙醇钇的研究

以金属钇和异丙醇为原料，以HgCl2/I2为复合催化剂，通过对金属钇的机械加工以增加其比表面，并将异丙醇脱水使其含水量降低至0．05％，体系在82℃回流5h，经过滤、减压蒸馏，得到了白色海绵状异丙醇钇，其产率高达83％，合成时间比文献报道的缩短了19h，产率提高了8％。文章确定了催化剂的最佳用量为20gY加入60mg HgCl2/I2，研究了合成产率与HgCl2/I2催化剂和HgCl2催化剂的依赖关系及异丙醇中含水量对合成产率的影响，并对HgCl2/I2的催化作用机理进行了初步探讨。     

Remote stereocontrol by the sulfinyl group: Mukaiyama aldol reactions of (S)-2-[2-(p-tolylsulfinyl)phenyl]acetaldehyde in the asymmetric synthesis of β-hydroxyacids and 1,3-diols

(S)-2-[2-(p-Tolylsulfinyl)phenyl]acetaldehyde reacts with different O-silylated ketenethioacetals in the presence of Yb(OTf)₃ yielding β-hydroxythioesters in high yields and diastereoselectivities. The obtained compounds were readily transformed into β-hydroxyacids and their corresponding diols. These Mukaiyama aldol reactions are a direct evidence of the ability of the sulfinyl group to control 1,5- and 1,6-asymmetric induction processes.     

A study of structural, compositional and optical properties of spray-deposited non-stoichiometric (Zn,Fe)S thin films

Non-stoichiometric ternary chalcogenides (Zn,Fe)S were prepared in the film form by pyrolytic spray deposition technique, using air/nitrogen as the carrier gas. The precursor solution comprised of ZnCl₂, FeCl₂ and thiourea. The depositions were carried out under optimum conditions of experimental parameters viz. carrier gas (air/nitrogen) flow rate, concentration of precursor constituents, nozzle substrate distance and temperature of quartz substrate. The deposited thin films were later sintered in argon at 1073 K for 120 min.The structural, compositional and optical properties of the sintered thin films were studied. X-ray diffraction studies of the thin films indicated the presence of (Zn,Fe)S solid solution with prominent cubic sphalerite phase while surface morphology as determined by scanning electron microscopy (SEM) revealed a granular structure.The chemical composition of the resulting thin films as analyzed by energy dispersive X-ray analysis (EDAX) reflected the composition of the precursor solutions from which the depositions were carried out with Fe at% values ranging from 0.4 up to 33.SEM micrographs of thin films reveal that the grain sizes of the thin films prepared using air as carrier gas and N₂ as carrier gas are in the vicinity of 300 and 150 nm, respectively.The diffuse transmittance measurements for thin films, as a function of wavelength reveal the dependence of direct optical band gap on Fe content and type of phase.     

A Symbolic Pole/Zero Extraction Methodology Based on Analysis of Circuit Time-Constants

This paper introduces a methodology for symbolic pole/zero extraction based on the formulation of the time-constant matrix of the circuits. This methodology incorporates approximation techniques specifically devoted to achieve an optimum trade-off between accuracy and complexity of the symbolic root expressions. The capability to efficiently handle even large circuits will be demonstrated through several practical circuits.     

A convenient semicarbazide resin for the solid-phase synthesis of peptide ketones and aldehydes

Use of a semicarbazide resin for the solid-phase preparation of peptide ketones and aldehyde led to optimal results in terms of both purity of the final product and overall yield. This resin was prepared without complication by activation of the commercial available aminomethyl polystyrene with CDI at room temperature, followed by treatment with tert-butyl carbazate. Furthermore, the TNBSA colorimetric assay has been adapted for checking the incorporation of the carbonyl moiety onto hydrazine-based resins.     

A Facile Synthesis of α-Phenylthio-α,β-Unsatuated Esters

α-phenylthio-α，β-unsaturated esters 6 were synthesized by Witting reaction of 3.which were prepared by a phenylsulfenyllation-trans-ylidation reaction.     

A convenient strategy of dimerization by microwave heating and using 2,5-diketopiperazine as scaffold

A novel and convenient microwave-assisted dimerization of an active peptide compound using the DKPs as scaffold is described. The key reaction giving rise to the diketopiperazine scaffold is the intermolecular coupling. No epimerization was detected in the reactions used. Conventional and microwave heating of the reactions are compared. Synthesis by microwave irradiation gave the desired compounds in higher yields and in shorter reaction times than those obtained by conventional heating.