电能高效高质转化技术与创新

电能转化是将电能转化为电能、磁能、热能、声能、光能等其他能量形式,是能源消费的核心基础,已渗透至经济发展和国防建设各个领域。电能高效高质转化技术作为绿色化、精细化能源消费革命的主体与核心技术,是国民经济和国防系统发展的基础、核心竞争力和综合实力的关键标志之一,也是国防和工业领域的“供能心脏”,对于推动我国能源低碳革命意义重大。我国电能转化技术与装备已取得了世界瞩目的成果,但仍存在工业电耗较高、装备卡脖子、国防有短板、基础研究薄弱等问题。为此,结合当前主要能源消费形式,重点梳理电能到电能、磁能、热能、声能、光能5种电能转化形式的基本原理、关键技术及发展现状,总结电能高效高质转换面临的难题及其发展对策,期望能够为我国电能转化技术与装备的发展提供一定参考。

Influence of pyrolysis temperature on structure and dielectric properties of polycarbosilane derived silicon carbide ceramic

β-SiC ceramic powders were obtained by pyrolyzing polycarbosilane in vacuum at 800-1200 °C. The β-SiC ceramic powders were characterized by TGA/DSC, XRD and Raman spectroscopy. The dielectric properties of β-SiC ceramic powders were investigated by measuring their complex permittivity by rectangle wave guide method in the frequency range of 8.2-18 GHz. The results show that both real part ε′ and imaginary part ε″ of complex permittivity increase with increasing pyrolysis temperature. The mechanism was proposed that order carbon formed at high temperature resulted in electron relaxation polarization and conductance loss, which contributes to the increase in complex permittivity.

Electrotransformation of Thermotoga maritima MS8

[Objective] The aim was to study on the electrotransformation of Thermotoga maritima MS8.[Method] Square waves,exponential waves and high voltage shock were used for the electrotransformation of T.maritima MS8,and the obtained transformants were detected by PCR.[Result] A single square electric pulse could be applied to cell sample in 0.2 cm ET cuvettes by using a Bio-Rad Gene Pulser set at 150 V,25 ms at room temperature,but the transformation efficiency was very low.[Conclusion] This research may improve the transformation efficiency of T.maritima MS8.

First-Principles Investigation on Triazine Based Thermally Activated Delayed Fluorescence Emitters

Three kinds of triazine based organic molecules designed for thermally activated delayed fluorescence （TADF） emitters are investigated by first-principles calculations. An optimal Hartree-Fork （HF） method is adopted for the calculation of energy gap between the first singlet state （S1） and the first triplet state （T1）. The natural transition orbital, the electron- hole （e-h） distribution and the e-h overlap diagram indicate that the S1 states for the three systems include both charge-transfer and some localized excitation component. Further quantitative analysis of the excitation property is performed by introducing the index Ar and the integral of e-h overlap S. It is found that symmetric geometry is a necessary condition for TADF emitters, which can provide more delocalized transition orbitals and consequently a small S1-T1 energy gap. Artful inserting aromatic groups between donors and acceptors can significantly enhance the oscillator strength. Finally, the energy state structures calculated with the optimal HF method is presented, which can provide basis for the study of the dynamics of excited states.

Zero-voltage switching converter absorbing parasitic parameters for super high frequency induction heating

This paper presents a novel mega-Hz-level super high frequency zero-voltage soft-switching converter for induction heating power supplies. The prominent advantage of this topology is that it can absorb both inductive and capacitive parasitic components in the converter. The switch devices operate in a zero-voltage soft-switching mode. Consequently, the high voltage and high current spikes caused by parasitic inductors or capacitors oscillation do not occur in this circuit, and the high power loss caused by high frequency switching can be greatly reduced. A large value inductor is adopted between the input capacitor and the switches, thus, this novel converter shares the benefits of both voltage-type and current-type circuits simultaneously, and there are no needs of dead time between two switches. The working principles in different modes are introduced. Results of simulation and experiments operated at around 1 MHz frequency verify the validity of parasitic components absorption and show that this convener is competent for super high frequency applications.

TiO2 Nanoparticles Produced by Electric-Discharge-Nanofluid-Process as Photoelectrode of DSSC

Self-made TiO2 nanoparticles were used as photoelectrode material of dye sensitized solar cell. The TiO2 thin film coats through spreading nanoparticles evenly onto the ITO glass via self-made spin-heat platform, and then TiO2 thin film is soaked in the dye N-719 more than 12 h to prepare the photoelectrode device. The TiO2 nanoparticles produced by electric-discharge-nanofluid-process have premium anatase crystal property, and its diameter can be controlled within a range of 20-50 nm. The surface energy zeta potential of nanofluid is from -22 mV to -28.8 mV, it is a stable particle suspension in the deionized water. A trace of surfactant Triton X-100 put upon the surface of ITO glass can produce a uniform and dense TiO2 thin film and heating up the spin platform to 200 oC is able to eliminate mixed surfac-tant. Self-made TiO2 film presents excellent dye absorption performance and even doesn＇t need heat treatment procedure to enhance essential property. Results of energy analysis show the thicker film structure will increase the short-circuit current density that causes higher conversion efficiency. But, as the film structure is large and thick, both the open-circuit voltage and fill factor will decline gradually to lead bad efficiency of dye-sensitized solar cell.

Automatic Stamping Charger---Stamping of Blended Coal-Theorical Study and Practice Analysis at TKCSA

The coke plant of a steel plant corresponds to the area that transforms a blend of coal into coke for using in blast furnace and steam to power plant. The coking plant of ThyssenKrupp CSA uses the heat recovery technology with stamping charger for stamping and preparation a blend of coals for charging and coking. Stamping technology adds several benefits to the process, such as increased density, homogeneity and alignment of the coal cake charged into the oven, as well as provides better control of the coking process, improves parameters of coke quality and allows coal blending with lower coking power, thereby reducing the production cost of coke and power generation. Through the automation of stamping charger, it is possible to evaluate and calculate the stamped coal density charged and the productivity gains this system provides.

Thermal transformation of δ-MnO_2 nanoflowers studied by in-situ TEM

ln-situ transmission electron microscopy in combination with a heating stage has been employed to real-time monitor varia- tions of δ-phase MnO2 nanoflowers in terms of their morphology and crystalline structures upon thermal annealing at elevated temperatures up to -665 ℃. High-temperature annealing drives the diffusion of the small δ-MnO2 nanocrystallites within short distances less than 15 nm and the fusion of the adjacent δ-MnO： nanocrystallites, leading to the formation of larger crystalline domains including highly crystalline nanorods. The annealed nanoflowers remain their overall flower-like morphology while they are converted to α-MnO2. The preferred transformation of the δ-MnO2 to the α-MnO2 can be ascribed to the close lattice spacing of most crystalline lattices between δ-MnO2 and α-MnO2, that might lead to a possible epitaxial growth of ct-MnO2 lattices on the 8-MnO2 lattices during the thermal annealing process.

Flexible thermocells for utilization of body heat

Plastic thermo-electrochemical ceils （thermocells） involving aqueous potassium ferricyanide/ferrocyanide electrolyte have been investigated as an alternative to conventional thermoelectrics for thermal energy harvesting. Plastic thermocells that consist of all pliable materials such as polyethylene terephthalate （PET）, fabrics, and wires are flexible enough to be wearable on the human body and to be wrapped around cylindrical shapes. The performance of the thermocells is enhanced by incorporating carbon nanotubes into activated carbon textiles, due to improved charge transfer at the interface. In cold weather conditions （a surrounding temperature of 5 ℃）, the thermocell generates a short-circuit current density of 0.39 A/m2 and maximum power density of 0.46 mW/m2 from body heat （temperature of 36℃）. For practical use, we have shown that the thermocell charges up a capacitor when worn on a T-shirt by a person. We also have demonstrated that the electrical energy generated from waste pipe heat using a serial array of the thermocells and voltage converters can power a typical commercial light emitting diode （LED）.

Quantum dot-sensitized solar cells employing Pt/C_(60) counter electrode provide an efficiency exceeding 2%

A microporous platinum/fullerenes (Pt/C 60) counter electrode was prepared by using a facile rapid thermal decomposition method,and the quantum-dot sensitized solar cell (QDSSC) of Pt/C 60-TiO 2-CdS-ZnS and Pt/C 60-TiO 2-CdTe-ZnS was fabrication.The technique forms a good contact between QDs and TiO 2 films.The photovoltaic performances of the as-prepared cells were investigated.The QDSSCs with Pt/C 60 counter electrode show high power conversion efficiency of 1.90% and 2.06%,respectively (under irradiation of a simulated solar light with an intensity of 100 mW cm 2),which is comparable to the one fabricated using conventional Pt electrode.