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71.
72.
Zhiwei Cao Zhifeng Liu Xiaohong Wang Anfeng Shi Haishan Luo Benoît Noetinger 《国际流体数值方法杂志》2017,85(4):247-263
In this paper, a numerical method to capture the shock wave propagation in 1‐dimensional fluid flow problems with 0 numerical dissipation is presented. Instead of using a traditional discrete grid, the new numerical method is built on a range‐discrete grid, which is obtained by a direct subdivision of values around the shock area. The range discrete grid consists of 2 types: continuous points and shock points. Numerical solution is achieved by tracking characteristics and shocks for the movements of continuous and shock points, respectively. Shocks can be generated or eliminated when triggering entropy conditions in a marking step. The method is conservative and total variation diminishing. We apply this new method to several examples, including solving Burgers equation for aerodynamics, Buckley‐Leverett equation for fractional flow in porous media, and the classical traffic flow. The solutions were verified against analytical solutions under simple conditions. Comparisons with several other traditional methods showed that the new method achieves a higher accuracy in capturing the shock while using much less grid number. The new method can serve as a fast tool to assess the shock wave propagation in various flow problems with good accuracy. 相似文献
73.
Zhengluo Wang Zhiwei Zhao Yanru Zhang Dr. Xiaopeng Yang Xuan Sun Dr. Jinyang Zhang Prof. Linrui Hou Prof. Changzhou Yuan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(3):863-873
The exploration of anode materials with a high degree of electrochemical utilization for Li-ion batteries (LIBs) still remains a huge challenge despite pioneering breakthroughs. Rational engineering of electrode structures/components by facile strategies would offer infinite possibilities for the development of LIBs. In this study, one-dimensional ultralong nanohybrids of ultrafine NiCoO2 nanoparticles dispersed in situ in and/or on the surface of amorphous N-doped carbon nanofibers (NCO@ANCNFs) were fabricated by a bottom-up electrospinning protocol. By virtue of synergistic structural/component features, the obtained ultralong NCO@ANCNFs with low NCO loading (≈33.6 wt %) show highly efficient Li+ storage performance with high reversible capacity, high rate capability, and long cycle life. The unusual reversible crystalline transformation during cycling was analyzed. Quantitative analysis revealed that the pseudocapacitive contribution mainly accounts for the superior lithium storage of the NCO@ANCNFs. Besides, the ability of the hybrid anode to deliver competitive Li-storage properties even without conductive carbon greatly enhances its commercial applicability. An NCO@ANCNFs//LiNi0.8Co0.15Al0.05O2 full battery was assembled and exhibited striking electrochemical properties. This contribution offers a scalable methodology to fabricate highly efficient hybrid anodes for advanced next-generation LIBs. 相似文献
74.
Zhang Hengkai Zhang Yaokang Yang Guang Ren Zhiwei Yu Wei Shen Dong Lee Chun-Shing Zheng Zijian Li Gang 《中国科学:化学(英文版)》2019,62(7):875-882
From a base material of conductive polymer(poly-(3,4-ethylenedioxythiophene):poly(styrenesulfonate),PEDOT:PSS),a flexible and high-conductivity(as low as 45Ω/sq)transparent electrode was fabricated on polydimethylsiloxane elastomer by an acid treatment and transfer process.Combined with the D-sorbitol-doped PEDOT:PSS electric glue,we successfully demonstrated a vacuum-free and ambient lamination fabrication process for semi-transparent perovskite solar cells using triple cation Cs_(0.05)(MA_(0.17)FA_(0.83))_(0.95)Pb(I_(0.83)Br_(0.17))_3perovskite.By this manufacturing-friendly lamination process,we fabricated semitransparent perovskite solar cell devices with power conversion efficiencies up to 16.4%and variable transparencies. 相似文献
75.
Zhiwei Cui Jun Zhou Teng Liu Yicong Wang Yue Hu Ying Wang Zhigang Zou 《化学:亚洲杂志》2019,14(12):2138-2148
A series of porphyrin‐containing polyimide (PI) photocatalysts were synthesized by a one‐step solvothermal method. Characterization results revealed that porphyrin was uniformly coupled into the PI framework through covalent bonding and the visible‐light absorption was greatly improved. The photodegradation activity of porphyrin‐containing PIs for methyl orange (MO) under visible light was enhanced significantly, with the highest pseudo‐first‐order rate constant 35 times higher than that of neat porphyrin and 10 times higher than that of porphyrin‐free PI. The enhancement is mainly attributed to an increased light harvesting accompanied by a varied HOMO level, which was clarified by control experiments, characterizations and theoretical calculations. This work provides an insight into multiple effects of dye molecules in dye‐containing heterogeneous photocatalysts. 相似文献
76.
77.
Zhiwei Miao Ming Xu Barbara Hoffmann Bruno Bernet Andrea Vasella 《Helvetica chimica acta》2005,88(7):1885-1912
Functionalised bicyclic exo‐glycals are readily obtained by base‐catalysed (typically MeONa in MeOH) alkynol cycloisomerisation of ethynylated cyclic saccharides. Thus, base treatment of the phenylethynyl‐ and halogenoethynylated 1‐O‐acetyl‐ribofuranoses 22 – 24 and the 4‐ethynylated 1‐thioglucopyranosides 30 – 33 gave – after deacetylation – selectively the (Z)‐configured exocyclic enol ethers 26 – 28 (84–91%) and 34 – 37 (63–76%), respectively, resulting from a trans‐5‐exo‐dig cyclisation. The ring closure to the trans‐dioxahexahydroindans 34 – 37 is favoured by a concerted intramolecular protonation of the intermediate vinyl anion by the neighbouring HO C(3). Cycloisomerisation of the 6‐O‐acetyl‐4‐(phenylethynyl)‐1‐thio‐α‐D ‐glucopyranoside 39 occurred via the corresponding phenylethynylated allenes to provide the galacto‐configured (Z)‐ and (E)‐cis‐dioxahexahydroindans 40 (30%) and 41 (51%). Surprisingly, the HO C(4) unprotected α‐d‐ galactopyranosyl‐buta‐1,3‐diyne 15 and the β‐D ‐glucopyranosyl‐buta‐1,3‐diyne 51 (and its 2‐bromoethynyl analogue) undergo a 6‐exo‐dig ring closure to the 2,5‐dioxabicyclo[2.2.2]octanes 16 – 19 and 52 / 53 , respectively, the ring closure requiring a boat conformation (B1,4 for 15 , 1,4B for 51 ). Ring strain (anti‐reflex effect) prevents an alkynol cycloisomerisation of 4‐(phenylbuta‐1,3‐diynyl, bromoethynyl, or iodoethynyl)levoglucosan 56 – 59 , and 56 reacted by elimination to the hex‐1‐ene‐3,5‐diyne 59 (82%), while isomerisation of 57 and 58 led to epimeric mixtures of the haloallenes 60 (82%) and 61 (68%). 相似文献
78.
Zhiwei Dong Xiucun Yang Guanjun You Shixiong Qian 《Physica B: Condensed Matter》2009,404(16):2122-2125
Ag nanoparticles embedded in soda-lime silicate glasses were fabricated by the ion-exchange technique. Effects of thermal treatment on the optical nonlinearity and ultrafast dynamics of Ag nanoparticles were investigated by applying time-resolved optical Kerr effect and pump-probe techniques. The results indicate that thermal treatment is an efficient method to improve the nonlinear optical performance of this kind of material. 相似文献
79.
80.
Tong Z Takagi S Tachibana H Takagi K Inoue H 《The journal of physical chemistry. B》2005,109(46):21612-21617
A unique guest-guest ion exchange method was developed for preparing a thin film of a nano-layered K(4)Nb(6)O(17).3H(2)O that possesses both (1) optical transparency and (2) ion-exchangeability under ambient conditions without calcination at high temperature. An optically transparent Ru(bpy)(3)(2+)-K(4)Nb(6)O(17) hybrid thin film, a photoresponsive electrode, was successfully prepared by the guest-guest exchange method by use of the intercalation compound MV(2+)-K(4)Nb(6)O(17) as a precursor. The optically transparent Ru(bpy)(3)(2+)-K(4)Nb(6)O(17) hybrid thin films have been characterized by X-ray diffraction, SEM, AFM, IR, and UV spectroscopies, as well as elemental analysis. The electrochemical behavior of the ITO/Ru(bpy)(3)(2+)-K(4)Nb(6)O(17) hybrid thin film electrode was studied; it also exhibits swift photoresponse in the visible region. 相似文献