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141.
Chao Luo Yujie Zhu Oleg Borodin Tao Gao Xiulin Fan Yunhua Xu Kang Xu Chunsheng Wang 《Advanced functional materials》2016,26(5):745-752
The sulfur‐based cathode materials suffer severely from poor cycling stability and low utilization, incurred by their stepwise reaction mechanism that generates polysulfide intermediates and the subsequent irreversible losses. In this work, those issues are significantly relieved by entrapping sulfur species in carbon host rich in oxygen functionalities. Sulfur species in such C/S composite are highly stabilized by their interaction with oxygen, and can deliver a reversible capacity of 508 mAh/(g of S) for 2000 cycles when coupled with Li, representing the best cycling stability up to date. More interestingly, extra capacity can be accessed by simply prelithiating the oxygen‐stabilized C/S composites down to 0.6 V for a few cycles, which enables a high capacity of 1621 mAh/(g of S) that eventually stabilizes at 820 mAh/(g of S) for 600 cycles. The mechanism for this electrochemical activation process is investigated with both spectroscopic and electrochemical techniques, which reveal that the inactive sulfur bonded to oxygen is liberated in the initial deep lithiation precycles and becomes electrochemically active. The oxygen‐stabilized sulfur can also be coupled with Na anode to form Na/S cell, confirming that the formation of S?O interaction in C/S composite generates promising sulfur‐based cathode materials for Li–S and Na–S batteries. 相似文献
142.
143.
Java-MaC: A Run-Time Assurance Approach for Java Programs 总被引:2,自引:1,他引:2
MoonZoo Kim Mahesh Viswanathan Sampath Kannan Insup Lee Oleg Sokolsky 《Formal Methods in System Design》2004,24(2):129-155
We describe Java-MaC, a prototype implementation of the Monitoring and Checking (MaC) architecture for Java programs. The MaC architecture provides assurance that the target program is running correctly with respect to a formal requirements specification by monitoring and checking the execution of the target program at run-time. MaC bridges the gap between formal verification, which ensures the correctness of a design rather than an implementation, and testing, which does not provide formal guarantees about the correctness of the system.Use of formal requirement specifications in run-time monitoring and checking is the salient aspect of the MaC architecture. MaC is a lightweight formal method solution which works as a viable complement to the current heavyweight formal methods. In addition, analysis processes of the architecture including instrumentation of the target program, monitoring, and checking are performed fully automatically without human direction, which increases the accuracy of the analysis. Another important feature of the architecture is the clear separation between monitoring implementation-dependent low-level behaviors and checking high-level behaviors, which allows the reuse of a high-level requirement specification even when the target program implementation changes. Furthermore, this separation makes the architecture modular and allows the flexibility of incorporating third party tools into the architecture. The paper presents an overview of the MaC architecture and a prototype implementation Java-MaC. 相似文献
144.
Gabriella Tranell Oleg Ostrovski Sharif Jahanshahi 《Metallurgical and Materials Transactions B》2002,33(1):61-67
The redox behavior of titanium in CaO-SiO2-TiO
x
melts was investigated using a slag-gas equilibrium technique. Titanium partitioning between Ti3+ and Ti4+ valency states and the ratio of activity coefficients of TiO1.5 and TiO2 were determined as functions of oxygen partial pressure, temperature, and slag composition. The equilibrium experiments were
carried out at temperatures between 1783 and 1903 K under CO-CO2-Ar gas atmosphere with oxygen partial pressure ranging from 10−12 to 10−7 atm (1.01×10−10 kPa to 1.01×10−5 kPa). The slags had CaO/SiO2 ratios between 0.55 and 1.35 and total titanium oxide concentrations from 7 to 50 mass pct. Experimental results showed that
the Ti3+/Ti4+ ratio in CaO-SiO2-TiO
x
slags, containing up to 50 mass pct TiO
x
, increased with decreasing oxygen partial pressure and decreased with increasing CaO/SiO2 ratio and decreasing temperature. Measured variation of the redox ratio Ti3+/Ti4+ with oxygen partial pressure closely followed the ideal behavior. Increasing the CaO/SiO2 ratio increased the ratio of activity coefficients of TiO1.5 and TiO2. The effect of total titania content on this ratio was more complex and in accord with Raman spectroscopy data. 相似文献
145.
146.
Oleg Bazhenov Vladimir Burlakov Sergey Dolgii Aleksey Nevzorov Natalya Salnikova 《International journal of remote sensing》2013,34(11):3024-3032
We consider the results of long-term remote optical monitoring obtained at the Siberian Lidar Station of Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences, Tomsk (56° 30′ N, 85° E). The scattering characteristics of stratospheric aerosol layer, obtained according to data of lidar measurements recorded since 1986, are presented. We analyse the trends of changes in the total ozone (TO) content over Tomsk for the period 1996–2013 according to data of spectrophotometric measurements employing Total Ozone Mapping Spectrometer (TOMS) data for the period 1979–1994. We determined the periods of elevated content of stratospheric aerosol over Tomsk after a series of explosive eruptions of volcanoes in the Pacific Ring of Fire and Iceland in 2006–2011. Since the second half of the 1990s we have recorded an increasing TO trend, equalling 0.65 DU/year for the period 1996–2013. 相似文献
147.
148.
Oleg Vasylkiv Yoshio Sakka Valeriy V. Skorokhod 《Journal of the American Ceramic Society》2006,89(6):1822-1826
CeCl3 ·7H2 O and GdCl3 ·6H2 O that were dissolved in water were precipitated with urea (NH2 CONH2 ) to produce matrix agglomerates for three-component nano-reactors. Mixing hexamethylenetetramine with dilute nitric acid resulted in the formation of well-dispersed nano-particles of cyclotrimetilene trinitramine (C3 H6 N6 O6 ) (RDX) in the solvent. Nano-reactors were produced by impregnating the nano-C3 H6 N6 O6 into the matrix agglomerates of an intermediate complex of cerium and gadolinium compounds. Blast initiation of the C3 H6 N6 O6 resulted in extremely rapid detonation and gaseous products formation at temperatures of 2000°–5000°C, which were compressed into a volume nearly equal to the initial volume of each RDX nano-particle. Multiple "nano-blasts" occurred in the volume of each nano-reactor. The impact of the blast waves led to fragmentation of the surrounding matter. The evolution of a large volume of gaseous products dissipated the heat of the process and limited temperature increase, thus reducing the possibility of local sintering among the primary particles. The short-term high temperature generated during the blasts enhanced the solid solubility of the metal oxides. Uniform aggregates of 22∼74 nm consisting of 6∼14 nm crystallites of gadolinia in ceria solid solution were synthesized. 相似文献
149.
Tatiana V. Magdesieva Magdalena Graczyk Oleg M. Nikitin Kim P. Butin 《Electrochimica acta》2006,52(3):1265-1280
We have studied a reaction between the reduced form of titanocene dichloride (Cp2TiCl2) and a group of organic halides: benzyl derivatives (4-XC6H4CH2Cl, X = H, NO2, CH3; 4-XC6H4CH2Br, X = H, NO2, PhC(O); 4-XC6H4CH2SCN, X = H, NO2) as well as three aryl halides (4-NO2C6H4Hal, Hal = Cl, Br; 4-CH3O-C6H4Cl). It has been shown that the electrochemical reduction of Cp2TiCl2 in the presence of these benzyl halides leads to a catalytic cycle resulting in the reductive dehalogenation of these organic substrates to yield mostly corresponding toluene derivatives as the main product. No dehalogenation has been observed for aryl derivatives. Based on electrochemical data and digital simulation, possible schemes of the catalytic process have been outlined. For non-substituted benzyl halides halogen atom abstraction is a key step. For the reaction of nitrobenzyl halides the complexation of Ti(III) species with the nitro group takes place, with the electron transfer from Ti(III) to this group (owing to its highest coefficient in LUMO of the nitro benzyl halide) followed by an intramolecular dissociative electron redistribution in the course of the heterolytic CHal bond cleavage.The results for reduced titanocene dichloride centers immobilized inside a polymer film showed that the catalytic reductive dehalogenation of the p-nitrobenzyl chloride does occur but with a low efficiency because of the partial deactivation of the film due to the blocking of the electron charge transport between the electrode and catalytic centers. 相似文献
150.
Tao Meng Yiquan Zou Oleg Khorev Yu Jin Huayong Zhou Yongliang Zhang Dingyu Hu Lanping Ma Xin Wang Jingkang Shen 《Advanced Synthesis \u0026amp; Catalysis》2011,353(6):918-924
An efficient method has been developed for the one‐pot copper(I)‐catalyzed synthesis of 3‐aminocoumarin and its derivatives, such as 3‐substituted methylideneaminocoumarins and chromeno[3,4‐d]imidazol‐4(1H)‐ones. Significantly, the strategy presents a straightforward and efficient approach to constructing biologically useful molecular scaffolds. 相似文献