In his first speech on February 17 to a joint session of Congress, US President Bill Clinton outlined his wision of smaller deficits through higher income taxes on the wealthy, increased energy taxes and selected spen...In his first speech on February 17 to a joint session of Congress, US President Bill Clinton outlined his wision of smaller deficits through higher income taxes on the wealthy, increased energy taxes and selected spending cuts including a one-year freeze on federal pay. US Secretary of State Warren Christopher arrived in Cairo on February 18 to start his six nation Middle East tour which will also take him to Jordan, Syria, Saudi Arahia, Kuwait, Israel and Lebanon.展开更多
China announced on April 16 its decision to send military observers and engineers to join UN transitional authorities in Cambodia. The contingent left Beijing on the same day. On April 21, Peruvian President Alberto F...China announced on April 16 its decision to send military observers and engineers to join UN transitional authorities in Cambodia. The contingent left Beijing on the same day. On April 21, Peruvian President Alberto Fujimori announced a 12-month plan to return Peru to democracy. He said he never intended to create a dictatorship when he launched his militarybacked crackdown on April 5 aimed at fighting corruption,展开更多
Word 97有着强大的绘图功能,如绘制线条、各种几何图形、流程图等都非常方便。如果在绘制过程中再配合使用<Ctrl>或<Shift>键,那更是如虎添翼。笔者在长期实践中总结出了关于<Ctrl>键和<Shift>键的运用技巧,刊...Word 97有着强大的绘图功能,如绘制线条、各种几何图形、流程图等都非常方便。如果在绘制过程中再配合使用<Ctrl>或<Shift>键,那更是如虎添翼。笔者在长期实践中总结出了关于<Ctrl>键和<Shift>键的运用技巧,刊登在此,以飨读者。展开更多
To solve the difficulty of designing digital impacting filter in the receiver of random-polar modulated Extended Binary Phase Shift Keying with Continuous Phase (CP-EBPSK), a design method based on Quantum-behaved Par...To solve the difficulty of designing digital impacting filter in the receiver of random-polar modulated Extended Binary Phase Shift Keying with Continuous Phase (CP-EBPSK), a design method based on Quantum-behaved Particle Swarm Optimization (QPSO) algorithm is proposed. Firstly, QPSO is introduced elaborately, and the basic flow of QPSO is also given. Then, the demodulation principle of digital impacting filter in the communication system of CP-EBPSK with random-polar is demonstrated, and QPSO is utilized to design the digital impacting filter, which also takes the effect of finite word length into consideration when implemented by hardware. Finally, the proposed method is simulated. Simulation results show that the digital impacting filter designed by new method can derive satisfied demodulation performance.展开更多
Based on vibration analysis, single-layered graphene sheet （SLGS） with multiple attached nanoparticles is developed as nanoscale mass sensor in thermal environments. Graphene sensors are assumed to be in simplysuppo...Based on vibration analysis, single-layered graphene sheet （SLGS） with multiple attached nanoparticles is developed as nanoscale mass sensor in thermal environments. Graphene sensors are assumed to be in simplysupported configuration. Based on the nonlocal plate the- ory which incorporates size effects into the classical theory, closed-form expressions lot the frequencies and relative fre- quency shills of SLGS-based mass sensor are derived using the Galerkin method. The suggested model is justified by a good agreement between the results given by the present model and available data in literature. The effects of tem- perature difference, nonlocal parameter, the location of the nanoparticle and the number of nanoparticles on the relative frequency shift of the mass sensor are also elucidated. The obtained results show that the sensitivity of the SLGS- based mass sensor increases with increasing temperature difference.展开更多
Quantum chemical calculations on some possible equilibrium geometries of C24O2 isomers derived from C24 （D6） and C24O have been performed using density functional theory （DFT） method. The geometric and electronic ...Quantum chemical calculations on some possible equilibrium geometries of C24O2 isomers derived from C24 （D6） and C24O have been performed using density functional theory （DFT） method. The geometric and electronic structures as well as the relative energies and thermal stabilities of various C24O2 isomers at the ground state have been calculated at the B3LYP/6-31G（d） level of theory. And the 1,4,2,5-C24O2 isomer was found to be the most stable geometry where two oxygen atoms were added to the longest carbon-carbon bonds in the same pentagon from a thermodynamic point of view. Based on the optimized neutral geometries, the vertical ionization potential and vertical electron affinity have been obtained. Meanwhile, the vibrational frequencies, IR spectrum, and 13C chemical shifts of various C24O2 isomers have been calculated and analyzed.展开更多
With the development of the society and culture, English vocabulary change rapidly. English has always been in a state of evolution. In recent years new words enter the English language at an increasing rate. This pap...With the development of the society and culture, English vocabulary change rapidly. English has always been in a state of evolution. In recent years new words enter the English language at an increasing rate. This paper makes an attempt to analyze eight ways of new English word formation, creating, blending, shortening, functional shift, back- formation, affixation, compounding and borrowing — by presenting mainly English examples.展开更多
文摘In his first speech on February 17 to a joint session of Congress, US President Bill Clinton outlined his wision of smaller deficits through higher income taxes on the wealthy, increased energy taxes and selected spending cuts including a one-year freeze on federal pay. US Secretary of State Warren Christopher arrived in Cairo on February 18 to start his six nation Middle East tour which will also take him to Jordan, Syria, Saudi Arahia, Kuwait, Israel and Lebanon.
文摘China announced on April 16 its decision to send military observers and engineers to join UN transitional authorities in Cambodia. The contingent left Beijing on the same day. On April 21, Peruvian President Alberto Fujimori announced a 12-month plan to return Peru to democracy. He said he never intended to create a dictatorship when he launched his militarybacked crackdown on April 5 aimed at fighting corruption,
基金Supported by the National Natural Science Foundation of China (No. 60872075)
文摘To solve the difficulty of designing digital impacting filter in the receiver of random-polar modulated Extended Binary Phase Shift Keying with Continuous Phase (CP-EBPSK), a design method based on Quantum-behaved Particle Swarm Optimization (QPSO) algorithm is proposed. Firstly, QPSO is introduced elaborately, and the basic flow of QPSO is also given. Then, the demodulation principle of digital impacting filter in the communication system of CP-EBPSK with random-polar is demonstrated, and QPSO is utilized to design the digital impacting filter, which also takes the effect of finite word length into consideration when implemented by hardware. Finally, the proposed method is simulated. Simulation results show that the digital impacting filter designed by new method can derive satisfied demodulation performance.
文摘Based on vibration analysis, single-layered graphene sheet （SLGS） with multiple attached nanoparticles is developed as nanoscale mass sensor in thermal environments. Graphene sensors are assumed to be in simplysupported configuration. Based on the nonlocal plate the- ory which incorporates size effects into the classical theory, closed-form expressions lot the frequencies and relative fre- quency shills of SLGS-based mass sensor are derived using the Galerkin method. The suggested model is justified by a good agreement between the results given by the present model and available data in literature. The effects of tem- perature difference, nonlocal parameter, the location of the nanoparticle and the number of nanoparticles on the relative frequency shift of the mass sensor are also elucidated. The obtained results show that the sensitivity of the SLGS- based mass sensor increases with increasing temperature difference.
文摘Quantum chemical calculations on some possible equilibrium geometries of C24O2 isomers derived from C24 （D6） and C24O have been performed using density functional theory （DFT） method. The geometric and electronic structures as well as the relative energies and thermal stabilities of various C24O2 isomers at the ground state have been calculated at the B3LYP/6-31G（d） level of theory. And the 1,4,2,5-C24O2 isomer was found to be the most stable geometry where two oxygen atoms were added to the longest carbon-carbon bonds in the same pentagon from a thermodynamic point of view. Based on the optimized neutral geometries, the vertical ionization potential and vertical electron affinity have been obtained. Meanwhile, the vibrational frequencies, IR spectrum, and 13C chemical shifts of various C24O2 isomers have been calculated and analyzed.
文摘With the development of the society and culture, English vocabulary change rapidly. English has always been in a state of evolution. In recent years new words enter the English language at an increasing rate. This paper makes an attempt to analyze eight ways of new English word formation, creating, blending, shortening, functional shift, back- formation, affixation, compounding and borrowing — by presenting mainly English examples.
