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Aiming at the problem of low machining accuracy of remote-sensing camera parts with spatial angle, this study analyzed the causes from human, machine, material, method, environment, and measurement, and proposed an experimental analysis method based on the spatial rotation of machine tool spindle according to the linkage machining function of the five-axis machining center. The cutting experiment was carried out through the self-built benchmark of the machine tool, and the machining errors of the machine tool spindle with different spatial angles were studied. The precision machining of the parts with spatial angles was realized by taking measures such as machine tool correction and numerical control program compensation. The experiment proved that this method is feasible and effective.

The cable laying vessel is a key factor for the submarine laying routing, insta llation, and layout. The loading and laying capabilities of a submarine cable vessel alw ays determine the speed and costs of corresponding cable construction engineering, wh ich will significantly affect the electricity transmission of the islands, wind farms, and other offshore energy engineering. Therefore, an overview on the recent development of domestic and international cable laying vessels and related construction equipment i s conducted with the summarizations of the development trends. Furthermore, a perspe ctive of the cable laying vessels in the future is also proposed.

The floater can be employed to provide additional buoyancy to the submarine cable during its landing to ensure its routing and connection with the onshore connectors. With the update of the voltage-class of the submarine cable, to ensure the efficiency and quality of the landing operations, the floater has been changed from the traditional waste tires to the new types of pre-fabricated floaters. In this paper, the characteristics of different floaters will be introduced and compared with the engineering applications. The development trends of the floaters for submarine-cable landing are proposed.

The special driving environment of highway extra-long tunnels causes high operational risks and difficult escape. The establishment of a sound emergency escape support system is essential for drivers to escape safely in risky accidents. Based on the factors such as the type and severity of tunnel operation risks, this paper studies and puts forward the level of extra-long tunnel operation risk management and the requirements for safe emergency escape of relevant personnel under different levels, and establishes and improves the composition of the extra-long tunnel emergency support system and the function, location and spacing of each facility in the subsystems. Considering the condition of extra-long tunnels, the research conclusions provide a scientific basis for emergency escape management and establishment technology, and proposes a safer support system for emergency escapes.

Nanostructuring, structure distortion, and/or disorder are the main manipulation techniques to reduce the lattice thermal conductivity and improve the figure of merit of thermoelectric materials. A single-phase α-MgAgSb sample, MgAg0.97Sb0.99, with high thermoelectric performance in near room temperature region was synthesized through a high-energy ball milling with a hot-pressing method. Here, we report the average grain size of 24–28 nm and the accurate structure distortion, which are characterized by high-resolution neutron diffraction and synchrotron x-ray diffraction with Rietveld refinement data analysis. Both the small grain size and the structure distortion have a contribution to the low lattice thermal conductivity in MgAg0.97Sb0.99.

Based on the principle of forced convection heat transfer in a single tube with air transverse sweep, an experimental device of forced convection heat transfer with equilibrium point tracking was developed. The device controls wind speed, heating power and other experimental working parameters by MCU, synchronously adjusting, collecting and analyzing working parameters in real time, to realize the tracking of thermal balance point. Newton cooling formula and criterion relation are adopted to calculate Nusselt number and Reynolds number automatically, to fit criterion relation and to display correlation curve automatically, and to realize automatic data analysis. The test results show that the experimental results are in good agreement with the empirical correlation formula within the Reynolds number range of 40 ~ 4000, which realizes the automatic tracking of thermal equilibrium point and meets the requirements of real-time automatic measurement in forced convection heat transfer experiment.

The article introduces the phenomenon of a single auxiliary engine overspeed fault alarm and stopping during a certain sea voyage. Through analysis and investigation, the post personnel finally accurately located the fault because the micro switch of the mechanical overspeed protection device was loose. Post personnel were eliminated in time and the status of the remaining units was also checked to ensure the stable operation of the ship’s power generating diesel engine.

During the past decades, Li-ion batteries have been one of the most important energy storage devices. Large-scale energy storage requires Li-ion batteries which possess high energy density, low cost, and high safety. Other than advanced battery materials, in-depth understanding of the intrinsic mechanism correlated with cell reaction is also essential for the development of high-performance Li-ion battery. Advanced characterization techniques, especially neutron-based techniques, have greatly promoted Li-ion battery researches. In this review, the characteristics or capabilities of various neutron-based characterization techniques, including elastic neutron scattering, quasi-elastic neutron scattering, neutron imaging, and inelastic neutron scattering, for the related Li-ion-battery researches are summarized. The design of in-situ/operando environment is also discussed. The comprehensive survey on neutron-based characterizations for mechanism understanding will provide guidance for the further study of high-performance Li-ion batteries.

In this paper, the ant colony algorithm is presented to optimize the university classroom arrangement and solve the corridor congestion problem. Firstly, the classroom capacity, the course time periods and the distance between classrooms are considered, and then the ant colony algorithm is applied to the corridor congestion problem by minimizing the distance between the students’ classroom of the courses. The experimental results show that the ant colony algorithm is able to construct feasible solutions and solve the classroom arrangement problem.

University classroom arrangement problem is considered as a sub-question of the university timetabling problem, which has been proved to be an NP-hard problem in combinatorial optimization field. In this paper, we firstly analyzed the relevant factors and set up a model of the problem. Then the genetic algorithm was applied to optimize the arrangement of classroom considering the moving distance of students between courses, which was caused by room changing. The experimental results have shown that the genetic algorithm could generate feasible solutions and optimize the classroom arrangement.

In this paper, the beetle rear wing is used as a bionic object to study the aerodynamic characteristics of the flapping wing aircraft during flapping. Firstly, a three-dimensional folding wing three-dimensional model was designed according to the folding mechanism of the beetle wing. Then the influence of different flapping angle of attack, torsion time and crease width on the aerodynamic characteristics of the rigid folding wing was analyzed by ANSYS FLUENT software. The results show that the flapping angle of attack has a great influence on the aerodynamic characteristics of the foldable wing. Appropriate reduction of the torsion time and crease width can improve the aerodynamic characteristics of the folded wing.

Software simulation is one of the most common methods to study worm propagation. However, simulation process and software interface, which lack unified description, cause inefficiencies of worm propagation simulation. In order to achieve a unified description for worm propagation simulation process, we propose a Worm Propagation Simulation Description Language (WPSDL), which characterizes the software interfaces and parameters of each module in simulation process in a unified way. Meanwhile, we develop a simulation system of worm propagation oriented our presented language. In this system, we use related commands of the description language as interactive instructions, and then implement worm propagation simulation for different types of network worms. In addition, we conduct a series of experiments to analyse the impacts of worm propagation mechanism and network topology structure. The experiments show that increasing infection ability and scanning rate can improve the propagation scale significantly, and the propagation delay can influence the outbreak time and explosion intensity of worm propagation. The experiments not only provide support for the study of worm propagation mechanisms, but also verify the practicability of the description language and the simulation system.

We introduce a technique for the measurement of femtosecond optical pulses. This technique significantly reduces the uncertainty coming from the filter when used in the traditional technique, and an accurate spectral phase is retrieved. With the retrieved phase, the electric field, phase, waveform, as well as the duration of femtosecond optical pulses can be precisely reconstructed. The simulated autocorrelation traces deduced from the reconstructed pulsed electric field are in good agreement with the measured ones. This technique removes the manual procedure of selection and adjustment of the filter, an automatic measurement being realized.

This paper reports an ytterbium-doped linear-cavity fiber laser with the optical length of 1.6 km passively mode-locked by a high modulation depth semiconductor saturable absorber mirror (SESAM). An ultra-low repetition rate of 191 kHz was achieved. The laser delivered the highly-chirped output pulses with the energy up to 75.2 nJ.

Lead zirconate titanate (PZT) film is prepared on Pt/Ti/SiO2/Si substrate by proposed processes based on the sol–gel method and rapid thermal anneal (RTA). The ratio of Zr/Ti in the PZT film is 40/60. The PZT film has a mixture of perovskite orientations in which the (110) orientation is dominant. The Pt/PZT/Pt capacitor has remanent polarization of approximately 28.8 µC cm−2 and coercive voltage of approximately 0.76 V at 3 V voltage amplitude. The Pt/PZT/Pt capacitor has excellent fatigue properties. Switch polarizations decrease to 93.1% after 6 × 1012 switch cycles. The excellent fatigue properties result from the ameliorations of PZT/Pt interface conditions, restraining Pb volatilization and the directions of crystal domains in the RTA process. Some electric properties of the PZT capacitor proposed are contrasted with those of PZT capacitors with a different anneal process in the preparation.

We demonstrate a self-starting 313 MHz repetition rate, 77 fs Yb:fiber laser incorporated with a phase-biased nonlinear amplifying loop mirror and intra-cavity dispersion compensation. Although all of the fibers are non-polarization-maintaining, the mode locking is environmentally stable.

Impact of band-engineering to the performance of charge trapping memory with HfO2/Ta2O5/HfO2 (HTH) as the charge trapping layer is investigated. Compared with devices with the same total HfO2 thickness, structures with Ta2O5 closer to substrates show larger program/erase window, because the 2nd HfO2 (next to blocking oxide) serving as part of blocking oxide reduces the current tunneling out of/in the charge trapping layer during program and erase. Moreover, trapped charge centroid is modulated and contributed more to the flat-band voltage shift. Further experiments prove that devices with a thicker 2nd HfO2 layer exhibit larger saturate flat-band shift in both program and erase operation. The optimized device achieves a 7 V memory window and good reliability characteristics.

We present an alternate adiabatic evolution for the Deutsch—Jozsa problem. The biggest difference of our adiabatic evolution constructed here with those appearing before is that an alternate initial Hamiltonian is used for the adiabatic evolution, with which the evolution task can be finished in O(1) time complexity. Our construction mostly resembles the one discussed by Das et al. [Phys. Rev. A 65 (2002) 062310], except for the initial system Hamiltonian of the adiabatic algorithm.

The nonpolar resistive switching characteristics of an Al/AlOx/indium tin oxide (ITO) device on a plastic flexible substrate are investigated. By analyzing the electron diffraction spectroscopy results and thermal coefficient of resistivity, it is discovered that the formation of aluminum and indium conducting filaments in AlOx film strongly depends on the polarity of the applied voltage. The metal ions arising from the Al and ITO electrodes respectively govern the resistive switching in corresponding operation polarity. After 104 times of mechanical bending, the device can perform satisfactorily in terms of resistance distribution, read sequence of high and low resistive states, and thermal retention properties.

We demonstrate a two-stage chirped pulse fiber amplification system which generates 50 nJ, 152 fs pulses at a repetition rate of 20 MHz.

The surface-emitting photoluminescence spectrum is an important factor which directly participates in the determination of the oscillating wavelength and the output power of a semiconductor disk laser. Here a theoretical model for calculating the surface-emitting photoluminescence spectrum is presented. The surface-emitting photoluminescence spectra of two samples, one with a resonant microcavity and the other with an antiresonant microcavity, are calculated; the simulated results are in good agreement with the experimental results.

Pt/SrBi2Ta2O9 (SBT)/Pt capacitors have been successfully fabricated using a metalorganic decomposition (MOD) technique. The switchable polarization of SBT capacitors showed a tendency to increase with the number of switching cycles at first and then decrease after 2×109 switching cycles. During the switching process, a competition existed between the depinning behavior of domains and the aggregation of defect charges at the interfaces between SBT thin films and electrodes. It was this competition that determined the fatigue characterization for SBT capacitors. Higher external voltages facilitated the recovery of polarization suppression, which suggests that more domains in the SBT thin films were easily depinned by a higher external field and the pinning depth due to defect charges was different.

We measured the timing error of femtosecond pulses amplified by a Ti:sapphire regenerative amplifier operated at a 1 kHz repetition rate using a modified cross-correlation technique. This technique can detect sub-femtosecond timing variation. By actively controlling the amplifier cavity length, we reduced the rms timing jitter of the regenerative amplifier into the sub-femtosecond range.

A novel method for simultaneous 3-D imaging using chirped ultrashort light pulses is proposed. Simultaneous imaging without scanning is possible by means of the conversion between the time and the color axes mediated by the chirped pulse. The theoretical limitation of the spatial resolution is discussed. We proved the efficacy of this method by measuring an area composing three flat steps made of three gauge blocks of different lengths with an accuracy of better than 0.3 mm. This technique is applicable for imaging of the shape of moving objects, or surface testing or inspection.