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As the main load-bearing structure of heavy machine tools, cranes, and other high-end equipment, the large-scale box structures usually bear moving loads, and the results of direct topology optimization usually have some problems: the load transfer skeleton is difficult to identify and all working conditions are difficult to consider comprehensively. In this paper, a layout design method of stiffened plates for the large-scale box structures under moving loads based on multiworking-condition topology optimization is proposed. Based on the equivalent principle of force, the box structures are simplified into the main bending functional section, main torsional functional section, and auxiliary functional section by the magnitude of loads and moments, which can reduce the structural dimension and complexity in topology optimization. Then, the moving loads are simplified to some multiple position loads, and the comprehensive evaluation function is constructed by the compromise programming method. The mathematical model of multiworking-condition topology optimization is established to optimize the functional sections. Taking a crossbeam of superheavy turning and milling machining center as an example, optimization results show that the stiffness and strength of the crossbeam are increased by 17.39% and 19.9%, respectively, while the weight is reduced by 12.57%. It shows that the method proposed in this paper has better practicability and effectiveness for large-scale box structures.

With the growth of network equipment, the security of network access environment becomes particularly important. Many network security technologies, such as vulnerability mining, fuzzy testing and intrusion detection, have attracted more and more attention. However, the effectiveness of these security technologies will be greatly reduced in the face of unknown protocols. By automatically extracting the format information of unknown protocols through the protocol reverse technology, the processing capability of the above security technologies in the face of unknown protocols can be enhanced. In this paper, by analyzing the changing characteristics of protocol fields, a field sequence coding method is proposed, which is suitable for reflecting the field sequence characteristics of different protocols and can improve the generalization ability of the model. Using the above field sequence coding method, a field classification model for unknown protocols is implemented based on the LSTM-FCN network, which is widely used in time series classification tasks. Finally, a binary protocol reverse method based on deep learning is proposed. The method is based on the field classification model and realizes the division and type identification of unknown protocol fields according to the classification results. In the experiment, the field classification model has high accuracy and recall in different protocols, which shows that the model has the ability to identify the field type according to the changing characteristics of the field. The proposed protocol reverse method also accurately and quickly identifies the field and its type, proving the reverse ability of the method to unknown binary protocols.

This design cleverly integrates modern machinery and control technology into the home system, and cleverly combines intelligent machinery and intelligent life, making family life more intelligent, comfortable and convenient. Use the ceiling as the carrier to realize the three-dimensional home design, make full use of the indoor top space, and solve the problems of small residential space and difficult storage. The main functions contained in this device are stored indoors. The introduction of this design conforms to the trend of intelligent family life and greatly facilitates people’s daily life.

This paper uses DPM model in Fluent to divide the mesh and conduct fluid analysis for the existing family filter, by using the Rosin - Rammler distribution simulated reality of different diameter of the plastic particles’ distribution in the water. Secondly, using particle tracking algorithm to calculate the distribution of particle diameter of the export, so as to check the existing household filter’s ability for the different plastic particle diameter.

A high voltage, microsecond regime, pulsed glow discharge has been applied to a standard Grimm type source on a LECO SA-2000 multichannel optical spectrometer. The spectrometer system has been equipped with fast time-resolved electronics in order to study the temporal response of the elemental emission lines. The aim of the research was to investigate possible gains in signal-to-background ratio (S/B) and detection limits compared to a conventional direct current (dc) mode of operation. It was found that the high instantaneous pulse power in itself gives approximately a factor 2 increase in S/B. By utilising time-resolved detection, gains in the range 5–10 are achieved. For nitrogen, it was found that the background from leakage of air could be reduced to approximately 1/3 compared with the dc mode. Another interesting observation was that certain nearly non-conducting materials, which cannot be run in dc mode, could be run in the microsecond pulsed mode.

Investigations have been performed using microsecond pulsed glow discharge atomic emission spectrometry (GD-AES) to determine the effect of the glow discharge parameters, including applied pulse voltage, pulse width, pulse frequency and gas pressure, on the resolution of depth profiling. The results indicate that a concave crater profile is obtained for low voltage, whereas the curvature is convex for high voltage. The criteria of a flat crater bottom and good depth resolution are fulfilled only with a limited range of voltages at each operating pressure. The results also imply that the pulse frequency and pulse width have little effect on the resolution of depth profiling; thus a wide dynamic range of layers from several nanometers to tens of micrometers can be analyzed by increasing or decreasing the pulse frequency and width. Under the optimized parameters, a thin coating of Cu (50 nm) on steel, an electroplated steel and a computer hard-disk with multiple thin layers were analyzed.

A high voltage, microsecond regime pulse dc glow discharge was applied to a standard Grimm source on a modified LECO SA-2000 direct reader spectrometer and to a duplicate Grimm source coupled to a scanning monochromator. The effects of experimental conditions, including pulse voltage, pulse frequency, pulse width and Ar pressure, on Cu atomic and ionic emission intensities were examined and compared with continuous discharge results. The pulsed Grimm source has a higher sputtering rate, greater signal intensity and lower detection limits. The pulsed signal for atomic lines shows a different temporal response from ionic lines. Pulsed Grimm GD-AES also offers control features advantageous in the measurement of thin surface layers.

The purpose of this paper is to discuss the physical properties of diffractionless beams, their propagation and transformation through optical systems. We start from the analysis of Durnin’s experiment to present a useful idea for the design of Bessel beam convertors. Then, the propagation of Bessel beams through ABCD optical systems are studied, and numerical calculations are performed to illustrate and compare the characteristics of truncated Bessel beams propagating through a sharp-edged aperture and a soft-edged one.

Based on the M 2 -factor concept and the equivalence between a beam generated by a gaussian Schell-model (GSM) source and a mixed-mode laser (MML) beam, a simple method is presented to estimate the number of effectively oscillating modes and the corresponding weighting factors of MML beams simultaneously.

Islanding detection is a significant technical barrier to the distributed generation (DG) industry. When islanding occurs, the inverter current of DG has a strong correlation with load voltage of DG. With respect to the correlation, this paper proposes an islanding detection method (IDM) based on periodic matching of the sequence perturbation. In this periodic code matching detection method, a periodic sequence is introduced to perturb the inverter current amplitude. The IDM can be achieved by calculating periodic matching degree between the islanding detection coefficient and the sequence. The influence on IDM imposed by sequence characteristics and load variation is also discussed in this paper. According to IEEE Std. 1547, an islanding detection model is designed and simulated in this paper. The simulation and experiment results indicate a strong ability to anti-harmonic noise when the 1-0 non-zeroing sequence with six bits is selected as the perturbation sequence. The proposed method introduces little damage to grid. In the normal range of voltage and frequency, this method can detect the islanding of DG reliably and effectively even if load varies.

A Grimm-type glow discharge ion source, operated in the microsecond pulsed mode, has been interfaced to a commercial time-of-flight mass spectrometer. Ion transport from the source to the mass spectrometer, an inherent limitation of a Grimm source and mass spectrometer combination, was evaluated. The primary discharge operating conditions found to influence transport efficiency were gas flow rate and source pressure. The configuration of the Grimm-type source also influenced ion transport, including use of a gas-directing sleeve device. The effect of transport efficiency was separated into two components: (1) total ion signal and (2) temporal resolution. The latter is an advantage afforded by use of a pulsed glow discharge source and time-of-flight spectrometer, which allows discrimination against interfering gaseous background ions by appropriate ion sampling time. Shown as an example is the identification of trace magnesium from potential background interference using an optimized source configuration based on this temporal resolution method.

In this paper, a thin-disk laser with the output power of kW level is demonstrated. The laser used is Nd:YAG laser medium for easiness to reach the threshold power densities of the pump and less heat to dissipate from the crystal. The thin disk of 1 mm thickness with 1.5-at. % Nd doped and a simple 4-pass pump coupling system is designed to fulfill the total absorption of the pump light. 2D-stacks diode array works as the pump source and a conventional optics is used for efficient and uniform pumping.

A diode-laser side-pumped E-O Q-switched TEM00 Nd:YAG slab laser that uses a large N.A. cylindrical lens and a thin slab pumping geometry has been investigated. The pumping scheme has the ability to match well the pump beam to the laser's fundamental transverse mode in two axes. Approximately 1.1 times diffraction limited laser beam is obtained. The slope efficiency is 31% and 18.9% at long-pump and Q-switched operation, respectively.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The diode laser side pumped E-O Q-switch Nd:YAG laser was described that produced energy O.36-mJ/pulse. 7-nspulse width ,pulse repetition rates 50-Hz, TEM00 mode.The laser has a zigzag slab geometry, side pumped with a quasi- cw 15Wdiode bar. We used a 1 .1%Nd:YAG Brewster-cut seven-bounce thin trapezoidal slab that was 1 .2mm thick.Using a cylindrical lens (f=1 .6nim),it made the diode laser couple in the slab. The laser resonator was a plane-concavecavity, radius of mirror curvature was 3m. The cavity length was about 20cm. The plane output mirror transitivity was T=0. 1 . Wedecided to the beam quality M2=1 . 1 . Q-switchlaser slope efficiency was 19%. keyword solid-state lasers, side pumped, diode laser, single transverse mode 1 .INTRODUCTION Diode-laser(LD) pumped solid-state lasers have been one ofthe most interesting and significant developments in laserengineering in recent years1. LD pumping offered high reliability, efficiency and compactness. Side pumping has been togenerate the fundamental transverse mode efficiently2. Recently a side pumping technique used in Q-switch cavity-dumpedand E-O Q-switch laser3 demonstrated efficiency side-pumped operation while still maintaining TEM00 operation. Wereported on a E-O Q-switched laser that used a numerical aperture(NA>1) and short focus length (f=1 .6mm) cylindricallens coupler thin Nd:YAG thin trapezoidal slab and generated 0.36-mJ, 7-ns, TEMo0. pulse repetition rates 50Hz whileusing