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Large gas turbine control system fail during operation inevitably. Due to the various failure causes and failure modes, the troubleshooting process is relatively complicated. Combining the current situation of gas turbine control system fault diagnosis, the fault examples of the gas turbine control system are sorted out and summarized into five types of faults. Using distributed database, micro-service framework Spring Cloud, front-end framework Vue.js, following the principle of separation of front-end and back-end , carry out the design and development of the fault diagnosis system for GT control system based on B/S architecture, so that power plant staff can use the system to analyze and diagnose faults, and improve the accuracy and efficiency of fault diagnosis of the GT control system.

As the increasingly prominent environmental problems caused by energy development and the urgent need for high-quality power supply, renewable energy and DC distribution network technologies have been rapidly developed. A large number of applications of converter products will inevitably become a development trend. The test technology of converters should also receive more attention. This paper designs a scheme of multi-functional converter electrical tests system based on full/half bridge hybrid MMC technology, and verifies the feasibility of its function based on digital simulation. It can conveniently meet the electrical test requirements of DC/DC converters, DC/AC and AC/DC converters (single-phase and three-phase). And based on its own characteristics, it can meet the test requirements of unidirectional converter and bidirectional converter.

In this paper, image processing technology is used to simulate the reconstructed images of holographic stereogram in different depth planes. The quality of the reconstructed image of a single hogel at different depths is analyzed firstly. The size of the hogel, the distance between the holographic stereogram and the LCD and the distance between the holographic stereogram and the imaging plane are all factors affecting the quality of the reconstructed image. By dividing the hogel into many sub-parts, the reconstructed images of each sub-parts are analyzed one by one, and by superimposing the reconstructed images of each sub-parts, the reconstructed images of the hogel at different depths can be obtained. Then, the relationship between the reconstructed images of each hogel is analyzed, and the reconstructed images of all hogels are translated and superimposed to obtain the reconstructed images of the holographic stereogram in different depth. The synthetic parallax images generated by using the effective perspective image segmentation and mosaicking (EPISM) algorithm proposed by our group are used to print the holographic stereogram. The experiment results show that the reconstructed images of the stereogram in different depth planes are consistent with the simulation results, which verifies the validation of the simulation.

Temperature is a significant factor in the application of graphene-based pressure sensors. The influence of temperature on graphene pressure sensors is twofold: an increase in temperature causes the substrates of graphene pressure sensors to thermally expand, and thus, the graphene membrane is stretched, leading to an increase in the device resistance, an increase in temperature also causes a change in the graphene electrophonon coupling, resulting in a decrease in device resistance. To investigate which effect dominates the influence of temperature on the pressure sensor based on the graphene&ndash, boron nitride (BN) heterostructure proposed in our previous work, the temperature characteristics of two BN/graphene/BN heterostructures with and without a microcavity beneath them were analyzed in the temperature range 30&ndash, 150 &deg, C. Experimental results showed that the resistance of the BN/graphene/BN heterostructure with a microcavity increased with the increase in temperature, and the temperature coefficient was up to 0.25%&deg, C&minus, 1, indicating the considerable influence of thermal expansion in such devices. In contrast, with an increase in temperature, the resistance of the BN/graphene/BN heterostructure without a microcavity decreased with a temperature coefficient of &minus, 0.16%&deg, 1. The linearity of the resistance change rate (&Delta, R/R)&ndash, temperature curve of the BN/graphene/BN heterostructure without a microcavity was better than that of the BN/graphene/BN heterostructure with a microcavity. These results indicate that the influence of temperature on the pressure sensors based on BN/graphene/BN heterostructures should be considered, especially for devices with pressure microcavities. BN/graphene/BN heterostructures without microcavities can be used as high-performance temperature sensors.

In order to accurately analyze the broadband pulsed amplification performances of the domestic picosecond petawatt laser system, which uses large aperture N31 or N41 neodymium glass as gain medium, the broadband pulsed amplification model is improved by introducing the actual stimulated emission cross section (SECS) of neodymium glass. Comparing with the SECS under Gaussian approximation, the amplified pulsed spectrum gain narrowing effect with different SECSs are analyzed. It is found that in the actual SECS of N31 neodymium glass laser, the gain-narrowing effect is enhanced, the output energy decreases, gain’s saturation effect weakens, system’s accumulated B integral augments, but the laser system turns insensitive to the center wavelength simultaneously. Based on the Shenguang II high energy picosecond petawatt laser system which uses N31 neodymium glass, the spectral shape, center wavelength, and energy stability of amplified output pulse are simulated by using different SECSs. It is shown that the super-Gaussian spectral shape narrows more greatly than Gaussian spectral shape, the spectrum bandwidth narrows from 10 to about 3 nm with gain larger than 107, and the accumulated B integral increases to 1.7. Additionally, the gain-narrowing effect makes the output spectrum (with 1054 nm of center wavelength) less affected by changing the inputted center wavelength from 1052 to 1056 nm, and the gain saturation effect can improve output energy stability to less than 2% (root mean square (RMS)) with about 3% (RMS) inputted energy stability, which are beneficial to the subsequent pulse compression and physical experiment. Based on the above analysis, a broadband pulsed amplified experiment is conducted by using Shenguang II petawatt laser system, the injected seed is about 10 nm (full width at half maximum (FWHM)) with 5 order super Gaussian shape at 1054-nm center wavelength, and 1.2 mJ with 3% (RMS) energy stability from optical parametric chirped pulse amplification. The amplified pulse with 1900 J at 1054.2 nm (3 nm FWHM) and stability < 2% (shot to shot) is achieved, and the spectral shapes and bandwidths after bar and disk amplifiers are measured, which are consistent with theoretical analysis results. The results can provide a necessary reference for constructing high energy broadband laser system and improving its performances in the future.

In order to promote the synergistic interaction between source network and storage, and enhance the load control capability, the adjustable load measurement technology based on blockchain has become the focus of research at home and abroad. This paper reviews the current research status of block chain technology and its application in declaration and issuance, market supervision, market settlement, load measurement, enhancing mutual trust of market transactions and information security. Distributed ledger from block chain under containerized edge service engine, improved directed and acyclic chart distributed ledger structure and adjustable load execution score three based on distributed ledger data. In this respect, the key and difficult points of technology are summarized. Combined with the current situation of power development demand, power market, electricity price mode, demand response, the possible problems and development trend of adjustable load measurement technology based on block chain are discussed in detail.

Objective The second sacral segment iliosacral screw (S2 screw) insertion is a demanding technique, with a high rate of screw malposition due to the complex pelvic anatomy. TiRobot™ is an orthopedic surgery robot which can be used for S2 screw fixation. We carried out a retrospective analysis of the accuracy of S2 screws using robot-assisted navigation.Methods A retrospective analysis of 16 patients admitted and managed by S2 screw fixation for unstable pelvic fractures was carried out for evaluation of its efficacy and safety. all patients with pelvic ring disruptions and sacral dysmorphism were evaluated radiographically and S2 screws were placed using a robot-assisted navigation technique. Screw position was assessed and classified using postoperative computed tomography. Fisher’s exact probabilities test was used to analyse the screws’ positions. Surgical time after reduction of the pelvis, insertion time for guide wire, number of guide wire attempts, and radiation exposure without pelvic reduction were also assessed.Results The excellent and good rate of screw placement was 100%. The fluoroscopy time after pelvic reduction was 7 (7, 9) seconds. The operation time after reduction of the pelvis was 29 (27,33). Time for guide wire insertion was 2.0 (2, 2) minutes. The number of guide wire attempts was 0.0 (0, 0). No postoperative complications or revisions were reported.Conclusion S2 iliosacral screws can be safely and accurately accomplished using a robot-assisted navigation technique in patients with unstable posterior pelvic ring disruptions and sacral dysmorphism.

Most researches on the static performance of stiffened panel joined by friction stir welding(FSW) mainly focus on the compression stability rather than shear stability. To evaluate the potential of FSW as a replacement for traditional rivet fastening for stiffened panel assembly in aviation application, finite element method(FEM) is applied to compare compression and shear stability performances of FSW stiffened panels with stability performances of riveted stiffened panels. FEMs of 2024-T3 aluminum alloy FSW and riveted stiffened panels are developed and nonlinear static analysis method is applied to obtain buckling pattern, buckling load and load carrying capability of each panel model. The accuracy of each FEM of FSW stiffened panel is evaluated by stability experiment of FSW stiffened panel specimens with identical geometry and boundary condition and the accuracy of each FEM of riveted stiffened panel is evaluated by semi-empirical calculation formulas. It is found that FEMs without considering weld-induced initial imperfections notably overestimate the static strengths of FSW stiffened panels. FEM results show that, buckling patterns of both FSW and riveted compression stiffened panels represent local buckling of plate between stiffeners. The initial buckling waves of FSW stiffened panel emerge uniformly in each plate between stiffeners while those of riveted panel mainly emerge in the mid-plate. Buckling patterns of both FSW and riveted shear stiffened panels represent local buckling of plate close to the loading corner. FEM results indicate that, shear buckling of FSW stiffened panel is less sensitive to the initial imperfections than compression buckling. Load carrying capability of FSW stiffened panel is less sensitive to the initial imperfections than initial buckling. It can be concluded that buckling loads of FSW panels are a bit lower than those of riveted panels whereas carrying capabilities of FSW panels are almost equivalent to those of riveted panels with identical geometries. Finite element method for simulating static performances of FSW and riveted stiffened panels is proposed and evaluated and some beneficial conclusions are obtained, which offer useful references for analysis and application of FSW to replace rivet fastening in aviation stiffened panel assembly.

Multi-objective optimization of the dynamic gear flowmeter was established by using computer software optimization toolbox. We established the objective function with flow pulsation coefficient minimum and smallest volume of the meter as optimized object, by establishing boundary constraint conditions and performance constraint conditions, choosing proper parameters and initial values, and then we can optimize the design parameters by the help of computer software using optimization function. The optimizing methods can greatly improved the design and optimizing efficiency, which can help us to get the optimal design in the shortest time.

The chord vibration frequency analysis is carried out based on the theory of vibration of continuous systems. The finite element software is used to analyze frequencies of different chords, which is compared with the theoretical frequency. The relevant conclusions demonstrate that studies on guitar chords’ sound quality and intonation using proposed finite element method are doable and necessary. It has certain directive significance in guitar production process.

As we know, the hydraulic problems, the ordinary gear flowmeter pulsation of the flow rate and the pressure pulsation of the defects, remain to be solved. The article started from the analysis of Instantaneous flow characteristics for general gear flow-meter, with the control variables method, relationship between the number of gear teeth and flow pulse rate was studied.The rule was discovered that while gear's number of teeth is bigger, the flow and press pulsation for general gear flowmeter is less. The paper conducted the simulation research on instantaneous flow characteristics for general gear flow-meter. The results show that: while z1=z2=30, the flow pulsation rate equals 7.05%. While z1=z2=8, the flow pulsation rate equals 24.45%. While z1=19, z2=14, the flow pulsation rate equals12.73%. This research has provided the theoretical basis for the gear flow-meter's design.

In order to solve the problem of heterogeneous network interconnection between PLC control network and monitoring software network in automatic storage system, OPC communication technology is used to build the network interconnection model. The integration of heterogeneous networks is achievable, and C# is used to design automatic storage system monitoring software. After taking test, the data transmission between PLC control network and computer control network is reliable. The monitoring software runs smoothly, and is applied successfully to one automatic storage simulation system.

In wireless sensor networks (WSNs), both efficient energy management and Quality of Service (QoS) are important issues for some applications. For creating robust networks, real-time services are usually employed to satisfy the QoS requirements. In this paper, we proposed a hierarchical real-time MAC (medium access control) protocol for (m,k)-firm constraint in wireless sensor networks shortly called HRTS-MAC. The proposed HRTS-MAC protocol is based on a dynamic priority assignment by (m,k)-firm constraint. In a tree structure topology, the scheduling algorithm assigns uniform transmitting opportunities to each node. The paper also provides experimental results and comparison of the proposed protocol with E_DBP scheduling algorithm.

Efficient energy management is a very important issue in wireless sensor network since wireless sensor nodes are usually battery-powered. Recently, S-MAC protocol based on low duty-cycle has been proposed to reduce energy consumption. Even though research effort has been made to evaluate performance of S-MAC by conducting various simulations, however, some important simulation parameters are not well evaluated yet. In this paper, we identify the performance of S-MAC under different amount of streams and different patterns such as data rate and traffic. Through analyzing the simulation results, we discover weakness of S-MAC as well as analyze impact of amount of streams and packet pattern.

Movement pattern recognition is the basis for flexible control of lower-limb rehabilitation aids. To improve the effect of lower-limb movement pattern recognition, an electromyographic recognition method to identify movement patterns without movement information was proposed. Firstly, the initial moment of feature extraction was detected by the integral of absolute value of surface electromyography (EMG) recorded from gluteus medius muscle. Secondly, the features were extracted from the surface EMG recorded from five main muscles of lower limb. Finally, Random Forest algorithm was applied to recognize the five movement modes (level-ground walking, stair ascent, ramp ascent, stair descent, and ramp descent), while the importance of every feature was estimated by the recognition precision and Gini index. The features with greater contribution were picked out and applied to recognize. The simulation result indicates that this method had achieved an average accuracy of 99.2% in five movement modes recognition, which is conductive to the further study of lower-limb rehabilitation aids.

Innate lymphocytes play a key role in maintaining the immune bowel barrier, which provides resistance to infection. However, the effects of probiotics on changes in the function of innate lymphocytes in the postoperative intestine remain known.Ninety-six male SD rats were divided into the blank group and the preoperative Lactobacillus intervention group, and parts of the ileum were sampled on days 0, 3, 5 and 7 after partial small bowel resection. Distal ileum samples were evaluated using immunohistochemistry to detect IL-5, IL-13, IL-17a and IL-22.(1) There were more immune cells in the experimental group than in the blank group on day. (2) After the first 3 days, the levels of IL-22 and IL-5 (p = 0.024) were higher in the experimental group than in the blank group. From the third to the fifth day, the IL-5 and IL-22 levels were higher and the IL-13 and IL-17A levels were lower in the experimental group than in the blank group. From the fifth to the seventh day, the IL-5 and IL-13 levels were lower and the IL-22 and IL17A levels were higher in the experimental group than in the blank group.Probiotics stabilize the fluctuation of the intestinal immune system postoperatively.

Background The role of β-adrenergic stimulation on viral myocarditis has been investigated in animal models of viral myocarditis. Excess stimulation of β-adrenergic receptors by catecholamines causes phosphorylation/activation of cAMP response element binding protein (CREB) by the cAMP signaling pathway. CREB as an important regulator of gene expression mediates the cardiovascular remodeling process and promotes anti-inflammatory immune responses. However, the CREB expression and phosphorylation have not been studied, and the effects of carvedilol (a nonselective β-adrenoceptor antagonist) on the CREB has not been investigated in the setting of acute viral myocarditis. Methods This study was therefore designed to examine the effects of carvedilol on the transcriptional factor CREB in a murine model of acute viral myocarditis. In a coxsackievirus B3 murine myocarditis model (Balb/c), effects of carvedilol on plasma noradrenaline, heart rate and blood pressure, myocardial histopathological changes and fibrosis, cardiomyocyte apoptosis, cardiac CREB and phosphorylated CREB, cytokine levels, and viral RNA were studied. Results The expression and phosphorylation of CREB were decreased with concomitant increase of IL-6 and TNF-α in murine coxsackievirus-induced acute viral myocarditis. The levels of IL-6 and TNF-α were correlated with the expression of CREB or phosphorylated CREB. Carvedilol increased the cardiac CREB expression and phosphorylation and decreased the plasma catecholamine levels and the production of IL-6 and TNF-α with amelioration of acute viral myocarditis. Conclusion These results show that CREB may be involved in the pathophysiology of viral myocarditis and carvedilol exerts some of its beneficial effects by increasing the CREB expression and phosphorylation.

Optical parametric frequency up-conversion and amplification, used for ultra-weak infrared image detection, is investigated both numerically and experimentally. A circum-circle model of spatial filtering is proposed to suppress the parametric fluorescence background noise. Combining the spatial filter, image relay module and band-pass filter, the fluorescence noise is suppressed by 70%. Accordingly, the image quality is significantly improved and the peak signal-to-noise ratio is increased by 22%. Based on the 10 Hz, mJ-level, 355 nm picosecond pump laser, the weak infrared image is amplified and up-converted into the visible region, and over 1.3108 (82 dB) optical gain is obtained at the same time. Our experiment demonstrates that the detection sensitivity of the conventional uncooled CCD can be as high as 7.4 photons per pixel when the high gain OPA is used as an image preamplifier. The scheme in this paper is expected to be used in single-photon-level sensitive infrared imaging.

Background In recent years, catheter ablation has increasingly been used for ablation of idiopathic premature ventricular complexes (PVCs) or ventricular tachycardias (IVTs). However, the mapping and catheter ablation of the arrhythmias originating from the vicinity of tricuspid annulus (TA) may not be fully understood. This study aimed to investigate electrophysiologic characteristics and effects of radiofrequency catheter ablation (RFCA) for patients with symptomatic PVCs and IVTs originating from the vicinity of TA. Methods Characteristics of body surface electrocardiogram (ECG) and electrophysiologic recordings were analyzed in 35 patients with symptomatic PVCs/ IVTs originating from the vicinity of TA. RFCA was performed using pace mapping and activation mapping. Results Among the 35 patients with PVCs/IVTs arising from the vicinity of TA, complete elimination of PVCs/IVTs could be achieved by RFCA in 32 patients (success rate 91.43%) during a median follow-up period of 21 months. PVCs/IVTs originating from the vicinity of TA had distinctive ECG characteristics that were useful for identifying the precise origin. An rS pattern was recorded in lead V1 in 93.1% of patients with PVCs/IVTs from the free wall of TA, vs 16.7% of patients with PVCs/IVTs from the septal TA, whereas a QS pattern in lead V1 occurred in 83.3% of patients with PVCs/IVTs from the septal TA vs 6.9% of patients with PVCs from the free wall of the TA. The precordial R wave transition occurred by lead V3 or earlier in all patients with PVCs/IVTs originating from the septal portion of the TA, as compared to transition beyond V3 in all patients with PVCs/IVTs from the free wall of the TA. Conclusions RFCA is an effective curative therapy for symptomatic PVCs/IVTs originating from the vicinity of TA. There are specific characteristics in ECG and the ablation site could be located by ECG analysis.

BACKGROUND: Elevated heart rate is associated with increased cardiovascular morbidity. The selective I(f) current inhibitor ivabradine reduces heart rate without affecting cardiac contractility, and has been shown to be cardioprotective in the failing heart. Ivabradine also exerts some of its beneficial effects by decreasing cardiac proinflammatory cytokines and inhibiting peroxidants and collagen accumulation in atherosclerosis or congestive heart failure. However, the effects of ivabradine in the setting of acute viral myocarditis and on the cytokines, oxidative stress and cardiomyocyte apoptosis have not been investigated. METHODOLOGY/PRINCIPAL FINDINGS: The study was designed to compare the effects of ivabradine and carvedilol in acute viral myocarditis. In a coxsackievirus B3 murine myocarditis model (Balb/c), effects of ivabradine and carvedilol (a nonselective β-adrenoceptor antagonist) on myocardial histopathological changes, cardiac function, plasma noradrenaline, cytokine levels, cardiomyocyte apoptosis, malondialdehyde and superoxide dismutase contents were studied. Both ivabradine and carvedilol similarly and significantly reduced heart rate, attenuated myocardial lesions and improved the impairment of left ventricular function. In addition, ivabradine treatment as well as carvedilol treatment showed significant effects on altered myocardial cytokines with a decrease in the amount of plasma noradrenaline. The increased myocardial MCP-1, IL-6, and TNF-α. in the infected mice was significantly attenuated in the ivabradine treatment group. Only carvedilol had significant anti-oxidative and anti-apoptoic effects in coxsackievirus B3-infected mice. CONCLUSIONS/SIGNIFICANCE: These results show that the protective effects of heart rate reduction with ivabradine and carvedilol observed in the acute phase of coxsackievirus B3 murine myocarditis may be due not only to the heart rate reduction itself but also to the downregulation of inflammatory cytokines.

In order to give the testers a barrier-free environment and to encourage the use of run-up in the height test, we combine the mechanical rotating feeler with the electronic display, achieving a high degree of accurate measurement of touch. The height instrument introduced in this paper adopts ATMEGA16 AVR as the microcontroller to collect and process the data from the sensor rod, driving the digital display at the same time.

Based on PLC, this paper blends the automatic control theory with the feed processing industry and carries out design and research on the feed production automatic control system. Mainly employing the method of combining the upper computer with the PLC, this system can collect, recognize and control data to progressively implement the automatic control of feed production process. VC and configuration software are generally used to program for the system of which the database adopts SQL Server2000 and the PLC resorts to ladder diagrams to design software programming. The running result shows that this system can detect and control safety parameters and achieve the automatic technology transform of feed production lines.

Animal bodies are mainly composed of hydrogels — polymer networks infiltrated with water. Most biological hydrogels are mechanically flexible yet robust, and they accommodate transportations (e.g., convection and diffusion) and reactions of various essential substances for life – endowing living bodies with exquisite functions such as sensing and responding, self-healing, self-reinforcing and self-regulating et al. To harness hydrogels’ unique properties and functions, intensive efforts have been devoted to developing various biomimetic structures and devices based on hydrogels. Examples include hydrogel valves for flow control in microfluidics[1], adaptive micro lenses activated by stimuli-responsive hydrogels[2], color-tunable colloidal crystals from hydrogel particles[3, 4], complex micro patterns switched by hydrogel-actuated nanostructures[5], responsive buckled hydrogel surfaces[6], and griping and self-walking structures based on hydrogels[7–9]. Entering the era of mobile health or mHealth, as unprecedented amounts of electronic devices are being integrated with human body[10–14], hydrogels with similar physiological and mechanical properties as human tissues represent ideal matrix/coating materials for electronics and devices to achieve long-term effective bio-integrations[15–17]. However, owing to the weak and brittle nature of common synthetic hydrogels, existing hydrogel electronics and devices mostly suffer from the limitation of low mechanical robustness and low stretchability. On the other hand, while hydrogels with extraordinary mechanical properties, or so-called tough hydrogels, have been recently developed[18–22], it is still challenging to fabricate tough hydrogels into stretchable electronics and devices capable of novel functions. The design of robust, stretchable and biocompatible hydrogel electronics and devices represents a critical challenge in the emerging field of soft materials, electronics and devices.