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1.
A clogging segment mechanical model is established on gas extraction horizontal borehole. Based on the air pressure extremes pmax of the construction site, we solve the corresponding critical clogging length L0 and find clogging will occur when L> L0. With the clogging segment mechanical model, we analyze the calculation method of the retreat drilling rod resistance in borehole. The influence rule of clogging length and air supplying system pressure on retreat drilling rod resistance is analyzed. Analysis results show that the main reason for difficult drilling clogging and retreat drilling rod is the higher pressure in borehole clogging segment. The retreat drilling rod resistance is especially sensitive to the change of air supplying system; therefore, the effective method of reducing the retreat drilling rod resistance is reducing the air supplying system pressure in borehole. The drilling construction status in Jiulishan coal mine is analyzed by using the clogging segment mechanical model, and three technical measures are put forward, including increasing slagging space, reducing slagging resistance and increasing drilling rod strength. When the improving measures are adopted, the pipe-sticking phenomena decreases, the drilling rod broken phenomenon are averted and the drilling efficiency increases by 17%. 相似文献
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为了改善城市绿化种植土壤普遍存在土壤无层次、侵入体多（渣砾、建筑垃圾）、紧实、肥力低等现象,进一步提升城市生态环境质量,以上海迪士尼绿化种植土项目为例,通过对其改良材料生产、种植土生产等环节进行研究探讨,详述了改良材料原场地控制、过程控制、进场控制及种植土生产过程控制等全过程监管的项目管理经验,以期为城市绿化种植土壤质量管理提供借鉴和参考。结果表明：加强土壤资源的保护和利用、严把改良材料质量关、提高绿化种植土壤机械化水平将会在一定程度上提高绿化种植土壤质量。 相似文献
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A comprehensive evaluation method based on fuzzy matter element analysis is proposed to solve problems of multiple performance and quality evaluation for computer numerical control (CNC) equipment. The fuzzy matter element theory is utilized to analyze multi-scale quality characteristics and attributes. Then, the comprehensive quality evaluation model for CNC equipment is founded by using fuzzy matter element analysis method. Analytic hierarchy process (AHP) and information entropy are applied to obtain the objective index weights. Furthermore, the combinational weight is calculated with the optimal mathematics model based on the least square method. Finally, the fuzzy matter element method is used to determine the assessment result. The case study indicates that the method has a certain rationality and feasibility. 相似文献
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For the problem of precision and real time control in the process of sulfuration,a new control model is put forward.All the noise existing in the sulfuration process are unified as one kind noise named as extensive noise,and the control system is self-adaptive in the process.The purpose of this strategy is to solve the problem preferred.The model comprises of two parts: one is Neutral Networks which deals with the advance sort,the other is dynamic self-adaptive system which is used to find the system's factors.The simulation result of dynamic self-adaptive system shows that this extensive noise controlled model is valid in the process. 相似文献
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Guiyang Huaxi district landscape bridge is seven miles the beach driving bearing type reinforced concrete box arch bridge, the design process of conventional arch bridge solutions with less thrust arch bridge to carry on the comparison, the combination of special terrain, geological conditions, finally chose the foundation excavation is small, economical, reasonable structure, less thrust of arch bridge using edge inclined rod and bearing platform consolidation, forming the free cantilever end method better solve the horizontal thrust at arch feet larger, by establishing the structure finite element model, analyzes the static force performance, the results show that the thrust of arch stress performance good, less economically feasible, beautiful appearance, and the scenic spot environment more harmonious. 相似文献
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This paper proposes a control strategy for the optimal control of the outsourcing production inventory system based on production point and production batch. The statistical probability distribution is used to describe the uncertainty of the production capacity of cooperative enterprises and the transportation time. The optimization model of the control parameters is developed with random production capacity for cooperative enterprises and random transportation time in order to minimize the holding cost,setup cost as well as the cost of production capacity waste. A simulation-based control parameters optimization algorithm is designed to solve the proposed model. The control strategy of production inventory system and the control parameters optimization algorithm proposed are validated by an example. We analyze the influence of the variation of the production point and production batch to the performance of the outsourcing production inventory system. 相似文献
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An algorithm of incremental model predictive control is proposed to solve a class of industrial production process real-time tracking problems. The basic idea is to establish a predictive model by adopting speed response on the basis of tracking error, and realize the optimization of the second time performance by using the soft constraint of the increment of control quantity and the online rolling optimization method. The theoretical analysis and Matlab simulation results show that the control algorithm can obtain good tracking performance, smooth dynamic response of the controlled object and strong robustness of the closed-loop system. 相似文献
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The robust control theory is used to solve the uncertainty of the optical extra-precise vibration isolation system. The wavelet theory is used to analyze the random vibration signal in the time-frequency domain and get the low frequency signal from the random vibration signal. The robust controller designed by the robust control theory is used to restrain the low frequency vibration. The active vibration isolation exploits the theory of robust control, which overcomes the uncertainty of model and the disturbance, and makes the control system to restrain the uncertainty of the model and the disturbance of the vibration. The simulation results prove that this method has shown good robustness and control precision in the vibration isolation of the optical extra-precise instrument and have good performance on restraining the low frequency vibration. 相似文献
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The authors analyze the influence in vector controlled induction machine caused by parameter variation and main flux saturation affects speed estimation of adaptive state observer. According to simulation of the modified scheme with saturated induction motor model, it is proved that when the vector control scheme operates in field weakening region, the main flux saturation will obviously influence precision of speed observer and bring great error of speed estimation. Thereby, the main flux saturation should be compensated to improve performance of the vector control system. 相似文献
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In order to solve the problem that the internal force of statically indeterminate prestressed and reinforced concrete bar system structures is difficut to determine when the structures come to the non-elastic state, a simple analysis method of experimental structures' internal force-sectioned dropping rigidity method is brought forward.In this method, according to the loading state of bars, the bars are divided into limited segments by the level of rigidity dropping, and the relative level of each segment is enacted; then the dropping modulus of each segment rigidity will be found by debugging time after time, and the checking point is the key distortion which was gained from the experiment; it is considered that the internal force which is calculated by elasticity analysis at the dropped rigidity can reflect the real internal force of the structures.It is basically proved that the method, which is brought forward in this paper, is effective by comparing its results with those from the experiment of a large size prestressed frame of two spans and single floor, of which the internal force redistribution is considered. 相似文献
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Macadamia nuts (‘nuts-in-shell’) are subjected to many impacts from dropping during postharvest handling. Kernels are enclosed in hard shells and quality may be lost from damage incurred during postharvest dropping. Kernel quality loss from dropping macadamias was investigated in three experiments in which nuts of several cultivars at different moisture contents were dropped onto a bed of nuts-in-shell or a metal plate. For each dropped treatment there was an undropped control at the same moisture content. Dropped and control kernels were assessed for quality parameters: whole kernel; shoulder damage; weight of pieces; oily kernels; and dusty kernels. Dropped and control kernels were also examined by scanning electron microscopy (SEM). Dropping macadamia nuts-in-shell at 3% moisture content onto nuts-in-shell significantly increased shoulder damage, oily kernels and dusty kernels. Shoulder damage doubled compared with the control (30% cf. 15%). Oily kernels more than doubled (38% cf. 18%). There were very few dusty kernels in controls at 3% moisture content, but 15–30% of kernels were dusty when dropped. Kernel quality was also reduced at higher moisture content when nuts were dropped onto nuts-in-shell twice, once at 10% and once at 20% moisture content. Shoulder damage was almost three times the control (46% cf. 16%), and 10% of kernels were dusty while controls had no dusty kernels. SEM showed that dropping caused an abraded abaxial cuticle with visible dust particles. Oily appearance following dropping was an indicator of cell membrane damage and potential for further deterioration in quality. Typical macadamia postharvest practices such as frequent dropping cause significant commercial losses due to quality reduction, visible as shoulder damage, oiliness and dustiness. 相似文献
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A human simulated intelligent control scheme based on sensory-motor schema for dynamic walking of biped robot is presented to solve the complex controller design.The dynamics model of a five-link planar biped is established. By imitating human walking movement and apprehending the posture change of the legs, the complex process of dynamic walking for biped robot is divided by four sequence phases. The multi-mode control law and the group of sensory-motor schema are designed based on the analysis of quality-quantity combination to the phase plane. Simulation results show that the proposed control strategy is effective to ensure continuous dynamic walking of biped robot and the control method is simple and easy to be realized. 相似文献
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It is one of the pivotal technology that mutually exclusive operation is in the system structural design of the parallel processing to solve resource conflict.Traditionally,the sharer resource mutually exclusive operation is managed by single-computer operation system time-sharing mode for multitask condition,but all of parallel nodes possess renovate right in multi-mode OS,so high-grade lock mechanism is a pivotal technology to solve share resource confilict in parallel process to prevent share resource accessing conflict.This article describes lock control arithmetic of mutually exclusive operation from system structure and puts forward mutually exclusive operation model based on NODS. 相似文献
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The dynamic model of multi-axle steering vehicle is improved by considering the impact of the front-axle mechanical steering on the vehicle steering performance and implying the front-axle wheel angle in control variables to reduce the difficulty of vehicle control. On the basis of modified dynamic model, the multi-axle vehicle is analyzed by combining model-following method with pole assignment process. The transient response and frequency domain characteristics of the yaw angle velocity and sideslip angle at different speeds are obtained. The results indicate that, using model-following method to control vehicle can obtain desired tracking effects. At high speed, the transient response has no overshoot, the response time is shortened, and the stability of vehicle is improved. 相似文献
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Zhang Peiyuan Yan Bo 《保鲜与加工》1999,(1):7-12
Under the condition that normal stress and shear stress are coupled in constitutive equations,a set of displacements which depend on geometric and physical properties of a thin wall rod is specially designated to minimize the coupling of basic deformations in control equations,and general forms to describe self balance system of internal forces are proposed with the model given by the present paper. 相似文献
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In order to realize the predictive function of BIM technology, the reliability theory and theoretical probability method are utilized to judge the uncertainty which exists in the process of construction. Meanwhile, the complicated relationship between construction schedule and prediction model is analyze, the random prediction model for construction schedule is established as well. Particularly, the influencing condition about a single factor in the process of construction is taken into consideration. Determinate model and random model for construction time as well as reliability analysis method for the construction time prediction which is based on a single influencing factor are studied .At the same time, The integrated management method of reliability prediction about construction schedule which is on basis of BIM management platform is discussed. The case study shows that the proposed method has delivered dramatic results to the control of construction schedule. 相似文献
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HACCP体系是食品生产企业实现产品安全的管理体系。针对亚麻油精炼的生产工艺进行了危害分析,确定5个关键控制点,并详细制定HACCP计划,将危害因素降到最低限度,确保亚麻籽油生产的质量安全,为油脂生产企业HACCP安全体系的构建提供参考模型。 相似文献
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Traditional structural design emphasizes checking whether a loaded structure satisfies design requirements without considering the construction process. There is a great difference in structures between the states in construction processes and design, however. To solve the above problems, a method of nonlinear time varying mechanics was adopted to analyze the construction process of a structure. The structural characteristics in each construction stage were analyzed by time varying mechanics and the variations of internal force and displacements obtained. We conclude that designs will not be safe if the time varying effect in the construction process analysis is not considered. We offer advice on the design and construction of large span structures. 相似文献