Search

The analysis of the loss components in electric motors of the rolling mill’s electric drive is shown in the work. The research was made by mathematical statistics approach. The dependences of the different loss components of the main electric drive motor on the rated values of electromagnetic torque are constructed for rolling mill. The most valuable for solving the tasks set in the work were sufficiently detailed data on the components of the losses. A detailed review of the component losses is allowed to reasonably identify the most important components of losses and offer the most effective ways to reduce total losses.

The granitioids in question are located in the geosynclinal fold belt of the Northern Tianshan Mountains. The magmas are intruded into a Carboniferous marine volcanic-sedimentary rock series, forming a contemporaneous, intermediate-basic to acid, composite intrusion. With a whole-rock Rb-Sr isochron age of 315.7 Ma, it is considered to be of middle Hercynian age. The granitoids have a SiO2 content of 48–78%, a calc-alkali index of 60 and silica-alkali indices ρ = 2.2–2.4 and σ= 1.5–2. From basic to acid compositions, the total REE content increases from 38 to 143 ppm. δEu ranges from 0.47 to 0.86 and the Eu anomalies are negative. The normalized curves of REE of various rock types are very similar. These coupled with the characteristics of trace element geochemistry show that the intrusion is an island arc-continental margin, calc-alkaline one. The δ18O values range from 5.8 to 8.9% and the 87Sr / 86Sr initial ratio is 0.705. The materials of the intrusion are composed of a mixture of the magmas at the top of the upper mantle and in the lower crust. This indicates that the rocks might be consanguineous, differentiated and evolved products and possess the characteristics of I -type granites.

This paper focuses mainly on the climatic and environmental variations 5 to 3 ka. B.P. with particular reference to one stable warmer and wetter millennium (7.2-6 ka B.P.). Some large-scale centennial warming was accompanied by an increase in precipitation owing to the expansion of the monsoon circulation, e.g. rapid warming during the period from 8.5 to 8.3 ka B.P. and was reflected in the high level of some inland lakes and the sudden expansion of vegetation in pollen diagrams. The growth of the Neolithic culture with agriculture and settlement in the present semi-arid area of Northwest China was undoubtedly related to the dramatic warming and wetting before 8 ka B.P. According to the proxy data of palynological studies, the deviation of annual mean temperature from today's about 7-6 ka B.P. was roughly estimated at about 1°C in South China, 2°C in the Changjiang (Yangtze) Valley, 3°C in North China and Northeast China. The strongest warming by 4–5°C was recorded in Qinghai-Xizang (Tibet) Plateau. The winter temperature rise was much greater than the annual average temperature. In the eastern half of China, the vegetation zones are mainly parallel to the latitude. During the climax of the Holocene warm period, the northern limit of the tropical monsoonal rain forest shifted less than 1° of latitude northward, the subtropical broad-leaved evergreen forest about 1° of latitude, the north subtropical deciduous and evergreen broad-leaved mixed forest about 3° of latitude in the coastal area but only 1–1.5° of latitude in mid-West China and the warm temperate deciduous forest moved 4° of latitude northward, greatly expanding its distribution. Further north, the cool temperate boreal forest withdrew from its southern boundary by about 2° of latitude. Global climatic warming in the mid-Holocene resulted in a sea-level rise. During the period from 6 to 5 ka BP. the sea-level was about 1–3 m higher than the present level. Large area of coastal lowland was submerged by sea water and frequency of occurrence of storm surges also increased during the high sea-level period.

As an effective mechanism acting on the intermediate nodes to support end-to-end congestion control, active queue management (AQM) takes a trade-off between link utilization and delay experienced by data packets. Most of the existing AQM algorithms are heuristic, and a lack systematic and theoretical design and analysis approach. From the viewpoint of control theory, it is rational to regard AQM as a typical regulating system. Although the PI controller for AQM outperforms the RED algorithm, the mismatches in the simplified TCP flow model inevitably degrade the performance of a controller designed with classical control theory. In this paper, a robust SMVS controller for AQM is put forward based on sliding mode variable structure control (SMVS), its superiority is insensitive to the noise and variance of the parameters, thus it very suitable to a time-varying network system. The principle and guidelines on design of a SMVS controller are presented in detail. The integrated performance is evaluated using ns simulations. The results show that SMVS is very responsive and robust against disturbances. At the same time, a complete comparison between the SMVS controller and PI controller is made. The conclusion is that both the transient and steady performance of the SMVS controller is superior to that of the PI controller, thus the SMVS controller is in favor of the achievement of AQM objectives.

The profile of the minority carrier concentration in a stripe geometry mesastructure InSb photodiode is computed in this paper using the topology finite element method and Giwens transformation. Accordingly, collected photocurrent characteristic curves are obtained. The paper sets up a base for optimizing the design of these devices. >

ATM networks oriented connections provide pure QoS (quality of service) for diversified services through a series of traffic management mechanisms, the ABR (available bit rate) flow control is especially important among these approaches. In the binary flow control scheme, the cell rate and queue length may oscillate with great magnitude to reduce link utilization, so that the EFCI (explicit forward congestion indication) algorithm is regard as ineffective, however its simplicity is attractive to high performance switch design. In this paper, the EFCI algorithm is analyzed based on classical control theory. It is found that the nonlinear hysteresis determines the congestion, and is the dominant reason that causes the oscillation. Then, a probability congestion detection approach, called p-EFCI is put forward. Numerical results show that the improved algorithm deeply constrains the oscillation magnitude, and the queue length is controlled in limited scope to guarantee cell zero loss.

Due to the energy limitation in nodes in the wireless sensor networks, the problem whether the node energy consumption is balanced becomes a primary one in the design of networks. Through building the node lifetime model, we conclude that the node lifetime is affected by the node residual energy and the communication distance. Additionally, both ends of the node lifetime are introduced as the influencing factors on edge weights. And then through the edge weight the node weight is controlled, so that the weighted scale-free topology with energy consumption balanced characteristics is obtained. Finally, theoretical proof shows that the distribution of the node weight, the edge weight, and the node degree all obey the power-law distribution. Simulation results show that this model has the good fault tolerance characteristics that the scale-free topology can have. And it also has obvious advantages in balancing the network energy consumption and prolonging the network lifetime.

In order to solve the problems of high sampling rate which could shorten the lifetime of wireless sensor networks in wild relics security system, the power spectrum reprocessing is applied to the feature extraction of seismic wave signal. This method is used to solve the target recognition problem, and three data sets are used to verify its effectiveness. The result shows that the power spectrum reprocessing can reduce the communication consumption and prolong the lifetime of networks. This method can also increase the accuracy of target classification. This method, indicating its good performance, had been applied to wild relics security system of Museum of the Terra-cotta Warriors and Horses of Qin Shihuang.