THE POSITION VARIATION OF THE WEST PACIFIC SUBTROPICAL HIGH AND ITS POSSIBLE MECHANISM

Using NCEP/NCAR daily reanalysis data and SCSMEX data, an investigation is carried out of the relationship between the position variation of the west Pacific subtropical high （WPSH） and the apparcnt heating in June 1998 based on the complete vertical vorticlty equation. It is tbund that the non-adiabatic heating plays an important role in the position variation of WPSH. In comparison with climatic mean status, the vertical change of non-adiabatic heating is stronger in the north side of WPSH in June 1998, but weaker in the south side of WPSH. The anomalous non-uniform heating induces anomalous cyclonic vorticity in South China, areas to lhe south of the Yangtze and its mid-lower valleys, but anomalous anticyclonic vorticity in the Indo-China Peninsula and South China Sea areas lead to the more southward position of WPSH than the mean.

A DETECTION METHOD OF HIGH RESOLUTION RADAR TARGETS BASED ON POSITION CORRELATION

This paper studies a detection method of targets of high resolution radar operating at the band of millimeter-wave(32-38GHz) under the background of the clutters, and proposes a new nonparametric detection method, which not only does less computation, but also is able to detect multiple extended targets radially distributed along distance "corridor", based on the position (range) correlation information of one-dimensional range images(or called range profiles) of high resolution radar targets. The experimental results, on the real echo data of tank illuminated by the millimeter-wave stepped frequency high resolution radar, have certified that such a method presented in this paper is a very effective detection method for multiple extended targets.

Influence of pantograph fixing position on aerodynamic characteristics of high-speed trains

To study the influence of the pantograph fixing position on aerodynamic characteristics of high-speed trains, the aerodynamic models of high-speed trains with eight cars were established based on the theory of com- putational fluid dynamics, and eight cases with pantographs fixed on different positions and in different operational orientations were considered. The pantographs were fixed on the front or the rear end of the first middle car or fixed on the front or the rear end of the last middle car. The external flow fields of the high-speed trains were numeri- cally simulated using the software STAR-CCM＋. The results show that the pantograph fixing position has little effect on the aerodynamic drag force of the head car and has a large effect on the aerodynamic drag force of the tail car. The influences of the pantograph fixing position on the aerodynamic lift forces of the head car, tail car and pan- tographs are obvious. Among the eight cases, considering the total aerodynamic drag force of the train and the aerodynamic lift force of the lifted pantograph, when the pantographs are fixed on the rear end of the last middle car and the lifted pantograph is in the knuckle-upstream ori- entation, the aerodynamic performance of the high-speed train is the best.

Position Control Optimization of Aerodynamic Brake Device for High-speed Trains

The aerodynamic braking is a clean and non-adhesion braking, and can be used to provide extra braking force during high-speed emergency braking. The research of aerodynamic braking has attracted more and more attentions in recent years. However, most researchers in this field focus on aerodynamic effects and seldom on issues of position control of the aerodynamic braking board. The purpose of this paper is to explore position control optimization of the braking board in an aerodynamic braking prototype. The mathematical models of the hydraulic drive unit in the aerodynamic braking system are analyzed in detail, and the simulation models are established. Three control functions--constant, linear, and quadratic--are explored. Two kinds of criteria, including the position steady-state error and the acceleration of the piston rod, are used to evaluate system performance. Simulation results show that the position steady state-error is reduced from around 12-2 mm by applying a linear instead of a constant function, while the acceleration is reduced from 25,71-3.70 m/s2 with a quadratic control function. Use of the quadratic control function is shown to improve system performance. Experimental results obtained by measuring the position response of the piston rod on a test-bench also suggest a reduced position error and smooth movement of the piston rod. This implies that the acceleration is smaller when using the quadratic function, thus verifying the effectiveness of control schemes to improve to system performance. This paper proposes an effective and easily implemented control scheme that improves the position response of hydraulic cylinders during position control.

Change in foveal position based on age and axial length in high myopic eyes

AIM：To evaluate the influence of age and axial length（AL） on the position of the fovea in patients with high myopia（HM）.METHODS：In this prospective study,96 patients（186 eyes） with HM were consecutively recruited from the Third Affiliated Hospital of Nanchang University.DRI-OCT Atlantis,fundus imaging,and IOL Master were used in this study.Three indices were measured：the distance between the fovea and the optic nerve head（ONH） center（DFO）,the vertical distance between the fovea and the horizontal line pass of the ONH center（VDFO）,and the horizontal distance between the fovea and the vertical line pass of the ONH center（HDFO）.These measurements were used to analyze the effects of different age groups（A1,A2,A3 groups） and AL（AL1,AL2,AL3,AL4 groups） on these indices.RESULTS：The results showed that there was no statistical significance in DFO among the age and AL groups（F=0.46,0.37;P=0.62,0.76,respectively）.In HDFO,there was also no statistical significance among the age and AL groups（F=0.10,0.48;P=0.90,0.69,respectively）.In VDFO,however,the difference in the age and AL groups was statistically significant（F=3.21,3.12;P=0.04,0.02,respectively）.Thus,VDFO were correlated with age and AL（r=0.21,0.23,all P〈0.01）,while HDFO and DFO were not correlated with age and AL（r=0.30,P〉0.05）.CONCLUSION：In high myopia,the foveal position changes mainly in the vertical direction along with factors of age and AL.

A Study on the Sensor Applications for Position Detection and Guideway Monitoring in High Speed Maglev

The high speed maglev is mainly characterized by propulsion using linear synchronous motor (LSM) and vehicle levitation from the guideway surface. In LSM propulsion control, the position detection sensor is used to detect running vehicle position for synchronized current generation. To maintain the stable levitating condition during vehicle running, the irregularity of guideway surface should be monitored by sensors measuring the displacement and acceleration between vehicle and guideway. In this study, the application methods of these sensors in the high speed maglev are investigated and through the experiments by using the small-scale test bed, the validity of examined methods is confirmed.

Treatable focal region modulated by double excitation signal superimposition to realize platform temperature distribution during transcranial brain tumor therapy with high-intensity focused ultrasound

Recently, the phase compensation technique has allowed the ultrasound to propagate through the skull and focus into the brain. However, the temperature evolution during treatment is hard to control to achieve effective treatment and avoid over-high temperature. Proposed in this paper is a method to modulate the temperature distribution in the focal region. It superimposes two signals which focus on two preset different targets with a certain distance. Then the temperature distribution is modulated by changing triggering time delay and amplitudes of the two signals. The simulation model is established based on an 82-element transducer and computed tomography （CT） data of a volunteer＇s head. A finite- difference time-domain （FDTD） method is used to calculate the temperature distributions. The results show that when the distances between the two targets respectively are 7.5-12.5 mm on the acoustic axis and 2.0-3.0 mm in the direction perpendicular to the acoustic axis, a focal region with a uniform temperature distribution （64-65 ℃） can be created. Moreover, the volume of the focal region formed by one irradiation can be adjusted （26.8-266.7 mm3） along with the uniform temperature distribution. This method may ensure the safety and efficacy of HIFU brain tumor therapy.

Positioning-control Based on Trapezoidal Velocity Curve for High-precision Basis Weight Control Valve

Traditionally, basis weight control valve is driven by a constant frequency pulse signal. Therefore, it is difficult for the valve to match the control precision of basis weight. Dynamic simulation research using Matlab/Simulink indicates that there is much more overshoot and fluctuating during the valve-positioning process. In order to improve the valve-positioning precision, the control method of trapezoidal velocity curve was studied. The simulation result showed that the positioning steady-state error was less than 0.0056%, whereas the peak error was less than 0.016% by using trapezoidal velocity curve at 10 positioning steps. A valve-positioning precision experimental device for the stepper motor of basis weight control valve was developed. The experiment results showed that the error ratio of 1/10000 positioning steps was 4% by using trapezoidal velocity curve. Furthermore, the error ratio of 10/10000 positioning steps was 0.5%. It proved that the valve-positioning precision of trapezoidal velocity curve was much higher than that of the constant frequency pulse signal control strategy. The new control method of trapezoidal velocity curve can satisfy the precision requirement of 10000 steps.

Genes for the high life： New genetic variants point to positive selection for high altitude hypoxia in Tibetans

People living on the high plateaus of the world have long fascinated biological anthropologists and geneticists because they live in ＂thin air＂ and epitomize an extreme of human biological adaptation.

A beam position measurement system of fully digital signal processing at SSRF

This fully digital beam position measurement instrument is designed for beam position monitoring and machine research in Shanghai Synchrotron Radiation Facility. The signals received from four position-sensitive detectors are narrow pulses with a repetition rate up to 499.654 MHz and a pulse width of around 100 ps, and their dynamic range could vary over more than 40 dB in machine research. By the employment of the under-sampling technique based on high-speed high-resolution A/D conversion, all the processing procedure is performed fully by the digital signal processing algorithms integrated in one single Field Programmable Gate Array. This system functions well in the laboratory and commissioning tests, demonstrating a position resolution (at the turn by turn rate of 694 kHz) better than 7 μm over the input amplitude range of -40 dBm to 10 dBm which is well beyond the requirement.

A Sprout of Dialectical Logic of Marx's Positive Free Philosophy —— A New Interpretation of Marx's Three High School Papers

The academic world has at least nine viewpoints on the Marx's thought in the high school period: devout religious theology,moral theology,liberalism,democracy,utopian socialism,populism,ethical communism,French materialism,the flash of historical materialism,etc. We believe that these views cannot reflect the background of Marx's thoughts in high school. Marx's three high school papers in 1835 reflected the germination of Marx's positive free thoughts in his high school. Marx's positive free thoughts contain a the relatively complete structure of three aspects of the general reason ability of freedom,the special conditions for freedom,and the specific historical form of freedom. The positive free thought in Marx's high school period is finally realized in his communist theory through the his revolution of dialectical materialism and historical materialism.

Different squatting positions after total knee arthroplasty: A retrospective study

BACKGROUND Total knee arthroplasty(TKA)has been shown to improve quality of life and reduce pain.High-flexion activities such as squatting,kneeling,and floor transfers are mainly listed as demanding tasks.Among them,squatting is an important position.AIM To provide a new squat position classification and evaluate the different squatting positions of a series of patients after primary TKA.METHODS From May 2018 to October 2019,we retrospectively reviewed 154 video recordings of the squatting-related motions of patients after TKA.Among the included patients,119 were women and 35 were men.Their mean age at the index surgery was 61.4 years(range,30 to 77).RESULTS The median follow-up was 12 mo(range,6 to 156 mo).We classified those squatting-related motions into three major variations according to squatting depth:Half squat,parallel squat,and deep squat.The angles of hip flexion,knee flexion,and ankle dorsiflexion were measured in the screenshots captured from the videos at the moment of squatting nadir.A total of 26 patients were classified as half squats,75 as parallel squats,and 53 as deep squats.The angles of hip flexion,knee flexion,and ankle dorsiflexion all differed significantly among the three squatting positions(P<0.001).In the parallel squat group,the mean knee flexion angle(°)was 116.5(SD,8.1;range,97 to 137).In the deep squat group,the mean knee flexion angle(°)was 132.5(SD,9.3;range,116 to 158).CONCLUSION Among the three squatting positions,deep squat showed the highest hip,knee,and ankle flexion angles,followed by the parallel squat.With the improvement of squatting ability,the patient's postoperative satisfaction rate was also significantly enhanced.However,the different squatting abilities of the patients cannot be effectively distinguished from the scoring results(P>0.05).Our squatting position classification offers a pragmatic approach to evaluating patients’squatting ability after TKA.

Numerical simulation of applied electromagnetic field and electromagnetic force in all-position welding

All-position welding is an important technology in energy sources, chemical, shipbuilding and other industries. When welding current is larger than 200 A, the molten metal tends to flow down due to the force of gravity. In order to ＂push＂ the molten metal into the weld, a new kind of U-frame excitation model, which could produce electromagnetic force to balance the gravity of the molten pool, was designed. The related parameters of the excitation model were simulated by Maxwell 3D, and the relationships between the parameters and the magnetic induction intensity were analyzed. Finally, the electromagnetic force in the molten pool was calculated, and the appropriate parameters of the U-frame excitation model were determined. The results of the simulation verify the feasibility of the all-position welding excitation model.

Implementation of Mooring Automatic Positioning System for Deepwater Semi-Submersible Platform Based on Dual-Stage Actuator

The automatic positioning control of mooring system for deepwater semi-submersible platform has become a key issue in the research and development field of deep-sea resources. The Dual- Stage Actuator (DSA) proposed in this paper can replace the single actuator to achieve the high speed and high precision positioning by cooperative control. The relative model and control algorithm of motion trajectory (CAMT) are designed and validated, which proves that the method proposed in this paper is effective.

Anomalously High Conductivity of Deformed Metals at the Positive Temperatures

The description of experimentally observed phenomenon of abnormally high electrical conductivity—'superconductivity' (SC) at the room and higher temperatures is represented. The effect was observed in metallic monospirals of small radius curvature with high density and regular distribution of dislocations. Transition into state of SC has been observed experimentally in the range from –50 up to 3000°C at the density of transmitting current up to 2·109 A/cm2. The experimental data confirming the watched phenomenon are represented. The explanations of this phenomenon are being proposed in the framework of the dislocation model.

Sleep Quality for Patients Receiving Noninvasive Positive Pressure Ventilation and Nasal High-Flow Oxygen Therapy in an ICU: Two Case Studies

Aim: The purpose of this case study was to examine the sleep quality of patients receiving noninvasive positive pressure ventilation (NPPV) or nasal high-flow oxygen therapy (NHF) in an intensive care unit and to investigate what types of nursing support are offered to such patients. Methods: We examined one patient each for NPPV and NHF. Polysomnography (PSG), review of the patient charts, and semi-structured interviews were used to collect the data for analysis. Results: Patients treated with NPPV or NHF demonstrated a noticeable reduction in deep sleep, with most of their sleep being shallow. Their sleep patterns varied greatly from those of healthy individuals. These results suggest that, in addition to experiencing extremely fragmented sleep, sleep in these patients was more likely to be interrupted by nursing interventions, such as during auscultation of breath sounds. Furthermore, it was revealed that “anxiety or discomfort that accompanies the mask or air pressure” in patients treated with NPPV and “discomfort that accompanies the nasal cannula or NHF circuit” in patients treated with NHF may be primary causes of disrupted sleep. Our results suggest a need for nursing care aimed at improving sleep quality in patients treated with NPPV or NHF.

An Adaptive Model and Algorithm for an Electro-hydraulic Position Servo System in Auto Gauge Control for Aluminum Hot Tandem Mill

The electro-hydraulic servo position control system(HPC) is the core of an auto gap control for a modern four-high continuous hot strip mill.The actuators are loaded with considerable external disturbances,rolling forces,and the system stiffness and position accuracy will become hypersensitive to the leakage and the compressibility of the oil.Many efforts have being made to increase the position accuracies.The conventional resources are proportion-integral-differential(PID) controller.But the PID controller is faint for a considerable external disturbance.In this paper,by introducing the adaptive control strategy of model reference the reciprocities of the system structure with the loads were analyzed.With the Lyapunov energy function,an adaptive control algorithm applied to improve the system accuracy was formulated.The system simulations and the selection of parameters of the model were also discussed.The simulations show the static state errors at 0.02%.Finally,the industrial experimental result was given.

精准时空感知赋能数字经济发展

当前数字经济的发展愈发依赖于精准时空信息,分析了通信导航融合感知网络对实现精准时空感知的作用与挑战,介绍了我国在通导融合研究方面取得的突破性进展,阐述了隐嵌信噪定位技术对5G网络定位性能的提升、异构多网多源融合对定位鲁棒性的保障,对北斗与5G深度融合的增量效应进行了讨论。从精准时空感知如何赋能数字经济发展的角度对通信导航融合网络做出进一步规划。

国有企业负责人经营业绩考核:制度特征分析与指标维度优化

业绩考核制度是落实企业责任、激发企业活力,并由此推动经济社会运行的重要机制。在对比股东主导和市场主导两种业绩考核逻辑,分析、认知国有企业负责人经营业绩考核制度的基础上,探究了业绩考核制度的本质特征,即国有企业负责人经营业绩考核制度是一项以考核为抓手的产权管理体系,是以目标设定与过程管理为核心的“自驱式”机制设计。强调应唯经营(而非考核)出业绩,并且正向激励与风险容错是业绩考核赋能企业发展的重要属性。现行业绩考核指标体系还难以引导国有企业高质量发展,建议围绕“产业布局、经营生态、创新驱动、风险管理、财务收益”五个维度进一步优化国有企业负责人经营业绩考核指标,且以年度考核为核心,形成导向明确、相对稳定、可预期的考核指标体系,并赋予企业负责人一定的自由裁量权,以提高考核制度效果,助力中国经济高质量发展。