Star Point Energy Center Correction of Star Simulator Based on Polar Coordinates

In this paper,various aberrations have been analyzed.Not only the effects of aberration on geometrical center position are taken into account,but also the deviation of displayed star position energy center caused by aberration is analyzed.These two aspects have been taken into comprehensive evaluation and star position correction.The correction method based on polar coordinates is proposed,and cumbersome partition correction and calculated quantity based on two-dimensional coordinates can be simplified.The experimental results show that the correction processing based on polar coordinates is simpler and easier compared with any other correction methods.In addition,the correction results are significantly more accurate.

Multi-objective coordination optimal model for new power intelligence center based on hybrid algorithm

In order to resolve the coordination and optimization of the power network planning effectively, on the basis of introducing the concept of power intelligence center (PIC), the key factor power flow, line investment and load that impact generation sector, transmission sector and dispatching center in PIC were analyzed and a multi-objective coordination optimal model for new power intelligence center (NPIC) was established. To ensure the reliability and coordination of power grid and reduce investment cost, two aspects were optimized. The evolutionary algorithm was introduced to solve optimal power flow problem and the fitness function was improved to ensure the minimum cost of power generation. The gray particle swarm optimization (GPSO) algorithm was used to forecast load accurately, which can ensure the network with high reliability. On this basis, the multi-objective coordination optimal model which was more practical and in line with the need of the electricity market was proposed, then the coordination model was effectively solved through the improved particle swarm optimization algorithm, and the corresponding algorithm was obtained. The optimization of IEEE30 node system shows that the evolutionary algorithm can effectively solve the problem of optimal power flow. The average load forecasting of GPSO is 26.97 MW, which has an error of 0.34 MW compared with the actual load. The algorithm has higher forecasting accuracy. The multi-objective coordination optimal model for NPIC can effectively process the coordination and optimization problem of power network.

Ultralow-Energy-Barrier H_(2)O_(2)Dissociation on Coordinatively Unsaturated Metal Centers in Binary Ce-Fe Prussian Blue Analogue for Efficient and Stable Photo-Fenton Catalysis

The low intrinsic activity of Fenton catalytic site and high demand for light-energy input inhibit the organic-pollution control efficiency of photo-Fenton process.Here,through structural design with density functional theory(DFT)calculations,Ce is predicted to enable the construction of coordinatively unsaturated metal centers(CUCs)in Prussian blue analogue(PBA),which can strongly adsorb H_(2)O_(2)and donate sufficient electrons for directly splitting the O-O bond to produceOH.Using a substitution-co-assembly strategy,binary Ce-Fe PBA is then prepared,which rapidly degrades sulfamethoxazole with the pseudo-first-order kinetic rate constant exceeding reported values by 1-2 orders of magnitude.Meanwhile,the photogenerated electrons reduce Fe(Ⅲ)and Ce(Ⅳ)to promote the metal valence cycle in CUCs and make sulfamethoxazole degradation efficiency only lose 6.04%in 5 runs.Overall,by introducing rare earth metals into transition metal-organic frameworks,this work guides the whole process for highly active CUCs from design and construction to mechanism exploration with DFT calculations,enabling ultrafast and stable photo-Fenton catalysis.

Analysis of good practice of Public Health Emergency Operations Centers

Objective: To study the public health Emergency Operations Centers(EOCs)in the US, the European Union, the UK and Australia, and summarize the good practice for the improvement of National Health Emergency Response Command Center in Chinese National Health and Family Planning Commission. Methods: Literature review was conducted to explore the EOCs of selected countries. Results: The study focused on EOC function, organizational structure, human resources and information management. The selected EOCs had the basic EOC functions of coordinating and commanding as well as the public health related functions such as monitoring the situation, risk assessment, and epidemiological briefings. The organizational structures of the EOCs were standardized, scalable and flexible. Incident Command System was the widely applied organizational structure with a strong preference. The EOCs were managed by a unit of emergency management during routine time and surge staff were engaged upon emergencies. The selected EOCs had clear information management framework including information collection, assessment and dissemination. Conclusions: The performance of National Health Emergency Response Command Center can be improved by learning from the good practice of the selected EOCs, including setting clear functions, standardizing the organizational structure, enhancing the human resource capacity and strengthening information management.

Coordinated control strategy for robotic-assisted gait training with partial body weight support

Walking is the most basic and essential part of the activities of daily living. To enable the elderly and non-ambulatory gait-impaired patients, the repetitive practice of this task, a novel gait training robot(GTR) was designed followed the end-effector principle, and an active partial body weight support(PBWS) system was introduced to facilitate successful gait training. For successful establishment of a walking gait on the GTR with PBWS, the motion laws of the GTR were planned to enable the phase distribution relationships of the cycle step, and the center of gravity(COG) trajectory of the human body during gait training on the GTR was measured. A coordinated control strategy was proposed based on the impedance control principle. A robotic prototype was developed as a platform for evaluating the design concepts and control strategies. Preliminary gait training with a healthy subject was implemented by the robotic-assisted gait training system and the experimental results are encouraging.

Spatial-temporal characteristics of the coupling coordination of social security and economic development in China during 2002–2018

Clarifying the relationship between social security and economic development is helpful to realize the sustainable social security system and the stable function of sustainable economic development.In this paper,the entropy method,coupling coordination degree,standard deviation ellipse model,and spatial autocorrelation were used to study the spatial-temporal characteristics of coupling coordination of social security and economic development in China from 2002 to 2018.The results indicate that the relationship between social security and economic development in China has been gradually strengthened in the process of mutual adaptation and common development.The benign interaction between the two was unstable,though the coupling coordination degree gradually transitioned to the primary coupling coordination type.Besides,from a spatial perspective,first,the coupling coordination degree of social security and economic development in China contracted in the east-west and north-south directions,and the coupling coordination clustered in the central region in this period;second,the coupling coordination degree generally presented a positive spatial autocorrelation,and regions with similar coupling coordination degrees were in a state of agglomeration;finally,the hot spots clumped together to form a continuous area in the eastern coastal area while the cold spots expanded toward the northwest and northeast.Furthermore,the random distribution areas exhibited a trend of contraction.

Stability analysis of the projectile based on random center manifold reduction

The center manifold method has been widely used in the field of stochastic dynamics as a dimensionality reduction method.This paper studied the angular motion stability of a projectile system under random disturbances.The random bifurcation of the projectile is studied using the idea of the Routh-Hurwitz stability criterion,the center manifold reduction,and the polar coordinates transformation.Then,an approximate analytical presentation for the stationary probability density function is found from the related Fokker–Planck equation.From the results,the random dynamical system of projectile generates three different dynamical behaviors with the changes of the bifurcation parameter and the noise strength,which can be a reference for projectile design.

Economic differences and coordinated development in Northwest China

Northwest China is one of the seven major geographical regions in China,including Shaanxi,Gansu,Qinghai,Ningxia and Xinjiang.Since the implementation of a series of national policies such as the western development,the economy of the provinces and autonomous regions in Northwest China has been greatly developed.But the imbalance in the development process is also very prominent.Through the analysis of the factors that affect the transfer of the center of gravity and the impact of the shift on the region,we can explore a better path of regional coordinated development.This paper selects five northwest provinces,according to the center of gravity transfer model,studies the changes of the economic center of gravity from 2000 to 2018,and uses the Theil index method to calculate the difference degree of regional economy.The results show that:the development of Northwest China is not balanced,the economic gap between provinces is large.The economic center of gravity moves to the southeast and deviates from the geographical center of Northwest China.There is a positive relationship between the change of gravity center and the size of economic difference.

High-Precision Nonsingular Integrator of Guiding-Center Orbit Close to Magnetic Axis in Tokamak Equilibrium Configuration

Equations of guiding-center motion without the coordinate singularity at the magnetic axis have been derived from the guiding-center Lagrangian.The poloidal magnetic flux is suggested to be included as one of the nonsingular coordinates for the computation of the guidingcenter orbit.The numerical results based on different nonsingular coordinates are verified using the GCM code which is based on canonical variables.A comparison of numerical performance among these nonsingular coordinates and canonical coordinates has been carried out by checking the conservation of energy and toroidal canonical momentum.It is found that by using the poloidal magnetic flux in the nonsingular coordinate system,the numerical performance of nonsingular coordinates can be greatly improved and is comparable to that of canonical variables in long-time simulations.

大学英语课程虚拟教研室建设的理论和实践研究

大学英语课程虚拟教研室是适应新时代大学英语教学特征,纾解大学英语教学难题的重要途径。本质上,大学英语课程虚拟教研室是基于现代信息技术平台,开展跨区、跨校协同学、教、研的课程基层教学组织,按功能可分为课程群类、专题教研类、学科服务类,其建设既要遵循虚拟教研室一般的共性要求,又要符合大学英语课程自身建设的要求,实践层面应该着力在课程共享和教研协同上下功夫。既有大学英语课程虚拟教研室起到了很好的示范作用,但在学科服务和平台融合方面仍需努力。

中国数字经济与文旅产业融合的协同关系及其影响因素

促进数字经济与文旅产业融合的协调适配是实现数字文旅高质量发展的关键路径,有效把握二者协同关系的时空演化特征及影响因素,对推动区域文旅产业转型升级、构建数字文旅产业发展新格局具有重要理论价值和现实意义。首先,在梳理两系统协同发展框架基础上构建综合评价体系;其次,运用协同关系测度模型、探索性空间数据分析刻画2011—2020年中国数字经济与文旅产业融合协同关系的时空演进特征;最后,采用时空地理加权回归方法识别其影响因素。结果表明:1)时序演进上,中国数字经济与文旅产业融合协同指数保持上升态势,从2011年的极低协同(0.180)提升至2020年的低级协同(0.279)。2)空间分布上,呈稳定的“东-中-西”递减梯度结构,空间协同特征与空间集聚特征显著。3)各解释变量对数字经济与文旅产业融合协同关系具有正向效应,政府调控和人力资本高值区在研究期末呈现自东向西扩散态势,而城镇化水平、技术实力和互联网供给能力在文旅资源禀赋优势更大、发展空间更具潜力的中部和西部地区表现出更明显的推动作用。

HEPS六极铁标定方案分析

六极铁作为高能同步辐射光源(High Energy Photon Source,HEPS)储存环八铁单元的重要部件之一,其技术工艺较为复杂,对加工精度和中心引出精度要求都很高。本文对HEPS六极铁的机械中心引出标定方案进行了研究,利用极缝偏差角对常规标定坐标系进行旋转,使三个极缝面更接近理论位置,从而减小磁铁主场斜分量;对每块磁铁进行两次机械中心标定,极缝间距的实测值与设计值的标准偏差在0.015 mm,坐标系旋转前后的基准点偏差标准值为0.09 mm,旋转角最大可达0.6 mrad。这种考虑极缝偏差角的建系方法可以提高标定的精度,能为实际工作中同类型、准直精度有相同要求的设备标定提供参考,有利于加速器装置的顺利安装,对加速器准直测量具有十分重要的意义。

高能光源磁铁的三坐标标定技术

针对高能同步辐射光源需要进行大批量磁铁的中心引出标定,提出了一种基于三坐标测量机的磁铁机械中心标定方案,确定了编写自动测量程序的流程和方法 ,参与完成了加速器中多种类型磁铁的标定。对176块储存环六极铁的三坐标机测量数据进行分析,结果表明:每块磁铁进行两遍机械中心标定,获得准直基准点的标定重复性在0.01 mm之内;极缝间距离的实测值与设计值标准偏差均在0.015 mm之内;标定效率相较激光跟踪仪提高了2倍。这种借助三坐标测量机的磁铁标定方法可以提高标定精度,降低人力成本,提高工作效率,能为加速器工程中磁铁中心的引出标定工作提供参考,保证加速器装置的安装顺利,满足加速器准直测量的工程进度要求。

卧式加工中心转台回转夹具定位销连线的数学建模及实例应用研究分析

卧式加工中心转台回转夹具的典型结构是通过在卧式加工中心工作台上配置转台、尾座和夹具体,进而构成摇篮式转台,该种方式可以使加工工序集中化,进一步提高零件的加工质量和加工效率。在基于摇篮式转台回转夹具构成型式分析的基础上,以定位销连线为研究对象,通过讨论定位销连线与转台回转轴线及机床坐标系三者之间平行关系的几种情况,进而建立数学模型,并通过实例的方式解决生产过程中遇到的实际问题。

D-band center coordination modulated enzyme-like activity in Fe-Cu dual-metal single-atom nanozymes

After explorations in a diversity of single-atom nanozymes(SAzymes),developing dual-centered SAzymes becomes a promising approach for superior catalytic performance.But confusing mechanisms including atomic coordination,spatial configuration,and metal–metal atom interaction hinder the development and design of SAzymes.Herein,a dual-centered Fe-Cu-N_(x)SAzyme exhibits excellent peroxidase(POD)-and catalase(CAT)-like activities with d-band center(ε_(d))coordination of Fe and Cu in multiple reaction stages,which plays a critical role in the adsorption of H_(2)O_(2)molecule and H_(2)O and O_(2)release.Therefore,the dband center coordination,which can be represented byε_(d)(Fe)–ε_(d)(Cu)shifts,leads to the competition between one-side and bilateral adsorption,which determines the favorable reaction path with lower energy barriers.Based on experimental statistics,simulated formation energies,and reaction barriers,3 configurations,Fe-Cu-N6-I,Fe-Cu-N_(8)-II,and Fe-Cu-N_(8)-III,are modeled and validated.Impressively,configuration-dependent catalytic selectivity and the competition between one-side and bilateral adsorption can be unveiled by d-band center coordination paradigm analysis.Theoretical simulations suggest that the unsymmetrical charge distribution over the three Fe-Cu configurations could tune the adsorption strength compared with the counterparts FeN_(4)and CuN_(4).The present work provides a potential route for optimizing enzyme-like catalysis by designing the dual-or even triple-metal SAzymes,which demonstrates the large space to modulate the metal atomic configuration and interaction.

基于渐消因子的ECEF-GLS估计算法

传统的误差配准算法假设系统偏差恒定或缓慢变化,当系统误差发生突变或快速变化时,这一假设不再成立。针对这一问题,研究了时变条件下的误差配准算法,引入渐消因子,对常规的基于地心地固坐标系的广义最小二乘算法(generalized least squares algorithm based on the earth-centered earth-fixed coordinate system,ECEF-GLS)进行了修正,弱化历史量测对配准的影响,并对渐消因子的选取问题进行了研究,给出了合理的设计方法。算法验证表明,基于渐消因子的ECEF-GLS估计算法能够对时变的系统偏差进行有效估计,精度满足配准要求。

基于双三次插值和高斯拟合的光条中心亚像素提取方法

针对结构光三维测量的高精度要求,提出一种基于双三次插值和高斯拟合的激光线条亚像素提取方法。该方法首先对光条图像进行感兴趣区域提取、高斯滤波等前处理,其次用形态学方法细化激光线条得到初始中心点,然后使用五点拟合法得到光条法线方向,在光条法线方向上取亚像素的拟合点,利用双三次插值得到亚像素坐标的像素值,最后进行高斯拟合,到光条亚像素中心。实验结果表明,算法平均精度值为0.389147像素,消耗时间为0.056 2 s,具有较高的提取精度和稳定性。

圆柱直齿渐开线外花键跨棒距坐标测量方法

花键是工程领域中传递转矩的重要联结零件,对外花键的齿厚关键参数跨棒距进行测量较为重要。针对圆柱直齿渐开线外花键的坐标测量,建立了外花键坐标测量方法,基于花键齿面模型获取其跨棒距测量的接触点坐标,分析得到花键的跨棒距数值。在花键测量中心上开展渐开线外花键跨棒距坐标测量试验,得到的跨棒距测量结果表明,建立的外花键跨棒距坐标测量方法可用于花键快速自动测量。

激发多元灵活性的数据中心协同优化运行方法

“双碳”目标加快了以新能源发电为主体的新型电力系统建设,大规模波动性新能源并网对系统灵活运行提出了更高的要求。而快速发展的大规模数据中心已成为电力系统灵活智能运行的新型资源。为此,在建模多数据中心负载处理时空灵活性的基础上,建立其制冷和储能辅助设备的灵活运行模型,以激发数据中心用能的多元灵活性;进而建立数据中心与电力系统协同优化双层模型,即上层模拟数据中心参与电力市场出清对节点电价的作用,下层给出电价引导后的数据中心用电行为决策;含3个数据中心的IEEE-30节点改进算例分析表明,相较于已有方法,所提优化运行策略能促进数据中心与电力系统的新能源交易,有效降低数据中心用电成本并提高区域新能源消纳水平。其中辅助设备运行灵活性能降低成本达11.78%,进一步提升区域新能源消纳水平达8.11%,减少电力系统碳排放达2.42%。

利用最小二乘法的网壳结构点云节点中心坐标提取

为解决网壳结构节点坐标测量困难、处理效率低等问题,本文提出基于网壳结构扫描点云的节点中心坐标提取方法:应用三维激光扫描技术采集网壳结构点云数据并预处理;然后基于设计模型,对初始点云模型进行网壳节点局部点云分割和节点多平面拟合,判定拟合平面的属性特征并修正侧面的法向量方向;最后利用空间约束关系及最小二乘算法求取网壳结构节点的精确中心坐标。以三亚国际免税城项目为例开展应用,结果表明所提方法求取的网壳结构节点中心坐标与全站仪实测结果偏差均值为2.89 mm,效率相比传统方法提高近4倍,较大提升了网壳结构节点中心坐标的提取精度和效率,为后续网壳结构施工偏差复核、幕墙板材的深化设计与加工等工程化应用提供了准确的数据支撑。