Estimation of Thermal Imaging System Operating Range Based on Background Radiation

Traditional operating range prediction methods assume that the atmospheric radiances in a target path and a background path are equal. But they are different in a real-world environment. To solve this problem,the influence of atmospheric radiance on operating range prediction is analyzed in this paper. Range estimation model in thermal imaging based on background radiation（ REBR） is proposed. Infrared image radiometric calibration is used to calculate the background radiation of a system entrance pupil. The result shows that,compared with traditional operating range prediction methods,the REBR method is more suitable for the actual atmospheric transmission process and the physical process of infrared imaging.

Nearly Perfect Absorbers Operating Associated with Fano Resonance in the Infrared Range

We fabricate a three-layer metamaterial of metal patterns/dielectric/metal films. The optical properties associated with Fano resonance of the metamaterials are investigated experimentally and theoretically. The results indicate that the introduction of Fano resonance due to symmetry breaking leads to a much wider absorption range. Furthermore, the amplitude and phase of reflection can be modulated effectively by adjusting various free parameters using the proposed structure.

Design of a high sensitivity and wide range angular rate sensor based on exceptional surface

It is found that when the parity–time symmetry phenomenon is introduced into the resonant optical gyro system and it works near the exceptional point,the sensitivity can in theory be significantly amplified at low angular rate.However,in fact,the exceptional point is easily disturbed by external environmental variables,which means that it depends on harsh experimental environment and strong control ability,so it is difficult to move towards practical application.Here,we propose a new angular rate sensor structure based on exceptional surface,which has the advantages of high sensitivity and high robustness.The system consists of two fiber-optic ring resonators and two optical loop mirrors,and one of the resonators contains a variable ratio coupler and a variable optical attenuator.We theoretically analyze the system response,and the effects of phase and coupling ratio on the system response.Finally,compared with the conventional resonant gyro,the sensitivity of this exceptional surface angular rate sensor can be improved by about 300 times at low speed.In addition,by changing the loss coefficient in the ring resonator,we can achieve a wide range of 600 rad/s.This scheme provides a new approach for the development of ultra-high sensitivity and wide range angular rate sensors in the future.

Supercapacitor electrode based on few-layer h-BNNSs/rGO composite for wide-temperature-range operation with robust stable cycling performance

Currently,developing supercapacitors with robust cycle stability and suitability for wide-temperature-range operations is still a huge challenge.In the present work,few-layer hexagonal boron nitride nanosheets(h-BNNSs)with a thickness of 2−4 atomic layers were fabricated via vacuum freeze-drying and nitridation.Then,the h-BNNSs/reduced graphene oxide(rGO)composite were further prepared using a hydrothermal method.Due to the combination of two two-dimensional(2D)van der Waals-bonded materials,the as-prepared h-BNNSs/rGO electrode exhibited robustness to wide-temperature-range operations from−10 to 50℃.When the electrodes worked in a neutral aqueous electrolyte(1 M Na2SO4),they showed a great stable cycling performance with almost 107%reservation of the initial capacitance at 0℃ and 111% at 50℃ for 5000 charge−discharge cycles.

Closed Range Composition Operators on a General Family of Function Spaces

In this paper, necessary and sufficient conditions for a closed range composition operator CФ on the general family of holomorphic function spaces F（p,q,s） and more generally on α-Besov type spaces F（p,αp-2,s） are given. We give a Carleson measure characterization on F （p, αp - 2, s） spaces, then we indicate how Carleson measures can be used to characterize boundedness and compactness of CФ on F（p,q,s） and F（p,αp- 2,s） spaces.

On Eigenvalues and Boundary Curvature of the Numerical Rang of Composition Operators on Hardy Space

For a bounded linear operator A on a Hilbert space H, let M(A) be the smallest possible constant in the inequality . Here, p is a point on the smooth portion of the boundary of the numerical range of A. is the radius of curvature of at this point and ?is the distance from p to the spectrum of A. In this paper, we compute the M(A) for composition operators on Hardy space H2.

Service Adaptable 3G Turbo Decoder for Indoor/Low Range Outdoor Environment

For the well-known 3G mobile communications standard UMTS, four different service classes have been specified. Considering two turbo decoding algorithms, like SOVA and log-MAP, it would be desirable to use an efficient turbo decoder. In this paper this decoder is shown to adapt dynamically to different service scenarios, considering parameters like performance and complexity for indoor/low range outdoor operating en-vironment. The scenarios show that for streaming service class real-time class applications the proposed de-coding algorithm depends on data rate;for the majority of scenarios SOVA is proposed, whereas log-MAP is optimal for increased data rates and medium-sized frames. On the other hand, conversational service class real-time applications cannot be established. For the majority of non real-time applications (interactive and background service classes) either algorithm can be used, while log-MAP is proposed for medium data rates and frame lengths.

A Novel Polymorphic Topology with Hybrid Control Strategy Based LLC Resonant Converter for Ultra-Wide Input Voltage Range Applications

To realize effective utilization of renewable energy sources,a novel polymorphic topology with hybrid control strategy based LLC resonant converter was analyzed and designed in this paper.By combining the merits of a full bridge LLC resonant converter,three-level half bridge LLC resonant converter,and variable frequency control mode,the converter realizes an intelligent estimation of input voltage by automatically changing its internal cir-cuit topology.Under this control strategy,different input voltages determine different operation modes.This is achieved in full bridge LLC mode when the input voltage is low.If the input voltage rises to a certain level,it operates in three-level half bridge LLC mode.These switches are digital and entirely carried out by the DSP(Digi-tal Signal Processor),which means that an auxiliary circuit is unnecessary,where a simple strategy of software modification can be utilized.Experimental results of a 500W prototype with 100V~600V input voltage and full load efficiency of up to 92%are developed to verify feasibility and practicability.This type of converter is suitable for applications with an ultra-wide input voltage range,such as wind turbines,photovoltaic generators,bioenergy,and other renewable energy sources.

SOME PROPERTIES OF THE INTEGRATION OPERATORS ON THE SPACES F(p,q,s)

We study the closed range property and the strict singularity of integration operators acting on the spaces F(p,pα-2,s).We completely characterize the closed range property of the Volterra companion operator I_(g)on F(p,pα-2,s),which generalizes the existing results and answers a question raised in[A.Anderson,Integral Equations Operator Theory,69(2011),no.1,87-99].For the Volterra operator J_(g),we show that,for 0<α≤1,J_(g)never has a closed range on F(p,pα-2,s).We then prove that the notions of compactness,weak compactness and strict singularity coincide in the case of J_(g)acting on F(p,p-2,s).

Two-stage Optimization for Active Distribution Systems Based on Operating Ranges of Soft Open Points and Energy Storage System

Due to the lack of flexible interconnection devices,power imbalances between networks cannot be relieved effectively.Meanwhile,increasing the penetration of distributed generators exacerbates the temporal power imbalances caused by large peak-valley load differences.To improve the operational economy lowered by spatiotemporal power imbalances,this paper proposes a two-stage optimization strategy for active distribution networks(ADNs)interconnected by soft open points(SOPs).The SOPs and energy storage system(ESS)are adopted to transfer power spatially and temporally,respectively.In the day-ahead scheduling stage,massive stochastic scenarios against the uncertainty of wind turbine output are generated first.To improve computational efficiency in massive stochastic scenarios,an equivalent model between networks considering sensitivities of node power to node voltage and branch current is established.The introduction of sensitivities prevents violations of voltage and current.Then,the operating ranges(ORs)of the active power of SOPs and the state of charge(SOC)of ESS are obtained from models between networks and within the networks,respectively.In the intraday corrective control stage,based on day-ahead ORs,a receding-horizon model that minimizes the purchase cost of electricity and voltage deviations is established hour by hour.Case studies on two modified ADNs show that the proposed strategy achieves spatiotemporal power balance with lower cost compared with traditional strategies.

Operating range of magnetic stabilization flow regime for magnetized fluidized bed with Geldart-B magnetizable and nonmagnetizable particles

The magnetic stabilization flow regime could also be created forGeldart-Bnonmagnetizable particles pro-vided some magnetizable particles are introduced and the magnetic field is applied.This study aimed toexplore the size(d_(pM))and density(ρ_(pM))effects of magnetizable particles on its operating range.The upperlimit(Umb;)could not be determined from the △P_(b)-U_(g)↓curve but could from analyzing the variation of △P_(b)-fluctuation with increasing U_(g).Due to the variation of U_(mfH)(lower limit)with d_(pM) and ppw,both U_(mbH)-U_(mfH) and(U_(mbH)-U_(mfH))/U_(mfH) were used to quantify the operating range of magnetic stabilization.U_(mbH)-U_(mfH) varied hardly with ρ_(pM) but increased significantly with decreasing ρ_(pM).(U_(mbH)-U_(mfH))/U_(mfH)increased as d_(pM) or ρ_(pM) decreased.lt was more difficult for the nonmagnetizable particles to escape fromthe network formed by the smaller/lighter magnetizable particles.For the same magnitude of change,dp had a stronger effect than ρ_(pM) on(U_(mbH)-U_(mfH))/U_(mfH).Neither U_(mbH)-U_(mfH) nor(U_(mbH)-U_(mfH):)/Uma variedmonotonously with the minimum fluidization velocity of the magnetizable particles,indicating that nostraightforward criterion for matching the magnetizable particles to the given nonmagnetizable particlescould be established based on their minimum fluidization velocities to maximize the operating range ofmagnetic stabilization.

Operator Matrix Forms of Positive Operators

If a 3-tuple (A:H_1→H_1,B:H_2→H_1,C:H_2→H_2) of operators on Hilbert spaces is given,we proved that the operator A:= on H=H_1⊕H_2 is≥0 if and only if A≥0,R(B) R(A1/2)and C≥B~* A^+ B, where A^+ is the generalized inverse of A. In general,A^+ is a closed operator,but since R(B) R(A1/2),B~* A^+ B is bounded yet.

TWO PROBLEMS ABOUT COMPOSITION OPERATORS ON HARDY SPACE

In this paper, two problems about composition operator on Hardy space are considered. Firstly, a new estimation of the norm of a class of composition operators is given. Secondly, the cyclic behavior of the adjoint operator of a composition operator is discussed.

A Note on Nilpotent Operators

We find that a bounded linear operator T on a complex Hilbert space H satisfies the norm relation |||T|na|| =2q, for any vector a in H such that q≤(||Ta||-4-1||Ta||2)≤1.A partial converse to Theorem 1 by Haagerup and Harpe in [1] is suggested. We establish an upper bound for the numerical radius of nilpotent operators.

Exploration of acceptable operating range for a compression system in a double bypass engine

The variable cycle engine is distinguished by its highly adjustable compression system,whose aerodynamic characteristic is extremely complex.To explore the regulation range of a double bypass engine compression system,a multi-dimensional analysis method is developed,through which the coupling mechanism between the compressor component and the bypass is examined.The operation zones of the compressor components and the bypass system are proposed,and the operation range of the compression system is obtained by calculating the overlapping part of the operation zones.The results show that in the double bypass mode,there exists a minimum mode selector valve area and a minimum core driven fan stage stall margin that ensures a feasible bypass flow,the two parameters correspond to each other.Under the given fan and core driven fan stage conditions,the maximum value of the inner bypass ratio is restricted by the upper limit of the forward variable area bypass injector and the maximum Mach number in the total bypass,while the minimum value of the inner bypass ratio depends on the lower limit of the forward variable area bypass injector geometry and the system recirculation margin.The single bypass mode is a unique condition of the double bypass mode,as the operation zone of the compressor component degenerates from a two-dimensional surface to a straight line.There are multiple bypass states available in the single bypass mode,while the regulation range of the bypass ratio is jointly restricted by the operation range of the high pressure compressor and the aerodynamic boundary of the forward variable area bypass injector.

Pressure and flowrate distribution in central exhaust shaft with multiple randomly operating range hoods

Central flues are now commonly adopted in high-rise residential buildings in China for cooking oil fumes(COF)exhaust.Range hoods of all floors are connected to the central shaft,where oil fumes were gathered and exhausted through the outlet at the building roof.As households may cook and use their range hood at random periods,there is great uncertainty of the amount of COF being exhausted.In addition,users can often adjust the exhaust rate of the range hood according to their needs.As a result,thousands of possible operating conditions consisting of distinct combinations of on/off conditions and fan speed occur randomly in the central COF exhaust system,causing the exhaust performance to vary considerably from condition to condition.This work developed a mathematical model for characterizing the operation of the central COF exhaust system in a high-rise residential building as well as its iterative solving method.Full-scale tests coupled with CFD simulation referring to a real 30-floor building were conducted to validate the proposed model.The results show that the model agreed well with the CFD and experimental data under various system operating conditions.Moreover,the Monte-Carlo method was introduced to simulate the random operating characteristics of the system,and a hundred thousand cases corresponding to distinct system operating conditions were sampled and statistically analyzed.

视程障碍现象仪在低温天气条件下的业务性能测试评估

文章利用在锡林浩特国家综合气象观测试验基地安装的3种不同型号的视程障碍现象仪观测的PM 10和PM 2.5数据,在满足资料完整性的基本条件下,分析各仪器在低温天气条件下的可靠性及适应性,并对同一型号两台设备进行数据一致性分析评估,检验视程障碍仪在低温环境下的应用效果。经过试验测试,各型号设备在低温环境下的可靠性较高、运行稳定,适应性较强;通过对3种型号6台设备进行绝对偏差分析,得出设备在低温环境下均通过一致性评估。研究结果为视程障碍现象仪业务化应用提供了重要参考依据。

光学相控阵性能参数仿真分析与实验研究

详细介绍了一维光学相控阵的扫描特性,仿真分析了各参数之间的理论关系。通过各参数与波长之间的关系研究,可知波长调制实现纵向角度控制不会明显改变光学相控阵参数变化,论证在波导上刻蚀光栅,利用光栅的衍射特性可实现二维光学相控阵光束扫描。通过实验,实现了一种256通道光栅二维光学相控阵系统,验证了探测距离大于50 m,测距精度优于5 cm,光束发散角小于0.25°,在1515~1595 nm波长范围内,可实现41.2°×11.9°的二维扫描范围。这些理论分析和实验研究为该领域的科研工作者提供理论指导和技术支持,具有重要的应用价值。

增程式电动汽车发动机的多工作点控制策略

为了研究不同的发动机多工作点控制策略对整车燃油经济性的影响,以某增程式电动汽车为研究对象,在满足整车动力性前提下,设计了发动机三工作点和五工作点控制策略。在不同循环工况下,对比分析了2种控制策略。仿真结果表明,三工作点和五工作点控制策略能够满足整车动力性要求,且三工作点控制策略的燃油经济性更优。