Recent progresses in the development of tubular segmented-in-series solid oxide fuel cells:Experimental and numerical study

Solid oxide fuel cells(SOFCs)have attracted a great deal of interest because they have the highest efficiency without using any noble metal as catalysts among all the fuel cell technologies.However,traditional SOFCs suffer from having a higher volume,current leakage,complex connections,and difficulty in gas sealing.To solve these problems,Rolls-Royce has fabricated a simple design by stacking cells in series on an insulating porous support,resulting in the tubular segmented-in-series solid oxide fuel cells(SIS-SOFCs),which achieved higher output voltage.This work systematically reviews recent advances in the structures,preparation methods,perform-ances,and stability of tubular SIS-SOFCs in experimental and numerical studies.Finally,the challenges and future development of tubular SIS-SOFCs are also discussed.The findings of this work can help guide the direction and inspire innovation of future development in this field.

Improved HHT and its application in narrowband radar imaging for precession cone-shaped targets

Imaging the spatial precession cone-shaped targets with narrowband radar is a new technical approach in mid-course recognition problem. However, most existing time-frequency methods still have some inevitable deficiencies for extracting microDoppler information in practical applications, which leads to blurring of the image. A new narrowband radar imaging algorithm for the precession cone-shaped targets is proposed. The instantaneous frequency of each scattering point is gained by using the improved Hilbert-Huang transform, then the positions of scattering points in the parameter domain are reconstructed. Numerical simulation and experiment results confirm the effectiveness and high precision of the proposed algorithm.

Study of the Dynamic Characteristics of A Cone-Shaped Recovery System on Submarines for Recovering Autonomous Underwater Vehicle

National navies equip their submarines with Autonomous Underwater Vehicle(AUV)technology.It has become an important component of submarine development in technologically-advanced countries.Employing advanced and reliable recovery systems directly improves the safety and operational efficiency of submarines equipped with AUVs.In this paper,based on aerial refueling technology,a cone-shaped recovery system with two different guiding covers(closed structure and frame structure)is applied to the submarine.By taking the Suboff model as the research object,STAR-CCM was used to study the influence of the installation position of the recovery system,and the length of the rigid rod,on the Suboff model.It was found that when the recovery system is installed in the middle and rear of the Suboff model at the same velocity and the same length of the rigid rod,the Suboff model has the good stability and less drag.It experiences the largest drag when being installed in the front of the rigid rod.Moreover,when the recovery system is installed in the front and middle of the rigid rod,the drag increases as its length increases,and the lift decreases as its length increases.Compared with the closed structure guiding cover,the Suboff model will have less drag and better stability when the recovery system uses the frame structure guiding cover.Besides,the deflection and vibration of the rigid rod were also analyzed via mathematical theory.

Forging process modeling of cone-shaped posts

Using the rigid visco-plastic Finite Element Method (FEM), the process offorging for long cone-shaped posts made of aluminum alloys was modeled and the correspondingdistributions of the field variables were obtained based on considering aberrance of grids, dynamicboundary conditions, non-stable process, coupled thermo-mechanical behavior and other specialproblems. The difficulties in equipment selection and die analysis caused by the long cone shape ofpost, as well as by pressure calculation were solved.

Theoretical and experimental research on influence of rotor taper on performance of cone-shape helical pumps

The structure of a rotor has full impact on the performance of cone-shaped helical pumps. Numerical simulation and experimental tests are applied to get pressure, velocity and flow of a cone-shaped helical pump, and explores flow condition of blood in artificial blood pump. Rotors with four different tapers of artificial pump are designed. The flow condition of blood at the entrance, near the front diffuser, near the rotor, near the rear diffuser and at the exit, the pressure difference between entrance and exit and flow of artificial blood pump with different taper rotors are simulated, and then the influence rules of rotor taper on the performance of cone-shaped helical pump are revealed. In order to verify the correctness of theoretical analysis, rotors with three different tapers are manufactured, physical model of artificial blood pump are built, and then the actual lift and flow of blood pump with different rotors are measured respectively. The results show that taper of rotor increases, the circumfluence of blood near the front and rear diffuser decreases, the blood flows more smoothly, the energy consumption is less, and then the guide role of blade is greater. The blood at the exit of blood pump flows along the axial direction steadily. As taper of rotor increases, the pressure difference between the entrance and exit and the flow of blood pump increase subsequently. The flow condition of blood and performance of blood pump with No.3 rotor are the best. The proposed research analyzes the influence of rotor taper on performance of blood pump quantitatively, and provides the theoretical reference for the design and improving of cone-shaped helical pump.

圆锥型场源瞬变电磁法测量数据反演（英文）

瞬变电磁法多匝小线圈装置是应用于地下有限空间、复杂地表地形的有效装置,但该装置的重叠绕制方式使其互感影响大,关断时间长。与之相比,我们提出的圆锥型场源的电感弱,关断时间短,可以有效兼顾减弱互感和适应复杂地形针对圆锥型场源场值,我们基于叠加原理,采用汉克尔变换和数值滤波法对层状介质中圆锥型场源进行了正演,验证了该场源的优势、探索了其激发的瞬变场特征,但由其激发的数据处理方法研究仍显不足。基于此,本文开展了根据"烟圈"反演结果设定初始模型的阻尼最小二乘反演方法研究。对瞬变电磁正演所获得的视电阻率进行"烟圈"反演,以"烟圈"反演结果设定的初始模型在频率域内进行了阻尼最小二乘反演。同时,从初始模型角度对阻尼最小二乘反演方法进行了改进,提出了以"烟圈"反演曲线的极值点和拐点为基点,建立阻尼最小二乘反演初始模型的方法。理论数据与实测数据反演结果表明,所研究的反演方法不仅使反演电阻率和层厚得到改善,也弥补了常规"烟圈"反演不具有分层效果的缺点,可以获得相对满意的层状反演结果。

Theoretical aspects and sensing demonstrations of cone-shaped inwall capillary-based microsphere resonators

In this paper, a detailed theoretical study on the characteristics of cone-shaped inwall capillary-based microsphere resonators is described and demonstrated for sensing applications. The maximum, minimum, slope, contrast, and width of the Fano resonance are analyzed. As the transmission coefficient of the capillary resonator increases, the absolute value of the slope of Fano resonances increases to reach its maximum, which is useful for sensors with an ultra-high sensitivity. There occurs another phenomenon of electromagnetically induced transparency when the reflectivity at the capillary–environment interface is close to 100%. We also experimentally demonstrated its capability for temperature and refractive index sensing, with a sensitivity of 10.9 pm∕°C and 431 d B∕RIU basedon the Fano resonance and the Lorentzian line shape, respectively.

Electrochemical Properties of Tubular SOFC Based on a Porous Ceramic Support Fabricated by Phase-Inversion Method

In this work, a tubular ceramic-supported solid oxide fuel cell （SOFC） was successfully fabricated by a low cost and simple process involving phase-inversion, brush coating and co-sintering. Properties in- cluding sintering behavior, microstructure of the tubular support as well as the electrochemical properties of single cell were investigated. The results show that a porous tubular support with finger-like pores and macrovoids was obtained after phase-inversion process. The tubular support is proved to be gaspermeable after sintering at 1400 ℃ with shrinkage of about 34%. The maximum power density of single tubular SOFC is 100 mW/cm2 and 122 mW/cm2 at 850 ℃ when fed with wet methane and hydrogen, respectively. The current collection, thickness of electrolyte and gas permeability of tubular support should account for the large total resistance. The present tubular design could be expected to deliver a higher voltage for longer support with several segmented-in-series cell stacks.

Structure Design and Finite Element Analysis of a Connection Assembly Program

The new connection assembly program contains four cone-shapes of fixed welders and four bolts.It is used for connecting the cover assembly of a Down-The-Hole( DTH) drill rig and its chassis.The design feasibility and reliability are evaluated according to the mechanical calculation and finite element method.

Analytical Theory of Superplastic Extrusion Technology

Based on the general solution to stress equilibrium differential equation and the analytical expressions in mechanical field of superplastic extrusion through cone-shaped die, in this paper the theoretical formulae have been established for the technological processing specifications of non-steady and steady extrusions through cone-shaped die. Experimental results on the typical superplastic alloy Zn-5wt/Al are in good agreement with the theoretical calculations.

Analytical Theory of Superplastic Extrusion

The forward extrusion through cone-shaped die,which is the basis for establishing the extrusion theory,can be simply considered to be two-dimensional in a spherical coordinates system in its treatment.This paper,for the first time,derives the analytical formulae and constraint equations for strain,strain-rate and stress of superplastic extrusions through cone-shaped die by simulating displacement function.In the present work,typical superplastic alloy Zn-5wt%Al was chosen as the example,so the results are of universal significance.The method can even be generalized to non-typical superplastic materials.