Design of a High Precision Multichannel 3D Bioprinter

Three-dimensional(3D)printing technology is expected to solve the organ shortage problem.However,owing to the accuracy limitations,it is difficult for the current bioprinting technology to achieve an accurate control of the spatial position and distribution of a single cell or single component droplet.In this study,to accurately achieve the directional deposition of different cells and biological materials in the spatial position for the construction of large transplantable tissues and organs,a high-precision multichannel 3D bioprinter with submicron-level motion accuracy is designed,and concurrent and synergistic printing methods are proposed.Based on the high-precision motion characteristics of the gantry structure and the requirements of concurrent and synergistic printing,a 3D bioprint-ing system with a set of 6 channels is designed to achieve six-in-one printing.Based on the Visual C++environ-ment,a control system software that integrates the programmable multi-axis controller(PMAC)motion,pneumatic,and temperature control subsystems was developed and designed.Finally,based on measurements and experiments,the 3D bioprinter and its control system was verified to fulfil the requirements of multichannel,concurrent,and syn-ergistic printing with submicron-level motion accuracy,significantly shortening the printing time and improving the printing efficiency.This study not only provides an equipment basis for printing complex heterogeneous tissue structures,but also improves the flexibility and functionality of bioprinting,and ultimately makes the construction of complex multicellular tissues or organs possible.

The Real-Time,High Precision Phase Difference Measurement of Electron Density in HL-2A Tokamak

This paper introduces a real-time high precision measurement of phase difference based on Field Programmable Gate Array（FPGA） technology,which has been successfully applied to laser grating interference measurement and real-time feedback of plasma electron density in HL-2A tokamak.It can track the changes of electron density while setting the starting point of the density curve to zero.In a laboratory test,the measuring accuracy of phase difference is less than 0.1°,the time resolution is 80 ns,and the feedback delay is 180 μs.

Constructions and Applied Examinations of a Kind of Square-Conservative Schemes in High Precision in the Time Direction

In order to meet the needs of work in numerical weather forecast and in numerical simulations for climate change and ocean current, a kind of difference scheme in high precision in the time direction developed from the completely square-conservative difference scheme in explicit way is built by means of the Taylor expansion. A numerical test with 4-wave Rossby-Haurwitz waves on them and an application of them on the monthly mean current the of South China Sea are carried out, from which, it is found that not only do the new schemes have high harmony and approximate precision but also can the time step of the schemes be lengthened and can much computational time be saved. Therefore, they are worth generalizing and applying.

Principle and key technology of generalized high precision simulation of TT&C channel

A generalized simulation method of the tracking,telemetry and control（TT＆C） channel,which is applicable to wideband and arbitrary radio frequency（RF） signal,is proposed.It can accurately simulate the dynamic transmission delay of the arbitrary RF signal in channels,especially regardless of any prior knowledge including signal form,signal parameters,and so on.The proposed method orthogonally demodulates the wideband and arbitrary RF signal to complex baseband by a known local oscillator（LO） signal.Whereafter,it takes measures to obtain the delay reconstruction signal of baseband signals based on the dynamic transmission delay between a ground station and a responder.Meanwhile,it manages to obtain the delay reconstruction signal of LO signals.The simulation output signal（the delayed RF signal） can be achieved through the synthesis of the two delay reconstruction signals mentioned above.The principle and its related key technology are described in detail,and the realizable system architecture is given.

High Precision Tungsten Isotope Measurements by MC-ICPMS

1 Introduction The short-lived 182Hf-182W system is generally acknowledged as the best chronometer of metal-silicate segregation that occurred during the early evolution of asteroids and terrestrial planets due to its following properties:(1)Hf-W fractionation commonly occurs during metal-silicate differentiation;(2)Both Hf and W are highly refractory elements,therefore most bulk

NONEL High Precision MS Delay Detonator

The NONEL high precision MS Delay Detonator (FDG-1detonator) is introduced. The main aspects about the FDG-1 detonator include the choice of structure, delay composition, control of the gas chamber, optimum charge and density, suitable explosives per meter in the NONEL tube, base firing charge and the main specifications. The improvement of the characteristics of FDG-1 detonator has been tested systematically. The testing method is reliable and its precision can meet the demand for usage.

A novel high precision Doppler frequency estimation method based on the third-order phase-locked loop

In deep space exploration,many engineering and scientific requirements require the accuracy of the measured Doppler frequency to be as high as possible.In our paper,we analyze the possible frequency measurement points of the third-order phase-locked loop(PLL)and find a new Doppler measurement strategy.Based on this finding,a Doppler frequency measurement algorithm with significantly higher measurement accuracy is obtained.In the actual data processing,compared with the existing engineering software,the accuracy of frequency of 1 second integration is about 5.5 times higher when using the new algorithm.The improved algorithm is simple and easy to implement.This improvement can be easily combined with other improvement methods of PLL,so that the performance of PLL can be further improved.

High precision patternable liquid metal based conductor and adhesive substrate enabled stretchable hybrid systems

Stretchable hybrid systems have been attracting tremendous attention for their essential role in soft robotics,on-skin electronics,and implantable devices.Both rigid and soft functional modules are typically required in those devices.Consequently,ensuring stable electrical contact between rigid and soft modules is a vital part.Here,we propose a simple,universal,and scalable strategy for the stretchable hybrid system through a highly precise printable liquid metal particle-based conductor and adhesive fluorine rubber substrate.The properties of liquid metal particle-based conductors could be easily tuned to realize high-precision patterning,large-scale printing,and the ability to print on various substrates.Additionally,the fluorine rubber substrate could form strong interfacial adhesion with various components and materials through simply pressing and heating,hence enabling stable electrical contact.Furthermore,we prepared a stretchable hybrid light-emitting diode(LED)display system and employed it in on-skin visualization of pressure levels,which perfectly combined rigid and soft modules,thus demonstrating the promising potential applications in complex multifunctional stretchable hybrid systems for emerging technologies.

High-precision solution to the moving load problem using an improved spectral element method

In this paper, the spectral element method(SEM)is improved to solve the moving load problem. In this method, a structure with uniform geometry and material properties is considered as a spectral element, which means that the element number and the degree of freedom can be reduced significantly. Based on the variational method and the Laplace transform theory, the spectral stiffness matrix and the equivalent nodal force of the beam-column element are established. The static Green function is employed to deduce the improved function. The proposed method is applied to two typical engineering practices—the one-span bridge and the horizontal jib of the tower crane. The results have revealed the following. First, the new method can yield extremely high-precision results of the dynamic deflection, the bending moment and the shear force in the moving load problem.In most cases, the relative errors are smaller than 1%. Second, by comparing with the finite element method, one can obtain the highly accurate results using the improved SEM with smaller element numbers. Moreover, the method can be widely used for statically determinate as well as statically indeterminate structures. Third, the dynamic deflection of the twin-lift jib decreases with the increase in the moving load speed, whereas the curvature of the deflection increases.Finally, the dynamic deflection, the bending moment and the shear force of the jib will all increase as the magnitude of the moving load increases.

Numerical model and experimental demonstration of high precision ablation of pulse CO_2 laser

To reveal the physical mechanism of laser ablation and establish the prediction model for figuring the surface of fused silica, a multi-physical transient numerical model coupled with heat transfer and fluid flow was developed under pulsed CO2laser irradiation. The model employed various heat transfer and hydrodynamic boundary and thermomechanical properties for assisting the understanding of the contributions of Marangoni convention,gravitational force, vaporization recoil pressure, and capillary force in the process of laser ablation and better prediction of laser processing. Simulation results indicated that the vaporization recoil pressure dominated the formation of the final ablation profile. The ablation depth increased exponentially with pulse duration and linearly with laser energy after homogenous evaporation. The model was validated by experimental data of pulse CO2laser ablation of fused silica. To further investigate laser beam figuring, local ablation by varying the overlap rate and laser energy was conducted, achieving down to 4 nm homogenous ablation depth.

A high precision programmable bandgap voltage reference design for high resolution ADC

A programmable high precision bandgap reference is presented, which can meet the accuracy requirements for all technology corners while a traditional bandgap reference cannot.This design uses SMIC 0.18 μm 1P4M CMOS technology.The theoretically achievable temperature coefficient is close to 0.69 ppm/°C over the whole temperature range.

Study of high-precision earth sensor with triple-FOV

Earth sensors are widely used in spacecraft for attitude determination. They need to have a very large field of view(FOV)( > 120°) and relatively low accuracy while being used in the aircrafts around orbit. A triple-FOV infrared earth sensor is proposed in this paper. It uses three pieces of standard infrared detectors with a wavelength range of 14;16μm,to sense the horizontal circle by detecting the infrared light emitted from the earth. From which,the geocentric vector can be obtained. A mathematic model is established and a validation model is set up to provide input parameters for the mathematic model. The simulation results of the two models show that the output of the mathematic model coincides with the known parameters. Based on the above analysis,a prototype has been built and tested. The test results show that the angle measurement error is about 0. 002° and hence such a triple-FOV earth sensor is capable to provide high-precision position information for autonomous navigation.

A portable high precision three dimensional trace measuring system for underwater target with high speed

The paper describes a portable high precision three-dimensional trace measuring system for underwater target with high speed. The mathematical model for location, the main error sources, the calibration method for the underwater array and the way to correct its state are discussed. Problems about the distance ambiguity and multi-path interference are also analyzed. Part of experimental results on lake and at sea are given as well.

High Resolution ID-TIMS Redefines the Distribution and Age of the Main Mesozoic Lacustrine Hydrocarbon Source Rocks in the Ordos Basin,China

Using high-precision zircon U-Pb ID-TIMS geochronology,tuffs from the Chang 9 shale and the Chang 7 shale were dated.The tuff in the Chang 9 shale is 241.47±0.17 Ma,which falls between the top tuff age of 241.06±0.12 Ma and the bottom tuff age of 241.558±0.093 Ma in the Chang 7 shale.These reveal that the Chang 9 and Chang 7 shales are contemporaneous,belonging to the Ladinian stage of the Middle Triassic.This insight expands the region of the main source rock of Chang 7 to the northeast and will inform the search for the deep Chang 9 shale petroleum system,increasing the scope for exploring the Chang 7 shale system in northern Shaanxi.The research results clarify the relationship between the two sets of shale in the Yanchang Formation and redefine the distribution range of the Chang 7 shale in the Ordos Basin.At the same time,it shows that there is a cross-layer problem in the stratigraphic division of the Yanchang Formation in different regions,the high-precision U-Pb dating technology providing a reference for the fine stratigraphic correlation of other continental basins in the world.

A high precision CMOS weak current readout circuit

This paper presents a high precision CMOS weak current readout circuit.This circuit is capable of converting a weak current into a frequency signal for amperometric measurements with high precision and further delivering a 10-bit digital output.A fast stabilization-enhanced potentiostat has been proposed in the design, which is used to maintain a constant bias potential for amperometric biochemical sensors.A technique based on source voltage shifting that reduces the leakage current of the MOS transistor to the reverse diode leakage level at room temperature was employed in the circuit.The chip was fabricated in the 0.35 μm chartered CMOS process, with a single 3.3 V power supply.The interface circuit maintains a dynamic range of more than 100 dB.Currents from 1 pA to 300 nA can be detected with a maximum nonlinearity of 0.3% over the full scale.

ON THE HIGH PRECISION ADAPTIVE OPEN BOUNDARY CONDITIONS FOR TRANSIENT WAVES

The adaptive open boundary conditions (AOBC) designed by Chen and Zou for transient waves overcome the limitation of the existing open boundary conditions (OBC) and can be used for the cases of waves with arbitrary incident angles. In this paper a new family of AOBC has been designed on the basis of the AOBC with first order mentioned above. In comparing with all other OBC with the same order, this new family of AOBC has the highest precision. It can be generalized into 3D problems without difficulty and its forms in different curvilinear coordinate systems can be got very easily. The distinguished advantages above mentioned of the AOBC will be discussed in this paper.

A High Precision Forecasting Model and Its Constructing Method for Vein Type Gold Deposits

A high precision forecasting and prospecting model incorporating the “field theory field structure analysis field simulation”, a temporal and spatial structural framework reflecting local extremely fine structures, is established to make an effective extraction and an integrated analysis of multivariate forecasting information. This model can best show not only the coupling between metallogenic anomalous structure, mineralized structure and information structure, but also the extraction, optimization, matching and summarization of key forecasting information. The technological keys to this model are the fine structural analysis of geological and geophysical and geochemical anomalous fields and metallogenic fields, and the establishment of occurrence patterns for the spatial location of orebodies.

A HIGH CONVERGENT PRECISION EXACT ANALYTIC METHOD FOR DIFFERENTIAL EQUATION WITH VARIABLE COEFFICIENTS

The exact analytic method was given by [1] . It can be used for arbitrary variable coefficient differential equations and the solution obtained can have the second order convergent precision. In this paper, a new high precision algorithm is given based on [1], through a bending problem of variable cross-section beams. It can have the fourth convergent precision without increasing computation work. The present computation method is not only simple but also fast. The numerical examples are given at the end of this paper which indicate that the high convergent precision can be obtained using only a few elements. The correctness of the theory in this paper is confirmed.

A research of arc welding inverter with high stable precision

This paper mainly introduces an output control method with high stable precision of a large power IGBT arc welding inverter. Experiments indicate that this kind of control mode can effectively improve the static and dynamic characteristics and stability of power supply system. And it can decrease the spatters in the welding process apparently. This power supply is especially suitable to automatic robot welding assembly line. It will be the developing direction of robot welding supply in the future.

High order symplectic conservative perturbation method for time-varying Hamiltonian system

This paper presents a high order symplectic con- servative perturbation method for linear time-varying Hamil- tonian system. Firstly, the dynamic equation of Hamilto- nian system is gradually changed into a high order pertur- bation equation, which is solved approximately by resolv- ing the Hamiltonian coefficient matrix into a ＂major compo- nent＂ and a ＂high order small quantity＂ and using perturba- tion transformation technique, then the solution to the orig- inal equation of Hamiltonian system is determined through a series of inverse transform. Because the transfer matrix determined by the method in this paper is the product of a series of exponential matrixes, the transfer matrix is a sym- plectic matrix; furthermore, the exponential matrices can be calculated accurately by the precise time integration method, so the method presented in this paper has fine accuracy, ef- ficiency and stability. The examples show that the proposed method can also give good results even though a large time step is selected, and with the increase of the perturbation or- der, the perturbation solutions tend to exact solutions rapidly.