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Cell encapsulation has proven to be promising in stem cell therapy. However, there are issues needed to be addressed, including unsatisfied yield, unmet clinically friendly formulation, and unacceptable viability of stem cells after cryopreservation and thawing. We developed a novel biosynsphere technology to encapsulate stem cells in clinically-ready biomaterials with controlled microsphere size. We demonstrated that biosynspheres ensure the bioviability and functionality of adipose-derived stromal cells (ADSCs) encapsulated, as delineated by a series of testing procedures. We further demonstrated that biosynspheres protect ADSCs from the hardness of clinically handling such as cryopreservation, thawing, high-speed centrifugation and syringe/nozzle injection. In a swine full skin defect model, we showed that biosynspheres were integrated to the destined tissues and promoted the repair of injured tissues with an accelerating healing process, less scar tissue formation and normalized deposition of collagen type I and type III, the ratio similar to that found in normal skin. These findings underscore the potential of biosynsphere as an improved biofabrication technology for tissue regeneration in clinical setting.

In this work, several key scaling laws of the quasi-static magnetic compression of field reversed configuration (FRC) plasma (Spencer et al 1983 Phys. Fluids 26 1564) are amended from a series of two-dimensional FRC MHD equilibriums numerically obtained using the Grad–Shafranov equation solver NIMEQ. Based on the new scaling for the elongation and the magnetic fields at the separatrix and the wall, the empirically stable limits for the compression ratio, the fusion gain, and the neutron yield are evaluated, which may serve as a more accurate estimate for the upper ceiling of performance from the magnetic compression of FRC plasma as a potential fusion energy as well as neutron source devices.

The scale-free features widely concerned by previous weighted network models seemed to not be the best choice to describe the link weight distributions of passenger air transportation networks. In this paper, by introducing an exponent α to the weight evolution rule of the earliest weighted model, and considering the spatial constraints of two-dimensional distances on linking probability, we have conducted rigorous analyses leading to the exponentially truncated power-law distribution for weights: P ( w ) = A ⋅ w − α ⋅ e − B w 1 − α , where A and B are parameters, α < 1. The theoretical expression is consistent with the empirical results of the American domestic passenger flight records from 1995 to 2020. The model would be applicable to different air transportation systems and to problems in other fields.

High-performance piezotronic semiconductor devices have been proven to apply in signal detection, energy converter, and other important fields. Avalanche breakdown is a classical current amplification mechanism. Combining the piezotronic polarization charges regulation of the avalanche process, we novelty proposed a piezotronic PIN diode based on ZnO and used the FEM to calculate the characteristic of the device. The gauge factor can reach 106. This study can guide the design of ultrahigh sensitivity piezotronic photodetectors.

Based on Zhuhai Miaowan artificial reef demonstration project, this paper studied the flow field characteristics of single box artificial reef and reef group under different spacing by using computational fluid dynamics (CFD) method. The results show that the box artificial reef has a significant effect on flow field. The maximum upwelling height near the reef is about 1.4 times the reef height, and the length of the back vortex is twice the reef size. In the reef group arrangement, the flow field distribution plays the best performance at the 5m spacing arrangement. The research results can provide guidance for reef structure optimization and practical arrangement in site.

In the last two years, three major technical improvements have been made on J-TEXT in supporting of the expanded operation regions and diagnostic capabilities. (1) The successful commission of the 105 GHz/500 kW/1 s electron cyclotron resonance heating (ECRH) system increasing the core electron temperature from 0.9 keV up to around 1.5 keV. (2) The poloidal divertor configuration with an X-point in the high-field side has been achieved. In particular, the 400 kW electron cyclotron wave has also been successfully injected into the diverted plasma. (3) A 256-channel electron cyclotron emission imaging diagnostic system and two sets of four-channel Doppler backscattering diagnostics have been successfully developed on J-TEXT, allowing detailed measurement of the electron temperature and density fluctuations for turbulence and MHD research. The locked mode (LM), especially the 2/1 LM, is one of the biggest threats to the plasma operation. Both the thresholds of 2/1 and 3/1 LM are observed to vary non-monotonically on electron density. The electrode biasing was applied successfully to unlock the LM from either a rotating or static resonant magnetic perturbation (RMP) field. In the presence of 2/1 LM, three kinds of standing wave (SW) structures have been observed to share a similar connection to the island structure, i.e. the nodes of the SWs locate around the O- or X-points of the 2/1 island. The control and mitigation of disruption is essential to the safe operation of ITER, and it has been systematically studied by applying a RMP field, massive gas injection (MGI) and shattered pellet injection on J-TEXT. When the RMP-induced 2/1 LM is larger than a critical width, the MGI shutdown process can be significantly influenced. If the phase difference between the O-point of LM and the MGI valve is +90° (or −90°), the penetration depth and the assimilation of impurities can be enhanced (or suppressed) during the pre-thermal quench (TQ) phase and result in a faster (or slower) TQ. A secondary MGI can also suppress the runaway electron (RE) generation, if the additional high-Z impurity gas arrives at the plasma edge before TQ. When the secondary MGI has been applied after the formation of the RE current plateau, the RE current can be dissipated, and the dissipation rate increases with the injected impurity quantity but saturates with a maximum of 28 MA s−1. The non-local transport is experimentally observed in the ion transport channel. The electron thermal diffusivity significantly increases with the ECRH power. Theoretical work shows that significant intrinsic current can be driven by electromagnetic turbulence, and the robust formation mechanism of the E × B staircase is identified from the Hasegawa–Wakatani system.

It is extremely difficult to obtain the analytical solution of some mechanical problems related to elliptic integrals. The motion of a small ball that rolls without sliding on a smooth hemisphere is a typical hyperelliptic integral problem of this kind. By utilizing elliptic integration theory and operational skills, we give the analytical method of the solution of the motion law of the small ball. At the same time, we exhibit the motion characteristic of the small ball.

Massive gas injection (MGI) experiments have been carried out in many tokamaks to study disruption dynamics and mitigation schemes. Two events often observed in those experiments are the excitation of the m = 2, n = 1 magnetohydrodynamic mode, and the formation of cold bubble structure in the temperature distribution before the thermal quench (TQ). Here m is the poloidal mode number, n the toroidal mode number. The physics mechanisms underlying those phenomena, however, have not been entirely clear. In this work, our recent NIMROD simulations of the MGI process in a tokamak have reproduced the main features of both events, which has allowed us to examine and establish the causal relation between them. In these simulations, the 3/1 and 2/1 islands are found to form successively after the arrival of impurity ion cold front at the corresponding q = 3 and q = 2 rational surfaces. At the interface between impurity and plasma, a local thin current sheet forms due to an enhanced local pressure gradient and moves inward following the gas cold front, this may contribute to the formation of a dominant 2/1 mode. Following the growth of the 2/1 tearing mode, the impurity penetration into the core region inside the q = 2 surface gives rise to the formation of the cold bubble temperature structure and initiates the final TQ. A subdominant 1/1 mode developed earlier near the q = 1 surface alone does not cause such a cold bubble formation, however, the exact manner of the preceding impurity penetration depends on the nature of the 1/1 mode: kink-tearing or quasi-interchange.

We proposed a technique of tunable plasma narrow-band filter (PNBF) to generate high-power narrow-band pulses based on a plasma mirror and pulse chirp. PNBFs have an ultra-wide free spectral range, high damage threshold, and accurate wavelength-tunable function, and tunable sub-nanometer pulses could be achieved by controlling the pulse chirp. The feasibility of the proposed technique was verified by both simulation and experiment. Three ~0.6 nm bandwidth pulses centered at different wavelengths were obtained respectively, maintaining good near and far-field beam quality. PNBF is expected to be an effective technique for high-power tunable narrow-band pulse generation with high-power ultrafast lasers.

In the presence of energetic particles (EPs) from auxiliary heating and burning plasmas, fishbone instability and Alfven modes can be excited and their transition can take place in certain overlapping regimes. Using the hybrid kinetic-magnetohydrodynamic model in the NIMROD code, we have identified such a transition between the fishbone instability and the β-induced Alfven Eigenmode (BAE) for the NBI heated plasmas on HL-2A. When the safety factor at magnetic axis is well below one, typical kink-fishbone transition occurs as the EP fraction increases. When q0 is raised to approaching one, the fishbone mode is replaced with BAE for sufficient amount of EPs. When q0 is slightly above one, the toroidicity-induced Alfven eigenmode (TAE) dominates at lower EP pressure, whereas BAE dominates at higher EP pressure.

As we all know, Dalton’s law of the partial pressure is equivalent to Dalton’s law of the partial volume. On the other hand, through experiments, it can be proved that Dalton’s law of the partial volume is correct, and Dalton’s law of the partial pressure can be derived from Dalton’s law of the partial volume, implying that both laws are equivalent to each other. Combined with the teaching of middle school physics and university basic physics, with different ideas and methods, this paper presents a variety of proof methods of Dalton’s law of the partial volume to be equivalent to Dalton’s law of the partial pressure. Different proof methods can improve the understanding and application of Dalton’s law of the partial pressure and law of the partial volume. It is proved that the relevant content of Dalton’s ideal gas partial pressure law is further supplemented and perfected, which plays a role throwing some light on this field.

Using the in-viscid two-field reduced magneto-hydrodynamic (MHD) model, a new analytical theory is developed to unify the Hahm–Kulsrud–Taylor (HKT) linear solution and the Rutherford quasi-linear regime. Adopting a quasi-linear approach, we obtain a closed system of equations for plasma response in the Taylor problem. An integral form of an analytical solution is obtained for the forced magnetic reconnection, uniformly valid throughout the entire regimes from the HKT linear solution to the Rutherford quasi-linear solution. In particular, the quasi-linear effect can be described by a single coefficient K s ∝ S 8 / 5 ψ c 2 , where S = τ R τ A and ψ c are the Lundquist number and amplitude of external magnetic perturbation, respectively. The HKT linear solution for the response can be recovered when the index K s → 0. On the other hand, the quasi-linear effect plays a key role in the island growth when K s ∼ 1. Our new analytical solution has also been compared with reduced MHD simulations with agreement.

The hydroxypropyl methylcellulose (HPMC) modified alginate fibers were prepared using wet-spinning method. The structure and properties of the fibers were characterized by Fourier transform infrared spectroscopy(FTIR), X-ray diffraction(XRD), Scanning electron microscopy(SEM) and Thermogravimetric analysis(TGA). The results showed that the hydrogen bonding interaction of alginate fibers was enhanced with the addition of HPMC. The comprehensive mechanical properties of HPMC modified alginate fibers reached the optimun when the relative percentage of HPMC was 6%, while the elongation at break and the tensile strength were 32% and 12% higher than those of pure alginate fibers, respectively. The roughness of tensile section and the fracture work increased, proving that the addition of HPMC improved the brittle fracture of alginate fibers. The thermal stability and water absorption of HPMC modified alginate fibers were better than those of pure alginate fibers.

Tuning the thermal conductivity of silicon nanowires (Si-NWs) is essential for realization of future thermoelectric devices. The corresponding management of thermal transport is strongly related to the scattering of phonons, which are the primary heat carriers in Si-NWs. Using the molecular dynamics method, we find that the scattering of phonons from internal body defects is stronger than that from surface structures in the low-porosity range. Based on our simulations, we propose the concept of an exponential decay in thermal conductivity with porosity, specifically in the low-porosity range. In contrast, the thermal conductivity of Si-NWs with a higher porosity approaches the amorphous limit, and is insensitive to specific phonon scattering processes. Our findings contribute to a better understanding of the tuning of thermal conductivity in Si-NWs by means of patterned nanostructures, and may provide valuable insights into the optimal design of one-dimensional thermoelectric materials.

In two-body problems, the problem of the two-body spring vibrator is a more typical and interesting mechanics problem. But the relative motion of the two-body spring vibrator involves elliptical integrals, so the problem is very complex and had not yet been solved analytically in the past time. In this paper, using the elliptical integral theory, we obtain the analytic solutions of the two-body spring vibrator motion law, so that we can discuss further the motion characteristics.

This article reports an evaluation on the linear ideal magnetohydrodynamic (MHD) stability of the China Fusion Engineering Test Reactor (CFETR) baseline scenario for various first-wall locations. The initial-value code NIMROD and eigen-value code AEGIS are employed in this analysis. A good agreement is achieved between two codes in the growth rates of $n=1-10$ ideal MHD modes for various locations of the perfect conducting first-wall. The higher-$n$ modes are dominated by ballooning modes and localized in the pedestal region, while the lower-$n$ modes have more prominent external kink components and broader mode profiles. The influences of plasma-vacuum profile and wall shape are also examined using NIMROD. In presence of resistive wall, the low-$n$ ideal MHD instabilities are further studied using AEGIS. For the designed first-wall location, the $n = 1$ resistive wall mode (RWM) is found unstable, which could be fully stabilized by uniform toroidal rotation above 2.9\% core Alfv\'en speed., Comment: 20 pages, 12 figures. arXiv admin note: text overlap with arXiv:1711.09043

Using the techniques of neural networks (NN), we study the three-dimensional (3D) five-state ferromagnetic Potts model on the cubic lattice as well as the two-dimensional (2D) three-state antiferromagnetic Potts model on the square lattice. Unlike the conventional approach, here we follow the idea employed by Li et al (2018 Ann. Phys., NY 391 312–331). Specifically, instead of numerically generating numerous objects for the training, the whole or part of the theoretical ground state configurations of the studied models are considered as the training sets. Remarkably, our investigation of these two models provides convincing evidence for the effectiveness of the method of preparing training sets used in this study. In particular, the results of the 3D model obtained here imply that the NN approach is as efficient as the traditional method since the signal of a first order phase transition, namely tunneling between two channels, determined by the NN method is as strong as that calculated with the Monte Carlo technique. Furthermore, the outcomes associated with the considered 2D system indicate even little partial information of the ground states can lead to conclusive results regarding the studied phase transition. The achievements reached in our investigation demonstrate that the performance of NN, using certain amount of the theoretical ground state configurations as the training sets, is impressive.

The turbo-expander is the core part of the helium refrigerator, and the gas bearing is the critical component influences the stability of the machine. There is 300 K operating temperature difference between the turbine wheel and the gas bearing regions in the helium turbo-expander. Therefore, it is necessary to consider the heat transfer between the bearing surfaces, nominally at room temperature, and the rest of the machine when studying bearing dynamic stability. This paper describes a cryogenic test platform that is being developed to analyze the dynamic performance of gas bearings with cryogenic gas supply. The system flow loop has been designed for bearing and small turbine testing at 80 K and above. The experimental method has been determined. All of the components are ready for the cold box assembly. The commissioning of the platform will be carried out in the near future.

To provide seed pulses with ultra-broad bandwidth and high temporal contrast for high power laser systems, cross-polarized wave (XPW) generation based on gadolinium gallium garnet (GGG) crystal was proposed after a high-gain preamplifier. By numerical simulation, specifications of conversion efficiency with ~23.3%, contrast enhancement by ~9.7 orders of magnitude and spectrum of 626–1167 nm (full width at half maximum ~ 259 nm) supporting Fourier-transfer-limit duration of 5.5fs was realized. XPW injected by fundamental wave of higher-order super-Gaussian temporal profiles presents superior characterizations. By contrast with BaF2, XPW with GGG performs a comparable contrast enhancement, higher efficiency and more remarkable spectrum broadening, indicating a prominent application in frontend.

In the new era, reform of the audit management of Official Audit Organs need systems thinking. This paper focus on the guidance and supervision of internal audit, which is the important content of the audit management system. Through the analysis of the present situation from various perspectives, aiming at the outstanding problems that still need to be paid attention to under the new situation. It explores a feasible way to coordinate the development of internal audit guidance and internal audit institutions, and tries to exemplify the application section on the basis of empirical analysis. To quantify the relevance between internal audit guidance and internal audit institutions through scientific method, introducing Principal Component Analysis and Monte Carlo Method, also provides some reference ideas for practical application.

The auto-correlation function and the cross-correlation of an autonomous stochastic system with nonlinear time-delayed feedback are investigated by using the stochastic simulation method. There are prominent differences between the roles of quadratic time-delayed feedback and cubic time-delayed feedback on the correlations of an autonomous stochastic system. Under quadratic time-delayed feedback, the nonlinear time delay fails to improve the noisy state of the autonomous stochastic system, the auto-correlation decreases monotonously to zero, and the cross-correlation increases monotonously to zero with the decay time. Under cubic time-delayed feedback, the nonlinear time delay can improve the noisy state of the autonomous stochastic system; the auto-correlation and the cross-correlation show periodical oscillation and attenuation, finally tending to zero with the decay time. Comparing the correlations of the system between with nonlinear time-delayed feedback and linear time-delayed feedback, we find that nonlinear time-delayed feedback lowers the correlation strength of the autonomous stochastic system.

The helium cryogenic system supplies supercritical helium cooling capacity at 4.5 K for the superconducting magnets in the EAST superconducting tokamak.Four low-temperature helium turbines are used in the 2 kW helium refrigeration system,and their performance and reliability are critical for the continuous operation of the tokamak.The turbines were made by the Helium Mechanics Company in Russia.The start-up process is very unstable,easily broken,and thus testing and improvements are needed.In this paper,we analyze the structure of the helium turbine,make improvements,and describe the testing process and results of the improved helium turbines.Some of the operational experiences during the start-up process and tests are also presented.

A highly reproducible spontaneous non-inductive low recycling no-ELM regime has been achieved in the EAST superconducting tokamak with the water-cooled tungsten divertor and molybdenum first wall. The salient feature is that after the L-H transition, emission intensity, divertor neutral pressure and the separatrix electron density all decrease, and the amplitude of ELMs decreases simultaneously until they disappear completely. This scenario exhibits a distinct density threshold, which is dependent on plasma current and wall condition. ELITE/NIMROD simulations indicate that the density at the foot of pedestal and ion diamagnetic effect may play a key role in the achievement of no-ELM operation; the low pedestal foot density might have a strong ion diamagnetic stabilizing effect, which can stabilize the medium-n and high-n Peeling-Ballooning modes. In order to achieve this low pedestal foot density condition, a number of techniques have been employed in EAST, i.e. through extensive lithium wall conditioning and active control of plasma configuration and strike point position. The low recycling no-ELM regime can be extended into a small ELMs regime by increasing the pedestal foot density to facilitate impurity control for long pulse operation, which has been demonstrated in EAST with a pulse length exceeding 101 s. Such a small ELMs regime provide a possible approach toward long-pulse steady-state H-mode operation in future devices.

Numerical calculations of resistive internal kink mode with effects of energetic particles (EPs) on HL-2A have been performed using the hybrid kinetic-MHD model inplemented in the NIMROD code. The m/n = 1/1 resistive internal kink mode is unstable in MHD limit. However, with kinetic effects of energetic ions, a fishbone mode is excited with mode frequency around 10 kHz. We calculate the impact of resistivity on the growth rate and frequency of ion fishbone mode, and the results are in good agreement with the analytic solutions, which are obtained by solving the fishbone dispertion relation including resistivity effect. The effects of β frac and cut off velocity of EP on fishbone mode are calculated in detail, where β frac is the ratio of EP pressure to background plasma pressure. This work presents a clear explanation of the stabilizing effect of ECRH on ion fishbone, which is first observed on HL-2A.

We construct analytical self-similar solutions for the generalized (3+1)-dimensional nonlinear Schrodinger equation with polynomial nonlinearity of arbitrary order. As an example, we list self-similar solutions of quintic nonlinear Schrodinger equation with distributed dispersion and distributed linear gain, including bright similariton solution, fractional and combined Jacobian elliptic function solutions. Moreover, we discuss self-similar evolutional dynamic behaviors of these solutions in the dispersion decreasing fiber and the periodic distributed amplification system.

We report on current profile evolution in EAST NBI driven plasmas where two neutral beams are injected, one during the current ramp phase and the second during flattop. At the end of the current ramp phase, it is found that a flat q profile with q 0 ~ 1 is achieved with low magnetic shear in the core. It is observed that plasma current and density both relax much faster than resistive time, even in the absence of sawtooth activity when H–L transition occurs. Density fluctuations associated with magnetic perturbations (3/2) as a precursor to the H–L transition are observed. It is likely that these modes play a role in fast current transport.

When discussing the association between birth weight and air pollution, previous studies mainly focus on the maternal trimester-specific exposures during pregnancy, whereas the possible associations between birth weight and weekly-specific exposures have been largely neglected. We conducted a nested 1:4 matched case-control study in Jinan, China to examine the weekly-specific associations during pregnancy between maternal fine particulate matter (aerodynamic diameter

Since the first commissioning in 2005, the cryogenic system for EAST (Experimental Advanced Superconducting Tokamak) has been cooled down and warmed up for thirteen experimental campaigns. In order to promote the refrigeration efficiencies and reliability, the EAST cryogenic system was upgraded gradually with new helium screw compressors and new dynamic gas bearing helium turbine expanders with eddy current brake to improve the original poor mechanical and operational performance from 2012 to 2015. Then the totally upgraded cryogenic system was put into operation in the eleventh cool-down experiment, and has been operated for the latest several experimental campaigns. The upgraded system has successfully coped with various normal operational modes during cool-down and 4.5 K steady-state operation under pulsed heat load from the tokamak as well as the abnormal fault modes including turbines protection stop. In this paper, the upgraded EAST cryogenic system including its functional analysis and new cryogenic control networks will be presented in detail. Also, its operational present status in the latest cool-down experiments will be presented and the system reliability will be analyzed, which shows a high reliability and low fault rate after upgrade. In the end, some future necessary work to meet the higher reliability requirement for future uninterrupted long-term experimental operation will also be proposed.

Considering a saturation laser model with cross-correlated additive and multiplicative noises, we derive the stationary probability distribution function Pst(I), the stationary intensity correlation function C(s) and the associated relaxation time Tc by virtute of the Novikov theorem and Stratonovich's decoupling ansatz. Based on numerical computation, we discuss the effects of the correlation strength λ, the cross-correlation time τ, and the noises intensity. The correlation strength λ attenuates the probability distribution and increases the intensity fluctuation of the laser system. The correlation strength λ and the noise intensity D and Q speed up the relaxation of the system from an arbitrary state to the steady state and enhance the stability of the laser intensity output. For the case of negative correlation (λ 0).