CAFe is a low-β helium/proton superconducting LINAC. It is as a demo LINAC for China initiative Accelerator-Driven System and constructed at the Institute of Modern Physics, Chinese Academy of ...Sciences. In this paper, an off-site characterization focusing on the capacitance measurements of cold button BPMs is presented firstly. Furthermore, a signal estimation and analysis of cold button BPMs is performed with regard to two kinds of beam commissioning, helium and proton beams. A good agreement between the calculation and the measurement proves that the developed theoretical model could accurately estimate the output signal of cold button BPMs. It considers the influence of low-β effect and long cable issues. Based on the transformation of the estimated signal from the time domain to the frequency domain, it is found that the amplitude spectra of cold button BPMs expand with the energy increasing and the bunch length shortening. The amplitude at the first harmonic frequency decreases, which causes the summed values from BPM electronics to be declined in the LINAC. However, the decline in summed values is not proportional to the decreasing of beam current. This is the reason why BPMs only give relative intensity and not absolute value for low-β beams when BPMs’ electronics using a narrow-band digital signal processing. These developments will be used for the cold BPM system and the fast machine protection system. It is dedicated to the driven LINAC of China initiative Accelerator-Driven System, which will deliver a 500 MeV, 5 mA proton beam in continuous wave operation mode.
The new wide-range readout electronics with a self-calibration function are designed for ionization chambers in the slow extraction of High-Intensity Heavy Ion Accelerator Facility, Booster Ring. ...These electronics consist of a programmable transimpedance amplifier, a self-calibration circuit, an 18-bit analog-to-digital converter, and a ZYNQ-7015 field-programmable gate array. It is capable of monitoring weak current signals of 40 pA-4 mA with a sampling rate of 5 MHz. The ZYNQ-7015 FPGA manages the operation mode of the analog front-end and the gain of the trans-impedance amplifier. It also performs digital signal processing algorithms and data communication with the host computer. The self-calibration circuit uses a combination of a Schmitt trigger and voltage-to-current converters to generate 2 square wave current signals with different peaks (2 μA, 2 mA). During offline tests, the effective number of bits is 12.98 bits, and the nonlinearity is less than 0.075% for a full scale. Finally, the readout electronics are deployed for ionization chambers' slow extraction measurements at the extraction line of the cooling storage ring of the Heavy Ion Research Facility in Lanzhou. With the help of a commercial DC-transformer in the HIRFL-CSR, these electronics not only execute an accurate current measurement, but also can monitor the extraction efficiency reliably. In a word, these electronics play an important role in the fields of extremely weak and high dynamic current signal measurements.
Arsenic is associated with several adverse health outcomes, and people with diabetes may be more susceptible to arsenic. In this study, we found that arsenic levels in some tissues such as liver, ...kidney, and heart but not lung of type 1 diabetes mellitus (T1DM) mice were higher than in those of normal mice after a single oral dose of arsenic trioxide for 2 h. However, little is known about the molecular mechanism of the increased tissue uptake of trivalent inorganic arsenic in mice with T1DM. This study aimed to investigate the expression of the mammalian arsenic transporters aquaglyceroporins (AQPs) and glucose transporter 1 (GLUT1) in T1DM mice and compare them with those in normal mice. Results showed that the levels of AQP9 and GLUT1 mRNA and protein were higher in T1DM mouse liver than in the normal one. The levels of AQP7 mRNA and protein were higher in T1DM mouse kidney. In the heart, we observed that the levels of AQP7 and GLUT1 mRNA and protein were higher in T1DM mice, but the levels of AQP9 mRNA and protein in the lung had no significant difference between both mice. These results suggested that T1DM may increase the expression of transporters of trivalent inorganic arsenic and thus increase the arsenic uptake in specific tissues.
•We investigated PTEN expression in peripheral nerve development and after injury.•PTEN expression profiles will facilitate the understanding of peripheral nerve development and ...regeneration.•Down-regulation of PTEN may be required to facilitate peripheral regeneration, such as during development.
Studies have suggested that phosphatase and tensin homolog (PTEN) plays an important role in neuroprotection and neuronal regeneration. To better understand the potential role of PTEN with respect to peripheral nerve development and injury, we investigated the expression pattern of PTEN at different stages of rat peripheral nerve development and injury and subsequently assessed the effect of pharmacological inhibition of PTEN using bpV(pic) on axonal regeneration in a rat sciatic nerve crush injury model. During the early stages of development, PTEN exhibits low expression in neuronal cell bodies and axons. From embryonic day (E) 18.5 and postnatal day (P)5 to adult, PTEN protein becomes more detectable, with high expression in the dorsal root ganglia (DRG) and axons. PTEN expression is inhibited in peripheral nerves, preceding myelination during neuronal development and remyelination after acute nerve injury. Low PTEN expression after nerve injury promotes Akt/mammalian target of rapamycin (mTOR) signaling pathway activity. In vivo pharmacological inhibition of PTEN using bpV(pic) promoted axonal regrowth, increased the number of myelinated nerve fibers, improved locomotive recovery and enhanced the amplitude response and nerve conduction velocity following stimulation in a rat sciatic nerve crush injury model. Thus, we suggest that PTEN may play potential roles in peripheral nerve development and regeneration and that inhibition of PTEN expression is beneficial for nerve regeneration and functional recovery after peripheral nerve injury.
The composition design of complex concentrated alloys originates from the composition design of amorphous alloys. To expand the composition design of alloys, herein, the compositions of novel ...Ti–Co–Ni–Zr complex concentrated alloys were obtained by the proportional mixing of Ti
Co intermetallics and Ni
Zr
binary eutectic. The theory and method of this new alloy design are also discussed. The as-cast Ti
Co
Ni
Zr
, Ti
Co
Ni
Zr
, and Ti
. Co
Ni
Zr
alloys were composed of body-centered cubic TiNi and Ti
Ni phases. The Ti
Co
Ni
Zr
alloy exhibited high yield strength (2 164 MPa) and compressive strength (2 539 MPa) under quasi-static compression at roomtemperature. The high strength of Ti
Co
Ni
Zr
alloy is related to the precipitation of Ti
Ni along the grain boundary and the precipitation in the crystal. This paper validates that using the proportional mixing method of intermetallics and eutectic alloy is an effective method to design complex concentrated alloys with high strength.
To meet the high time-resolution requirements of a fast ionization profile monitor (IPM), a 64-channel electrical signal acquisition system with a fast response frequency of 1 MHz has been developed. ...This article initially describes an ultralow noise transimpedance amplifier, which is an analog front-end (AFE) electronics aiming to achieve a balance between the accuracy and bandwidth, as well as to truly reflect the microstructure of short beam pulses. Subsequently, a synchronized multichannel data transmission system based on field-programmable gate arrays (FPGAs) transmits data streaming with the low latency and high throughput, and meanwhile, it provides data homogeneity in time across channels. The system is designed in a modular way to easily extend up to 128 channels. The nonlinearity of the readout electronics is less than 0.2% in the dynamic range of 15 nA-<inline-formula> <tex-math notation="LaTeX">15~\mu \text{A} </tex-math></inline-formula>, and the relative resolution is 0.15% at the input current of 15 <inline-formula> <tex-math notation="LaTeX">\mu \text{A} </tex-math></inline-formula>. The spurious-free dynamic range (SFDR) is about 82.43 dB at a fundamental frequency of 1 kHz, and the effective number of bits (ENOB) of the analog-to-digital conversion (ADC) is better than 13 bits. The relative synchronization time discrepancy between channels is better than 2.5% of the sampling cycle. Finally, the system is deployed for the beam profile measurement with an IPM. The obtained peak value shows a good proportionality with the beam intensity increment, and all the electronics properties achieve reasonable and excellent performance.
To explain the different prediction accuracies of a single characteristic parameter in amorphous alloy (AM), solid solution alloy (SS) and high entropy alloy containing intermetallic compound (IM), ...three methods were proposed. The first was that the simple division in the whole value range of the characteristic parameter can qualitatively explain the high or low prediction accuracies of characteristic parameters in three type of AM, SS and IM alloys. To consider the mutual interference to the decision boundary in the whole eigenvalue range, the second was that the histogram of the probability density distribution of eigenvalues was used to qualitatively explain the prediction accuracies of characteristic parameters in different regions. The third was that the Gaussian fitting curves of the histogram of probability density distribution for characteristic parameters was considered. The prediction accuracies of the characteristic parameters in different alloys were explained by using the method of normalized area or the sum of the normalized areas of the two characteristic parameters. The analysis results were basically consistent with the results of model learning. To explain the prediction accuracies of two or three parameter combinations, an expression was defined to simply express the interference ability of the single characteristic parameter to the decision boundary division. The comparison of the prediction accuracies of two or three parameter combinations was analyzed by the expression of the decision-boundary interference ability of a single characteristic parameter. Three parameter combinations had the highest average prediction accuracy, however, the average prediction accuracies of four parameter combinations had been over fitted for AM, SS and IM alloys. This work provided a new interpretation method for the prediction accuracy of phase composition of AM, SS and IM alloys based on support vector machines in machine learning.
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•Simple division explains prediction accuracies of characteristic parameters in three type alloys.•Histogram of probability density distribution explains prediction accuracies of parameters.•Prediction accuracies were explained by using method of normalized area of two parameters.•Prediction accuracies was analyzed by expression of decision-boundary interference ability.•A new interpretation method was provided for prediction accuracy of phase composition.
Improving the anti-carbon deposition and anti-sintering ability under the premise of maintaining high catalytic activity is the core issue of Ni-based catalysts applied in CO methanation reactions. ...To address this issue, a La0.75A0.25NiO3/SiO2 (A = Ce, Sr, Sm, and Ca) catalyst is prepared via a citric acid complexation method. XRD results show that the substituted elements (Sr, Sm, and Ca) enter the LaNiO3 lattice and partially replace the A-site element La. The reduced Ni0 is beneficial to improve the medium temperature activity of the catalyst. The substitution of different elements produces different electronic effects that significantly affect the size of the Ni particles and the interaction between Ni and La2O3. The catalyst with doped Ca2+ as the A-site substituted element demonstrates better adsorption, storage, and migration capabilities for oxygen due to the lattice distortion that easily produces oxygen vacancies. Catalysts doped with Sr, Sm, and Ca as the A-site substituted element produce La2O2CO3 after the reactions, which plays a role in eliminating carbon deposits.
Due to high ramping rates on the Booster Ring (BRing), which is the key part of the high-intensity heavy-ion accelerator facility (HIAF) complex at the Institute of Modern Physics (IMP), thin-wall ...vacuum chambers are required for all magnets to maintain the eddy currents at a tolerable level. A novel thin-wall vacuum chamber supported by ceramic rings was discussed and evaluated for the HIAF at the IMP to reduce the manufacturing cost, reduce the difficulty, shorten the production cycle, and improve the quality. Because the beam coupling impedance aspects are highly important for beam stability, several approaches were used to evaluate the impedance on the ceramics-loaded tube. In this article, we describe the results from the single- and two-wire bench measurements and the numerical simulations. The simulated and measured impedance results are consistent with each other. Several effective methods to mitigate the impedance were proposed and investigated in detail. According to the simulation and measurement results of the beam coupling impedance mitigation, this novel ceramic-ring copper-coated thin-wall vacuum chamber structure will be considered for application to the HIAF project with the highest priority.
Improving the anti-carbon deposition and anti-sintering ability under the premise of maintaining high catalytic activity is the core issue of Ni-based catalysts applied in CO methanation reactions. ...To address this issue, a La
0.75
A
0.25
NiO
3
/SiO
2
(A = Ce, Sr, Sm, and Ca) catalyst is prepared via a citric acid complexation method. XRD results show that the substituted elements (Sr, Sm, and Ca) enter the LaNiO
3
lattice and partially replace the A-site element La. The reduced Ni
0
is beneficial to improve the medium temperature activity of the catalyst. The substitution of different elements produces different electronic effects that significantly affect the size of the Ni particles and the interaction between Ni and La
2
O
3
. The catalyst with doped Ca
2+
as the A-site substituted element demonstrates better adsorption, storage, and migration capabilities for oxygen due to the lattice distortion that easily produces oxygen vacancies. Catalysts doped with Sr, Sm, and Ca as the A-site substituted element produce La
2
O
2
CO
3
after the reactions, which plays a role in eliminating carbon deposits.
