[en] The control system is one of the key items for Beijing Free Electron Laser (BFEL) upgrade project. This paper presents the design and implementation of the Programmable Logical Controller (PLC) control system based on Experimental Physics and Industrial Control System (EPICS). The system is steady, reliable and easy to expand. Design of both software and hardware, and the EtherNet/IP driver for the communication between PLC and EPICS are also described. (authors)

[en] The effect of lignin on the physicomechanical, tribological, and morphological characteristics of corn stalk fiber-reinforced friction materials was investigated in this study by testing various lignin contents and fabricated composites. Experimental results indicated that a decrease in lignin content benefits the fade resistance, wear resistance, and recovery behaviors of the friction materials. Sample FMC-3 containing fibers with a lignin content of 6.7% exhibited the optimum friction stability and wear performance among the tested samples; it has fade rate of 10.2%, recovery rate of 105.3%, and sum wear rate of 1.817 × 10⁻⁷ cm³ (N · m)⁻¹. Worn surface analyses revealed that a suitably low content of lignin may improve fiber-matrix interface bonding and stable secondary plateau formation, which effectively enhance the tribological behavior of friction materials. (paper)

[en] Objective: To evaluate the value of iterative reconstruction (iDose) in low-dose CT cardiac imaging in patients with congenital heart disease (CHD). Methods: Eighty-eight consecutive CHD patients referred for preoperative or post-operative CT were randomly diveded into 4 groups and undergone a prospective ECG-gated MDCT angiography with protocol A (routine low-dose depending on patient weight), B (30% of A), C (50%), and D (70%D), respectively. Filtered back projection (FBP) and grades 2, 4, 6 of iDose were used for all reconstruction. Noises were measured at the root of ascending aorta and main pulmonary artery. Image qualities were graded (scale from one to five) and compared among 4 groups. Results: The lowest image noise was measured in images reconstructed with grade 6 of iDose(P < 0.05) while the highest one was measured in that with FBP in all groups. The subjective scores in Group D with iDose 6 reconstruction were no less than 3. The subjective score in Group D with iDose 6 was similar to that in Group A with FBP. Effective radiation dose in group D was (0.65±0.43) mSv. Conclusion: Using iDose technique would reduce noise and improve image quality effectively. Grade 6 of iDose might be the best choice and would reduce effective dose by 70% in MDCT angiography in CHD patients. (authors)

[en] An integrable lattice hierarchy is constructed from a discrete matrix spectral problem, in which one of the Suris systems is the first member of this hierarchy. Some related properties such as Hamiltonian structure of this lattice hierarchy are discussed. The Suris system is solved by the N-fold Darboux transformation. As a result, the multi-soliton solutions are derived and the soliton structures along with the interaction behaviors among solitons are shown graphically. Finally, the infinitely many conservation laws of the Suris system are given.

[en] To obtain a natural fibre reinforced non-asbestos organic non-metallic friction composite with good wear resistance and environmental-friendly performances, friction composites reinforced with different lengths of abaca fibre were fabricated by a compression molder equipment and evaluated by using a constant-speed friction test machine. The worn surface morphologies were observed and analyzed using a Scanning Electron Microscopy (SEM). Experimental results show that the length of abaca fibre had no significant effect on the density and hardness, but was obvious on impact strength. The impact strength increased and then decreased with the increasing of length of abaca fibres. Abaca fibres, especially short fibre (lengths of 5 mm, 10 mm), could improve the wear resistance of the friction composites. Meanwhile, the increase of test temperature could result in the increasing of wear rates of the friction composites. A large amount of secondary plateaux presented on the worn surface of specimens FC1 and FC2 which showe relatively smooth worn surfaces and yield the better wear resistance performance. (paper)

[en] With the development of Internet of Things, there is the various temperature and humidity monitoring product on the market, but there is almost no product that fits for the application of high energy physics experiment, which requires many kinds of sensors, long communication distance and distributed deployment. According to the experience of BESIII temperature and humidity monitoring system, the new temperature and humidity monitoring system is developed by use of MCU minimum system. The system can collect the signal of DS 18820, SHT75 and DC 0-5V and connect with PC by the interface TCP/IP. At the same time, the PC monitoring software is provided with the hardware in Windows and Linux to fulfill all SCADA function. The system is easily used and is flexibly configured and is widely used in the field of high energy physics experiment, industrial monitoring, agricultural circumstance monitoring and building automation. (authors)

[en] In this paper, we propose a large-scale and non-contact surface topography measurement method using a non-contact scanning probe microscopy (SPM) technique, scanning ion conductance microscopy (SICM), combined with the sub-aperture stitching technique. The phase correlation techniques were first applied to the three-dimensional (3D) images measured by the SICM to acquire an initially coarse stitching position. Then the tip–tilt compensated sub-aperture stitching algorithm is utilized to eliminate tilts and translations among adjacent images and expand the lateral measuring range of the existing hopping mode SICM system. This SICM and the stitching based method has been used to measure some large-scale samples (micrometer to millimeter scale) in a non-contact, quantitative and high resolution way. Simulation and experimental results on these samples verify the feasibility of this method and the effectiveness of the stitching algorithm. A measuring range of 1.08 mm  ×  0.55 mm and a lateral resolution of 100 nm or even higher were obtained in these experiments. Compared with atomic force microscopy (AFM), the non-contact feature of the proposed method ensures less damage to the surface topography. The non-optical feature makes the data stitching simpler than the existing optical microscopic methods, which need consider how to compensate the vignetting effect caused by the inhomogeneity of light. (paper)

[en] Based upon a momentum-source method, a numerical simulation method has been developed to calculate the tip-jet drive rotor/fuselage flowfield. The momentum-source term is used to describe the effect of rotor on its flowfield. The mass-source term is used to describe the tip-jet. According to the characteristics of rotor/fuselage flowfield and requirements of momentum-source and mass-source method, a hybrid mesh generation approach is developed. In the present method, on the basis of the known movement, geometric and aerodynamic characteristics on blade section, a scheme containing momentum-source and mass-source term is adopted for the solution of N-S equations. By the present method, the downwash flowfields of rotor and rotor/fuselage are simulated, and some meaningful conclusions are obtained. (paper)

[en] China Spallation Neutron Source (CSNS) is one of the most important basic scientific research facilities in China, and it has been put into operation since 2018. GPPD is the first neutron instrument to start the experiment. In order to ensure the stability and reliability of experiments of GPPD instrument, an experimental control system was designed and developed. In this paper, the experimental control system is designed according to the relevant theory, and the physical experiment control function of neutron experiment is realized. After CSNS started to provide neutron beam stably in early 2018, the operation control of GPPD was realized. (authors)

[en] Rockwool fibre, which is the important one of mineral fibres, shows tremendous potential as reinforcing components in composite materials. The purpose of this study is to evaluate the influence of rockwool fibre on physical, mechanical and tribological properties of friction composites. The friction composites were fabricated by a compression molder and evaluated by using a friction test machine. The experimental results show that friction coefficient of all specimens has an obvious increasing trend with the increasing of test temperature, the heat fade doesn’t occur in the test processes, and the existence of rockwool fibre could remarkable increase friction coefficient and restraint the heat fade at high temperature. Specimen F-3 containing 9 wt% rockwool fibres has the lowest wear rate, and presents best wear resistance. The worn surfaces morphologies were using the Scanning Electron Microscopy (SEM) for the sake of the tribological behavior and wear mechanism. The results reveal that the specimen F-3 presents a smoother friction surface with larger stable contact plateaus. (paper)