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Exposed to the natural light-dark cycle, 24 h rhythms exist in behavioral and physiological processes of living beings. Interestingly, under constant darkness or constant light, living beings can maintain a robust endogenous rhythm with a free running period (FRP) close to 24 h. In mammals, the circadian rhythm is coordinated by a master clock located in the suprachiasmatic nucleus (SCN) of the brain, which is composed of about twenty thousand self-oscillating neurons. These SCN neurons form a heterogenous network to output a robust rhythm. Thus far, the exact network topology of the SCN neurons is unknown. In this article, we examined the effect of the SCN network structure on the FRP when exposed to constant light by a Poincaré model. Four typical network structures were considered, including a Nearest-neighbor coupled network, a Newman-Watts (NW) small world network, an Erdös-Rényi (ER) random network and a Barabási-Albert (BA) scale free network. The results show that the FRP is longest in the BA network, because the BA network is characterized by the most heterogeneous structure among these four types of networks. These findings are not affected by the average node degree of the SCN network or the value of relaxation rate of the SCN neuronal oscillators. Our findings contribute to the understanding of how the network structure of the SCN neurons influences the FRP.

When a high energy nanosecond (ns) laser induces breakdown in the air, the plasma density generated in the rarefied atmosphere is much smaller than that at normal pressure. It is associated with a relatively lower absorption coefficient and reduces energy loss of the laser beam at low pressure. In this paper, the general transmission characterizations of a joule level 10 ns 1064 nm focused laser beam are investigated both theoretically and experimentally under different pressures. The evolution of the electron density (n e ), the changes in electron temperature (T e ) and the variation of laser intensity (I) are employed for numerical analyses in the simulation model. For experiments, four optical image transfer systems with focal length (f) of 200 mm are placed in a chamber and employed to focus the laser beam and produce plasmas at the focus. The results suggest that the transmittance increases obviously with the decreasing pressure and the plasma channels on the transmission path can be observed by its self-illumination. The simulation results agree well with the experimental data. The numerical model presents that the maximum n e at the focus can reach 1019 /cm3, which is far below the critical density (n c ). As a result, the laser beam is not completely shielded by the plasmas.

In-service welding repair is important to ensure natural gas pipelines’ safe and reliable operation. The temperature distribution in the welding heat treatment process directly affects the pipeline’s bearing capacity and local stress distribution. This study studied the temperature distribution of a high steel pipeline generated by the heat treatment process for the long-term transportation of oil and gas was studied experimentally. The medium frequency induction heating method is applied to heat the tube body by winding a heating belt on the outer wall of the steel pipe to simulate pre-welding and post-welding heat treatment. At the same time, a thermocouple is used to record the temperature change of each position during the whole heating process to obtain data. Through numerical analysis and fitting, the distribution law of the temperature field in the heat treatment process of steel pipe is established to guide the field heating temperature control.

Due to the special interest and unique advantage of bovine serum albumin among various proteins, we carried out researches into effects of bovine serum albumin on photophysical characters of meso-tetrakis(sulfonatophenyl) porphyrin. The laser source we chose is picosecond pulse trains containing 20 subpulses of 70 picoseconds width separating by 13 nanoseconds at 532 nanometers. The theoretical analysis was carried out with a generalized five-level model representing the molecular populating structure. The two-dimensional paraxial field combined with the rate equations was solved by Crank-Nicholson numerical method. The nonlinear optical absorption mechanism in porphyrin is mainly two-step two-photon absorption. We found meso-tetrakis(sulfonatophenyl) porphyrin always shows prominent optical limiting effects binding with or without bovine serum albumin. In the presence of bovine serum albumin, the photophysical parameters of porphyrin get certain influence and cause slight weakening of optical limiting for porphyrin.

A transfer reaction and cluster-decay experiment, C( O, Mg α+ Ne)α, was performed at a beam energy of 96 MeV. Both recoil and decay α particles were detected in coincidence, allowing us to deduce the energy-momentum of a Ne fragment. A number of resonant states of Mg were reconstructed up to an excitation energy of approximately 30 MeV. Owing to the experimentally achieved excellent resolutions of the Q-value and excitation-energy spectra, the relative decay widths for each resonant state in Mg to various final states of Ne were extracted, along with the total decay width. The obtained results provide good testing ground for theoretical descriptions of multiple clustering configurations in Mg.

Duplex stainless steel has been widely applied to industry. In this paper, nondestructive testing, chemical composition analysis, metallographic analysis, hardness test, and scanning electron microscope were used to study the causes of the crack in the butt joint girth weld of pipe and flange. Both steel pipe and flange are duplex stainless steel S31803. Through analysis, it was judged that the crack was a crystalline crack, generated in the welding process, which was related to the welding process and the control of the welding installation gap between the steel pipe and the flange with unequal wall thickness.

Thermally oxidized MWCNTs (OMWCNTs) are fabricated by a thermal treatment of MWCNTs at 500 °C for 3 h in an oxygen-containing atmosphere. The oxygen content of OMWCNTs increases from 1.9 wt% for MWCNTs to 8.3 wt%. And the BET specific surface area of OMWCNTs enhances from 254.2 m2 g−1 for MWCNTs to 496.1 m2 g−1. The Fe2O3/OMWCNTs nanocomposite is prepared by a hydrothermal method. Electrochemical measurements show that Fe2O3/OMWCNTs still keeps a highly reversible specific capacity of 653.6 mA h g−1 after 200 cycles at 0.5 A g−1, which shows an obviously higher capacity than the sum of that of single Fe2O3 and OMWCNTs. The OMWCNTs not only buffer the volume changes of Fe2O3 nanoparticles but also provide high-speed electronic transmission channels in the charge–discharge process. The thermal oxidation method of OMWCNTs avoids using strong corrosive acids such as nitric acid and sulfuric acid, which has the advantages of safety, environmental protection, macroscopic preparation, etc.

In this study, the performance test and defect anatomy analysis were carried out for a girth weld of the pipeline. The results of the girth weld tensile test, groove hammer break test and Vickers hardness test showed no obvious abnormality, and the impact toughness and bending test results were not ideal. In the conventional inspection process, it was found that there were tiny unfused girth welds at 6 o 'clock and 9 o 'clock positions, and the maximum direction size of defects on the wall thickness section was 1.57 mm. The defects at the position from 6 o 'clock to 7 o 'clock found by on-site X-ray detection were identified as the existing non-fusion defects by anatomical analysis, and should be considered as the root of incomplete welding defects that could not be completely eliminated during repair welding. The length and height of the defects are 9 mm and 1.38 mm.

With the increasing complexity of the distribution network, the requirements for fault location are becoming higher and higher. In this paper, the Beetle swarm algorithm, which combines the particle swarm optimization algorithm with the Beetle whisker algorithm, is introduced to locate the fault of the multi-source power system with distributed generators through the python simulation ieee33 node example. Compared with the single particle swarm optimization algorithm, the Beetle swarm algorithm has the characteristics of high stability and high fault tolerance.

Photoreflectance (PR) spectroscopy is a powerful and non-destructive experimental technique to explore interband transitions of semiconductors. In most PR systems, the photon energy of the pumping beam is usually chosen to be higher than the bandgap energy of the sample. To the best of our knowledge, the highest energy of pumping laser in reported PR systems is 5.08 eV (244 nm), not yet in the vacuum ultraviolet (VUV) region. In this work, we report the design and construction of a PR system pumped by VUV laser of 7.0 eV (177.3 nm). At the same time, dual-modulated technique is applied and a dual channel lock-in-amplifier is integrated into the system for efficient PR measurement. The system’s performance is verified by the PR spectroscopy measurement of well-studied semiconductors, which testifies its ability to probe critical-point energies of the electronic band in semiconductors from ultraviolet to near-infrared spectral region.

Artificial muscle is a research topic that combines new driving methods, intelligent materials and bionics. To overcome the weaknesses of the electric actuator made of bio-gel materials, e.g. poor driving effect and short working life, the working mechanism of artificial muscle based on sodium alginate/cellulose (SCAM) and how to improve its performance have explored in this study. First of all, the basic process of preparing conductive artificial muscle with sodium alginate and carboxymethyl cellulose (CMC) as the main materials were defined. Secondly, the addition amount of CMC was optimized based on parameters such as the single-cycle output force, working life and curvature. Thirdly, the electrochemical and microscopic testing methods were applied to expound the internal reaction mechanism of improving the response characteristics of samples based on the FITR. The results show that the addition of CMC enables SCAM to have better response characteristics in the electric field, which is applicable to the practical application of flexible machinery and bio-gel artificial muscle.

Cold atmospheric plasmas (CAPs) have shown great applicability in agriculture. Many kinds of CAP sources have been studied in agricultural applications to promote plant growth and cure plant diseases. We briefly review the state-of-the-art stimulating effects of atmospheric-pressure dielectric-barrier-discharge (AP-DBD) plasmas, after the direct or indirect treatment of plants for growth promotion and disease control. We then discuss the special demands on the characteristics of the CAP sources for their applications in plant mutation breeding. An atmospheric and room temperature plasma (ARTP) jet generator with a large plasma irradiation area, a high enough concentration of chemically reactive species and a low gas temperature is designed for direct plant mutagenesis. Experimental measurements of the electrical, thermal and optical features of the ARTP generator are conducted. Then, an ARTP-P (ARTP for plant mutagenesis) mutation breeding machine is developed, and a typical case of plant mutation breeding by the ARTP-P mutation machine is presented using Coreopsis tinctoria Nutt. seeds. Physical and agricultural experiments show that the newly-developed ARTP-P mutation breeding machine with a large irradiation area can generate uniform CAP jets with high concentrations of chemically reactive species and mild gas temperatures, and have significant mutagenesis effects on the Coreopsis tinctoria Nutt. seeds. The ARTP-P mutation breeding machine may provide a platform for systematic studies on mutation mechanisms and results for various plant seeds under different operating conditions in future research.

Multiple synthetic beacons are required for atmospheric-turbulence compensation in an extended-field-of-view multi-conjugate adaptive optics (MCAO) telescope. In this paper, we report on the first successful implementation of a microsecond-pulse sodium guidestars constellation laser system, based on a small angle precise polarized combining and splitting technology. At Lijiang Observatory of China, four-ways ∼20 W yellow laser beam with kHz repetition-rate and hundred-μs pulse width were projected into the sky through one small-aperture launching telescope, and generated a distinctive four-point grouping on a field of view of 40″ with variable configurations of linear, parallelogram, rhomboid and square. The sodium return signal could easily avoid Rayleigh light interference by the pulse synchro controlling technology delivering a higher spatial resolution. Moreover, the increase in return photons for alternated circularly and alternated linearly polarized light has been investigated. We believe that the above results could serve as a future reference for the MCAO system on large-aperture telescopes worldwide.

As the key link of power transmission in the power distribution system, the distribution transformer is the core of the entire power distribution system and is responsible for the electrical connection between the medium voltage side and the low voltage side, and based on this to further ensure the stable operation of the power distribution system. Data types, sources, selection principles and data processing methods relate to the operating state of distribution transformers; then expound the meaning of operating state indicators, and build a distribution transformer operating state index model; finally, an improved weight method is used to determine the distribution transformers of the weight coefficient of the running status indicator. Therefore, it is appropriate to verify the membership function and membership matrix selected in this paper. It is suitable for the fuzzy comprehensive evaluation calculation of the reliability of distribution transformers, which verifies the accuracy of the reliability evaluation results. The maintenance strategy of distribution transformers based on reliability assessment can be optimized according to the operation status of the equipment so as to improve the operation reliability of distribution transformers and ensure the safe, reliable and economical operation of the equipment. The maintenance strategy of distribution transformers based on reliability assessment can be optimized according to the operation status of the equipment, which is to improve the operation reliability of distribution transformers and ensure the safe, reliable and economical operation of the equipment.

Accidents such as overvoltage, personal injury and motor damage caused by singlephase disconnection faults occur frequently in active distribution networks. In response to this problem, firstly, the negative-sequence differential impedance is defined and a protection method based on negative-sequence differential impedance is proposed, the method uses the amplitude of negative-sequence differential impedance as an action quantity and uses its phase to construct an adaptive braking threshold. Secondly, in case of protection failure under overload, the zero-sequence voltage amplitude difference is proposed as an auxiliary criterion, and the influence of different types of distributed generators on the zero-sequence voltage difference on both sides of the fault fracture is analyzed. Finally, it is verified by simulation that the method can be positioned reliably and is not affected by the neutral point grounding method, transition resistance, load and distributed generators.

The suspected circumferential weld defects found in the pipeline inspection process were tested and studied. It was found that there was slag inclusion in the girth weld at 9 o’clock, which had not been found in the early stage or in the laboratory nondestructive testing process. The defects are most likely due to incomplete slag removal between layers and low welding wire energy. There was a root crack at the 6 o’clock position of the weld, and the crack length was 10 mm, which was close to the original film and the detection result of excavation. The misjudgment of the field rebeat and the laboratory test results may be caused by the pits in the weld cover and the bottom weld. The crack is caused by the crystal crack formed along the middle of the columnar crystal during the solidification process of backing welding due to the increase of residual stress caused by the reduction of welding layers and the group stress caused by the steel tube.

The synergistic effects involving surface adsorption and photocatalytic degradation commonly play significant roles in the removal of persistent synthetic organics from wastewater in the case of porous semiconductors. Inspired by the visible-light harvesting advantages of porphyrin-based MOFs, a capsule-like bimetallic porphyrin-based MOF (PCN-222(Ni/Hf)) has been successfully constructed through a facile hydrothermal method. In which, the Hf (IV) ions were exactly bonded to the carboxyl groups substituted on the porphyrin rings, meanwhile the Ni (II) ions were finely bonded to the -N inside the porphyrin rings. The adsorption/photocatalytic performances were assessed by using four persistent dyes including rhodamine B (RhB), basic violet 14 (BV14), crystal violet, and acid black 210 (AB210) as the target substances, and enhanced total removal efficiency was obtained by the bimetallic PCN-222(Ni/Hf) in comparison with that of single PCN-222(Hf). The electrochemical analyses and the sacrificial agent capture experiments were carried out to elucidate the photocatalytic mechanism, and the adsorption/photocatalytic stability of PCN-222(Ni/Hf) is also investigated. The work has broadened the applications of porphyrin-based MOFs in the removal of organics by combining their excellent surface adsorption capacity and photocatalytic activities.

A multi-nucleon transfer and cluster decay experiment, Li( B, C + Be) , is conducted at an incident beam energy of 55 MeV. This reaction channel has a significantly large Q-value, which favors populating the high lying resonant states in C. The decay paths, from these resonances to various states of the final nucleus Be, can be selected, owing to the experimentally achieved optimal resolution of the Q-value spectrum. A number of resonant states are reconstructed from the forward emitting Be + fragments, and their major molecular structures can be detected according to the selective decay paths and relative decay widths. A state at 22.4(2) MeV validates the previously measured and theoretically predicted band head of the positive-parity -bond linear-chain molecular band. Two additional resonances at 22.9(2) and 24.2(2) MeV are identified and consistent with the predicted and members of the same molecular band, thus providing novel evidences for the existence of the exotic clustering chain structure in neutron-rich carbon isotopes. A few high energy resonances, which also indicate the presence of the -bond molecular structure, are observed; however, further studies are still required to clarify their ascription in band systematics.

Aiming at the problems of low performance index and redundant information of multi-class physical health factors, a method of building rolling bearing health factors based on improved restricted Boltzmann machine is proposed. By fusing multi-class physical health factors, the virtual health factor of rolling bearings is constructed. Extracting physical health factors in time domain and frequency domain of rolling bearing vibration monitoring signals as inputs; the performance degradation mechanism model is added to the regularization term of the Restricted Boltzmann Machine, the performance degradation information contained in the input data is mined, the virtual health factor construction model of rolling bearings is built, and the model parameters are adjusted by the health factor evaluation criteria to improve the performance of the virtual health factor. The life cycle test of rolling bearings shows that compared with the principal component analysis method, the monotonicity of virtual health factors based on the improved restricted Boltzmann mechanism is increased by 147.6% and 38.5%, the trend is increased by 113.8% and 16.1%, and the robustness is increased by 60% and 8.42%, respectively.

As an intangible cultural heritage, the folk song Huar is a precious name card of Chinese national culture. Its protection and inheritance are of great significance for promoting multi-ethnic cultural identity and enhancing cultural confidence. Genre research is an important topic in the study of Huar. However, current Huar genre researches are mainly based on qualitative methods. Digital Humanities is an emerging discipline that applies computing and digital technology to the study of the humanities. Comparing to traditional methods, Digital Humanities is a more accurate and efficient method of style analysis on literary texts. Through the methods of Digital Humanities, we can objectively show and verify the similarities and differences between Huar genres, and make up for the lack of objectivity in the traditional Huar genre research. Therefore, in this paper we combined qualitative and quantitative methods to make a comparative style analysis on Hehuang Huar and Taomin Huar from two aspects, namely rhythm and sentence pattern. Furthermore, we explored the reasons in depth behind these surface rules from the perspectives of music, literature, nationality and history. We simultaneously use hierarchical clustering to verify the discrimination of genres on specific style features. The result of this research shows that the research perspective and methods of digital humanities can provide objective conclusions for Huar researches, which can provide data support and scientific basis for researchers or enthusiasts to distinguish, appreciate and study Huar.