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Aiming at the discharge problem of inductively coupled plasma (ICP), a closed wave-transmitting cavi-ty configuration is designed, the fluid mechanics model of ICP is established, and the multi physical simulation software COMSOL is used for three-dimensional simulation research. The variation laws of typical parameters such as electron density, electron temperature and plasma potential with time in the discharge process are analyzed. On this basis, the power of radio frequency power supply, the air pressure in the cavity and other conditions are changed to obtain the parameter range and spatial gradient distribution of ICP. The results show that the discharge power mainly affects the numerical range of plasma parameters, and the change of air pressure has an effect on the numerical value and spatial distribution of plasma parameters. When the power of radio frequency power supply increases from 100 W to 300 W, the peak electron density increases from 2.54×1017 m-3 to 5.68×1017 m-3, and the electric potential induced in the heating zone and the corresponding electron temperature decrease slightly after the reaction is stable. Increasing the air pressure in the cavity within a certain range will significantly increase the electron density. The air pressure increases from 10 Pa to 30 Pa, and the electron density increases from 9.12×1017 m-3 to 3.62×1018 m-3. However, the uniformity of plasma parameter distribution will deteriorate if the air pressure is too high.

At present, the valence state (connectivity) of most covalent organic frameworks (COFs) building units is low, mostly trivalent and tetravalent, making only 18 types of topological structures of COFs materials. On the contrary, the valence states of MOFs building blocks vary from 3 to 24, making them have more than 2 000 topological structure types. If a higher valence COFs building block can be designed, it will greatly enrich its topological structure type and material number. To this end, a hexahedral boron-phosphorus unit (-B4 P4 O12-) and five linear organic linkers (phenyl, fluorophenyl, toluene, naphthalene, biphenyl) were selected, and five high-valent boron-phosphorus covalent organic frameworks (BP-COFs) with lta topology were theoretically designed by molecular mechanics methods. The results show that the five materials have structural characteristics that are conducive to hydrogen storage applications, such as low density (0.52 ~ 1.17 g⋅cm-3), large specific surface area (1 274.12 ~ 4 033. 95 m² ⋅g-1) and high porosity (0. 55% ~ 0.78%). The Grand Canonical Monte Carlo (GCMC) method was used to predict the physical adsorption properties of hydrogen molecules on five materials at 298 and 77 K, and the structure-activity relationship between material structure and hydrogen adsorption properties was analyzed. The results show that the five BP-COFs materials have strong hydrogen adsorption capacity. Especially at 77 K, BP-COF-10 and BP-COF-11 have the best performance in hydrogen storage performance. BP-COF-10 has the highest volumetric hydrogen storage capacity at 77 K, reaching 52.86 g⋅L-1. BP-COF-11 has a large accessible specific surface area and high porosity. It has a good hydrogen storage capacity at 77 K and a gravimetric hydrogen storage capacity of 9.90% at 5 000 kPa. With the increase of pressure, the hydrogen storage capacity of BP-COF-11 still maintains a good upward trend. BP-COF-7 has the largest hydrogen storage capacity at 298 K, and the hydrogen storage capacity reaches 4.83 g⋅L-1 at 5 000 kPa. This indicates that the designed material has good hydrogen storage potential. This study will provide a theoretical reference for the experimental development of new high-performance hydrogen storage materials. [ABSTRACT FROM AUTHOR]

Aiming at low accuracy of recognition in complex leakage images of subway tunnels, this paper studied the application of image recognition algorithms in tunnel water-leakage disease, was using two kinds of neural networks: U-Net and PSP-Net. Based on the subway tunnel images, tunnel leakage disease sample data set was constructed, where 5000 subway tunnel disease image data and 4000 labeled images were included. This data set could be used for deep neural convolution network training. U-Net and PSP-Net deep learning frameworks were established, and the neural networks were trained by self-made data set. The accuracy of the prediction results from U-Net and PSP-Net was evaluated, and the performance of the two networks in the application of leakage disease identification was compared. U-Net had stronger coverage for the disease and quick detection, while PSP-net had higher accuracy fit to fine detection. [ABSTRACT FROM AUTHOR]

Objective*To analyze the characteristics of lipoprotein subclasses of family members with familial hypertriglyceridemia (FHTG). Methods*A FHTG family with 13 members meeting the diagnostic criteria of the FHTG family was collected at the First Hospital of Lanzhou University. They were divided into the high triacylglycerol (TAG) group (7 persons) and the control group (6 persons) according to whether the level of TAG of the family members increased (≥2.26 mmol/L). Through the face-to-face investigation, age, gender, height, weight, body mass index (BMI), waist circumference, living habits and medical history and other general information of each member were collected. Based on the survey results, a family tree was drawn. After 8-12 h in abrosia, peripheral venous blood samples of the family members were collected for biochemical testing. The vertical auto profile (VAP) was used to determine the serum lipoprotein subclasses of the study subjects, including TAG, total cholesterol, lowdensity lipoprotein cholesterol (LDL-C), low-density lipoprotein (LDL), very low-density lipoprotein (VLDL), very low-density lipoprotein 3 (VLDL3), high-density lipoprotein cholesterol (HDL-C), high-density lipoprotein 2 (HDL2), high-density lipoprotein 3 (HDL3), intermediate-density lipoprotein, remnant-like lipoprotein particle, lipoprotein a and non-high-density lipoprotein. The LDL pattern was obtained by VAP method based on the analysis of LDL max time value. The vertical lipoprotein profile (VLP) was used to determine the serum low-density lipoprotein particle (LDL-P) of the study subjects. The levels of lipoprotein subclasses between the control group and the high TAG group were compared by independent sample t test. Results*Compared with the control group, the high TAG group in FHTG pedigree had remarkably higher levels of height, weight, BMI and waist circumference (P=0.022, P= 0.000, P=0.001, P=0.000). There was statistical significance in gender difference between the two groups (P=0.029), but there was no significant difference in age (P=0.561). Compared with the control group, the high TAG group had remarkably higher levels of TAG, VLDL, VLDL3 and LDL-P (P=0.003, P=0.033, P=0.020, P=0.043), and remarkably lower level of HDL-C, HDL2 and HDL3 (P=0.000, P=0.001, P=0.001). The LDL pattern in the high TAG group was small and dense, while the LDL pattern in the normal control group was mixed or large and sparse. There were no significant differences between other indicators. Conclusions*In addition to the TAG and HDL-C commonly used in clinical practice, VLDL, VLDL3, LDL-P, small and dense LDL, HDL2 and HDL3 are expected to become the indicators for FHTG diagnosis and treatment. [ABSTRACT FROM AUTHOR]

Spacecraft missions are characterized by complex missions, high risks, high costs, high reliability, and long periods. In order to meet the needs of more complex spacecraft mission development in the future, model-based systems engineering (MBSE) methods is introduced in the spacecraft design and development. A model-based spacecraft development process and six types of model systems that meet the needs of the spacecraft development process are proposed, which are composed of demand model, function model, process model, architecture model, product model, and verification model. Taking the lunar water resource exploration as a hypothetical task, the MBSE modeling process and its model are presented, which fully embodies the advantages of the MBSE method in spacecraft design and simulation verification. [ABSTRACT FROM AUTHOR]