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Objective: To design a multifunctional cooking experimental platform with negative pressure and superheated steam, providing consumers with greener, healthier, and more diverse cooking methods. Methods: The research status of integrated cooking equipment was analyzed, and the application status of superheated steam and negative pressure technology in the food industry was summarized and analyzed. The performance parameters of the multifunctional cooking experimental platform were determined. Based on the characteristics of each function of the experimental platform, the cooking chamber, furnace door and other components were designed, and the overall plan of the experimental platform was developed. Results: The multi-functional cooking experimental platform developed has four functions: negative pressure, steam, microwave, and baking. It can achieve negative pressure extraction of -28 kPa and direct injection of 390 ℃ superheated steam into the cavity. The heating effect of hot air and microwave is good. Conclusion: The multifunctional cooking experimental platform developed has high feasibility and practicality.

Microfluidic chips are driven by microfluidic pumps and controlled by microfluidic valves in microfluidic systems to achieve accurate manipulation of microfluidics. With the continuous improvement of microfluidic chip integration, liquid channels have become more complex and have smaller volumes. How to achieve fluid drive and control at the micro scale has become a key focus in chip design. The paper elaborates on the current research status, key technologies, and development trends of micro pumps and micro valves both domestically and internationally, aiming to provide reference and guidance for the development of related industries and technological research.

Objective: Comprehensive utilization of Dianhong rose resources to improve the added value of products. Methods: The single-factor experiment and response surface experiment were used to optimize the extraction process of supercritical CO2 with essential oil yield as the measurement index. The composition and relative content of different rose oils were analyzed by GC-MS. The components and relative contents of different rose oils were analyzed by GC-MS, and the antioxidant activities of different rose oils were evaluated. Results: The results showed that the optimal extraction parameters were as followed: particle size of 40 mesh, extraction pressure of 25.5 MPa, extraction temperature of 45.5 ℃, extraction time of 123 min, CO2 flow rate of 20 L/h. Under these conditions, the essential oil yield of rose was 1.185%. A total of 74 compounds were identified from different Dianhong rose oil, and the total volatile substances of Anning Dianhong rose essential oil were the highest. The essential oil of Yunnan Dianhong rose had good ability to scavenge free radicals. The antioxidant activities of essential oil from different producing areas were obviously different. Conclusion: The essential oil extracted by supercritical CO2 has good quality and can be used as a natural antioxidant.

Multi-stage reinforced SiCf/SiC-SiCw composites were prepared by introducing SiC whiskers into SiCf/SiC composite, and BN interphase was deposited on the surface of SiC whiskers by chemical vapor infiltration (CVI). The mechanical properties of composites were evaluated. The results show that the compressive strength of the composites can be significantly improved on account of the reinforcing mechanism of SiC whiskers, such as the whisker pull-out, whisker bridging and crack deflection, which can extend the crack propagation path and increase the energy consumption capacity. The compressive strength of the composites is increased from 549.7 MPa to 673.9 MPa, with an increase of 22.6%, when the addition of SiC whisker is 20%(volume fraction). After depositing the BN interphase on SiC whiskers, the tensile strength, flexural strength and fracture toughness of the composites were 414.0 MPa, 800.3 MPa and 22.2 MPa·m1/2,which are increased by 13.9%,8.8% and 19.0%, respectively, compared with the composite reinforced with the uncoated whisker.

The numerical calculation for nuclear reactor coupled system is the fusion, integration and upgrade of the existing numerical technologies in various related fields. Generally, the whole nuclear power plant has several different coupling mechanisms inherently, such as the multiphysics coupling, multiscale coupling and multisystem coupling, which is an ultralargescale strong nonlinear coupling system. Moreover, each coupling mechanism has its own mathematic features. The combination of different coupling mechanisms is such complicated, which is still an open issue for nuclear engineering community. Simultaneous solution methods, such as Jacobianfree Newton Krylov (JFNK) method and NewtonKrylov (NK) method, are a promising choice for effectively solving such complex nonlinear largescale system. In the first part of this work, the recent progress of numerical calculation for nuclear coupling system worldwide is reviewed, especially, several existing coupling methods are summarized and compared. In the second part, it focuses on the development of simultaneous solution methods as well as the coupling platform for high temperature gas-cooled reactor (HTR) full coupled system by Institute of Nuclear and New Energy Technology (INET), Tsinghua University. Due to the multiphysics, multiscale, multicomponent, multicircuit and multimodule coupling features in HTR, the key technologies, such as the JFNK method with nonlinearelimination, scaling factor and steam generator model, were presented and discussed. In detail, the JFNK method with nonlinearelimination was firstly proposed to deal with the multiscale temperature coupling between the global pebblebed and the local fuel sphere. The scaling factor technology was used to transform the illposed Jacobian matrix into the wellposed one in the multiphysical coupling issue. For the steam generator model, the dynamical residual method is conducted for the twophase flow in the second circuit to avoid the multisolution issue when the phase generation or the phase disappearance occurs. Moreover, a unified framework was proposed to tackle the multi-level coupling structure in HTR system, after several attempts were made. In this framework, the whole coupling system is gradually decomposed into systemlevel issue, componentlevel issue and physical fieldlevel issue, and solved as a whole system by the simultaneous solution method. However, to completely solve the whole HTR nuclear power plant system, there are still many works to do, such as the fundamental algorithm research, program framework development and engineering applications.

The melt infiltration method is one of the main preparation method of SiC matrix composites. Complex reactions and multi-component diffusion are involved in molten-Si infiltration of a C-based preform. In this study, SiC-TiSi2 was fabricated by Si melt infiltration and the TiSi2 was in-situ formed in the matrix of SiC. In order to explore the reaction mechanism of SiC-TiSi2, SEM, EDS and micro-beam XRD were determined to characterize the phase constitute and micro-structure in different regions along the Si melt infiltration direction. The results demonstrate that SiC, TiSi2 and Ti5Si3 which concentrate on the Si/SiC interface are found to be formed through the Si melt infiltration into the C-TiC preform. With the increase of temperature, the liquid phase of Ti-Si appears when exceeding the Si-TiSi2 eutectic temperature. And the liquid Ti-Si eutectic precipitates TiSi2 in the Si region during the cooling period of the sample. Moreover, the isolated SiC grain in Si region is produced by the precipitation from the dissolution of solid C in liquid Si.

Flake graphite iron, compacted graphite iron and spheroidal graphite iron with various tensile strengths were cast. They were selected and grouped according to roughly the same tensile strength, and then the main cutting force in each group was measured and compared. The microstructures of different cast irons were characterized. The relationship between the cutting force and microstructure was established. Results show that the graphite morphology in cast irons determines the strength. In order to obtain the same strength of the cast iron with sharply edged graphite, more or finer pearlite in the matrix is needed. Graphitic cast irons with high pearlite content and smaller pearlite interlamellar spacing have higher hardness. For the cast irons with different graphite morphologies, but almost the same tensile strength, the main cutting force is obviously different, along with the hardness. Harder cast irons have a greater cutting force, but the difference in cutting force is not proportional to hardness.

According to the different performance degradation paths, reliability curves and parameters of each product in service phase, the reliability and remaining life of components at current moment can be evaluated in real-time reliability assessment by integrating real-time status, historical information and service time of components. The realtime reliability evaluation is valued because it is more personalized, precise, real-time and lean than traditional methods. Furthermore, the results from real-time reliability assessment can also represent the health status of component at current time. In the current research, real-time reliability assessment mainly relies on regression analysis and time series analysis, but these two methods are mainly used to describe the component degradation process, and cannot reflect the influence of external random environment on the component state change. At the same time, due to these limitations of time, economy and test conditions, it is also worth studying how to obtain more accurate and practical reliability distribution and determine a detection interval under the condition of less data. Therefore, based on the analysis of real-time reliability evaluation principle, a more appropriate real-time reliability evaluation method and the detection interval decision model are proposed by means of random degradation process, parameter sequence test joint distribution estimation and failure risk. The result from this method is a quantized value, which is convenient for the direct application of the follow-up maintenance decision research. Therefore, the research in this paper has extensive reference value and practical application prospect.

In the title compound, [Ni(C12H8N2)(H2O)4](C12H10O8), the NiII ion is six-coordinated by two N atoms from one phenanthroline ligand and by the O atoms of four water molecules in a distorted octahedral geometry. In the crystal, intermolecular O—H...O hydrogen bonds form an extensive three-dimensional network, which consolidates the crystal packing.

In the title compound, {[Cu(C12H10O8)(C12H8N2)]·H2O}n, the CuII ion is five-coordinated by two N atoms from one phenanthroline ligand and three O atoms from three different H2L2− anions (H4L is bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic acid) in a distorted square-pyramidal geometry. Each H2L2− ion bridges three CuII atoms to form a zigzag sheet parallel to the ab plane. The crystal structure is consolidated by O—H...O hydrogen bonds.