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The effects of zinc addition on the general corrosion of 316L austenitic stainless steel and Stellite 6 cobalt-based alloy were studied in simulated pressurized water reactor primary water with 0, 10, and 40 μg·L–1 zinc additions. The corrosion rate and metal release rate of the two materials were determined by using the weight loss method. The surface and cross-sectional morphology, thickness, and element distribution of the oxide film were examined by scanning electron microscopy and transmission electron microscopy-energy dispersive spectroscopy (TEM-EDS). The crystallographic structures of the outer and inner oxides were identified by atomic-resolution TEM imaging with fast Fourier transform. The results reveal that the addition of 10 μg·L–1 Zn did not have a statistically significant effect on the corrosion rate and corrosion product release rate of 316L stainless steel within the initial 1000 h of exposure. Increasing the concentration of Zn to 40 μg·L–1 significantly reduced the corrosion rate, corrosion product release rate, and oxide film thickness of 316L stainless steel. Specifically, the oxide film thickness decreased from 250 to 95 nm. For the Stellite 6 cobalt-based alloy, composed of γ-Co matrix and Cr23C6 carbides, the galvanic corrosion effect between γ-Co matrix and Cr-rich carbides was observed under all zinc addition conditions. The oxide film thickness of Cr23C6 carbide in the Stellite 6 cobalt-based alloy was comparatively thinner than that of the γ-Co matrix, which is mainly ascribed to the preferential oxidation of the γ-Co matrix. Extensive interfacial oxidation was observed between γ-Co matrix and Cr23C6 carbide, which can be attributed to the occurrence of electrochemical galvanic corrosion between these two phases. The carbides have a higher nobility compared to the γ-Co matrix. The corrosion rate, corrosion product release rate, and oxide film thickness of Co-based alloy all decreased with increasing zinc concentrations. The average oxide film thickness of the preferentially oxidized γ-Co substrate decreased from 200 to 60 nm, and the average oxide film thickness of Cr23C6 carbide decreased from 100 to 40 nm. Microstructural analysis of the oxide film demonstrated that Zn2+ promotes the denser outer oxide film formation by forming a zinc-incorporated spinel, which retards the outward diffusion of metal ions and the inward diffusion of oxygen ions, reduces the oxygen partial pressure at the oxide/metal interface, and promotes the formation of a continuous protective Cr2O3 inner oxide film, thus significantly suppressing the corrosion and metal release of 316L austenitic stainless steel and Stellite 6 cobalt-based alloy in high-temperature water.

The taste and flavor of fermented vinegars are closely related to the fermentation microorganisms. In order to investigate the vertical distribution of bacterial community in the acetic acid fermentation stage of Zhenjiang aromatic vinegar, and to investigate the enrichment effect of different media on the culturable bacteria from Cupei. In this study, the bacterial diversity of Cupei and enriched culture samples were determined by high-throughput sequencing. The results showed that the number of OTUs in the surface, middle and bottom Cupei samples were 66, 76 and 111, respectively. The dominant bacterium in the surface layer was Acetobacter, while the dominant bacterium in the middle and bottom layers was Lactobacillus. The richness and diversity of bacterial flora became more abundant and diverse with the depth of fermentation. Meanwhile, high-throughput sequencing after enrichment showed that the oligotrophic medium enriched higher bacterial diversity than the nutrient-rich medium. This study revealed that there were differences in bacterial diversity in different depths of Cupei. And it also proposed an oligotrophic medium for bacterial isolation to make isolation of fermentation microorganisms from Cupei more efficient.

Objective To investigate the knowledge acquisition status for blood transfusion of transfusion related medical staff in underdeveloped cities in western China and explore its influencing factors. Methods A questionnaire consisted of blood transfusion laws and regulations, clinical blood transfusion theory and blood transfusion technology was designed, randomly distributed to medical staff and blood transfusion departmenttechnicians of 17 secondary/tertiary hospitals in Wuwei and then collected on the spot. The knowledge acquisition of blood transfusion of each group was compared using statistical description method, and its influencing factors were analyzed by multivariate logistic regression analysis. Results A total of 507 questionnaires were issued, and 498 valid questionnaires (98.22%) were collected. The scores of transfusion related laws and regulations, blood transfusion theory and blood transfusion technology of doctor group(n=158), nurse group(n=239) and transfusion technician group(n=101)were 4.56-5.97(5.06±0.73)(P

In order to derive the volume utilization factors of Roots rotor for pump simply and efficiently，a novel inverse method of volume utilization factors is proposed based on the causal relationship between volume utilization factors and the average theoretical flow，and the different effects of two profile structures with and without clearance on volume utilization factors are analyzed. All results show that the inverse method from the average theoretical flow which is the effect to the volume utilization factors which are the cause is simple and efficient，the results are accurate and reliable，and the general applicability is strong； the profile structure with clearance is beneficial to maximize the volume utilization factor； by controlling the upper limit of profile factor，the shape factors and volume utilization factors are indirectly influenced by the curve type of conjugate profile； volume utilization factor can be simplified as a single variable function of shape factors，and the type of conjugate profile determined by profile factors has little influence on the volume utilization factors etc. It provides a new idea and method for calculating the volume utilization coefficient and other profile characteristics of rotor pump.

In order to realize non-flow ripple and non-axial force of roots pump with helical rotor and greater capacity utilization and smaller internal leakage as desired by its lightweight，for high cross shape coefficient of rotor，a construction method for chord height line of pitch arc of half lobe as internal conjugate profile segment and top profile segment with radial equal arc gap is proposed，from coupled relation without axial force between volume pair with helical rotor and power pair with helical gear，its coupled design method with non-axial force is derived and an example is given. All results show that plane-convex conjugate gap and top equal arc gap can effectively restrain conjugate leakage and radial leakage，and cause larger shape coefficient of 1.6 and larger volume utilization coefficient of 0.58 to come true，helical angle of 60° can realize theoretical non-flow ripple，and coaxial design with equal cross pitch radius of helical rotor and standard helical gear can be derived from helical angle of 20°~25°，and the coaxial design method is simple，etc. It provides a theoretical basis for future high quality development of roots pump.

The traditional modification design has some disadvantages such as complex calculation，uncontrollable tooth profile curve shape and unstable meshing performance，the pressure angle of the gear tooth profile has a great influence on the meshing force transmission performance. Therefore，a new tooth profile modification design method is proposed based on the distribution law of the pressure angle of the cycloid tooth profile. Based on the pressure angle distribution trend obtained by calculation and analysis，the mathematical model of tooth profile modification with straight-line method is established，and the function representation between the tooth profile pressure angle and the modification amount is deduced，the tooth contact analysis model is constructed，and the transmission error of modified cycloid-pin gear is obtained. Through the comparative measurement experiment of the tooth profile shape and transmission error of the cycloid，the correctness and effectiveness of the method proposed in the article are verified. This method considers the mutual influence between the pressure angle of the cycloidal gear tooth profile and the modification amount，and the technical problems of traditional modification method in calculation，processing，and active design are solved，and the trend of modification amount can be flexibly controlled，while ensuring the meshing performance，it obtains the design tooth profile that is closer to the theoretical cycloid.

Cycloidal gear adopts one-dimensional probe sampling mechanism when detecting on the gear measuring center. Due to the sensitive direction of one-dimensional probe is inconsistent with the definition direction of tooth profile normal error， the error calculation process is tedious， and even the error result is inaccurate， which can not truly reflect the machining shape of the actual tooth profile. For this， a closed reconstruction method is proposed and it is applied to the error detection process of RV cycloidal gear， which can not only accurately obtain the machining error of any point of cycloid gear tooth profile， but also the error result can reflect the actual shape of tooth profile. Based on the closed curve reconstruction theory， using the characteristics of the periodic extension of the closed curve， the nodal vector and control vertex of the head and end points are determined， and the reconstructed tooth profile is completely closed and continuous at the closed point. On this basis， an error calculation model is established， and the real tooth profile error is calculated. The practicality and effectiveness of this method are verified by comparison of examples， which provides data basis for subsequent finishing processing.

To derive a unified calculation model for gear cross-section area suitable for arbitrary tooth profile. Firstly， based on the external conjugate relation between two identical gear， it is analyzed that cross-section area of gear is composed of pitch circle area， plus conjugated area， and minus minimum top gap area. Secondly， based on the geometric relationship of conjugate profile， the simplest calculation formula without error of the conjugated area and simplified calculating method of minimum top gap area adopts partial hob are given. Finally， example calculation and analysis of gear cross-section area with involute profile are carried out. All results show that the pitch circle area is much larger than conjugated area and minimum top gap area， but calculation method of minimum top gap area determined calculation accuracy of cross-section area， the theory error of gear cross-section area is 0.24%，which could be used in high precision calculation of gear cross-section area. It is concluded that the conjugated area formula is suitable for volume utilization coefficient calculation in arbitrary tooth profile without error for pump.

To realize the higher performance design of involute rotor, based on four possible top structure, from seven aspects of profiles parameterization, the limit value of shape coefficient, volume utilization coefficient, size optimization and so on, the higher performance profiles with wide top for high-sealing zone is finally constructed. Then, from lightweight of rotor as design object, the optimization model is constructed. Finally, an innovative configuration of profiles is given to eliminate trapped-gas phenomenon. All results show that the innovative profiles is meet high performance requirement for maximizing volume utilization coefficient and minimizing radial top leakage. The trapping-gas phenomenon is eliminated better by the new avoid-arc, which is easy machined. The shape coefficient or volume utilization and top half angle have approximately negative linear correlation, etc. It is concluded that the full parametric modeling and design method can be used for other rotor profiles with radial high-sealing zone.

To achieve the abundant relief of high-speed trapped-oil for gear pump，based on the same tooth profile parameters and working conditions，the experiment，simulation and theoretical analysis are carried out successively. Secondly，the shape，position and size of the new groove are given. Finally，the case calculation of trapped-oil pressure were carried out. The results show that the theoretical analysis is correct by the consistency of experiment，simulation and theoretical results. Under the speeds of 1 000 r/min， 3 000 r/min， 5 000 r/min and 0.03 mm small backslash， the increase rate of the pressure peak of the new groove and the rectangular groove are 1.75%，15%，41.5% and 9.50%，85% and 236.25% respectively. It shows that the rectangular groove can meet the relief requirement of trapped-oil under low speeds， and the new groove can meet the relief requirement of trapped-oil under medium speeds. Under the high speeds of 5 000 r/min and 0.2 mm large backlash， the pressure increase rate of the new groove is 22.75%， which indicates that it can meet the relief requirement under high speed.

Lutetium yttrium silicate (LYSO) has become the most prominent scintillation crystal material in positron emission tomography (PET) because of its outstanding comprehensive performance. In recent years, the emerging All-Digital PET technology based on the Multi-Voltage Threshold (MVT) method has digitized the origin of scintillation pulses, thereby improving key metrics such as spatial resolution and system sensitivity; this advancement has also given rise to new applications like proton therapy monitoring and positron lifetime spectroscopy. Unlike traditional time interval sampling methods, MVT represents a longitudinal sampling technique based on voltage-time, offering inherent advantages in rapidly varying pulse signal sampling domains. Consequently, tailoring the scintillation luminescence properties of LYSO crystals to adapt to the MVT sampling method becomes a new development direction for LYSO scintillation crystals under the demand of digital PET applications. This paper reviews the scintillation principles, performance modulation, and growth techniques of LYSO crystals. It outlines strategies for adjusting key properties of LYSO crystals, such as light output, decay time, and uniformity to align with the sampling characteristics of All-Digital PET. Furthermore, the paper presents the research progress of fast-decaying and highly uniform digitally modified LYSO crystals developed by the research team to meet the demands of All-Digital PET. Finally, based on the current research status of LYSO and the new demand for digital PET, the future development direction of LYSO scintillation crystals is discussed.

The concept of 6G has been proposed and has attracted the wide attention of academe. Generally speaking, the 6G network will optimize the performance of 5G, and expand the network scenarios which are difficult to achieve within 5G. However, the introduction of new scenarios and technologies will also bring new security threats to cyber security. The research progress on the key technologies and implementation methods of the 6G were conducted. To summarize a vision of core technologies of 6G, the research work of major 5G/6G research institutions, companies and enterprises were focused on . On this basis, the possible security problems and security challenges in 6G network were put forward. Finally, according to the existing network techniques, the possible solutions and proposed a general security model for 6G networks were discussed.