Effect of cooling rate on microstructure and mechanical properties of CB2 tempered martensitic steel

The cooling rate of casting has a significant effect on microstructure and mechanical properties of castings.The 9Cr-1.5Mo-1Co cast steel,referred to as CB2,is one of the most promising alloys for various cast components to be used under ultrasupercritical conditions.In this study,HRTEM,SEM,and XRD methods were used for qualitative and quantitative analyses of contents,phases,and sizes of the inclusions and precipitates,as well as microstructure observation of the tempered martensitic steel at different cooling rates.Traditional tensile tests were conducted to characterize the material mechanical properties.Results show that the size of the boron nitride and precipitate,the width of the martensite lath and the content of theδ-ferrite are reduced as the cooling rate increases from 5-8℃·min^-1(CB2-S steel)to 50-60℃·min^-1(CB2-F steel).The precipitates are mainly composed of M23C6 and a small amount of M3C.The average diameters of the M23C6 precipitates in CB2-F and CB2-S are 202 nm and 209 nm,respectively.The inclusions are mainly composed of BN,Al2O3 and MnO2,and the inclusion ratios are 0.1969%for the CB2-F and 0.06556%for CB2-S steel.The average martensite lath widths of CB2-F and CB2-S steels are 289 nm and 301 nm,respectively.Furthermore,the M3C having a diameter of about 150 nm and a thickness of 20 nm is observed in theδ-ferrite of the tempered CB2-S steel.The presence of theδ-ferrite reduces the precipitation strengthening and dislocation density in CB2-S steel.In addition,the lower cooling rate stabilizes theδ-ferrite structure at room temperature.

Effect of ultrasonic field treatment on degassing of 2024 alloy

The 2024 aluminum alloy was prepared with different ultrasonic processes.Effects of ultrasonic treatment parameters including ultrasonic power,treatment time,treatment temperature,and frequency resonance,as well as C_(2)Cl_(6) degasser on degassing of the 2024 aluminum alloy were investigated.Results indicate that increasing ultrasonic power at the same ultrasonic treatment time can improve the degassing effect.The optimum degassing efficiency can be obtained under the resonant ultrasound condition.With the combination of 1%C_(2)Cl_(6) addition and 150 W ultrasonic treatment for 40 s,the hydrogen content of the alloy is decreased by 52.9%.At the same time,the tensile strength and elongation are increased by 28.3%and 92.3%,respectively,and the yield strength is slightly increased by 6.7%.The degassing mechanism is also discussed.

Determination of quantum toric error correction code threshold using convolutional neural network decoders

Quantum error correction technology is an important solution to solve the noise interference generated during the operation of quantum computers.In order to find the best syndrome of the stabilizer code in quantum error correction,we need to find a fast and close to the optimal threshold decoder.In this work,we build a convolutional neural network(CNN)decoder to correct errors in the toric code based on the system research of machine learning.We analyze and optimize various conditions that affect CNN,and use the RestNet network architecture to reduce the running time.It is shortened by 30%-40%,and we finally design an optimized algorithm for CNN decoder.In this way,the threshold accuracy of the neural network decoder is made to reach 10.8%,which is closer to the optimal threshold of about 11%.The previous threshold of 8.9%-10.3%has been slightly improved,and there is no need to verify the basic noise.

Effect of hydromorphone hydrochloride combined with ropivacaine for PCEA after transurethral resection of prostate on pain mediators and stress response

Objective: To study the effect of hydromorphone hydrochloride combined with ropivacaine for patient-controlled epidural analgesia (PCEA) after transurethral resection of prostate on pain mediators and stress response. Methods: A total of 138 patients who received transurethral resection of prostate in Ankang Central Hospital between May 2014 and October 2016 were selected and randomly divided into group A and group B, group A received postoperative hydromorphone hydrochloride combined with ropivacaine for PCEA, and group B received postoperative morphine hydrochloride combined with ropivacaine for PCEA. The serum contents of pain mediators, inflammatory response cytokines and stress hormones of the two groups were detected before surgery as well as 12 h, 24 h and 48 h after surgery. Results: 12 h, 24 h and 48 h after surgery, serum SP, BK, HIS, CX3CL1, CCL2, IL-1β, TNF-α, IL-10, ACTH, CORT, TSH, FT3, FT4 and GH levels of both groups of patients were significantly higher than those before surgery, and serum SP, BK, HIS, CX3CL1, CCL2, IL-1β, TNF-α, IL-10, ACTH, CORT, TSH, FT3, FT4 and GH levels of group A were significantly lower than those of group B. Conclusion: Hydromorphone hydrochloride combined with ropivacaine for PCEA can effectively reduce the pain and stress after transurethral resection of prostate.

Clinical Application and Mechanism of Acupuncture in the Brain-Gut Interaction

Acupuncture and moxibustion is an important part of traditional medicine.Acupuncture and moxibustion can affect the digestive function of human body by interfering with the interaction between the brain and the intestines,while simultaneously having a benign adjustment effect on the mental state.In recent years,a large number of clinical studies at home and abroad have further proved the importance of acupuncture and moxibustion in the treatment of physical and mental diseases,and related mechanism studies have provided modern scientific evidence for the intervention of acupuncture and moxibustion in the brain-gut interaction from the perspectives of intestinal flora and brain functional imaging.On this basis,we integrate relevant viewpoints to provide ideas and methods for future research.