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This paper puts forward a kind of new technology for metal matrix difficult-to-machine materials based on compound energy field. The new technology combine electrochemical jet machining and abrasive jet machining technology, which obtain the high quality of processing surface and greatly improve processing efficiency. Aiming at the new technology, the experimental device of compound machining is established, a large number of process experiments are carried out. The different process parameters are studied for the influence of the machining efficiency, including the machining gap, voltage and jet pressure. The experimental results show that the compound machining can be applied to machining or polishing complex shape parts of metal matrix structure difficult-to-machine materials, so it has widely application prospects.

Based on the 16V265H high power diesel engine as the research object, used GT-Fuel and GT-Power to build the simulation model and study solenoid valve parameters such as spring pre-tightening force, moving parts mass and spring stiffness to the influence on engine combustion performance. Through calculation and analysis, we got a set of reasonable solenoid valve parameters. The experiment proved that the simulation model can well simulate the actual operation of diesel engine and the solenoid valve parameters are feasible.

The paper studied that the catalysis mechanism of electrochemical-particles jet compound machining(ECPJM) based on particles impact. The theory was analysed and experiment was carried. The results show that particles impact promoted electrochemical-particles jet compound machining. So the particles impact had the catalysis of the anodic dissolution in the electrochemical-particles jet compound machining. The results also indicate that the processing velocity can be improved under the particles impact, obtaining the surface quality in the electrochemical-particles jet compound machining.

The theory of electrochemical jet machining was introduced, and effect of different parameters on anodic electric field intensity is finite element analyzed by ANSYS software. The Simulation results show that, the electric field shares the same distribution under different electrolysis voltage, which generally contains three parts, uniform distribution area, gradually weakened area, scattered area. In the uniform distribution area, electric field shows comparative uniformity. The anode electric field generated by different jet distance is also obvious distribution areas, the electric field intensity shows decreasing trend. Electric field intensity is found to have a close relationship with electro jet nozzle diameter, in which a faster jet velocity would bring more concentrated distribution of the electric field as well as a smaller size of electric field.

According to this theory, the cavitation mechanism of ultrasonic-pulse electrochemical compound machining (UPECM) based on particle impact is proposed in the paper. The mechanism was studied particularly, and validated by experiments. The results show that ultrasonic cavitation promote pulse electrochemical compound machining, and particle impact has the catalysis of the anodic dissolution in the ultrasonic-pulse electrochemical compound machining. The results also indicate that the processing velocity can be improved under the particle impact, obtaining the surface quality in UPECM compound machining.

Due to the missile in flight, the airflow temperature around the missile body shall rise and the surface of the missile body shall also be heated. It introduces the engineering calculation method of thick wall aerodynamic heating of the missile, including air flow parameters, heat exchange coefficient and the head surface temperature calculation formula of the missile body.

Parameters optimization design of high-speed moving object is a very complex question. It involves many other subjects both in theoretical research and engineering application. Therefore, it is very significant to research on motion parameter optimization design of high-speed moving object. Firstly, in the known initial moment, the entering depth of moving object is; the initial velocity is; the length of moving object is L; the angle into the water is; and the average relative density of object is. It researches on the optimization of the best slenderness ratio, cavitation number and cavitator radius of high-speed objects. And then it specifically deduces the best motion displacement under the known initial momentum. Finally, it takes computer simulation and imitation to all optimized parameters and gives specific numerical examples by applying MATLAB, which provides theoretical basis for actual experiments.

This paper introduces material nonlinear finite element method and the establishment of finite element equation and realizes accurate modeling and calculation of folding rudder using material nonlinear finite element method. According to calculation and analysis, it is shown that the stress in contact part is relatively large due to stress concentration and material enters plastic deformation area. The influence of material nonlinearity on deformation calculation cannot be neglected. In this paper, deformation calculation results well coincide with experimental results.

The application of ultrasonic polishing and machining pulse electrochemical machining compound finishing is presented in the paper. The machining principle and experimental set-up of UPM-PECM compound finishing are introduced in the paper, discussing mechanism and model of the UPM-PECM in theory, and carrying on the experiment, which would co-act on hard-brittle metals in the machining. Furthermore, the material removal depth of UPM-PECM compound finishing is approximately proportional to the polishing time, and would decrease with the polishing time. This study indicates that machining velocity, machining accuracy and surface quality can be improved under UPM-PECM.

The ZnSe thin films are co-deposited in the ZnSO4, Na2SeO3 and sodium citrate acidic solution, and the mechanism of the ultrasonic and pulse electrodeposition for ZnSe films is explained by the electrode-solution interface action model. Ultrasonic increases the activation energy of the [ZnCit]- and HSeO3 - and improves flow field of the solution between electrode and solution interface. The pulse current promotes the diffusion of solution and advantageously realizes the co-deposition of ZnSe films. The ZnSe thin films are pulse electrodeposited in zinc sulfate, selenite sodium and sodium citrate acidic solution with the action of ultrasonic. Finally, the ZnSe films have been characterized by the scanning electron microscope (SEM), the energy dispersion analysis of X-ray (EDAX) and X-ray diffraction (XRD).

The experiment of ultrasonic assisted pulse electrochemical compound finishing is carried in this paper. The machining principle of the compound finishing is discussed in this paper. Processing experiments of compound finishing are carried out to study the effects of the main processing para- meters, including the particle size, the ultrasonic vibration amplitude, the minimum gap between the tool head and workpiece and the pulse voltage, on the material removal rate and the surface quality for hard and brittle metal materials. The curves of the corresponding relationships are also obtained. The study indicates that the processing velocity, machining accuracy and surface quality can be improved under the compound finishing, obtaining the processing technology conductions of the compound finishing. Introductions

The principle, of which the ZnSe thin films are co-deposited in the ZnSO4 and Na2SeO3 acidic solution by electrochemistry, is explained by the electrode-solution interface action model. The current density and the duty cycle of the pulse current promote the diffusion of solution and affect the co-deposition of the ZnSe films. The ZnSe thin films are pulse electrodeposited in zinc sulfate, selenite sodium and sodium citrate acidic solution. The sodium citrate, which is one kind of complex agent, simultaneous also one kind of buffer agent and has certain buffer action, would affect the quality of the ZnSe films. Finally, the ZnSe films have been characterized by the scanning electron microscope (SEM) and the energy dispersion analysis of X-ray (EDAX).

Background Germline mutations in PALB2 gene make a small contribution to heritable breast cancer susceptibility. A recent report has revealed that women with mutations in the PALB2 gene were more than nine times as likely to develop breast cancer compared to those without. The aim of this study is to understand the status of PALB2 mutations among Chinese high-risk breast cancer patients in a multi-ethnic region in China. Methods 152 patients with hereditary predisposition to breast cancer from the Xinjing region of China were enrolled in the study, and 100 control samples from healthy women were collected in the same locality. We sequenced the coding sequences and flanking intronic regions of PALB2 gene from DNA samples obtained from all subjects by direct sequencing. Results A total of 4 deleterious PALB2 mutations were identified in 152 breast cancer patients with a prevalence of about 2.6 % (4/152). The PALB2 mutation prevalence was 3.2 % (3/95) in cases with family history of breast cancer. In addition to the four deleterious mutations, we identified nine missense variants in 12 patients, using the prediction Softwares SIFT and PolyPhen, four of which might be disease associated (in 5 patients). Two of the 4 patients with deleterious mutations and 2 of the 5 patients presenting putative deleterious missense mutations had triple-negative breast cancer. No PALB2 mutation carriers were identified in 100 healthy controls. Conclusion PALB2 mutations account for a small, but not negligible, proportion of patients with hereditary predisposition to breast cancer in the Xinjing region of China.

To compare the positive rates and complications of ultrasound-guided transrectal and transperineal prostate biopsies.We retrospectively analyzed 156 cases of ultrasound-guided transrectal (n = 97) and transperineal (n = 59) prostate biopsy, and compared the positive rate and post-biopsy complications between the two approaches.The positive rates in the transrectal and transperineal groups were 48.4% and 44.1%, respectively, with no significant difference between the two approaches according to different PSA levels (P0.05). No statistically significant differences were observed between the transrectal and transperineal groups in the post-biopsy incidence rates of such complications as hematuria (54.6% vs 42.4%, P0.05), lower urinary tract symptoms (17.5% vs 22.0%, P0.05), dysuria (9.3% vs 6.8%, P0.05), and acute urinary retention (7.2% vs 6.8%, P0.05). However, the incidence rates of post-biopsy infection and rectal bleeding were remarkably higher (15.5% vs 3.4%, P0.05 and 50.5% vs 3.4%, P0.01) while that of perineal swelling markedly lower in the former than in the latter (3.1% vs 13.6%, P0.05).Transrectal and transperineal biopsies are both effective for the diagnosis of prostate cancer. Since their complications vary, the choice between the two methods depends on the specific condition of the patient.