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Drop-weight impact experiments are performed on a thin layer of cyclotetramethylenete tranitramineand cyclotrimethylene trinitramine (RDX) powdery explosives, which were mixed with a few large-sized explosive or NaCl salt granules. The drop-weight impact machine is equipped with the high-speed photographic systems for observing the impact process. It showed that the mixed explosives are more sensitive than pure powdery explosives. Hard salt particles could greatly enhance the burning probability of powdery explosives because frictional heat between salt particles and target explosive powders, stress concentration, and new generated fragments of large granule jointly contribute to heat accumulation at the junction of dissimilar materials. Burning front always initiates at the interface of powdery explosive and additive granule. Adiabatic shear bands were frequently observed in the mixture of ultra-fine RDX powdery explosive with RDX large granules, which mainly resulted from the softening effect of ultra-fine powders once the temperature arises. [ABSTRACT FROM AUTHOR]

Objective: To investigate the protective effect of nicorandil on contrast-induced acute kidney injury (CIAKI) in patients with acute ST-segment elevation myocardial infarction (STEMI) after emergency percutaneous coronary intervention (PCI). Methods: This is a single-center, retrospective control study. A total of 156 patients with STEMI were divided into the nicorandil group (n = 55) and the control group (n = 101). The incidence of CIAKI, defined as an increase of >25% or absolute values > 44.2 μmol/L in serum creatinine (Scr) from baseline within 72 h of exposure to a contrast agent after exclusion of other causes, was the primary endpoint. The secondary endpoints were: (1) changes of Scr, estimated glomerular filtration rate (eGFR), uric acid, and β2-microglobulin at 24/48/72 h and 5 to 7 days after PCI; (2) the peak value difference of creatine kinase isoenzymes (CK-MB) after PCI; (3) adverse events within 6 months after PCI. Results: The overall incidence of CIAKI was 21.8%; the incidence of CIAKI in the nicorandil group was significantly lower (12.7% [7/55]) than in the control group (26.7% [27/101]) (P = .043). Compared with the control group, Scr, uric acid, and β2-microglobulin levels were lower, and the level of eGFR was higher in nicorandil group (P all < .05). The peak value of CK-MB in the nicorandil group was lower than that in the control group (105.30 [56.61, 232.04] vs 178.00 [77.08, 271.91]U/L, P = .042). There was no significant difference in adverse events between the 2 groups within 6 months after PCI. Moreover, multivariate logistic regression analysis showed that hypertension and diabetes were independent risk factors for CIAKI, while nicorandil treatment was a protective factor. Conclusion: Our data suggest that intravenous nicorandil after emergency PCI has a protective effect on the occurrence of CIAKI in STEMI patients. [ABSTRACT FROM AUTHOR]

In view of problem that current underground explosion-proof computer has no monitoring function for electric quantity of battery, a design scheme of electric quantity of battery monitoring system of underground explosion-proof computer based on USB protocol was proposed. In the system, small single-chip microcomputer with AD conversion is used to collect and process electric quantity of battery, the collected data is transmitted to module of USB to serial port，then sampling value of electric quantity of battery can be got by upper computer through virtual serial port. The test result showed that the indexes of the system accord with working time of load, data transmission has higher reliability and relative error of AD conversion can meet with demands of collection of electric quantity of battery.

In order to solve the problem that rescue communication system, which is laid casually in process of emergency rescue for mine accident, has no function of real-time communication among satellite, ground and underground and remote command center cannot directly get information of disaster situation, a mine communication device for emergency rescue commanding which combined with underground wired audio and video communication system and ground satellite video communication system was proposed and realization scheme of audio and video transmission by satellite of the device was mainly introduced. The prototype test result showed the device has stable networking, long communication distance and strong anti-disaster ability, which solves the problem of real-time communication among satellite, ground and underground in emergency rescue commanding.

In view of problems that charger of Ni-MH batteries based on MAX713 is only used in charging for 1～16 Ni-MH batteries and exists virtual filling, the paper proposed a design scheme of intelligent charger of Ni-MH batteries which can charge for more than 16 Ni-MH batteries. The charger takes MAX713 as basis and uses serial way to link batteries, and is added timing detection function which can ensure fully filling of Ni-MH batteries through controlling relay by single-chip microcomputer. The actual application showed that the charger has certain practicability.