Study on experiment measurement method of braking force of muzzle brake for vibration analysis

The braking force of the muzzle brake affects not only the strength of the connection thread of the muzzle brake, but also the vibration response of the artillery structure. Due to the complex formation process of the braking force of the muzzle brake, the current theoretical calculation method is used to estimate. This paper presents an experimental measurement method for artillery force of muzzle brake, which describes the measurement principle and deduces the calculation formula. The small-caliber cannon with muzzle brake is selected as the test object. A verification shooting experiment is carried out to obtain the size of the artillery force of the muzzle brake. The measurement values of the artillery force are basically consistent with the theoretical ones. The measurement method and principle introduced in this paper can be applied in the actual artillery force measurement of the muzzle brake. In this paper, the strain measurement principle is used to complete the experimental test of the braking force of the muzzle brake. This paper innovatively proposes a new method for testing the braking force, which has the advantages of simple operation, no need to manufacture special tooling, and low cost

Experimental study on ground vibration response in gun firing environment

In order to know the ground vibration response law of gun firing environment, a large caliber gun was taken as the research object, and the ground vibration response law of gun firing environment was tested. Several acceleration sensors are arranged on the ground around the gun, and the ground vibration acceleration response laws of the gun position in the firing environment are obtained. The firing of gun will cause the ground vibration of gun position. In the bore period, as long as the projectile is fired, there will be acceleration response on the ground of the gun position. The maximum acceleration response of ground vibration in the bore period of projectile is less than 0.03 g. The maximum acceleration response of ground vibration is less than 0.1 g after projectile exits the muzzle and before the muzzle shock wave reaches the ground. If the sensor bracket is placed on the ground around the gun, when the muzzle shock wave does not reach the sensor position, the influence of ground vibration on the sensor can be neglected. Once the muzzle shock wave reaches the sensor position, its influence should be paid attention to

Endothelium in the pharyngeal arches 3, 4 and 6 is derived from the second heart field.

Oxygenated blood from the heart is directed into the systemic circulation through the aortic arch arteries (AAAs). The AAAs arise by remodeling of three symmetrical pairs of pharyngeal arch arteries (PAAs), which connect the heart with the paired dorsal aortae at mid-gestation. Aberrant PAA formation results in defects frequently observed in patients with lethal congenital heart disease. How the PAAs form in mammals is not understood. The work presented in this manuscript shows that the second heart field (SHF) is the major source of progenitors giving rise to the endothelium of the pharyngeal arches 3 - 6, while the endothelium in the pharyngeal arches 1 and 2 is derived from a different source. During the formation of the PAAs 3 - 6, endothelial progenitors in the SHF extend cellular processes toward the pharyngeal endoderm, migrate from the SHF and assemble into a uniform vascular plexus. This plexus then undergoes remodeling, whereby plexus endothelial cells coalesce into a large PAA in each pharyngeal arch. Taken together, our studies establish a platform for investigating cellular and molecular mechanisms regulating PAA formation and alterations that lead to disease

Study on the measuring method of moving time in the bore of projectile for vibration analysis

The movement time of the projectile is the basic parameter for studying the gesture of the projectile. It is also the time base for the test of projectile shots. At the same time it is the time base for the test of gun vibration response. A test method for the moving time in the bore of a projectile which is based on the barrel strain test is proposed in this paper. First, paste a plurality of strain gauges along the axis of the barrel. Then take the rising edge time of the strain-time curve of each measuring point as the movement time of the Projectile. The artillery fired and the projectile moved at high speed inside. By testing the external surface strain time curve, and then through data processing, the time of a large-caliber artillery projectile in orbit was obtained. Through the firing test in the shooting range, the validity and correctness of the method are verified

Research on vibration displacement test method for large-caliber artillery muzzle

In order to solve the problem of muzzle vibration displacement test of large caliber under high elevation, this paper presents a test method by two high-speed photography. The method fully considers the influence of the muzzle torsion on the measurement results, and accurately obtains the three-dimensional vibration displacement of the muzzle of the large caliber artillery. Finally, through the result analysis, the accuracy of the measurement results can reach 0.1 mm, which shows the advantage of the sub-pixel-based high-speed camera processing method in the muzzle vibration displacement test of the conventional artillery. This paper proposes an innovative test method that accurately measures the vibration displacement of the muzzle using a non-contact method

Fibronectin signals through integrin α5β1 to regulate cardiovascular development in a cell type-specific manner.

Fibronectin (Fn1) is an evolutionarily conserved extracellular matrix glycoprotein essential for embryonic development. Global deletion of Fn1 leads to mid-gestation lethality from cardiovascular defects. However, severe morphogenetic defects that occur early in embryogenesis in these embryos precluded assigning a direct role for Fn1 in cardiovascular development. We noticed that Fn1 is expressed in strikingly non-uniform patterns during mouse embryogenesis, and that its expression is particularly enriched in the pharyngeal region corresponding with the pharyngeal arches 3, 4, and 6. This region bears a special importance for the developing cardiovascular system, and we hypothesized that the localized enrichment of Fn1 in the pharyngeal region may be essential for cardiovascular morphogenesis. To test this hypothesis, we ablated Fn1 using the Isl1(Cre) knock-in strain of mice. Deletion of Fn1 using the Isl1(Cre) strain resulted in defective formation of the 4th pharyngeal arch arteries (PAAs), aberrant development of the cardiac outflow tract (OFT), and ventricular septum defects. To determine the cell types responding to Fn1 signaling during cardiovascular development, we deleted a major Fn1 receptor, integrin α5 using the Isl1(Cre) strain, and observed the same spectrum of abnormalities seen in the Fn1 conditional mutants. Additional conditional mutagenesis studies designed to ablate integrin α5 in distinct cell types within the Isl1(+) tissues and their derivatives, suggested that the expression of integrin α5 in the pharyngeal arch mesoderm, endothelium, surface ectoderm and the neural crest were not required for PAA formation. Our studies suggest that an (as yet unknown) integrin α5-dependent signal extrinsic to the pharyngeal endothelium mediates the formation of the 4th PAAs

High frequency large stroke design and simulation experimental research on shaking table

Firstly, this paper introduces the design of high frequency large stroke vibration table according to the applicable environment. Secondly, the three-dimensional solid model is established which is based on solidworks2012 environment. The kinematics and dynamics simulation of the shaking table model are carried out. The vibration test curve of the vibrating table is obtained, and the reason of the change of the vibration curve under different vibration frequency is analyzed. Finally, this paper concludes that this exciting scheme is feasible and effective

Gliclazide impurity F: N-[(perhydro­cyclo­penta­[c]pyrrol-2-yl)amino­carbon­yl]-o-toluene­sulfonamide

The title compound, C15H21N3O3S, is known to be an impurity of gliclazide [systematic name: N-(hexa­hydro-1H-cyclopenta[c]pyrrol-2-ylcarbamo­yl)-4-methyl­benzene­sulfonamide], a sul­fonyl­urea anti­diabetic drug. Gliclazide has a p-tolyl group substituting the sulfonamide functionality, while the title mol­ecule contains an o-tolyl group. Both five-membered fused rings adopt envelope conformations. In the crystal, N—H⋯O hydrogen bonds are formed between HN(C=O)NH groups, building centrosymmetric dimers. These dimers are further linked through N—H⋯O(sulfon­yl) contacts, forming chains in [100]

Green finance pilot reform and corporate green innovation

This study investigates the impact of the green finance pilot reform on corporate green innovation using the formation of the China Green Finance Pilot Reform in 2017 as a quasi-natural experiment. It shows that the green finance pilot reform increases corporate green innovation. Furthermore, by highlighting the differences between green enterprises and heavily polluting enterprises, it also shows that the positive relationship between the green finance pilot reform and corporate green innovation is more pronounced in green enterprises than in heavily polluting enterprises. The mechanism analysis shows that the green finance pilot reform mainly affects corporate green innovation by easing financing constraints and reducing financing costs. The heterogeneity analysis indicates that the positive relationship between the green finance pilot reform and corporate green innovation is more pronounced in non-state-owned enterprises and large-scale enterprises. As a result, the effect of the green finance pilot reform on corporate green innovation gives rise to certain green innovation incentives. It is thus necessary to optimise the external corporate governance environment by promoting the green finance pilot reform and further offers practical implications for corporate green innovation decision-making