ABSTRACT
Objective To study dynamic compression performance of adipose tissues, so as to further reveal the damage mechanism, and provide references for medical treatment.Methods Based on the improved split Hopkinson pressure bar (SHPB) experimental device, the adipose tissue dynamic compression experiment was conducted. The stress-strain curves of adipose tissues at different strain rates were obtained. Then the numerical model of SHPB was established, and the experimental process was simulated and analyzed. The numerical simulation for penetration process of 32 mm diameter rubber non-lethal projectile into the simulated target in human abdomen was carried out.Results Adipose tissues had a noticeable strain rate effect. The stress-strain curves at two high strain rates were approximately straight lines. The slope was similar, and the elastic modulus was 3.25 MPa, which was about 6 times of that under a quasi-static state. The simulation curves of fat SHPB were consistent with the experimental curves, which verified correctness of the constitutive model. In the process of non-lethal projectile penetrating human abdomen, an annular convex area similar to water wave appeared on skin surface, and the fat layer absorbed about 67% of the impact kinetic energy.Conclusions The experimental data of adipose tissues are very accurate. Numerical simulation can reproduce the penetration process well, and provide references for studying the damaging effect of non-lethal weapons on human body.
ABSTRACT
At present, China's medical service costs keep rising, and residents' out-of-pocket medical expen-ses are also increasing heavily. The prepayment reform of medical insurance is considered as an important starting point to solve the problem. It is of great significance to evaluate the effect of prepaid medical insurance reform on con-trolling medical expenses and reducing economic burden when sick. In order to achieve the objective of this study, a use of CHARLS data 2011 &2015 and DIDPSM theory, and a combination of the Interaction Item Model and PSM model, and make use of a natural experiment developed from experimental reform stage for the comprehensive promo-tion stage of new rural cooperative medical system (NCMS) in 2012, were very crucial. This paper finds that:(1) Prepayment system can control the rise in outpatient and inpatient expenses. Compared with those who did not partici-pate in NCMS in the initial stage of reform, after the universal reform, outpatient and inpatient expenses dropped by 6. 3％ and 41％, the average decrease was 1041yuan and 2895yuan, respectively. (2) After the universal reform, the insured patients' medical burden of outpatient and inpatient reduced by 17％ and 33％. Prepayment system has, to some extent, resisted the rise in medical expense, and alleviated the burden of medical treatment. (3) On the basis of PSM, the estimated value and significance of coefficients have not changed, the effect of PPS reform is good. The poli-cy implication is that accelerating the prepayment system reform is the key way to control the growing medical expenses.