Oscillation of S5 helix under different temperatures in determination of the open probability of TRPV1 channel

Transient receptor potential vanilloid subtype 1 (TRPV1) is a polymodel sensory receptor and can be activated by moderate temperature (≥ 43 ℃). Though extensive researches on the heat-activation mechanism revealed some key elements that participate in the heat-sensation pathway, the detailed thermal-gating mechanism of TRPV1 is still unclear. We investigate the heat-activation process of TRPV1 channel using the molecular dynamics simulation method at different temperatures. It is found that the favored state of the supposed upper gate of TRPV1 cannot form constriction to ion permeation. Oscillation of S5 helix originated from thermal fluctuation and forming/breaking of two key hydrogen bonds can transmit to S6 helix through the hydrophobic contact between S5 and S6 helix. We propose that this is the pathway from heat sensor of TRPV1 to the opening of the lower gate. The heat-activation mechanism of TRPV1 presented in this work can help further functional study of TRPV1 channel.

Design method of reusable reciprocal invisibility and phantom device

Reusable reciprocal invisibility and phantom device is proposed and designed based on multi-folded transformation optics and equivalent components. In comparison with the reported reciprocal invisibility cloaks, the material parameters of the device presented here are homogeneous, and the hiding of the target object does not require any “anti-object” at all,which dramatically breaks through the limitations of the “anti-object” design in previous reciprocal cloak design. Perfectly illusion effect is also found by reasonably setting the material parameters of the restored medium of the device, which can be used to confuse detection radars while hiding target objects. Last but not least, the proposed device has an open structure,which enables the target object enclosed by the device to perform material exchange and simplex transfer of information with the outside world through open channels. In other words, the proposed device has a reusable function, enabling stealth or phantom of new target objects without changing any parameters of the device.

Static and dynamic evolution of CO adsorption onγ-U(100)surface with different levels of Mo doping using DFT and AIMD calculations

Alloys of uranium and molybdenum are considered as the future of nuclear fuel and defense materials.However,surface corrosion is a fundamental problem in practical applications and storage.In this study,the static and dynamic evolution of carbon monoxide(CO)adsorption and dissociation onγ-U(100)surface with different Mo doping levels was investigated based on density functional theory and ab initio molecular dynamics.During the static calculation phase,parameters,such as adsorption energy,configuration,and Bader charge,were evaluated at all adsorption sites.Furthermore,the time-dependent behavior of CO molecule adsorption were investigated at the most favorable sites.The minimum energy paths for CO molecu-lar dissociation and atom migration were investigated using the transition state search method.The results demonstrated that the CO on the uranium surface mainly manifests as chemical adsorption before dissociation of the CO molecule.The CO molecule exhibited a tendency to rotate and tilt upright adsorption.However,it is difficult for CO adsorption on the surface in one of the configurations with CO molecule in vertical direction but oxygen(O)is closer to the surface.Bader charge illustrates that the charge transfers from slab atoms to the 2π*antibonding orbital of CO molecule and particularly occurs in carbon(C)atoms.The time is less than 100 fs for the adsorptions that forms embryos with tilt upright in dynamics evolution.The density of states elucidates that the overlapping hybridization of C and O 2p orbitals is mainly formed via the d orbitals of uranium and molybdenum(Mo)atoms in the dissociation and re-adsorption of CO molecule.In conclusion,Mo doping of the surface can decelerate the adsorption and dissociation of CO molecules.A Mo-doped surface,created through ion injection,enhanced the resistance to uranium-induced surface corrosion.

Numerical Research on The Nozzle Damping Effect by A Wave Attenuation Method

Nozzle damping is one of the most important factors in the suppression of combustion instability in solid rocket motors.For an engineering solid rocket motor that experiences combustion instability at the end of burning,a wave attenuation method is proposed to assess the nozzle damping characteristics numerically.In this method,a periodic pressure oscillation signal which frequency equals to the first acoustic mode is superimposed on a steady flow at the head end of the chamber.When the pressure oscillation is turned off,the decay rate of the pressure can be used to determine the nozzle attenuation constant.The damping characteristics of three other nozzle geometries are numerically studied with this method under the same operating condition.The results show that the convex nozzle provides more damping than the conical nozzle which in turn provides more damping than the concave nozzle.All the three nozzles have better damping effect than that of basic nozzle geometry.At last,the phase difference in the chamber is analyzed,and the numerical pressure distribution satisfies well with theoretical distribution.

Tillage force and disturbance characteristics of different geometric-shaped subsoilers via DEM

With the increased use of agricultural machinery in field operations,soil compaction has become increasingly severe,and the plough pan has become deeper.Subsoiling is an excellent way to address this problem.However,it is limited by high energy consumption,which is closely related to tillage force.To investigate the effect of the geometric shape of shanks and tines on tillage force and soil disturbance in loam,a layered soil model in accordance with the actual conditions was established and five different subsoilers were simulated via discrete element modeling.The results indicated that the shank impacted soil disturbance and tine impacted tillage force.The draft force of curved shank and chisel tine was 8%less than that of the straight shank and sweep tine.The straight shank and sweep tine produced a larger furrow profile and a higher furrow width.The subsoiler with curved shank and chisel tine(C-C)exhibited the lowest specific resistance(12.87,17.52,19.46 and 21.18 kN/m^2 in the 30,35,40 and 45 cm tillage depth,respectively)considering the draft force and soil disturbance characteristics.Hence,these results will facilitate in the selection of a suitable subsoiler and design of new subsoilers with lower energy consumption requirements for loam areas worldwide.