校车连体型主动式安全气囊保护效果的研究优化

针对校车6岁儿童乘员的保护,根据原始的校车主动式安全气囊模型,建立连体型主动式安全气囊模型,以提高对偏位儿童的保护效果。基于MADYMO建立校车乘员约束系统,并仿真验证连体型气囊有效性,并对气囊参数进行单因素分析。根据5个灵敏因素,利用正交试验对连体型气囊的一系列参数进行优化,结果表明:优化后的偏位儿童完全伤害评价指标比单体型气囊降低了35.1%,双人乘坐和单人乘坐两种工况的伤害指标升高了8.5%和13.1%,但其值仍远小于规范限值。在正常乘坐保护效果达标的情况下,进一步提高了对偏位乘坐儿童的保护性能。

两种用于实验模拟空间等离子体漂移速度剪切的方法

E×B漂移速度剪切广泛存在于日地空间等离子体,是一种重要的不稳定性自由能来源。相对于空间被动观测,在地面等离子体实验中主动激发E×B漂移速度剪切有助于对相关不稳定过程的研究。我们设计并测试了两种主动激发E×B漂移速度剪切的方法:双等离子体叠加法和环电极法。初步结果表明,两种方法可以提供不同强度和空间尺度的E×B漂移速度剪切,并可以满足后续有关电离层不均匀体研究以及等离子体过程研究等空间等离子体地面实验的需求。

New strategy of S,N co‐doping of conductive‐copolymer‐derived carbon nanotubes to effectively improve the dispersion of PtCu nanocrystals for boosting the electrocatalytic oxidation of methanol

Efficacious regulation of the geometric and electronic structures of carbon nanomaterials via the introduction of defects and their synergy is essential to achieving good electrochemical performance.However,the guidelines for designing hybrid materials with advantageous structures and the fundamental understanding of their electrocatalytic mechanisms remain unclear.Herein,superfine Pt and PtCu nanoparticles supported by novel S,N‐co‐doped multi‐walled CNT(MWCNTs)were prepared through the innovative pyrolysis of a poly(3,4‐ethylenedioxythiophene)/polyaniline copolymer as a source of S and N.The uniform wrapping of the copolymer around the MWCNTs provides a high density of evenly distributed defects on the surface after the pyrolysis treatment,facilitating the uniform distribution of ultrafine Pt and PtCu nanoparticles.Remarkably,the Pt_(1)Cu_(2)/SN‐MWCNTs show an obviously larger electroactive surface area and higher mass activity,stability,and CO poisoning resistance in methanol oxidation compared to Pt/SN‐MWCNTs,Pt/S‐MWCNTs,Pt/N‐MWCNTs,and commercial Pt/C.Density functional theory studies confirm that the co‐doping of S and N considerably deforms the CNTs and polarizes the adjacent C atoms.Consequently,both the adsorption of Pt1Cu2 onto the SN‐MWCNTs and the subsequent adsorption of methanol are enhanced;in addition,the catalytic activity of Pt_(1)Cu_(2)/SN‐MWCNTs for methanol oxidation is thermodynamically and kinetically more favorable than that of its CNT and N‐CNT counterparts.This work provides a novel method to fabricate high‐performance fuel cell electrocatalysts with highly dispersed and stable Pt‐based nanoparticles on a carbon substrate.

Bioresponsive micro-to-nano albumin-based systems for targeted drug delivery against complex fungal infections

As a typical human pathogenic fungus,Cryptococcus neoformans is a life-threatening invasive fungal pathogen with a worldwide distribution causing w700,000 deaths annually.Cryptococcosis is not just an infection with multi-organ involvement,intracellular survival and extracellular multiplication of the fungus also play important roles in the pathogenesis of C.neoformans infections.Because adequate accumulation of drugs at target organs and cells is still difficult to achieve,an effective delivery strategy is desperately required to treat these infections.Here,we report a bioresponsive micro-to-nano(MTN)system that effectively clears the C.neoformans in vivo.This strategy is based on our in-depth study of the overexpression of matrix metalloproteinase 3(MMP-3)in infectious microenvironments(IMEs)and secreted protein acidic and rich in cysteine(SPARC)in several associated target cells.In this MTN system,bovine serum albumin(BSA,a natural ligand of SPARC)was used for the preparation of nanoparticles(NPs),and then microspheres were constructed by conjugation with a special linker,which mainly consisted of a BSA-binding peptide and an MMP-3-responsive peptide.This MTN system was mechanically captured by the smallest capillaries of the lungs after intravenous injection,and then hydrolyzed into BSA NPs by MMP-3 in the IMEs.The NPs further targeted the lung tissue,brain and infected macrophages based on the overexpression of SPARC,reaching multiple targets and achieving efficient treatment.We have developed a size-tunable strategy where microspheres"shrink"to NPs in IMEs,which effectively combines active and passive targeting and may be especially powerful in the fight against complex fungal infections.

Derivative ghost imaging

We propose a new experimentally verified ghost imaging(GI) mechanism,derivative GI.Our innovation is that we use the derivatives of the intensities of the test light and the reference light for imaging.Experimental results show that by combining derivative GI with the standard GI algorithm,multiple independent signals can be obtained in one measurement.This combination greatly reduces the number of measurements and the time required for data acquisition and imaging.Derivative GI intrinsically does not produce the storage-consuming background term of GI,so it is suitable for on-chip implementation and makes practical application of GI easier.