半导体激光对蝗虫与其寄主植物组织热效应的分析比较

为比较半导体激光对蝗虫与其寄主植物组织的生物热效应差异,为激光杀灭蝗虫提供理论依据.选取808nm连续激光对东亚飞蝗幼虫与营养期狗尾草植物进行辐照效应理论研究,建立了激光照射下生物组织热作用的二维数学模型,采用Matlab有限元数值分析方法求解了Pennes生物传热方程,得到了组织内部温度随激光辐照时间和组织空间位置的分布规律.数值分析结果表明,对于蝗虫与植物组织,温度分布有着同样的规律,但温度沿着径向比轴向扩散范围广.在相同的激光辐照条件下,植物组织的温升不明显,保持在初始温度水平;蝗虫组织的温升则远远高于植物组织.     

精密机械结构的自适应压电分流阻尼抑振

为提高压电分流阻尼系统对多模态振动的抑制能力,提出了一种基于负阻抗变换器的频率自适应模拟电感电路.并应用于压电分流电路的设计,使压电分流电路能适应结构振动频率的变化而一直处于谐振状态,从而达到最佳的阻尼抑振效果,并研究了分流电路构型和各元件阻抗对抑振效果的影响.将此电路应用于典型精密机械结构--硬盘驱动器磁头驱动臂的多模态振动响应抑制,取得了良好的抑振效果,结构的前3阶稳态响应传递函数的幅值分别降低了8.15 dB、12.06 dB和2.11 dB.     

基于对抗补丁的可泛化的Grad-CAM攻击方法

为了验证Grad-CAM解释方法的脆弱性,提出了一种基于对抗补丁的Grad-CAM攻击方法.通过在CNN分类损失函数后添加对Grad-CAM类激活图的约束项,可以针对性地优化出一个对抗补丁并合成对抗图像.该对抗图像可在分类结果保持不变的情况下,使Grad-CAM解释结果偏向补丁区域,实现对解释结果的攻击.同时,通过在数...     

基于静电排斥力的大冲程MEMS变形镜

设计并制造了一种基于静电排斥力的大冲程MEMS变形镜,此变形镜采用了三个多晶硅结构层和一个金属反射层的设计.利用表面硅工艺完成了变形镜的加工,结合有限元分析软件和白光干涉仪对三种不同驱动器电极空间分布方式的静电排斥型变形镜进行了分析和研究.测试结果表明,静电排斥型变形镜在200V下能实现1.7 μm以上的位移,冲程较传...     

High‐Strength and High‐Toughness Double‐Cross‐Linked Cellulose Hydrogels: A New Strategy Using Sequential Chemical and Physical Cross‐Linking

Polysaccharide‐based hydrogels have multiple advantages because of their inherent biocompatibility, biodegradability, and non‐toxicic properties. The feasibility of using polysaccharide‐based hydrogels could be improved if they could simultaneously fulfill the mechanical property and cell compatibility requirements for practical applications. Herein, the construction of double‐cross‐linked (DC) cellulose hydrogels is described using sequential chemical and physical cross‐linking, resulting in DC cellulose hydrogels that are mechanically superior to single‐cross‐linked cellulose hydrogels. The formation and spatial distribution of chemically cross‐linked domains and physically cross‐linked domains within the DC cellulose hydrogels are demonstrated. The molar ratio of epichlorohydrin to anhydroglucose units of cellulose and the concentration of the aqueous ethanol solution are two critical parameters for obtaining mechanically strong and tough DC cellulose hydrogels. The mechanical properties of the DC cellulose hydrogels under loading‐unloading cycles are described using compression and tension models. The possible toughening mechanism of double‐cross‐linking is discussed.     

Remote‐Loaded Platelet Vesicles for Disease‐Targeted Delivery of Therapeutics

The recent emergence of biomimetic nanotechnology has facilitated the development of next‐generation nanodelivery systems capable of enhanced biointerfacing. In particular, the direct use of natural cell membranes can enable multivalent targeting functionalities. Herein, this study reports on the remote loading of small molecule therapeutics into cholesterol‐enriched platelet membrane‐derived vesicles for disease‐targeted delivery. Using this approach, high loading yields for two model drugs, doxorubicin and vancomycin, are achieved. Leveraging the surface markers found on platelet membranes, the resultant nanoformulations demonstrate natural affinity toward both breast cancer cells and methicillin‐resistant Staphylococcus aureus. In vivo, this translates to improved disease targeting, increasing the potency of the encapsulated drug payloads compared with free drugs and the corresponding nontargeted nanoformulations. Overall, this work demonstrates that the remote loading of drugs into functional platelet membrane‐derived vesicles is a facile means of fabricating targeted nanoformulations, an approach that can be easily generalized to other cell types in the future.     

Nanoporous PtRu Alloy Enhanced Nonenzymatic Immunosensor for Ultrasensitive Detection of Microcystin‐LR

A novel nonenzymatic immunosensor for sensitive detection of Microcystin‐LR (MC‐LR) is constructed using a graphene platform combined with mesoporous PtRu alloy as a label for signal amplification. Primary antibody‐Microcystin‐LR (Ab₁) is immobilized onto the surface of a graphene sheet (GS) through an amidation reaction between the carboxylic acid groups attached to the GS and the available amine groups of Ab₁. Mesoporous PtRu alloy, prepared by corrosion PtRuAl alloys, is employed as a label to immobilize secondary antibody (Ab₂). The resulting nanoparticles, PtRu‐Ab₂, are used as labels for the immunosensor to detect MC‐LR. Under optimal conditions, the immunosensor exhibits a wide linear response to MC‐LR that ranges from 0.01 to 28 ng·mL^?1, with a low detection limit of 9.63 pg·mL^?1 MC‐LR. The proposed immunsensor shows good reproducibility, selectivity, and stability. The assayed results of polluted water with the sandwich‐type sensor are acceptable. Importantly, this methodology may provide a promising ultrasensitive assay strategy for other environmental pollutants.     

一种有效的增益误差校准方法

本文针对增益误差对空间谱估计性能的影响，提出了一种基于算术平均值的平滑校准方法，并将它与其它核准方法进行了比较，理论分析和实验仿真均表明了本文提出的方法具有更好的稳健性能和校准效果。     

B在SiGe中的应变补偿作用

用超高真空化学气相淀积方法生长出不同硼(B)掺杂浓度的应变SiGe合金材料,研究了B对SiGe合金的应变补偿作用.结果表明,B的掺入使SiGe的应变减小,B对Ge的应变补偿率为7.3,即平均掺入1个B原子可以补偿7.3个Ge原子引起的应变.同时获得B的晶格收缩系数为6.23×10-24cm3/atom.