Information security serves as the cornerstone for ensuring the stable development of today’s highly digitized era. As cryptographic primitives with high security and robust encryption capabilities, physical unclonable functions (PUFs) are recognized as one of the critical solutions to address information leakage issues. However, the encoding of PUFs often relies on the inherent properties of materials, which limits the potential for further enhancement of their encoding capacity (EC). In this study, we introduce a four-level encoding scheme by leveraging the stochastic characteristics of free radical chemical reactions and energy deposition in the fabrication process of silicon carbide (SiC) color centers. A multilevel multimodal PUF (MMPUF) encoding strategy (ES) for flexible substrates with high EC, low cost, and simple and fast readout was constructed. The spatially random distribution of SiC and silicon vacancy (Vsi) color-center concentrations as well as the offsets of the laser pyrolysis position along the X- and Y-axes are four independent physical properties that ensure the encoding performance of the PUF, achieving a high encoding capacity of 24×10×10 and secure, stable, and unclonable encoding. Furthermore, the integration of the PUF tags with the products through a doping manufacturing process, rather than simple attachment, enhances the security and practicality of the anti-counterfeiting system. The proposed encoding hierarchy based on the offsets provides a novel encoding solution for improving PUF EC.

In order to achieve a low-cost, simple, fast, and green preparation method of graphene quantum dots (GQDs), a method for one-step preparation of GQDs by laser-induced polyimide powder was proposed. By controlling the laser parameters and using low-cost precursor material polyimide (PI) powder, a bright blue fluorescent GQDs solution was successfully prepared, and the whole experimental process was simulated by ReaxFF molecular reaction dynamics. The results show that the GQDs solution with blue fluorescent can be prepared by laser -induced PI power in one step. The scraped black matter contained GQDs. After the samples were tested by UV-vis, PL, TEM, and Raman, the prepared GQDs had an average particle size of 6.14 nm, a quantum yield of about 11.4%, and stable fluorescence properties. The whole process of the proposed method can be carried out at ambient temperature without any other chemical reagents or complicated subsequent processing, and has the advantages of simplicity, rapidity, environmental protection, and low cost, which not only provides a new reference for the green synthesis of quantum, but also has the potential for large-scale production.

提出了一种既具有抗伽马(γ)辐照又具有电磁屏蔽性能的氧化钨(WO3)/石墨烯泡沫(GF)/聚二甲基硅氧烷(PDMS)复合力敏结构.该结构以GF良好的三维多孔网状结构所形成的良好导电网络来实现电磁屏蔽.WO3粉填充来实现γ辐照屏蔽.通过真空辅助法,将WO3/PDMS溶液回填进入GF中制得.通过60Co-γ射线对复合结构进行不同剂量的辐照,并对辐照前后复合结构的电磁屏蔽性能、电导率及力敏特性进行了测试分析.结果表明:所制备的复合结构随着辐照剂量的增加,依旧保持较好的电磁屏蔽效能、导电性和良好的重复性与稳定性.该复合力敏结构具有较好的γ屏蔽效果和电磁屏蔽性能,为柔性可穿戴器件应用于辐照及电磁辐射环境中提供了参考.

The optical properties of CdSe/ZnS quantum dots(QDs)embedded in polydimethylsiloxane(PDMS)flexible materials after irradiated with γ-rays were studied.As an embedding matrix,PDMS exhibits the advantage of high radiation hardness.The luminescence spectra and fluorescence lifetime of the irradiated and unirradiated samples were tested.The fluorescence intensity of QDs decreases with the increase of the irradiation dose according to the result of luminescence spectra.The fluorescence intensity of the QDs decreases by 80％after irradiation with a dose of 1 kGy,but the position of the emission peak and the spectral shape of the QDs remain consistent before and after irradiation.In addition,the fluorescence lifetime of QDs is shortened after irradiation.Based on the fluorescence response of QDs to the irradiation of y-rays and combined with flexible materials,our work provides a theoretical basis for the application of QDs as a new wearable dosimeter.

固态原子自旋磁传感器具有磁灵敏度高、体积小等优势,在精密测量领域具有很好的发展前景.面向高灵敏度固态原子自旋磁传感器对大功率高均匀微波激发天线的需求,设计了一种类环形磁耦合天线结构,通过增加不规则移相回路和环形开口结构使微波场在环形天线中心处叠加,产生大功率高均匀微波场.实验中,通过仿真得到该结构S11参数为-20.8dB,微波非均匀性小于6%.同时,通过与传统环形天线对比测试,该类环形天线使固态原子自旋ODMR谱对比度提升了330%,相应的磁传感灵敏度提升了约450%,实现了对固态原子自旋磁传感结构的灵敏度提升,为高灵敏固态原子自旋传感测量技术提供了技术支撑.

In this study, a graphene foam/polydimethylsiloxane (GF/PDMS) force-sensitive composite with excellent electrical, mechanical, and electromagnetic interference (EMI) shielding performances was prepared. GF with different contents of graphene was prepared by chemical vapor deposition (CVD) and GF/PDMS composites were prepared by vacuum-assisted impregnation. The electrical test and morphology detection indicated good conductivity and flexibility of the proposed composite. Indeed, the GF/PDMS composite with 0.4 wt% graphene had the highest conductivity (4 S cm−1). The EMI shielding performance of the GF/PDMS composite with 0.4 wt% graphene in the X-band was tested and its EMI shielding effectiveness (SE) was 32 dB. After repeated bending for 10000 times, the EMI SE of the proposed composite exhibited negligible changes. The force sensitivity test showed that the sensitivity of the proposed composite was 8.7 KPa−1 under the tensile strain of 30%–50%. Under the pressure of 600–1000 KPa, the sensitivity of the proposed composite was 0.15 KPa−1. Under the stress of 1000 KPa, the EMI shielding coefficient of the proposed composite was 25 dB, which was reduced by 21.9%. The results demonstrated that GF/PDMS with low filler contents (0.4 wt%) exhibited high conductivity (4 S cm−1), high EMI SE (32 dB), and excellent mechanical properties.

In order to obtain a force-sensitive composite structure with high-performance electromagnetic interference (EMI) shielding, this paper proposes a method for preparing flexible force-sensitive composites by backfilling PDMS into a carbon nanotube (CNT) sponge using a vacuum-assisted method. Compared with CNTs/PDMS force-sensitive composites with different content prepared by the traditional solution blending method, the CNT sponge/PDMS force-sensitive composite prepared by the vacuum-impregnation method demonstrated sensitivity of 70 in a strain range of 35–50

In this paper, a carbon nanotube (CNT)/polydimethylsiloxane (PDMS) composite force-sensitive structure with good flexibility is proposed and fabricated, and the measurement of scanning electron microscopy (SEM) and Raman are carried out. The equivalent circuit of force-sensitive test of structure is performed and analyzed under direct current (DC) and alternating current (AC) conditions. Under AC conditions, experimental results further show that the sensitivity and sensitivity factors of force-sensitive structures are 0.15 KPa−1 and 2.17 in the pressure range of 600–1000 KPa compressive stress and 20–50% tensile stress, respectively. These results are increased by 36.4% and 38.2% compared to the results of compressive stress (0.11 KPa−1) and tensile stress (1.57) under DC conditions, respectively. It shows that the carbon nanotube/PDMS composite has higher test accuracy under AC conditions.

This study aimed to design a polydimethylsiloxane multi-walled carbon nanotube composite force-sensitive structure. Five composite materials with different volume fractions of carbon nanotubes were prepared, and the microscopic morphology of the samples recorded. Conductive pathways were formed inside the composite materials. The force-sensitive performance was verified through tensile experiments on the material. The sample with a content of 3 vol. % had a sensitivity of up to 165, which was good for detecting small strains. The samples were irradiated with 60Co-γ rays, and the irradiation doses were 5, 10, 20, 50, and 100 kGy. After irradiation with the highest dose of 100 kGy, the sensitivity of the sample with a content of 3 vol. % was reduced to 125. The samples exposed to different irradiation doses were stretched and released 3000 times to verify the repeatability of the force sensitive characteristics; almost no difference was found in the resistance strain results of the sample. Experiments showed that the designed composite force-sensitive structure had high sensitivity, good repeatability, and good resistance to gamma radiation.

This paper proposes a new type of flexible force-sensitive structure that is resistant to gamma radiation and is made of tungsten oxide (WO3) powder, polydimethylsiloxane (PDMS), and carbon nanotube (CNT) sponge. The thickness of the sample was 2.2 mm, the middle interlayer was composed of a carbon nanotube (CNT) sponge and PDMS to form a conductive layer, and the upper and lower layers were made of tungsten oxide and PDMS, which formed a gamma-ray shielding layer. When the particle size of the tungsten oxide powder was 50 nm, 100 nm, and 1 µm, the composite force-sensitive structure exhibited better force-sensitive performance. The composite force-sensitive structure was irradiated with doses of 5, 20, 50, and 100 KGy through 60Co- rays with an energy of 1.25 MeV. The results showed that the force-sensitive characteristics changed little in significance after irradiation by different doses of gamma rays, indicating that the force-sensitive structure has good resistance to gamma radiation. This flexible stress sensor can be used in soft robots and health inspection, even in harsh environments without significant performance loss.

采用简单、绿色、低成本的方法合成石墨烯量子点(GQDs)一直是研究者们不断追求和探究的热点.本文首先采用简单、低成本的激光诱导聚二甲基硅氧烷(PDMS)方法成功制备出有缺陷的少层石墨烯,然后再以所制备的石墨烯为碳源,采用一步水热法成功制备出了分散性良好、横向平均尺寸约为6.67 nm、发稳定蓝色荧光的GQDs溶液.分别采用透射电镜(TEM)、拉曼光谱、紫外吸收光谱和荧光光谱对GQDs的形貌和荧光特性进行了表征.以硫酸奎宁为标准参考物,计算所得GQDs的荧光量子产率约为6.3％.本研究提出的制备GQDs的方法具有简单、低成本、低污染的优势,为石墨烯量子点的制备提供了一种新途径、新参考,也为石墨烯量子点大规模商业化制备提供了潜力.

This paper studied the radiation hardness of InAs Quantum Dot(QD) embedded in high electron mobility transistor (HEMT) for force-sensitive structure, and further verified its high irradiation properties and high sensitivity. The transfer characteristics, output characteristics, structural changes and force-sensitivity of InAs QD-HEMT and HEMT structure are analyzed after irradiated with 1900-Mev 181Ta ions at different fluences. The experiment results of electrical characterization indicated that the radiation hardness of InAs QD-HEMT was 3.5 times higher than that of HEMT. The mechanical sensitivity of pristine InAs QD-HEMT structure was 0.153 mA/KPa, which was higher than that of pristine HEMT structure by 0.088mA/KPa, and the force-sensitivity of InAs QD-HEMT structure was less affected by irradiation. The results indicate that InAs QD-HEMT force-sensitive structure has a strong tolerance to heavy ion irradiation. The irradiation hardens, and force-sensitive characteristics of the device can be improved by using InAs QD-HEMT structure, which can provide radiation protection for MEMS sensors applied in a harsh radiation environment.

辐射对空间通信系统中使用的传感器件的不利影响是需要重点考虑的问题,作为力学传感器件的核心部件,对力敏传感单元的抗辐照特性的研究就尤为重要.设计了一种InAs量子点(QD)嵌入式高电子迁移率晶体管(HEMT)力敏结构,通过60Co-γ射线对InAs QD-HEMT结构进行了不同剂量的辐照,并对辐照前后结构的电学特性、力敏特性进行了测试分析.实验结果表明:随着辐照剂量的增加,InAs QD-HEMT结构的电学特性发生退化,灵敏度不断降低.经过150 Mrad剂量辐照后InAs QD-HEMT结构的漏极电流降低了约21％,灵敏度降低了63.4％.结果表明:高剂量辐照后InAs QD-HEMT结构仍具有工作性能,为MEMS传感器应用于强辐照环境提供研究基础.

A force-sensitive structure of an InAs Quantum Dot (QD) embedded in a high electron mobility transistor (HEMT) is presented in this paper. The size of an InAs QD is about 30 nm prepared by the S-K growth mode, and the force-sensitive structure is fabricated by molecular beam epitaxy (MBE). The force-sensitivity characteristic of the QD HEMT is studied by the electrical and mechanical properties. The electrical characteristics show that the InAs QD-HEMT has linear, cut-off, and saturation operating states, and produces different output currents under different gate voltages, which shows that the structure is reasonable. Furthermore, the results of the output characteristics under different pressure show that the output voltage of the QD-HEMT decreases with the increase in pressure, which indicates that the InAs QD-HEMT has a vital mechanical–electrical coupling characteristic. The output voltage of the InAs QD-HEMT in the range of 0–100 kPa shows that the sensitivity was 1.09 mV/kPa.

利用60Co-γ射线对设计的GaAs基HEMT力敏结构进行了不同剂量的辐照,通过对辐照前后结构的电学特性、力敏特性分析对比,得到了γ辐照对力敏结构的损伤影响.与未辐照样品相比,90 MRad剂量辐照后HEMT力敏结构的漏极电流降低了约74％,辐照剂量高于100 MRad时,样品被击穿,失去工作特性.力敏特性测试结果表明,随着辐照剂量的不断增加,结构的灵敏度发生降低,90 MRad剂量辐照后结构的灵敏度降低了76％.

This paper presents a type of Ag/polydimethylsiloxane (Ag/PDMS) nanocomposite material for use in strain gauge element applications. In these elements, the Ag nanoparticles work as conductive elements by electron tunneling and the PDMS forms the tunneling dielectricstructure. In our experiments, the piezoresistance and piezocapacitance characteristics of these Ag/PDMS composites have been studiedunder applied rain/stress. From the results, the gauge factors for piezoresistance and piezocapacitance can reach up to 153 and 224, respectively. Also, when acting as strain elements, the Ag/PDMS composites show fine levels of repeatability and stability. The results given here prove that the material can be used to form anew type of high-sensitivity element for sensor applications. The detectionmethod used for the sensor signals also offersdiversity by including both piezoresistance and piezocapacitance.

The amount of exposure received by the imaging device and the sensitivity of the device all had crucial impacts to the image quality and the polarization information in the polarization imaging technology. We analyzed the influence to the sky polarization information when changed the amount of exposure and the sensitivity of the imaging device respectively. In the sunny weather day,device is easy to overexposure,so the approach to be first taken was to reduced the amount of exposure.Experiments show that when reduced the amount of exposure by 5 times,the accurate of polarization information can be increased 48%. Secondly,the device sensitivity was changed by controlling the ISO degree. Experiments show that when each ISO level is lower in one grade,the similarity can be increased 5%. And the similarity can be achieved the maximum when the ISO is 100,the measurement accuracy can be up to about 70%.

为研究双环谐振腔结构力敏传感特性,设计了不同半径比的基于绝缘衬底上硅的双环微腔结构.通过理论分析以及实验测试并结合有限元仿真得出:半径比为3∶1的双环结构的灵敏度为80.26 pm/MPa;而半径比为1∶1的双环结构的灵敏度高达128.87 pm/MPa,具有高的检测灵敏度,表明双环微腔敏感结构单元可应用于应力检测领域.

The solar meridian is the significant feature of the atmospheric polarization pattern.It can be used as an important reference benchmark to obtain the important of navigation information.Therefore, by detecting the po-sition of the solar meridian in the atmospheric polarization pattern, a two-dimensional heading information of moving object can be got.However, the simulation results show that at different angle of the sun, the extraction accuracy of sun's meridian and heading calculating precision will be affected.When the solar elevation angle is less than 30 °, heading angle error is maintained at less than 0.02 °, which can be ignored; when the solar elevation angle changed from 30 °to 60 °, heading error is increased slowly from 0.02 °to 0.05 °;When the solar elevation angle greater than 60 °, heading angle error increases sharply, up to 0.1 °or more;and when the solar elevation angle reaches 90 °,heading measurement can not be done completely.Through theoretical analysising, the distribution of the feature points near the solar meridian would diverge as the solar elevation angle becoming large.So there will be some errors when fitting using least square method.And based on this analysis a appropriate error compensation during calculating the heading angle in the future can be made.And more optimization algorithm will be proposed to improve the calculating precision in the future.

To reduce the influence of the temperature change of filter based on micro ring resonator,study tempera?ture properties of micro-ring resonator,the simple ring and cascaded rings resonators based on silicon-on-insulator was designed and fabricated. The micro-ring resonators were heated by temperature controller and the transmission spectrum shift was observed via the vertical grating coupling method and the wavelength scanning way. From the theoretical analysis,experimental test and linear simulation,it has been concluded that the temperature coefficient is 105 pm/℃,97 pm/℃and 80 pm/℃,27 pm/℃in simple ring,double rings,triple rings and nine rings,respective?ly. In a word,the sensitivity to temperature is decreased and the temperature drift is inhibited with the increase of the number of rings.