Magnetically coupled oscillators applicable to high-sensitivity mass detection

Microsystem Technologies - In this paper, a system of magnetically coupled oscillators consisting of a Π-shaped horizontal cantilever and a rectangular vertical cantilever with a frequency...     

面向无人驾驶地图更新的安全信任管理方案

地图的实时性和准确性在无人驾驶车辆导航中发挥着重要作用。基于卫星图像的数字地图能够保证地图中道路信息的准确性,但是根据相关路况信息进行实时更新时,由于车辆用户数较多且来源复杂,因此无法确保数据的安全性和可靠性。提出一种基于区块链的认证与信任管理方案。利用无证书签名技术实现车辆的匿名认证,保证车辆身份的可验证性和不可否认性。设计基于区块链的信任管理机制,通过存储在区块链上的历史信任值计算路况消息的可信度,同时将可靠的路况信息发送给地图更新服务器,根据车辆提供信息的真实与否更新车辆信誉值,实现车辆信誉的同步与更新。从计算开销、通信开销和信任管理功能等方面验证了该方案的有效性。仿真结果表明,该方案具有较高的地图更新效率和防骗能力,能够确保数据来源的安全性和可靠性,为无人驾驶车辆提供实时路况更新服务。     

Study of tool trajectory in blisk channel ECM with spiral feeding

Electrochemical machining (ECM) plays an important role in blisk manufacturing. There are two steps in blisk ECM: machining of channels and precise shaping of blade profiles. In channel machining, channels are machined in the workpiece with allowance left to the following process. Therefore, the main aim of channel machining with ECM is to improve the allowance distribution. With this aim, a new ECM method for blisk channels, spiral feeding ECM, is developed in which the cathode feeds from blade tip to hub along with rotation motion around its axis. Through this combined motion, twisted channels are produced in the workpiece. The relationship between feed position and rotation angle is presented in the form of a mathematical model. Experiments with a feed rate of 1 mm/min confirm that spiral feeding ECM is feasible and efficient. Compared with radial ECM, the allowance differences in blank back and blank basin decrease by 32.7% and 33.6%, respectively. The surface roughnesses Ra in blank back, blank basin, and hub are 0.358, 0.308, and 0.102 µm, respectively. Thus, the allowance distribution is improved to be more uniform considerably and the surface quality is relatively high.     

Pathogen-mimicking nanocomplexes: self-stimulating oxidative stress in tumor microenvironment for chemo-immunotherapy

A novel drug-loaded pathogen-mimicking nanocomplex (MSN-DOX-SP-LPS) has been constructed for synergistic chemo-immunotherapy.

     

Regulation of cell fate by near infrared-responsive telomerase activity

Here we develop a strategy using near infrared (NIR) modulation of telomerase activity based on gold nanocage@smart polymer system. Using this biocompatible design, we can regulate cellular behavior. This system has been used in vivo by taking advantages of NIR. This is the first example for optical modulation of telomerase activity in living cells and tissues.

     

Characteristic analysis of Fe3O4 nanoparticles modified by oleic acid and undecylenic acid

Carbonization of magnetic polymer microspheres is one of the methods for the preparation of magnetic carbon materials. Fe₃O₄ magnetic particle characteristics considerably influence the magnetic content and size distribution of magnetic polymer microspheres. The characteristics of Fe₃O₄ nanoparticles modified by oleic acid (OA) and undecylenic acid (UA) were analyzed by X-ray diffraction, Fourier transform infrared, scanning electron microscopy, dynamic laser light scattering, thermogravimetry/differential thermogravimetry, vibrating sample magnetometer, and water contact angle. Fe₃O₄ nanoparticles modified by OA and UA are nearly spherical and exhibit superparamagnetism. Fe₃O₄ particle size and saturation magnetization are slightly influenced by the OA and UA composition. OA and UA both are chemically adsorbed onto Fe₃O₄ as bidentate chelates. OA shows easier adsorption onto Fe₃O₄ than UA. OA groups have an expanded arrangement on OA@Fe₃O₄, whereas UA groups have a condensed arrangement on UA@Fe₃O₄. Particle lipophilicity decreases and particle clustering increases with decreasing OA content and increasing UA content on OA-UA@Fe₃O₄ nanoparticles.     

Plasmon‐Enhanced Spectroscopies with Shell‐Isolated Nanoparticles

Shell‐isolated nanoparticle‐enhanced Raman spectroscopy (SHINERS), due to its versatility, has been able to break the long‐term limitations of the material‐ and substrate‐specific generalities in the traditional field of surface‐enhanced Raman spectroscopy. With a shell‐isolated work principle, this method provides an opportunity to investigate successfully in surface, biological systems, energetic materials, and environmental sciences. Both the shell material and core morphology are being improved continuously to meet the requirements in diverse systems, such as the electrochemical studies at single crystal electrode surfaces, in situ monitoring of photoinduced reaction processes, practical applications in energy conversion and storage, inspections in food safety, and the surface‐enhanced fluorescence. Predictably, the concept of shell‐isolated nanoparticle‐enhancement could be expanded to the wider range for the performance of plasmon‐enhanced spectral modifications.     

Drug‐Loaded Mesoporous Tantalum Oxide Nanoparticles for Enhanced Synergetic Chemoradiotherapy with Reduced Systemic Toxicity

Combining chemotherapy and radiotherapy (chemoradiotherapy) has been widely applied in many clinical practices, showing promises in enhancing therapeutic outcomes. Nontoxic nanocarriers that not only are able to deliver chemotherapeutics into tumors, but could also act as radiosensitizers to enhance radiotherapy would thus be of great interest in the development of chemoradiotherapies. To achieve this aim, herein mesoporous tantalum oxide (mTa₂O₅) nanoparticles with polyethylene glycol (PEG) modification are fabricated. Those mTa₂O₅‐PEG nanoparticles could serve as a drug delivery vehicle to allow efficient loading of chemotherapeutics such as doxorubicin (DOX), whose release appears to be pH responsive. Meanwhile, owing to the interaction of Ta with X‐ray, mTa₂O₅‐PEG nanoparticles could offer an intrinsic radiosensitization effect to increase X‐ray‐induced DNA damages during radiotherapy. As a result, DOX‐loaded mTa₂O₅‐PEG (mTa₂O₅‐PEG/DOX) nanoparticles can offer a strong synergistic therapeutic effect during the combined chemoradiotherapy. Furthermore, in chemoradiotherapy, such mTa₂O₅‐PEG/DOX shows remarkably reduced side effects compared to free DOX, which at the same dose appears to be lethal to animals. This work thus presents a new type of mesoporous nanocarrier particularly useful for the delivery of safe and effective chemoradiotherapy.     

White‐Emissive Self‐Assembled Organic Microcrystals

Organic semiconductor micro‐/nanocrystals with regular shapes have been demonstrated for many applications, such as organic field‐effect transistors, organic waveguide devices, organic solid‐state lasers, and therefore are inherently ideal building blocks for the key circuits in the next generation of miniaturized optoelectronics. In the study, blue‐emissive organic molecules of 1,4‐bis(2‐methylstyryl)benzene (o‐MSB) can assemble into rectangular microcrystals at a large scale via the room‐temperature solution‐exchange method. Because of the Förster resonance energy transfer, the energy of the absorbed photons by the host matrix organic molecules of o‐MSB can directly transfer to the dopant organic molecules of tetracene or 1,2:8,9‐dibenzopentacene (DBP), which then emit visible photons in different colors from blue to green, and to yellow. More impressively, by modulating the doping molar ratios of DBP to o‐MSB, bright white‐emissive organic microcrystals with well‐preserved rectangular morphology can be successfully achieved with a low doping ratio of 1.5%. These self‐assembled organic semiconductor microcrystals with multicolor emissions can be the white‐light sources for the integrated optical circuits at micro‐/nanoscale.     

Flexible Nonvolatile Transistor Memory with Solution‐Processed Transition Metal Dichalcogenides

Nonvolatile field‐effect transistor (FET) memories containing transition metal dichalcogenide (TMD) nanosheets have been recently developed with great interest by utilizing some of the intriguing photoelectronic properties of TMDs. The TMD nanosheets are, however, employed as semiconducting channels in most of the memories, and only a few works address their function as floating gates. Here, a floating‐gate organic‐FET memory with an all‐in‐one floating‐gate/tunneling layer of the solution‐processed TMD nanosheets is demonstrated. Molybdenum disulfide (MoS₂) is efficiently liquid‐exfoliated by amine‐terminated polystyrene with a controlled amount of MoS₂ nanosheets in an all‐in‐one floating‐gate/tunneling layer, allowing for systematic investigation of concentration‐dependent charge‐trapping and detrapping properties of MoS₂ nanosheets. At an optimized condition, the nonvolatile memory exhibits memory performances with an ON/OFF ratio greater than 10⁴, a program/erase endurance cycle over 400 times, and data retention longer than 7 × 10³ s. All‐in‐one floating‐gate/tunneling layers containing molybdenum diselenide and tungsten disulfide are also developed. Furthermore, a mechanically‐flexible TMD memory on a plastic substrate shows a performance comparable with that on a hard substrate, and the memory properties are rarely altered after outer‐bending events over 500 times at the bending radius of 4.0 mm.