Key Engineering Materials Vols. 609-610

Abstract: A high nonlinear, dispersion flattened hybrid nanofiber with a silicon/silica cross-slot-structure nanocore is firstly proposed and analyzed, which is insensitive to polarization for implementing quasi-TE and quasi-TM fundamental modes transmission due to cross slot effect. Simulation results show that fundamental mode of ultra-small mode effective areas and high nonlinearity at TE and TM polarizations, which are confined in the narrow cross slot by four silicon ribs, can be achieved via this cross sot structure core. Moreover, the cladding of four large-air-holes promotes tailoring the group velocity dispersion (GVD) and enhancing nonlinearity furthermore. Our results indicate that ultra-small Aeff of 0.098μm² and flat anomalous GVD with less than 13.5 ps.km^-1.nm^-1 dispersion ripple at C-band are realizable.

Abstract: In this work, a facile method was presented to produce Ag nanoball (NB)/ZnO hollow nanosphere (HNS) hybrid structure. Large scale, two-dimensional (2D) ZnO HNS arrays were fabricated on sapphire substrates using the polystyrene (PS) nanospheres as the template. Ag film were deposited on ZnO HNS arrays by radio frequency (RF) magnetron sputtering and then aggregated into Ag NBs on the top of ZnO HNS by the laser irradiation treatment. The size and distribution of Ag NB arrays were controlled by employing different ZnO HNS supporting structure templates. The scanning electron microscopy (SEM) was applied to visually study the evolution process of Ag NB/ZnO NHS arrays. X-ray diffraction (XRD) was carried out to characterize crystal structures of the samples. Obvious surface enhanced Raman (SERS) signals were observed from the Ag NB/ZnO NHS nanocomposite structure compared with that in the ZnO HNS structure by using the R6G as the testing agent. Theoretical simulation results demonstrate that the Raman enhancement originates from the significant enhanced local electromagnetic field induced by the surface plasmon resonance (SPR) of Ag NBs.

Abstract: This paper presents a RF MEMS shunt switch with design, fabrication and measurement. The designed switch that avoids unstable and collapse could be used to RF MEMS devices. The photoresist is used as sacrifice layer and switch material is Aluminum. To make the surface of MEMS switch smooth, the method of multiple spreading thick photoresist and dry etching is proposed. A size of 130×230 (μm)² MEMS switch with 1 μm height and 0.45 μm unevenness is demonstrated in a configuration. Continuous tuning of 1 μm is achieved by loading 33 volt DC voltage between MEMS switch beam and signal line. The RF performance shows 0.1-0.4dB insertion loss and 18-30 dB return loss of the switch. The fabrication, design, and measurement results of the MEMS switch are detailed.

Abstract: A fabricating process of prototype thermoelectric device based on vertical silicon nanowires (SiNWs) for on-chip integration was presented. The SiNWs with diameter of 200 nm and height of 1 μm were fabricated by electron beam lithography and inductively coupled plasma etching. The gaps between the NWs were filled by the spin-on glass, which isolated the top and bottom electrodes. A serpentine platinum resistance thermometer coil was formed on the NWs to create temperature gradient across the NWs and measure the temperature of the top of NWs. I-V characteristics of the vertical device before and after annealing were measured. The nonlinear I-V curves were obtained, but the annealed one demonstrated 1000-fold reduction in resistance than the unannealed one.

Abstract: Fuze Micro-Electro-Mechanical System (MEMS) has become a popular subject in recent years. Studies have been done for the application of MEMS-based fuze safety and arm devices. The existing researches mainly focused on reducing the cost and volume of the fuze safety device. The reduction in volume allows more payloads and, thus, makes small-caliber rounds more effective and the weapon system more affordable. At present, MEMS-based fuze safety devices are fabricated mainly by using deep reactive ion etching (DRIE) or LIGA technology, and the fabrication process research on the fuze MEMS safety device is in the exploring stage. In this paper, a new trans-scale fabrication method of metal-based fuze MEMS safety device is presented based on UV-LIGA technology and the micro Wire-cut Electrical Discharge Machining (WEDM). The method consists of fabrication of micro-spring by UV-LIGA technology, the fabrication of mesoscale structure by WEDM, the micro assembly of micro spring and mesoscale structure. Because UV-LIGA technology and WEDM technology were introduced, the production cycle was shortened and the cost was reduced. The overall dimension of the micro-fuse safety device is 9.5×12.3×0.6 mm and the smallest dimension is 10μm. Besides, four problems in the fabrication process have been solved effectively, which is helpful for the fabrication of similar kinds of micro devices. The fabrication method presented in this paper provides a new option for the development of MEMS fuze.

Abstract: Intelligent weather station system based on MEMS sensors is designed. The automatic meteorological system includes a MEMS temperature sensor, MEMS humidity sensor, MEMS pressure sensor, MEMS wind speed sensor and the sensor intelligent control system, etc. The intelligent control system has functions such as precise timing, multiple sensor data automatic acquisition, storage and uploading, which realizes the intelligent control of this weather station system.

Abstract: A new micro-fine manufacturing method is proposed, that is the ultrasonic modulating compound synchronous pulse electro-discharged and electrochemical machining. By the micro-fine machining way, the μm-level precision may be acquired. The low voltage, the low electric conductivitys working fluid mixed with the nm powders is used, as the ultrasonic vibration effect and the nm powders' catalyst effect between the electrodes, the micro-spark electro-discharged and the micro-electrolysis machining can be realized, the micro electro-discharged sparks can remove the electrolytic passivation film on the workpiece surface, ultrasonic vibrating blast wave can remove the machining outcomes and renew the working fluid, the better micro-fine machining precision can be acquired. Micro-fine compound machining system is build, the processing parameters can be adjusted online within a certain range, the synchronous pulses can be developed by the cutting circuit, the synchronization of frequency and phase can be ensured between the ultrasonic vibration and the electronic power, the precision and the process stability can be improved effectively. The mechanism tests are carried about the ultrasonic modulating compound discharge-electrochemical machining, a few of micro-structures are machined in μm-level machining precision, the fine machining mean's feasibility and technical superiority are verified too.

Abstract: This paper has proposed a MEMS planar zigzag slot for fuze to discriminate between drop impact acceleration and smooth start acceleration. It can fulfill the requirements that fuze power should be activated reliably in smooth start environment and kept off in service handling environment. The planar zigzag slot is used in medium and large caliber ammunition. At first, a structure consists of a spring, a mass with an anchor, a fixed zigzag slot and two baffles has been proposed. Then, the working principle of the structure and motion of anchor after colliding to zigzag slot has been analyzed. At last, key parameters of the structure on the performance of acceleration recognition is studied by dynamic simulation.

Abstract: Micro-pump is a fundamental component of micro-fluid machine, which has obtained an extensive use in medical care, bio-engineering, and the other fields. Its application will continuously be expanded. Its structure is different from the conventional mechanical pump as its size and flow limit, thus it is difficult to directly apply traditional method to micro-pump modeling. Firstly, the paper introduces the structure of the cantilever piezoelectric micro-pump, in which its input/output can be seen as two separate one-way valves, and its structure can be simplified for a simple beam model. Secondly, presents a port model based on bond graph port analysis, and selects the basic components in order to understand the micro-fluid characteristics of the micro-pump. Finally, gives the result of simulation to obtain the process of the volume change of micro-pump companying with the input pressure and the displacement of deformable film..

Abstract: The shock resistance of the MEMS device can be improved by simplifying its structure, but it will reduce accuracy. A commonly implemented solution that strengthens the shock resistance is the use of stopper. However, the collision between MEMS structure and stopper in shock environment may lead to the failure of the device. Hence, stopper should have a fine protection performance. In this study, the design method and principle of the MEMS device in the shock environment were analyzed. It was pointed out that the reliability design methodology of the MEMS device based on statics theory was insufficient. Next, the response of MEMS device to shock was studied and the shock dynamics model was established. Based on the model, the shock response of the traditional design and designs with different stoppers were analyzed. At last, experiments were carried out and the protection performance of different stoppers was evaluated. Results show that the use of stopper can obviously improve the shock resistance of the device. Elastic stopper can strengthen the shock resistance of the device greatly because of the excellent protection ability, while hard stopper may cause the emergence of the sharp stress wave.