Papers by Keyword: Miniaturization

Abstract: For the evaluation of final component properties under consideration of production-induced material characteristics, it is necessary to determine the mechanical parameters of parts and structures. Thus, there is a need of new test methods for the material characterization and quality control of produced goods. The miniaturization of the test specimens offers the potential for the local testing of the material properties at almost any position on the component. However, due to the reduction in size of the test specimens, size effects can occur which may affect the material behavior. For this reason, this contribution analyses the influence of size effects on the derived material parameters in dependence of the specimen size and material by using upsetting tests according to DIN 50106:2016 standard. The materials Cu-OFE (copper), X5CrNi18-10 (stainless steel) and AA7075-T6 (aluminum) are investigated to ensure a broad transferability of the findings. The specimens are cut from a bar stock by using a high precision 3D micro electrical discharge milling machining. Due to the small size, every specimen is measured with an optical 3D coordinate measuring system to determine the exact size. Through these investigations, the reproducibility and scatter in the determination of material properties for scaled cylindrical upsetting specimens are evaluated. Furthermore, limits of geometric dimensions at constant aspect ratios are derived. The results of this investigation enable an estimation of the geometrical influence of the specimen size in regard to the mechanical properties.

Abstract: Conventional Bioreactor systems for cultivating cells in Life Science have been widely used for decades. An in vitro cell cultivation bioreactor should reliably and reproducibly mimic the in vivo microenvironment of the cultured cells. Normally, mammalian cell cultures are performed in conventional bioreactor devices such as culture flasks and culture-dishes. However, these tools have fundamental limitations due to being inappropriate for high throughput screening and consume a considerable amount of resources and time [1]. Therefore, there is a trend towards miniaturization, disposables and even micro platforms that fulfill increasing demands strongly aiming for production and testing of novel pharmaceutical products. Here we present the development and manufacture of a disposable miniaturized flow-through bioreactor system that can be produced in large numbers at low costs. nanoporous hollow fibers are located at the fluidic sources and drains of the miniaturized bioreactors and retain cells. The necessary mixture of oxygen and carbon dioxide is provided via diffusion through a semi-permeable membrane. Fluidic connections allow the continuous feeding of the cells adding nutrient solution at constant rates at the inlet of the micro bioreactor and removing the solution at the same rate at the outlet. This medium can be collected and used for subsequent analysis. Different designs and concepts for such bioreactors were carried out with varying numbers of plates, and integrated or joined miniaturized reactor chambers. First tests show full technical and biological functionality, cells could successfully be cultivated at high viability rates for some days.

Abstract: A intelligent logistics monitoring microsystem has been designed based on STM32F103T8, which is high ability, low power consumption and low cost. The radio frequency (RF) chip CC1101, the acceleration sensor BMA280 and the temperature and humidity sensor HTU21D are selected to acquire the corresponding data for the intelligent logistics microsystem, which are ultra-low power consumption and ultra-small size. Moreover, in order to further reduce power consumption, the interrupt mode is adopted in the data acquisition module and the sleep mode is used in the MCU module in the software control. On the other hand, in order to further optimize the performance of miniaturization, the SWD (Serial Wire Debug) protocol is used. Meanwhile, the system will alarm the transportation officer once the acquired data met or exceed the threshold, which will help him to take corresponding measures timely, thus reducing the risk of occurrence effectively.

Abstract: A miniaturized circularly polarized (CP) antenna for ultra-high frequency (UHF) radio-frequency identification (RFID) reader is designed in the present paper. For the aim of miniaturizing antenna, the square radiating patch is opened by four T-shape slots. This can extend the route of surface current, as a result the operating frequency drops and the size reduces. In additional two diagonal corners of the radiation patch are truncated by a square to achieve CP operation. The designed antenna is calculated and optimized by HFSS. The optimized antenna exhibits satisfied performances, and is therefore suitable for UHF RFID reader applications. The designed antenna shows the advantages of small size, simple structure, and low cost.

Abstract: in this paper, a Novel slot antenna for multi-frequency operation with coplanar waveguide (CPW)-fed are designed, which is loaded with slits. The designed antenna operates over the frequency ranges of 860MHz (3.11GHz-3.97GHz) and 1170MHz (5.08-6.25GHz), respectively. The proposed antennas are suitable for WLAN 5.2/5.8GHz and WiMAX 3.5/5.5GHz applications.

Abstract: This essay will find a new way to prevent technical unlocking and violence through the cylinder lock through the narrow cylinder bore for the purpose of improving the performance of the theft. The miniaturization of the keyhole and cylinder locks, it makes the lock cylinder by means of the implementation does not have enough space, greatly limits the unlocking illegal activities. Meanwhile, the new lock cylinder has the advantage of mutual opening rate lower.

Abstract: Many parts of today´s world are manufactured by cold forming operations or more precisely by mechanical upsetting such as wheelmounts or bevel gears because cold forming has several advantages compared to other machining operations. Due to size effects, the maximum achievable upset ratio in mechanical upsetting decreases with decreasing size of the work piece, so that upsetting becomes inefficient in micro range. Here, one promising approach is the laser rod end melting process generating a so called preform which allows upset ratios of several hundred within one stage. This preform is subsequently calibrated by a mechanical upsetting process. A numerical simulation showing the open die upsetting process of preforms, modeled with Abaqus, is presented in this work. Results of numerically determined natural strain are compared with an analytical model showing that the analytical model is a reasonable approximation. The maximum achievable average natural strain of preforms in upsetting is experimentally determined to be at least φ*=2.75.

Abstract: The letter reports the analysis of the reduced-size planar microstrip Wilkinson power divider which uses miniaturized microstrip line instead of conventional quarter wavelength transmission line. The full design formulae of the miniaturized Wilkinson power divider with arbitrary power ratio is first proposed.3dB one-stage and two-stage miniaturized Wilkinson power divider are designed according to the formulae. The ADS EM simulation results of the one-stage miniaturized Wilkinson power divider when the smaller electrical angle is 45 degrees show its reflection coefficient<-20dB,isolation>20dB and the transmission loss<0.4dB in the bandwidth of 28.9-34.9GHz,for the two-stage reduced-size Wilkinson power divider its reflection coefficient <-20dB,isolation>20dB and the transmission loss<0.4dB in the bandwidth of 26-37.5GHz.This kind of miniaturized Wilkinson power divider has a very compact size as well as good match and isolation.

Abstract: A compact and circular polarized antenna for UHF band RFID handset reader was designed, and realized by cutting slits in the antenna patch and etching slots on the ground. Numerical simulation was performed for the characteristics of the antenna with the software HFSS 13.0.The simulation results show that when the size of antenna patch is 68mm×68mm, -10dB return loss impedance bandwidth is 49MHz,VSWR is less than 2 and the largest gain is -0.61dB for antenna in 907～931MHz. Compared with the traditional reader antenna with the same material of the substrate，the improved antenna has a much higher gain．and the size was reduced by 20% and the max gain is raised -0.11dB.

Abstract: TEM horn antenna is one kind of directional Ultra-wideband antenna with simple structure. Based on the design method of TEM horn antenna, satisfied impedance and radiation character are obtained by simulation and experiment research. On this basis, by means of metal ridged loaded, background dielectric material loaded and distributed lossy metal loaded respectively, the miniaturization character is realized. The simulation analysis results show that load of traditional TEM horn antenna can get efficiently improvement in structure and performance which have widely application foreground in pulse radiation communication system and ultra-wideband radar system.