Key Engineering Materials Vols. 609-610

Abstract: The comb-shaped capacitive micro-machined gyroscope employing an electrostatic comb drive and capacitive sensing structure is a typical type of MEMS sensor. Because of design and processing limitation and other factors, there are problems related to parallelism, dimensional accuracy and shape accuracy of the fabricated comb capacitor. These problems induce error into the calculation of the capacitance of the comb capacitor. The capacitance of the comb capacitor can be better calculated by the modeling the corner effect with various equipotential lines.

Abstract: This paper designs a micro-pump silicon diaphragm vibration pickup sensor. In this newsensor which is based on piezoresistive effect, four MOSFETs with nc-Si/c-Si heterojunction drainand source are manufactured on the surface of silicon wafer by using the technique of CMOS andPECVD, at edge of <100> orientation of the N-type silicon diaphragm rectangle, and using MEMStechnology, the back of the four MOSFETs device silicon substrate processed into silicon cup, whichconstitutes the vibration pickup sensor. The micro-pump silicon diaphragm vibration pickup sensornot only has all the advantages of conventional force sensitive resistance vibration pickup sensor, butalso has the advantages of small temperature drift, high detection precision, and it can satisfy themicro-pump silicon diaphragm vibration requirements.

Abstract: Besides the conductive patterning substrate, spatially well-defined microfibrous architectures can also be electrospun by using an insulating topographically structured collector (e.g. a nylon fabric). In both cases, it is proposed that the formation of the electrospun microfibrous patterns can be ascribed to the re-distribution of static electric field whenever collectors with different topography are introduced. Moreover, a series of simulation of the static electric field for various collectors (e.g. flat Al foil, conductive and insulating patterned substrates) have been systematically made to illustrate the formation mechanism, respectively. Our results are considered to warrant further scientific understanding on the formation of electrospun microfibrous patterning constructs, and helpful for easy generation of spatially defined architectures which have applications in a variety of areas such as tissue engineering, cell adhesion, proliferation and migration, etc.

Abstract: Under launch impact load, LIGA nickel that manufacturing MEMS fuze safety and arming (S&A) device will have obvious strain rate effect. By using finite element analysis software ANSYS/LS-DYNA, simulation models of a small-caliber ammunition MEMS fuze setback S&A device with strain rate effect and without strain rate effect were respectively established. The results of the two simulation modules were quite different. Comparisons between experimental results and simulation results show that simulation results considering strain rate effect agree well with experimental results, which proves strain rate effect should not be ignored in the simulation of MEMS S&A device.

Abstract: In this paper, a novel locking mechanism of MEMS S&A device has been proposed. Through establishing the mathematical model of the motion for the slider and simulating the physical model by the non-linear dynamic mechanics, appropriate novel locking mechanism is designed to meet two items, one item is the slider can slide to the bottom under the launch overload conditions; the other item is the slider cant be pulled back after the launch overload conditions. Through the experiment, the feasibility of the above research is confirmed.

Abstract: Compact compound imaging system with large CCD target surface has been researched. The target surface reaches 50mmX50mm, and reduces the system processing and installation difficulty. We present the system overall plan and discuss the imaging characteristics. The imaging results for sector resolution target show that the system can image with multi channel crosstalk free. The results show that whether the single convex lens system or double convex lens system, the definition and contrast of single channel graphs are poor. However we can get the super resolution image by POCS algorithm. The reconstructed results show that image quality has been obviously improved compared with the single channel image, which proof the availability of the compact compound imaging system with large CCD target surface. Key words: Compact ompound imaging system, Microlens array, Doublet lens, POCS

Abstract: Tumor of bladder is one of the most common tumors of the urinary system, the vast majority of which come from the epithelial tissue, and of which more than 90% are transitional cell tumors. Tumor of bladder ranks fourth in men and tenth in women. Intravesical instillation of Bacillus Calmette-Guerin (BCG) is recognized as the best way to prevent the recurrence of bladder cancer. But BCG would be excreted with the urine after staying about one hour in the bladder, which has a serious impact on its efficacy. In addition, repeated infusions bring great pains to the patients. This research intends to design a new sustained-release BCG integrated composite materials based on homogenized freeze-dried BCG. The release experiments in vitro of the composite materials show that the release property is good and release time of BCG is more than 48 hours.

Abstract: MEMS gyroscope can be used in various field such as stabilization, controlling and guiding, navigation and so on. Bias variation over temperature is the key performance in MEMS gyroscope. The encapsulation moisture has great influence on the bias variation of MEMS gyroscope.By experiments on gas recharged, roast temperature, die attach adhesive and encapsulation shell, method to depress the encapsulation moisture is obtained. By DPA, the encapsulation moisture of sensing element encapsulated by the reformative method can be reduced to less than 1000 ppm, and the performance on temperature of MEMS gyroscope is improved.

Abstract: Considering the long-term, flexible blood glucose monitoring demand, a sensor monitoring system for interstitial fluid (ISF) ultrafiltration sampling and on-line monitoring of blood glucose is presented. In this paper, the glucose sensor chip used in this system will be introduced in detailed. This sensor chip was developed by MEMS technique and it has the advantages of less ISF consumption, smaller structures and easier integration. Otherwise, the silicon glucose sensor chip is provided with diffusion control of the analyte through a porous silicon membrane into a silicon etched cavity containing the agarose immobilised enzyme. First, glucose monitoring principle of this sensor system will be intrudouced briefly. Then, this paper focuses on the design and fabrication of the key component, which is the MEMS sensor chip with diffusion control. Finally, experiments were carried out, and results show that the sensor chips signal response time at increasing glucose concentrations is about 5s; The linear range is large enough to cover the required broad area of blood glucose (0.2 ~ 20 mmol / L), the sensitivity is 9.76 nA/mmol.L-1, and the correlation coefficient is 0.9954. In addition, experiments results of sensor chip with different pore membrane were compared with each other. We can see that different measuring range and sensitivity can be obtained, which agrees with the theoretical analysis.

Abstract: A novel evanescent field optical fiber sensor based on a solid-core photonic crystal fiber with large holes has been introduced and successfully fabricated. Experiments show that the ethanol solution of unit concentration causes 0.461dB attenuation of absorbance. The finite element numerical simulation of the grapefruit photonic crystal fiber has been performed. The energy overlap factor is 0.0039 when holes are filled with air, and that is 0.012 when holes are filled with water for the different effective refractive index of the holes. Besides, the relationship between the maximum power transmission and the refractive index is also studied and analyzed. This research provides helpful instructions to the study of evanescent field sensing based on the solid-core photonic crystal fiber with large holes especially for biochemical detection.