Key Engineering Materials Vols. 562-565

Abstract: This paper presents a new type of measurement and recording device for motion information of the vehicle, and proposes proposes a method of the multi-sensor data fusion. The system utilized a kind of MEMS-Based sensors, such as the angular rate gyros, the accelerometer, the magnetometer, the absolute pressure sensor, the differential pressure sensor and the GPS module. It is for measuring vehicle`s angular rate movement, acceleration, magnetic heading, altitude, air speed, latitude and longitude coordinates respectively. The entire system is integrated in a small circuit board with a small size, low power and high-stability characteristics.

Abstract: Abstract. Microsphere resonator is widely studied for the high quality factor Q and small mode volume. Aimed at the sensor applications, the resonant point tracking and locking method is proposed for measuring the resonant frequency shift. To avoid external noises, such as air flow and vibration, spot-packaged coupling structure is adopted. The robustness of microsphere-taper coupling unit is greatly improved. And this lays a foundation for resonant point tracking and locking. By employing modulation method, the demodulation signal is obtained. To lock the laser frequency to resonant point, PID circuits will adjust the center frequency of laser until the intensity of demodulation signal becomes zero. In the experiment, resonant tracking and locking is realized on the rotating platform with rotation rate 2 r/s.

Abstract: A new bonding technique mainly for PMMA microfluidic chips is presented in this paper. In this technique, polymer microfluidic microchannels were bonded by microwave radiation. Its strength and time can be controlled accurately in watt and second level. There are so many techniques for mass-production of polymer microfluidic chip, such as heat bonding, ultrasonic bonding. However, we may find different kinds of shortages when we use these techniques. In this paper, the experiment result shows that microwave radiation’s strength and time have effects on microfluidic chip`s bonding strength. The microwave absorbing coating can also have a certain degree influence on microfluidic chip`s bonding strength.

Abstract: Cellular culture is a complex process for cells are grown under certain given conditions, generally not in vivo. In this paper, a novel microfluidic was designed for cellular culture in a long term. Its structure mainly consists of two parts: channels and chambers. In this architecture, two kinds of channels are designed. One is used to load cell into chambers, the other is for the load of culture solution and drugs. Due to diffusion effect, the culture solution and drugs can permeate into chambers through a amount of ostioles. Finite element simulation was utilized to demonstrast the velocity field distribution and concentration field distribution. Comparisons were made to verify the rationality of the design. The simulation results suggest that this novel microfluidic is appropriate suitable in terms of culturing cells.

Abstract: A five layer microfluidic chip which is designed and fabricated for interstitial fluid (ISF) transdermal extraction, collection, and measurement toward the application of continuous and real-time glucose monitoring is presented in this paper. The microfluidic chip consists of a Venturi tube generating vacuum for ISF extraction and fluid manipulation, a novel volume sensor of electrolytic fluid for normal saline input volume control and ISF volume measurement, pneumatic valves for fluid management, and access ports for glucose sensor integration. The output vacuum of the Venturi tube is tested, and a less than 88kPa vacuum has been achieved, when 220kPa external pressure is applied. The feasibility of using the volume sensor to control and measure the normal saline input volume is confirmed by high accuracy and low coefficient of variation (CV=0.0040, n=12). The microfluidic chip is ready for glucose sensor integration in continuous glucose monitoring.

Abstract: Nanotechnology generates nanomaterials with many unique characteristics, which could play an active role in intensifying mud cake quality, raising cuttings removal ability, reducing friction, maintaining borehole stability, and improving the cementing quality. In this paper, a series of nanomaterials were introduced, and all of them had great influence on the properties of drilling fluids or completion fluids, which would be significantly important to wellbore stability, formation damage control, borehole cleaning, safety drilling, cementing quality, environmental protection, and the improvement of the progress and success rate of petroleum development and production. Finally, the further applications of nanomaterials in drilling fluids and completion fluids are also prospected.

Abstract: This work reported an analysis of a noticeable relaxation phenomenon caused by undesirable air bubbles in high-pressure microfluidic systems. A model with compression of air bubble considered was established to address the experimental observed pressure relaxation. The results indicated that the dominative factors were flow rate, flow resistance and initial diameter of the trapped air bubble. Meanwhile, the calculated relaxation times in different cases provided a design guideline for high-pressure microfluidic chip to avoid the long-term pressure relaxation.

Abstract: The Smart Meteorological Microsystems (SMM) is a kind of microsystems for meteorological information acquisition. SMM consists of two MEMS temperature and humidity sensors, a shell, a micro processor, a communication module, a GPS module, two pressure sensors and their peripheral circuits. The shell is built for protecting the sensors from being damaged when the sensors working in the harsh environment. However the shell also prevents the heat from transferring, leading to the appearance of temperature difference between the areas inside and outside the shell. The environment factors can lead to some temperature measurement errors. In order to solve these problems, this paper has designed an innovative structure of SMM shell. To improve the accuracy of temperature measurement, this paper has analyzed the heat transfer-fluid coupled simulations of temperature field in SMM under the working condition by using COMSOL Multiphysics. According to the results of the simulations, the structure of the SMM shell has been optimized. Either the structure or analysis has been reported in neither domestic nor international papers. As a result, what this paper has done is of a great value.

Abstract: Here we demonstrate a microfluidic-based analysis system based on single cell capture array, which can physically trap individual cell using micrometer-sized structures. A stable and in vivo-like microenvironment was built with the novel structure at the single-cell detection level. The microfluidic-based design can decouple single cells from fluid flow with the help of micropillars. The size and geometry of the cell jails are designed in order to discriminate between mother and daughter cells. It provides an experimental platform to efficiently monitor individual cell state for a long period of time. Furthermore, the parallel microfluidic array can ensure accuracy. In addition, finite element method (FEM) was employed to predict fluid transport properties for the most optimal fluid microenvironment.

Abstract: AIM: To study the preparation and characterization of the Mn_0.5Zn_0.5Fe₂O₄ (MZF) magnetic nanoparticles and the antitumor function of MZF nanomagnetic fluid hyperthermia (NMFH) combined with As₂O₃ on GLC-82 cells.METHODS: The MZF magnetic nanoparticles were prepared by the method of chemical coprecipitation.,which were detected by transmission electron microscopy (TEM) and energy dispersive spectrometry (EDS). In vitro heating test of MZF magnetic fluid in an alternating magnetic field (AMF) was carried out. After that, we studied the therapeutic effects on cultured GLC-82 cells treated by thermochemotherapy of NMFH combined with As₂O₃ at various concentrations (2,5,8μM) were evaluated by MTT assay and flow cytometry assay (FCM).RESULTS: The MZF magnetic nanoparticles were prepared successfully. Their shapes are approximately global and their diameters are about 30 nm. EDS showed MZF magnetic nanoparticle contained Mn, Zn, Fe elements. The corresponding fluid of MZF magnetic nanoparticle could rise to 40~50°C due to different concentration in a AMF and keep stable from then on. MTT assay and FCM revealed that the thermochemotherapy effect of the MZF magnetic nanoparticles combined with As₂O₃ can cause significantly inhibit cellular growth observed by MTT test assay and obviously induce cellular apoptosis by FCM detecting (p<0.05). The apoptotic indexes of GLC-82 cells of the pure As₂O₃ group,pure MZF magnetic nanoparticles hyperthermia group and thermochemotherapy of NMFH combined with As₂O₃ group were 4.98%,16.30%,22.53%,respectively,while the apoptotic index of the negative control group was 0.56%.CONCLUSION: The MZF magnetic nanoparticles successfully were prepared through improved co-precipitation process and have good power absorption capabilities in the high frequency AMF, then they can rise to a steady temperature. MZF magnetic nanoparticles have hyperthermia effects on tumor and their antitumor effect significantly increase when combined with As₂O₃.