A portable and low-cost design of parallel-plate capacitor sensor is proposed and investigated for detection of heavy and alkali metal ions concentration in liquid solution.The application of a thin and long-sided par...A portable and low-cost design of parallel-plate capacitor sensor is proposed and investigated for detection of heavy and alkali metal ions concentration in liquid solution.The application of a thin and long-sided parallel PCB plate allows one to measure the dielectric response of each sample through capacitive sensing technique.The measurements were based on the peak output voltage corresponding to the capacitance of the output measured by an oscilloscope with metal ions concentration of the solution varying from 0 to 10 ppm and input frequency ranging from 1 kHz to 10 MHz.The ICF of Li,Na and K in chloride solution was 2.4,2.1 and 1.9 MHz,respectively.The ICF of Na and K in hydroxide solution was 1.5 MHz and 1.1 MHz,respectively,while the ICF of Pb(NO_(3))_(2)was 490 kHz.The detected ICF was applied to further construct the portable sensor system,which is simple in design,low-cost in fabrication and easy to operate.The finding of ICF of each chemical element is necessary to solve the selectivity challenge of the capacitance-based sensor,which will be appropriate for chemical,environmental and engineering applications.展开更多
The Cl2-sensitive heteropolysiloxanes(HPS) film was formed on the interdigital capacitor based on silicon dioxide by means of sol-gel process and spin-on technique.Measurements of interdigital capacitance were perform...The Cl2-sensitive heteropolysiloxanes(HPS) film was formed on the interdigital capacitor based on silicon dioxide by means of sol-gel process and spin-on technique.Measurements of interdigital capacitance were performed at room temperature for frequencies 100 Hz,1 kHz and 10 kHz.It is shown that there is a linear relationship between the capacitance and the concentration of chlorine gas.Influences of the measurement frequency and film thickness of silicate on the sensitivity of the sensor to C12 gas were discussed.And organically modified N,N-diethylaminopropyl-trimethoxysilane (APMS) had a much higher sensitivity.展开更多
A low cost of die area and power consumption CMOS image sensor readout circuit with fixed pattern noise(FPN) cancellation is proposed.By using only one coupling capacitor and switch in the double FPN cancelling correl...A low cost of die area and power consumption CMOS image sensor readout circuit with fixed pattern noise(FPN) cancellation is proposed.By using only one coupling capacitor and switch in the double FPN cancelling correlative double sampling(CDS),pixel FPN is cancelled and column FPN is stored and eliminated by the sampleand-hold operation of digitally programmable gain amplifier(DPGA).The bandwidth balance technology based on operational amplifier(op-amp) sharing is also introduced to decrease the power dissipation of traditional multi-stage switched capacitor DPGA.The circuit is designed and simulated using 1P6M 0.18 μm 1.8 V/3.3 V process.Simulation results indicate that the proposed CDS scheme can achieve an FPN of less than 1 mV.The total sampling capacitor per column is 0.9 pF and no column-wise power is dissipated.The die area and FPN value are cut by 70% and 41% respectively compared with amplifier-based CDS.The op-amp sharing gain stage can achieve a 12-bit precision and also implement an 8-bit gain controlling within a gain range of 24 dB.Its power consumption is 1.4 mW,which is reduced by 57% compared with traditional schemes.The proposed readout circuit is suitable for the application of low power cost-sensitive imaging systems.展开更多
文摘A portable and low-cost design of parallel-plate capacitor sensor is proposed and investigated for detection of heavy and alkali metal ions concentration in liquid solution.The application of a thin and long-sided parallel PCB plate allows one to measure the dielectric response of each sample through capacitive sensing technique.The measurements were based on the peak output voltage corresponding to the capacitance of the output measured by an oscilloscope with metal ions concentration of the solution varying from 0 to 10 ppm and input frequency ranging from 1 kHz to 10 MHz.The ICF of Li,Na and K in chloride solution was 2.4,2.1 and 1.9 MHz,respectively.The ICF of Na and K in hydroxide solution was 1.5 MHz and 1.1 MHz,respectively,while the ICF of Pb(NO_(3))_(2)was 490 kHz.The detected ICF was applied to further construct the portable sensor system,which is simple in design,low-cost in fabrication and easy to operate.The finding of ICF of each chemical element is necessary to solve the selectivity challenge of the capacitance-based sensor,which will be appropriate for chemical,environmental and engineering applications.
文摘The Cl2-sensitive heteropolysiloxanes(HPS) film was formed on the interdigital capacitor based on silicon dioxide by means of sol-gel process and spin-on technique.Measurements of interdigital capacitance were performed at room temperature for frequencies 100 Hz,1 kHz and 10 kHz.It is shown that there is a linear relationship between the capacitance and the concentration of chlorine gas.Influences of the measurement frequency and film thickness of silicate on the sensitivity of the sensor to C12 gas were discussed.And organically modified N,N-diethylaminopropyl-trimethoxysilane (APMS) had a much higher sensitivity.
基金Supported by National Natural Science Foundation of China (No.60806010,No.60976030)Tianjin Innovation Special Funds for Science and Technology (No.05FZZDGX00200)
文摘A low cost of die area and power consumption CMOS image sensor readout circuit with fixed pattern noise(FPN) cancellation is proposed.By using only one coupling capacitor and switch in the double FPN cancelling correlative double sampling(CDS),pixel FPN is cancelled and column FPN is stored and eliminated by the sampleand-hold operation of digitally programmable gain amplifier(DPGA).The bandwidth balance technology based on operational amplifier(op-amp) sharing is also introduced to decrease the power dissipation of traditional multi-stage switched capacitor DPGA.The circuit is designed and simulated using 1P6M 0.18 μm 1.8 V/3.3 V process.Simulation results indicate that the proposed CDS scheme can achieve an FPN of less than 1 mV.The total sampling capacitor per column is 0.9 pF and no column-wise power is dissipated.The die area and FPN value are cut by 70% and 41% respectively compared with amplifier-based CDS.The op-amp sharing gain stage can achieve a 12-bit precision and also implement an 8-bit gain controlling within a gain range of 24 dB.Its power consumption is 1.4 mW,which is reduced by 57% compared with traditional schemes.The proposed readout circuit is suitable for the application of low power cost-sensitive imaging systems.
