The characteristics of electrokinetic flow in a microchannel depend on both the nature of the surface potential, i.e. whether it is uniform or nonuniform, and the electric potential distribution along the channel. In this paper, the nonlinear Poisson-Boltzmann equation is used to model the electrical double layer and the Lattice Boltzmann Model coupled with the constraint of current continuity is used to simulate the flow field in a rectangular microchannel with step change surface potential. The results show that step change ion distribution caused by step change surface potential will influence significantly the electric potential distribution along the channel, the velocity profiles and the volumetric flow rate. This may indicate that if disturbance on the ion distribution due to nonuniform surface potential and velocity distortion is large and not negligible, the electric potential distribution along the channel in both pressure-driven and electroosmotic flow may not be linear.
{"title":"Lattice Boltzmann Simulation of Microfluidics with Non-uniform Zeta Potentials: Requirements of Flow Rate and Current Continuities","authors":"F. Tian, Baoming Li, D. Kwok","doi":"10.1109/ICMENS.2004.85","DOIUrl":"https://doi.org/10.1109/ICMENS.2004.85","url":null,"abstract":"The characteristics of electrokinetic flow in a microchannel depend on both the nature of the surface potential, i.e. whether it is uniform or nonuniform, and the electric potential distribution along the channel. In this paper, the nonlinear Poisson-Boltzmann equation is used to model the electrical double layer and the Lattice Boltzmann Model coupled with the constraint of current continuity is used to simulate the flow field in a rectangular microchannel with step change surface potential. The results show that step change ion distribution caused by step change surface potential will influence significantly the electric potential distribution along the channel, the velocity profiles and the volumetric flow rate. This may indicate that if disturbance on the ion distribution due to nonuniform surface potential and velocity distortion is large and not negligible, the electric potential distribution along the channel in both pressure-driven and electroosmotic flow may not be linear.","PeriodicalId":344661,"journal":{"name":"2004 International Conference on MEMS, NANO and Smart Systems (ICMENS'04)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116715221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We have studied the influence of π-coupling on electronic and structural properties of self-assembled 1,4-dithiol benzene (HSC₆H₄SH) molecule with the first principle DFT-KS method. The isolated molecule shows well defined electronic properties, which drastically change once the molecule is packed into a dense 1-D molecular wire. The HOMO-LUMO gap for a dimer decreases by 1.2 eV when intermolecular distance changes from 6.9 to 3.3 Å, while it sharply decreases by 2.2 eV for a wire containing seven (7) molecular units. It is found that intermolecular distances between molecular units, as well as the number of molecules in the molecular wire are the two main correlated factors that influence the magnitude of the changes. In fact, the two parameters that influence the electronic structure properties of the wires are clearly related to magnitude of π-electron interaction in the vicinity of the HOMO-LUMO gap region.
{"title":"The Effect of π-Coupling on the Electronic Properties of 1,4-Dithiol Benzene Stacking","authors":"M. Layachi, Y. Savaria, A. Rochefort","doi":"10.1109/ICMENS.2004.141","DOIUrl":"https://doi.org/10.1109/ICMENS.2004.141","url":null,"abstract":"We have studied the influence of π-coupling on electronic and structural properties of self-assembled 1,4-dithiol benzene (HSC₆H₄SH) molecule with the first principle DFT-KS method. The isolated molecule shows well defined electronic properties, which drastically change once the molecule is packed into a dense 1-D molecular wire. The HOMO-LUMO gap for a dimer decreases by 1.2 eV when intermolecular distance changes from 6.9 to 3.3 Å, while it sharply decreases by 2.2 eV for a wire containing seven (7) molecular units. It is found that intermolecular distances between molecular units, as well as the number of molecules in the molecular wire are the two main correlated factors that influence the magnitude of the changes. In fact, the two parameters that influence the electronic structure properties of the wires are clearly related to magnitude of π-electron interaction in the vicinity of the HOMO-LUMO gap region.","PeriodicalId":344661,"journal":{"name":"2004 International Conference on MEMS, NANO and Smart Systems (ICMENS'04)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125104444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents a new design of a closed-loop sigma-delta accelerometer using an acceleration prediction feedback element. Thanks to a Kalman state estimator associated with a Linear-Quadratic-Gaussian (LQG) controller, the proof mass is maintained near its position of equilibrium. Consequently, operating on the relatively small proof mass displacement makes it possible to enhance the performance of the sigma-delta converter. This architecture shows an increase of more than 20 dB in signal quantization noise ratio compared to conventional sigma-delta accelerometers and has the advantage of being a completely digital solution.
{"title":"Resolution Enhancement of a Sigma-Delta Micro-Accelerometer Using Signal Prediction","authors":"É. Colinet, J. Juillard, S. Guessab, R. Kielbasa","doi":"10.1109/ICMENS.2004.127","DOIUrl":"https://doi.org/10.1109/ICMENS.2004.127","url":null,"abstract":"This paper presents a new design of a closed-loop sigma-delta accelerometer using an acceleration prediction feedback element. Thanks to a Kalman state estimator associated with a Linear-Quadratic-Gaussian (LQG) controller, the proof mass is maintained near its position of equilibrium. Consequently, operating on the relatively small proof mass displacement makes it possible to enhance the performance of the sigma-delta converter. This architecture shows an increase of more than 20 dB in signal quantization noise ratio compared to conventional sigma-delta accelerometers and has the advantage of being a completely digital solution.","PeriodicalId":344661,"journal":{"name":"2004 International Conference on MEMS, NANO and Smart Systems (ICMENS'04)","volume":"88 5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122853435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A monolithically packaged SAW (Surface Acoustic Wave) radio transponder and pressure sensor is developed for the application to a TPMS (Tire Pressure Monitoring System). The device contains the wireless transponder, which converts analog signal into digital one without any auxillary electronic circuits and then transmits the converted data wirelessly. No power sources are needed for wireless transponder and pressure sensor. The touch-mode pressure sensor converts externally applied pressure into a capacitance, and the SAW radio transponder radiates sensor values as pulse train to the interrogation (measurement) unit. The realization of the mechanical A/D conversion is possible since the SAW radio transponder has been connected to the touch-mode capacitive pressure sensor. The SAW radio transponder and touch-mode sensor have been fabricated using a surface micromachining and a bulk micromachining technologies, respectively. The performance of the integrated, passive and wireless pressure sensor meets the design specifications such as linearity, sensitivity and noise figure. Finally, experimental results on the radio transponder and sensor without power source are presented.
{"title":"A Monolithically Packaged Cordless Sensor System Embedding MEMS A/D Converter and Saw Transponder","authors":"Jae-Geun Oh, Bumkyoo Choi, Seung-Yop Lee","doi":"10.1109/ICMENS.2004.12","DOIUrl":"https://doi.org/10.1109/ICMENS.2004.12","url":null,"abstract":"A monolithically packaged SAW (Surface Acoustic Wave) radio transponder and pressure sensor is developed for the application to a TPMS (Tire Pressure Monitoring System). The device contains the wireless transponder, which converts analog signal into digital one without any auxillary electronic circuits and then transmits the converted data wirelessly. No power sources are needed for wireless transponder and pressure sensor. The touch-mode pressure sensor converts externally applied pressure into a capacitance, and the SAW radio transponder radiates sensor values as pulse train to the interrogation (measurement) unit. The realization of the mechanical A/D conversion is possible since the SAW radio transponder has been connected to the touch-mode capacitive pressure sensor. The SAW radio transponder and touch-mode sensor have been fabricated using a surface micromachining and a bulk micromachining technologies, respectively. The performance of the integrated, passive and wireless pressure sensor meets the design specifications such as linearity, sensitivity and noise figure. Finally, experimental results on the radio transponder and sensor without power source are presented.","PeriodicalId":344661,"journal":{"name":"2004 International Conference on MEMS, NANO and Smart Systems (ICMENS'04)","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131526221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents a novel Ion Sensitive Field Effect Transistor (ISFET), as a pH sensor, read-out circuit that uses three Operational Floating Current Conveyors (OFCC). This read-out circuit provides a linear sensitivity to pH over a wide range (pH values 2-12). Moreover, it provides an output current that is linearly related to the measured pH. It uses only one type of active element (i.e. OFCC) that makes this circuit easier to be both integrated and fabricated using a conventional CMOS process. Our simulation results demonstrate that the read-out circuit works reliably and can be a suitable sensor read-out circuit for lab on a chip biomedical applications.
{"title":"A Novel pH Sensor Current Mode Read-Out Circuit Using Operational Floating Current Conveyor","authors":"Y. Ghallab, Wael Badawy","doi":"10.1109/ICMENS.2004.16","DOIUrl":"https://doi.org/10.1109/ICMENS.2004.16","url":null,"abstract":"This paper presents a novel Ion Sensitive Field Effect Transistor (ISFET), as a pH sensor, read-out circuit that uses three Operational Floating Current Conveyors (OFCC). This read-out circuit provides a linear sensitivity to pH over a wide range (pH values 2-12). Moreover, it provides an output current that is linearly related to the measured pH. It uses only one type of active element (i.e. OFCC) that makes this circuit easier to be both integrated and fabricated using a conventional CMOS process. Our simulation results demonstrate that the read-out circuit works reliably and can be a suitable sensor read-out circuit for lab on a chip biomedical applications.","PeriodicalId":344661,"journal":{"name":"2004 International Conference on MEMS, NANO and Smart Systems (ICMENS'04)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127775614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In 1978 Marty et al. described for the first time the preparation of gelatin nanoparticles using desalting or desolvating agents. The desolvation process using acetone or other non-solvents works only with very low concentrations of gelatin (0.1%) [1]. By increasing the gelatin concentration in the solution the formation of aggregations during desolvation and cosslinking also dramatically increases. In 1985 the molecular weight of gelatin was described to be between 60000-90000 Da [2]. With improved analytical equipment, the specification of the molecular weight of one of the largest gelatin producers worldwide (DGF Stoess AG, Eberbach, Germany) is today from below 20000 to over 400000 Da. This shows the heterogeneity of gelatin and makes it more understanding why there are many difficulties in the preparation of nanoparticles from this substance.
{"title":"New Biocompatible Nanoparticles Based on Fractionized Gelatin as Drug Delivery Systems for Nucleic Acids and Peptides","authors":"C. Coester","doi":"10.1109/ICMENS.2004.113","DOIUrl":"https://doi.org/10.1109/ICMENS.2004.113","url":null,"abstract":"In 1978 Marty et al. described for the first time the preparation of gelatin nanoparticles using desalting or desolvating agents. The desolvation process using acetone or other non-solvents works only with very low concentrations of gelatin (0.1%) [1]. By increasing the gelatin concentration in the solution the formation of aggregations during desolvation and cosslinking also dramatically increases. In 1985 the molecular weight of gelatin was described to be between 60000-90000 Da [2]. With improved analytical equipment, the specification of the molecular weight of one of the largest gelatin producers worldwide (DGF Stoess AG, Eberbach, Germany) is today from below 20000 to over 400000 Da. This shows the heterogeneity of gelatin and makes it more understanding why there are many difficulties in the preparation of nanoparticles from this substance.","PeriodicalId":344661,"journal":{"name":"2004 International Conference on MEMS, NANO and Smart Systems (ICMENS'04)","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134500581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, we report the fabrication and characterization of electro-chemical actuator using platinum nanowire networks. Reversible strain amplitudes of ~ 0.04% have been observed by controlling the surface electronic charge density of the nanowire network through an applied voltage in an electrolyte solution. Displacement amplitudes of up to 3mm was observed for an applied voltage of only ±3 V, much smaller compared to most commercial piezoceramic materials. These results indicate the potential application of platinum nanowires for construction of artificial muscles and materials with tunable electronic properties.
{"title":"A Platinum Nanowires Actuator: Metallic Nano-Muscles","authors":"Shaoxin Lu, B. Panchapakesan","doi":"10.1109/ICMENS.2004.20","DOIUrl":"https://doi.org/10.1109/ICMENS.2004.20","url":null,"abstract":"In this paper, we report the fabrication and characterization of electro-chemical actuator using platinum nanowire networks. Reversible strain amplitudes of ~ 0.04% have been observed by controlling the surface electronic charge density of the nanowire network through an applied voltage in an electrolyte solution. Displacement amplitudes of up to 3mm was observed for an applied voltage of only ±3 V, much smaller compared to most commercial piezoceramic materials. These results indicate the potential application of platinum nanowires for construction of artificial muscles and materials with tunable electronic properties.","PeriodicalId":344661,"journal":{"name":"2004 International Conference on MEMS, NANO and Smart Systems (ICMENS'04)","volume":"96 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134526760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A miniaturized piezoresistive six-degree of freedom (6DOF) accelerometer has been developed and fabricated using bulk micromachining technology. Most accelerometers developed so far, sense accelerations in only three axial directions. This accelerometer measures three components of linear acceleration and three components of angular acceleration on three orthogonal axes in the frequency bandwidth of 300Hz. The average measured sensitivities of the fabricated sensor for linear accelerations and angular accelerations show a cross-axis sensitivity of <2%. Comparison of the obtained experimental results and finite element simulation shows good agreement. The sensor is ideal for use in biomechanical research applications such as the study of human gesture recognition systems.
{"title":"Design & Fabrication of Piezoresistive Six Degree of Freedom Accelerometer for Biomechanical Applications","authors":"R. Amarasinghe, D. Dao, T. Toriyama, S. Sugiyama","doi":"10.1109/ICMENS.2004.48","DOIUrl":"https://doi.org/10.1109/ICMENS.2004.48","url":null,"abstract":"A miniaturized piezoresistive six-degree of freedom (6DOF) accelerometer has been developed and fabricated using bulk micromachining technology. Most accelerometers developed so far, sense accelerations in only three axial directions. This accelerometer measures three components of linear acceleration and three components of angular acceleration on three orthogonal axes in the frequency bandwidth of 300Hz. The average measured sensitivities of the fabricated sensor for linear accelerations and angular accelerations show a cross-axis sensitivity of <2%. Comparison of the obtained experimental results and finite element simulation shows good agreement. The sensor is ideal for use in biomechanical research applications such as the study of human gesture recognition systems.","PeriodicalId":344661,"journal":{"name":"2004 International Conference on MEMS, NANO and Smart Systems (ICMENS'04)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123167479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A self-organizing "bucket brigade" or charge transportation system is studied. This system serves as a prototype of controlled dynamic self-assembly with applications to micro- and nanoelectromechanical systems (MEMS and NEMS). An experimental system is described and results of several experiments presented. Two theoretical approaches to the analysis of the system are described. A physics-based first-principles model is used to analyze the system in detail. From this, a rules-based model is abstracted from which other self-organizing transportation systems may be designed.
{"title":"A Self-Organizing Bucket Brigade","authors":"J. Pelesko","doi":"10.1109/ICMENS.2004.22","DOIUrl":"https://doi.org/10.1109/ICMENS.2004.22","url":null,"abstract":"A self-organizing \"bucket brigade\" or charge transportation system is studied. This system serves as a prototype of controlled dynamic self-assembly with applications to micro- and nanoelectromechanical systems (MEMS and NEMS). An experimental system is described and results of several experiments presented. Two theoretical approaches to the analysis of the system are described. A physics-based first-principles model is used to analyze the system in detail. From this, a rules-based model is abstracted from which other self-organizing transportation systems may be designed.","PeriodicalId":344661,"journal":{"name":"2004 International Conference on MEMS, NANO and Smart Systems (ICMENS'04)","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134473532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Klaus Zwiorek, Julia Kloeckner, E. Wagner, C. Coester
With the development of the two step desolvation method for the preparation of gelatin nanoparticles, it is possible to reproducibly generate homogeneous colloidal spheres. After the establishment of a surface modification to achieve stable nucleotide loading onto the particles, the goal of this study was to test this new biodegradable and simple producible non-viral gene delivery system in vitro. Two different types of gelatin nanoparticles, referring to size and zeta (ζ) potential were investigated. Therefore, we varied conditions as for example the loaded DNA amount and the conjugation media to find a preferable setup. All preparations were tested on B16F10 murine melanoma cells using pCMVLuc as reporter gene. To evaluate our results, we used commonly known, but non-biodegradable, polyethylenimine (PEI) polyplexes as "gold standard" for in vitro transfection. Additionally, we performed accompanying cell viability assays and hemolysis studies with the preparations tested to substantiate the thesis of low cell toxicity of gelatin nanoparticles. Different setups resulted in efficient gene delivery. The achieved levels of gene expression were good but lower as with optimized PEI polyplexes. Nevertheless, the already achieved results show gelatin nanoparticles as promising biodegradable alternative to existing non-viral gene delivery systems.
{"title":"In Vitro Gene Transfection with Surface-Modified Gelatin Nanoparticles","authors":"Klaus Zwiorek, Julia Kloeckner, E. Wagner, C. Coester","doi":"10.1109/ICMENS.2004.81","DOIUrl":"https://doi.org/10.1109/ICMENS.2004.81","url":null,"abstract":"With the development of the two step desolvation method for the preparation of gelatin nanoparticles, it is possible to reproducibly generate homogeneous colloidal spheres. After the establishment of a surface modification to achieve stable nucleotide loading onto the particles, the goal of this study was to test this new biodegradable and simple producible non-viral gene delivery system in vitro. Two different types of gelatin nanoparticles, referring to size and zeta (ζ) potential were investigated. Therefore, we varied conditions as for example the loaded DNA amount and the conjugation media to find a preferable setup. All preparations were tested on B16F10 murine melanoma cells using pCMVLuc as reporter gene. To evaluate our results, we used commonly known, but non-biodegradable, polyethylenimine (PEI) polyplexes as \"gold standard\" for in vitro transfection. Additionally, we performed accompanying cell viability assays and hemolysis studies with the preparations tested to substantiate the thesis of low cell toxicity of gelatin nanoparticles. Different setups resulted in efficient gene delivery. The achieved levels of gene expression were good but lower as with optimized PEI polyplexes. Nevertheless, the already achieved results show gelatin nanoparticles as promising biodegradable alternative to existing non-viral gene delivery systems.","PeriodicalId":344661,"journal":{"name":"2004 International Conference on MEMS, NANO and Smart Systems (ICMENS'04)","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132104048","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：