Showing papers by "Bei Peng published in 2015"

Modeling Nanoparticle Targeting to a Vascular Surface in Shear Flow Through Diffusive Particle Dynamics

Abstract: Nanoparticles are regarded as promising carriers for targeted drug delivery and imaging probes. A fundamental understanding of the dynamics of polymeric nanoparticle targeting to receptor-coated vascular surfaces is therefore of great importance to enhance the design of nanoparticles toward improving binding ability. Although the effects of particle size and shear flow on the binding of nanoparticles to a vessel wall have been studied at the particulate level, a computational model to investigate the details of the binding process at the molecular level has not been developed. In this research, dissipative particle dynamics simulations are used to study nanoparticles with diameters of several nanometers binding to receptors on vascular surfaces under shear flow. Interestingly, shear flow velocities ranging from 0 to 2000 s−1 had no effect on the attachment process of nanoparticles very close to the capillary wall. Increased binding energy between the ligands and wall caused a corresponding linear increase in bonding ability. Our simulations also indicated that larger nanoparticles and those of rod shape with a higher aspect ratio have better binding ability than those of smaller size or rounder shape.

Testing, measurement, and characterization of nanomaterials

Abstract: 1School of Mechatronics Engineering, University of Electronic Science and Technology of China, Chengdu, Sichuan 611731, China 2Department of Mechanical Engineering, Binghamton University, State University of New York (SUNY), Binghamton, NY 13902-6000, USA 3Department of Mechanical Engineering and Mechanics, Lehigh University, PA 18015, USA 4Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695-7910, USA

The Influence of Die-Attach Adhesives on the Packaging of MEMS Accelerometer

Abstract: The attachment of the micromechanical silicon die to the substrate is one of the most critical steps in the packaging of highly accurate MEMS (microelectro-mechanical systems) accelerometer. The stress and strains, induced during die-attach process because of TCE (thermal coefficient of expansion) mismatches between different materials, will adversely affect the output characteristics of the accelerometer sensor. In this paper, three different materials: OE138, DG-3S and H70E are selected as the die-attach adhesives of a MEMS comb capacitive accelerometer. The stress and deformation of the silicon die, after the accelerometer model is cured from 80 °C to 20 °C, are evaluated with the aid of finite element analysis (FEA). As the results show, Young’s modulus and the thickness of the adhesives are the most significant factors influencing the stress and deformation of the silicon die. Soft adhesive material (OE138) have better stress absorption, and the stress and deformation of the silicon die decrease with the increasing thickness of the adhesive. Consequently, a soft and thick adhesive is recommended for the die-attach packaging of MEMS accelerometer.

The Research on MEMS Micro Capacitance Sensor Detection Based on MS3110

Abstract: A universal capacitive readout integrated circuit MS3110 is used to measure capacitances in micro capacitance sensor. The configuration, operating principle and process of MS3110 are introduced and a method of programming the inner register on-chip with STM32 is presented with the control block diagram. Performance of MS3110 has been tested by the inner adjust capacitance. A comb micro accelerometer is designed and manufactured. A tentative equivalent electric model of accelerometer is built according to a series of capacitance tests, and the influence of parasitic capacitance in accelerometer system is discussed.

A Mass Loss Penetration Model to Investigate the Dynamic Response of a Projectile Penetrating Concrete considering Mass Abrasion

Abstract: A study on the dynamic response of a projectile penetrating concrete is conducted. The evolutional process of projectile mass loss and the effect of mass loss on penetration resistance are investigated using theoretical methods. A projectile penetration model considering projectile mass loss is established in three stages, namely, cratering phase, mass loss penetration phase, and remainder rigid projectile penetration phase.

Design of Minimal Capacitance Detect Circuit for MEMS Capacitive Sensor

Abstract: The capacitance among the structure of the accelerometer is rather small, usually at sub-pF level. Detection of the capacitance among the sensor’s tiny structure and analysis of the variation of these capacitances are necessary to improve the sensor’s performance. In this paper, one capacitance detect circuit for minimal capacitance is designed. Simulation and experiment results indicate a good linearity when the circuit is applied to detect capacitance range from 0.5pF to 5pF.