基于VERICUT平台的五轴微加工系统数控加工程序仿真

为验证由针对自主研制的五轴微加工系统编写的数控加工程序后置处理模块生成的数控加工程序的正确性,本文分析了自主研制的五轴微加工系统的运动结构,得出了五轴微加工系统的各进给轴间的拓扑关系,通过VERICUT虚拟加工仿真平台建立了五轴微加工系统的加工仿真模型。以一典型椭球面结构的零件为例,在微加工系统的加工仿真模型中对其加工过程进行了仿真,仿真结果验证了数控加程序以及坐标转换关系的正确性。

Fabrication and Simulation of an Electromagnetic Microrelay

The fabrication and simulation of an electromagnetic microrelay are presented based on micro electromechanical systems (MEMS) technique.The microrelay dimensions of about 4mm×4mm×0 5mm are fabricated with the common technique of micromachining.Compared with the traditional relays,a planar coil is substituted for a solenoid coil to favor the MEMS fabrication.Moreover,a bi supporter cantilever beam with high sensitivity is fabricated to act as the movable electrode of the microrelay.Theoretical calculations and simulations are also carried out with respect to the electromagnetic force yielded by the exciting electromagnetic coil.The structure and parameters concerning the electromagnetic microrelay can be optimized using the results.

Enabling electrically tunable radio frequency components with advanced microfabrication and thin film techniques

Multi-function,multiband,cost-effective,miniaturized reconfigurable radio frequency(RF)components are highly demanded in modern and future wireless communication systems.This paper discusses the needs and implementation of multiband reconfigurable RF components with microfabrication techniques and advanced materials.RF applications of fabrication methods such as surface and bulk micromachining techniques are reviewed,especially on the development of RF microelectromechanical systems(MEMS)and other tunable components.Works on the application of ferroelectric and ferromagnetic materials are investigated,which enables RF components with continuous tunability,reduced size,and enhanced performance.Methods and strategies with nano-patterning to improve high frequency characteristics of ferromagnetic thin film(e.g.,ferromagnetic resonance frequency and losses)and their applications on the development of fully electrically tunable RF components are fully demonstrated.

Fabrication of THz Dipole Antenna Using Lift-off Method

The microfabrication technique for THz dipole antenna,"lift-off" was studied in this paper.Its procedure has been examined in detail,and discreetly tweaked.Particularly,Chlorobenzene is suggested to assist the formation of undercut indispensible for fulfilling "lift-off".The experimental results of fabricated antennas confirm the effectiveness of this method.

提高灌封机速率和灌封质量的攻关及验证

目的 提高灌封机速率和灌封质量以达到高产高质的效果。 方法 通过改变电机转速提高灌封机速率来增产增效 ,以加微氧技术和改造汽化炉系统工艺管道的方法来提高成品率及产品质量。结果 产量翻一番 ,封口质量明显改善 ,减轻操作工劳动强度。结论 提高电机转速 ,采用直径 ,1.5 mm的微管输氧并将汽化气压力控制在 0 .1MPa、氧气压力控制在 0 .2 MPa。

Direct writing of graphene patterns and devices on graphene oxide films by inkjet reduction

Direct writing of graphene patterns and devices may significantly facilitate the application of graphene-based flexible electronics. In terms of scalability and cost efficiency, inkjet printing is very competitive over other existing direct- writing methods. However, it has been challenging to obtain highly stable and clog-free graphene-based ink. Here, we report an alternative and highly efficient technique to directly print a reducing reagent on graphene oxide film to form conductive graphene patterns. By this ＂inkjet reduction＂ method, without using any other microfabrication technique, conductive graphene patterns and devices for various applications are obtained. The ionic nature of the reductant ink makes it clog-free and stable for continuous and large-area printing. The method shows self-limited reduction feature, which enables electrical conductivity of graphene patterns to be tuned within 5 orders of magnitude, reaching as high as 8,000 S.m-1. Furthermore, this method can be extended to produce noble metal/graphene composite patterns. The devices, including transistors, biosensors, and surface- enhanced Raman scattering substrates, demonstrate excellent functionalities. This work provides a new strategy to prepare large-area graphene-based devices that is low-cost and highly efficient, promising to advance research on graphene- based flexible electronics.

Investigating design principles of micropatterned encapsulation systems containing high-density microtissue arrays

Immunoisolation is an important strategy to protect transplanted cells from rejection by the host immune system.Recently,microfabrication techniques have been used to create hydrogel membranes to encapsulate microtissue in an arrayed organization.The method illustrates a new macroencapsulation paradigm that may allow transplantation of a large number of cells with microscale spatial control,while maintaining an encapsulation device that is easily maneuverable and remaining integrated following transplantation.This study aims to investigate the design principles that relate to the translational application of micropatterned encapsulation membranes,namely,the control over the transplantation density/quantity of arrayed microtissues and the fidelity of pre-formed microtissues to micropatterns.Agarose hydrogel membranes with microwell patterns were used as a model encapsulation system to exemplify these principles.Our results show that high-density micropatterns can be generated in hydrogel membranes,which can potentially maximize the percentage volume of cellular content and thereby the transplantation efficiency of the encapsulation device.Direct seeding of microtissues demonstrates that microwell structures can efficiently position and organize pre-formed microtissues,suggesting the capability of micropatterned devices for manipulation of cellular transplants at multicellular or tissue levels.Detailed theoretical analysis was performed to provide insights into the relationship between micropatterns and the transplantation capacity of membrane-based encapsulation.Our study lays the ground for developing new macroencapsulation systems with microscale cellular/tissue patterns for regenerative transplantation.

A preliminary experimental validation of superposition strategy in thermal management of integrated circuit with multiple hot-spots

Thermal management is a key issue in the integrated circuit(IC)design.In this paper,the superposition strategy was experimentally validated using a modeling IC device,which was fabricated by laboratory-level microfabrication technique.Metal thin film resistors on the top of dielectric layer were used to analogize the multiple hot-spots in the modeling IC device.The measured temperature rise with multiple hot-spots agrees well with the predictions given by the superposition calculations.With the help of the superposition strategy,thermal management of IC device can be significantly simplified by decomposing the system into sub-systems and optimizing each part individually.The influence coefficients in the superposition strategy extracted from the experimental measurement offer the IC designers a useful engineering tool to facility the thermal optimization and evaluate the thermal performance of IC devices.