Recent Patents on Engineering - Volume 1, Issue 2, 2007

Electrostatic discharge (ESD) protection has been a very important reliability issue in microelectronics, especially for integrated circuits (ICs). ESD protection design for giga-Hz high-speed input/output (I/O) circuits has been one of the key challenges to implement high-speed interface circuits in CMOS technology. Conventional on-chip ESD protection circuits at the I/O pads often cause unacceptable performance degradation to high-speed I/O circuits. Therefore, ESD protection circuits must be designed with minimum negative impact to the high-speed interface circuits and to sustain high enough ESD robustness. In this paper, ESD protection design considerations for high-speed I/O circuits are addressed, and the patents related to on-chip ESD protection designs for high-speed I/O circuits are presented and discussed.

While manual ICSI has been able to accomplish artificial fertilization rather satisfactorily, it has also been associated with several drawbacks inherited from its manual manner of operation. Piezo-assisted ICSI is currently gaining attention and preference because of its ability to perform sperm injection in a precise manner, which has significantly improved the result. A number of piezoactuators for this purpose have been proposed. This paper discusses the publications and patents pertaining to this application, as well as a proposed device to further improve the result.

Heat transfer is one of the most difficult tasks in thermal management of electronic components and directly influences cost, reliability and performances. Heat pipes are efficient heat transfer devices used in many applications, e.g. electronic systems, spacecrafts thermal control, energy collectors, power generation, chemical engineering, air conditioning, engine cooling and others. At normal operating temperatures all heat pipes have heat transfer limits imposed by the capillary transport capabilities in presence of high heat fluxes. Typical wick or capillary structures and common working fluids show advantages in some aspects and disadvantages in others. After a general introduction and a short description of the history of heat pipes developments, an overview of the current intellectual property environment and market is presented to identify trends for future developments. Then an overview of recent patents related to heat pipes technology is presented, with particular reference to: flat heat pipes, flexible heat pipes, innovative wick structures, phase change materials, innovative working fluids. Concerning flat and flexible heat pipes, a number of patents are shown that are characterized by different geometries and materials and, differently from usual cylindrical heat pipes, are particularly suited for use in microelectronics applications. Patents related to innovative wick structures are shown that are aimed to overcome some limitations associated with usual wick structures (woven mesh or sintered powder). Patented heat pipes architectures are also described that are designed to enlarge the operating temperature range by using appropriate phase change materials. In addition, recent patents are shown that exploit the use of binary mixtures as working fluids to improve the heat pipes efficiency compared to conventional pure working fluids.

Development of differential quadrature related generalized methods, discrete element analysis methods and EDQ based time integration methods has been carried out in the past few years. The related numerical algorithms are summarized and presented. Four discrete analysis techniques related patents are also reviewed. Some engineering problems are solved using the developed DQ related discrete analysis methods. Numerical results are also presented. They prove the effectiveness of the developed algorithms.

Today's papermakers face the ever-increasing challenge of producing good quality paper while keeping prices low. This is achieved by using cheaper raw materials such as mechanical pulps and mineral fillers. To increase productivity, machine speeds have also increased. To meet these challenges, it is crucial that the papermakers are able to effectively retain mineral fillers and fiber fines while simultaneously improving dewatering rate. Microparticle retention aid systems, typically utilizing anionic colloidal silica and/or clay-based particles in combination with cationic polymers, have been developed to help deal with these challenges. Generally, microparticle retention aid systems have shown better retention and dewatering performance compared to the classical single or dual polymer retention aid systems. In the past decade, many variations of the microparticle system have been developed to further improve its performance. With respect to the silica-based particles, these include modifications to their physical and chemical structures. In the case of the clay-based particles, various methods have been devised to keep the suspension dispersed, either by mixing the clay-based particles with silica-based particles or synthetic metal silicates. Cationic microparticle systems are also available. Examples include cationic bentonite and fibrous alumina, which are used in combination with cationic or non-ionic polymers. A patent literature search on microparticle retention systems was conducted. It covered the period from 1990 to 2005. The various inventions are described in this paper.

Mutual coupling is a common problem in the applications of antenna arrays. It significantly affects the operation of almost all types of antenna arrays. Over the past years, there have been many different kinds of methods suggested to decouple (or to compensate for) the mutual coupling effect in antenna arrays. The effectiveness of these methods varied and depended upon the types of antenna arrays being considered and the applications in which the antenna arrays were used. In this paper, a brief review of the decoupling methods for the mutual coupling effect in antenna arrays is presented. These include patented and non-patented methods. The methods are grouped under seven categories for antenna arrays in communications and four categories for antenna arrays in magnetic resonance imaging (MRI). The various methods will be first briefly described and their operation principles will be explained. Then some comments on their scopes of application and their comparisons or relations to other methods will be given. The problems associated with these methods will also be analysed. This is the first review on this topic and we believe that it helps to give an overview of the decoupling methods which have been so far proposed in the literature. We also believe that this review will help clarify some main differences and relations between the various decoupling methods and provide some information for future research on the problem of mutual coupling.

Design phase, the front-end of a development process, is known to have the highest impact on the lifecycle cost of products. Presumably, it is considered necessary for product developers to legally protect the product design technologies that they have invented. This paper categorically reviews a group of selected patents, which were filed in the last twenty years, in this area of concerns. From the structural review, several patterns and trends were identified. The product development pipelines in corporations have visibly undergone technological revolution during the last two decades. Notably, design methodologies and product data management techniques were the prominent classes of patents observed. Furthermore, this work has revealed the recent focuses of the industry in the areas of collaborative design and environmental-friendly design.

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