Browsing by Author "Chang, JH"

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An energy aware, cluster-based routing algorithm for wireless sensor networks
(2005)
Chang, JH
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Jan, RH
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資訊工程學系
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Department of Computer Science
Cluster-based routing protocol has special advantages to enhance scalability and efficiency of the routing protocol. The technique to network clustering that maximizes the network lifetime is an important topic of research in wireless sensor networks. In this paper, we present all energy aware cluster-based routing algorithm (ECRA) for the wireless sensor networks such that the network lifetime can be maximized. ECRA randomly selects some nodes as cluster-heads to construct Voronoi diagram and rotates the intra-cluster nodes to distribute the energy load to all sensors in the network. The simulations show that ECRA algorithm outperforms than direct communication, static clustering and LEACH. The system lifetime of ECRA is approximately 2 times than LEACH. This is because the ECRA rotates intra-cluster-heads to balance the load to all nodes in the sensor networks.
Temperature cycling effects between Sn/Pb solder and electroless copper plated AIN substrate
(1995-12-01)
Chiou, BS
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Chang, JH
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Duh, JG
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
Thermal cycling effects on Sn/Pb solder and electroless Cu-plated AIN substrates are investigated. X-ray diffraction patterns reveal the existence of Cu2O for the electroless Cu-plated AIN after thermal cycling in an environmental chamber. Moisture in the chamber results in the oxidation of electroless plated Cu and fracture takes place at the Cu2O/Cu interface. The oxidation of Cu is also confirmed by Auger depth profile and electrical sheet resistance measurement. For the solder/Cu/AIN system, fracture occurs at the Cu/solder interface. No intermetallic compounds between solder and Cu are found after thermal cycling. Stress resulting from the thermal expansion mismatch is the major cause of loss of adhesion.
The annealing behavior of copper deposit electroplated in sulfuric acid bath with various concentrations of thiourea
(2004-09-25)
Kao, YL
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Tu, GC
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Huang, CA
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Chang, JH
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材料科學與工程學系
The annealing behavior of electroplated copper deposits is reported in this study. The copper deposits were electroplated with a current density of 0.7 A/cm(2) at 53 degreesC in a sulfuric acid bath containing various concentrations of thiourea. The hardness values of the copper deposits were measured before and after annealing, and the differential scanning calorimetry (DSC) diagrams of the as-electroplated copper deposits were recorded. An improvement of the softening resistance of the copper deposits was observed when the bath contained thiourea greater than or equal to3 mg/L. By adding thiourea in the plating bath, smaller grain size of the copper deposits can be achieved. As thiourea content increased greater than or equal to3 mg/L, the twin boundary of the copper deposits was significantly increased, and many sulfur-rich particles were deposited along the grain boundaries and a few within the grains of the deposit. These sulfur-rich particles are capable of impeding migration of the grain boundaries and improving the softening resistance of the copper deposits during annealing. The aforementioned microstructures of the copper deposits were examined with transmission electron microscope (TEM) integrated with energy-dispersive X-ray spectrometer (EDX) for chemical composition analysis. (C) 2004 Elsevier B.V. All rights reserved.