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With continuous concerning on the toxic of element Pb, Pb-free solder was gradually used to replace traditional Sn-Pb solder. However, during the transition period from Sn-Pb to Pb-free solder, mixing of Sn-Pb and Pb-free is inevitable occurred in certain products, and in China where Sn-Pb solder was still used extensively in certain areas especially. Correspondingly, understanding reliability of Sn-Pb solder joints was very important, and further studies were needed.

Thermal shock test between −55°C and 125 °C was conducted on Sn-37Pb solder bumps in the BGA package to investigate the microstructure evolution and the growth mechanism of interfacial intermetallic compound (IMC) layer. The effects of thermal shock on the mechanical property and fracture behavior of Sn-37Pb solder bumps were discussed.

Pb-rich phase was coarsened and voids were increased at first; Pb-rich phase was refined and voids were decreased secondly with the increase of thermal shock cycles; the shear strength of solder bumps was slightly decreased after thermal shock, but was back up to 73.67MPa at 2,000 cycles; interfacial IMCs of solder bumps was from typical scallop-type into smooth, the composition of IMCs was from Cu₆Sn₅ into Cu₆Sn₅ and Cu₃S_n after thermal shock with 1,500 and 2,000 cycles; 20.0 per cent of solder bumps at 1,500 cycles and 9.5 per cent of solder bumps at 2,000 cycles were failure respectively.

Compared with the board level test method, the impact shear test for the single solder bump is more convenient and economical and is actively pursued by the industries. The shear strength of solder bumps was slightly decreased after thermal shock, but was back up to 73.67 MPa at 2,000 cycles; 20.0 per cent of solder bumps at 1,500 cycles and 9.5 per cent of solder bumps at 2,000 cycles were failure.

The purpose of this paper is to design and measure an H‐plane substrate integrated waveguide (SIW) 72 GHz backfired horn antenna chip. The SIW horn was fabricated on a standard 0.5‐μm GaAs process with substrate thickness of 100 μm.

Planar SIW horn design method with standard GaAs circuit design rule was adopted. The input reflection coefficient and output antenna gain was simulated at the FEM‐based 3D full‐wave EM solver, Ansoft HFSS and measured at the Agilent E8361C Network Analyzer and Cascade 110 GHz probe station.

The measured input −6 dB bandwidth is about 0.9 GHz at a center frequency of 72.39 GHz. The maximum antenna power gain extracted from the path loss at 72.39 GHz is about −3.64 dBi.

Thin substrate exhibits larger capacitance and energy stores rather than radiates. Flat cutting restricts the arc lens design and results in the radiation plane mismatches to the air. Simple taper transition design makes the input bandwidth much narrower. The problems can be further improved by selecting thicker substrate and the multi‐section input CPW GSG pads to microstrip transition.

Unlike the traditional anechoic chamber, the antenna measurement station is exposed to the open space and chip antenna was supported by the FR4 substrate and the metal probing station plate. A fully characterization of the antenna open space environment before the measurement is needed.

An H‐plane SIW 72 GHz horn antenna was designed and studied. The antenna was using the GaAs 0.5‐μm MMICs process design rule includes the SIW designed cylindrical metal bars all being restricted in standard rectangular shape. Compare to traditional bulky waveguide horn antenna, the antenna chip size is only 1.8×1.7 mm². The on‐wafer measurement is conducted to measure the input return loss and the maximum antenna power gain of the on‐chip antenna. The designed on‐chip SIW horn antenna is useful for the integrated design of the E band GaAs MMICs single‐chip RF transceiver.

The purpose of this paper is to introduce a non‐uniform Chebyshev distributed low‐pass filter (LPF) with dumbbell‐shaped photonic bandgap structure (PBGs), implemented in the 50 Ω microstrip line, with improved defected ground structure.

The non‐uniform distribution of PBGs and dumbbell‐shaped DGS of PBGs have been discussed in open literatures. In this study, the influence of FF of PBGs in dumbbell‐shaped PBG is represented.

By varying filling factor (FF) of the periodic structure from 0.25 to 0.8 of the dumbbell squares can generate better rejection band than uniform dumbbell LPF. Different FF of each square can produce different band rejection range and then yields the LPF with different cutoff. By using chirp adjustment of distance between PBGs, the band rejection performance can be optimized.

It can be seen that the chirped and non‐uniform dumbbell‐shaped PBGs generate excellent bandgap performances in linearly varying period (chirped devices) than those of structures with constant period (non‐chirped or uniform devices).

China’s property industry in the past few years has made great progress and it is now vital to improve its management processes. Explains the traditional system of management for urban residential districts (urban living quarters) in China and the professional management pattern now becoming popular in the southern part of China. Comparing these two different management patterns, claims that the professional management pattern will sooner or later be adopted and accepted for all urban residential districts throughout China.

The purpose of this paper is to present the results of a study on heat transfer through a textile assembly consisting of fabric and air layers based on a theoretical model capable of dealing with conductive, convective and radioactive heat transfer.

Quantificational results were given out by the aid of finite element (FE) analysis software MSC MARC Mentat.

Significant findings through this paper include the change in heat flux against time and the transit temperature distribution at the cross‐section of the fabric assembly. The size of the air gaps has a significant influence on the heat transfer. The balance heat flux drops by 40 per cent when the air gap increases from 2 to 10 mm. The influence of the air gap tends to become smaller as the air gap is further increased. The number of fabric layers in the textile assembly has a noted influence, more so when the ambient temperature is lower. Comparisons between the theoretical and tested results show a good agreement.

This paper has established a new method for clothing comfort study by making use of a general purpose FE method software package.

The purpose of this paper is to understand the recovery mechanism of poly(trimethylene terephthalate) (PTT) shape memory fabrics.

Tests were designed to study the effects of force, temperature and their combinations on the fabrics' crease recoveries. In the test a cantilever device and an ironing force which simulated people ironing their clothes were used, respectively.

Temperature was found to have little effect on the recovery of both the warp and filling of the fabrics. Crease recoveries did not improve significantly when the temperature was increased to above the polymer's glass transition. However, forces, applied in primarily compressive and tensile modes to simulate ironing and hand stroking actions, were found to be very effective in the fabrics' crease recoveries. Recoveries were 81‐87 per cent even when the applied force was very small, at 5 N/cm². When forces were applied at elevated temperatures, just below and above the polymer's glass transition, there were no significant improvements in crease recoveries. Therefore, force was the main factor in PTT shape memory fabrics' recovery mechanism for the fabrics to return to their initial shapes.

The results suggest that PTT shape memory fabric has excellent shape recoverability and easy care property and it has large application potentiality.

Proposes that traditional Chinese values of leader as head can be useful in that they can promote applying abilities for mutual benefit for leadership and employees. A total of 200 managers working in organizations in Shanghai, China, indicated their traditional leadership values and level of applying abilities for mutual benefit with employees. A total of 200 employees working for these managers indicated their applying abilities with their manager and their manager’s leader effectiveness and their own job commitment. Applying abilities mediates between leader as head and leader effectiveness. Findings help to clarify that traditional Chinese leadership values involve support and relationship building, not necessarily domination and suppression. These results were interpreted as suggesting that Chinese managers and employees could develop effective leader relationships by strengthening their traditional values and orienting them to promoting applying abilities for mutual benefit.

The purpose of this paper is to investigate the extent to which the geographical location of and thus the geographical distance between buyer and supplier impact on the efficacy of purchasing practices (i.e. strategic purchasing management, tactical purchasing management, relational purchasing management) in terms of operational performance.

The authors utilise cross-country data collected through the International Purchasing Survey group across a variety of countries and industry sectors. The authors conduct exploratory factor analysis to assess construct validity and regression analysis to test the varying effects of purchasing practices on operational performance. The authors split the sample to compare potential differences in the efficacy of purchasing practices between buyers and suppliers through geographical characteristics.

The results indicate that the efficacy of purchasing practices does indeed vary depending on differences in geographical location. Specifically, the authors identify that in cases where the buyer and supplier are located in the same country tactical and relational purchasing tools have a positive impact on operational performance. However, in cases where they are situated in different countries none of the purchasing tools seems to significantly improve operational performance.

Research that has taken a cross-country perspective on the efficacy of supply chain practices is surprisingly sparse. Since most supply chains are becoming more and more global it is important to consider the geographical location of the supply chain members when assessing the performance benefits of supply chain practices such as purchasing tools. Thus, the authors introduce and test the concept of geographical distance on the efficacy of purchasing practices at the dyadic level. To test the implications of geographical distance for purchasing practices the authors use a large-scale cross-country survey.

Rotational speed and load-carrying capacity are two mutual coupling factors which affect high precision and stable operation of a hydrostatic thrust bearing. The purpose of this paper is to study reasonable matching relationship between the rotational speed and the load-carrying capacity.

A mathematical model of relationship between the rotational speed and the load-carrying capacity of the hydrostatic bearing with double-rectangle recess is set up on the basis of the tribology theory and the lubrication theory, and the load and rotational speed characteristics of an oil film temperature field and a pressure field in the hydrostatic bearing are analyzed, reasonable matching relationship between the rotational speed and the load-carrying capacity is deduced and a verification experiment is conducted.

By increasing the rotational speed, the oil film temperature increases, the average pressure decreases and the load-carrying capacity decreases. By increasing the load-carrying capacity, the oil film temperature and the average pressure increases and the rotational speed decreases; corresponding certain reasonable matching values are available.

The load-carrying capacity can be increased and the rotational speed improved by means of reducing the friction area of the oil recess by using low-viscosity lubricating oil and adding more oil film clearance; but, the stiffness of the hydrostatic bearing decreases.

The purpose of this paper is to conduct a survey on research in fabric and cloth simulation using mass spring model. Also in this paper some of the common methods in process of fabric simulation in mass spring model are discussed and compared.

This paper reviews and compares presented mesh types in mass spring model, forces applied on model, super elastic effect and ways to settle the super elasticity problem, numerical integration methods for solving equations, collision detection and its response. Some of common methods in fabric simulation are compared to each other. And by using examples of fabric simulation, advantages and limitations of each technique are mentioned.

Mass spring method is a fast and flexible technique with high ability to simulate fabric behavior in real time with different environmental conditions. Mass spring model has more accuracy than geometrical models and also it is faster than other physical modeling.

In the edge of digital, fabric simulation technology has been considered into many fields. 3D fabric simulation is complex and its implementation requires knowledge in different fields such as textile engineering, computer engineering and mechanical engineering. Several methods have been presented for fabric simulation such as physical and geometrical models. Mass spring model, the typical physically based method, is one of the methods for fabric simulation which widely considered by researchers.