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Article
Publication date: 19 September 2018

Hongyan Shi, Xiaoke Lin, Qiuxin Yan and JiaNan Zhang

The purpose of this paper is to study and obtain the influence of resin and filler properties of printed circuit board (PCB) on the drilling force during micro drilling.

Abstract

Purpose

The purpose of this paper is to study and obtain the influence of resin and filler properties of printed circuit board (PCB) on the drilling force during micro drilling.

Design/methodology/approach

Experiments were carried out to study the influence of PCB on micro-hole drilling force under high spindle speed. A drilling force measurement system was applied, and then, the influence of resin and filler properties of PCBs on the force was analyzed. The proportion of resin and filler in the PCB was defined as four levels, and the influence of PCBs based on the drilling force measurement was summarized.

Findings

The drilling force decreased with the decrease in the feed rate, and lower filler (16-30 per cent) and average resin (31-50 per cent) would have a positive impact on the drilling force. At the same time, the size of uniform and fine fillers would help to reduce the drilling force.

Originality/value

The drilling force measurement system was applied, and the influence of PCBs on force was analyzed, which could provide a reference value on the optimization of the drilling force during micro drilling.

Details

Circuit World, vol. 44 no. 4
Type: Research Article
ISSN: 0305-6120

Keywords

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Article
Publication date: 7 August 2017

Hongyan Shi, Xiaoke Lin and Yun Wang

The purposes of this paper are to study the characterization of drill bit breakage in printed circuit board (PCB) drilling process based on high-speed video analysis and…

Abstract

Purpose

The purposes of this paper are to study the characterization of drill bit breakage in printed circuit board (PCB) drilling process based on high-speed video analysis and to provide an important reference for micro drill bit breakage prediction.

Design/methodology/approach

Based on PCB drilling experiment, the high-speed camera was used to observe the micro drill breakage process and the chip removal process. The variation of chip in the drilling process was studied and one of the key reasons for the drill bit breakage was analysed. Finally, the swing angles’ feature during the breakage process of the micro drill was analysed and researched with the image processing tools of MATLAB.

Findings

The micro drill was prone to breakage mainly because of the blocked chips. The breakage process of the micro drill can be divided into the stage of stable chips evacuation, the stage of blocked chips and the stage of drill bit breakage. The radians of swing angles were basically in the range of ±0.01 when the drilling possess is normal. But when the radians of swing angles considerably exceeded the range of ±0.01, the micro drill bit may be fractured.

Originality/value

This paper presented the method to study the characterization of drill bit breakage in the PCB drilling process by using high-speed video analysis technology. Meanwhile, an effective suggestion about monitoring the radians of swing angles to predict the breakage of micro drill bit was also provided.

Details

Circuit World, vol. 43 no. 3
Type: Research Article
ISSN: 0305-6120

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Article
Publication date: 10 May 2018

Hongyan Shi, Xiaoke Lin, Qiuxin Yan and Xiong Liang

The purpose of this paper was to study the influence of properties of printed circuit boards (PCBs) on the temperature during micro drilling and obtain the influential…

Abstract

Purpose

The purpose of this paper was to study the influence of properties of printed circuit boards (PCBs) on the temperature during micro drilling and obtain the influential mechanism of PCBs based on temperature measurement.

Design/methodology/approach

Experiments were carried out to study the influence mechanism of PCB properties on micro hole drilling temperature under high spindle speed. The temperature measurement platform was applied, then the influence of components ratio of PCBs on the temperature of micro-drilling was analyzed by using comparative analysis method. The mass ratio of each kind of material in the PCB was defined as four levels and the influence mechanism of properties of PCBs based on temperature measurement was summarized.

Findings

Average filler and lower resin would have a positive impact on micro hole drilling temperature, and the smaller filler size and the even distribution would make it better.

Originality/value

An infrared temperature measurement platform was applied and influential mechanism of PCB properties on temperature was analyzed, which could provide the reference value on the optimization of temperature during micro drilling.

Details

Circuit World, vol. 44 no. 3
Type: Research Article
ISSN: 0305-6120

Keywords

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Article
Publication date: 2 March 2015

Xiaoke Ku and Rob Hagmeijer

– The purpose of this paper is to create a computationally efficient reduced model (RM) for the moments of droplet size distribution (DSD) in condensing flow.

Abstract

Purpose

The purpose of this paper is to create a computationally efficient reduced model (RM) for the moments of droplet size distribution (DSD) in condensing flow.

Design/methodology/approach

The kinetic equation (KE) exactly describes the time dependence of the DSD and can be regarded as the most rigorous representation of a system with condensation. Because of the typical wide range in droplet size, the KE requires excessive computational time and is not attractive for most practical applications. To reduce the overall computational efforts, a novel set of moment equations, derived from the KE has been proposed.

Findings

To demonstrate the simplicity and accuracy of the model, the authors employ a typical nucleation pulse experiment for which benchmark KE-solutions have also been computed. Comparison of predicted moments from both the RM and the KE approach reveals that the RM is capable of capturing the evolving feature of moments with reasonable accuracy.

Originality/value

The authors have created a novel reduced method for numerical computations of the lower-order moments of the DSD in condensing flow. Unlike the typical method of moments, the RM eliminates the need for assumptions on the shape of the distribution function and could estimate the moments at very low computational cost.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 25 no. 2
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 3 August 2020

Chen Kuilin, Feng Xi, Fu Yingchun, Liu Liang, Feng Wennan, Jiang Minggang, Hu Yi and Tang Xiaoke

The data protection is always a vital problem in the network era. High-speed cryptographic chip is an important part to ensure data security in information interaction…

Abstract

Purpose

The data protection is always a vital problem in the network era. High-speed cryptographic chip is an important part to ensure data security in information interaction. This paper aims to provide a new peripheral component interconnect express (PCIe) encryption card solution with high performance, high integration and low cost.

Design/methodology/approach

This work proposes a System on Chip architecture scheme of high-speed cryptographic chip for PCIe encryption card. It integrated CPU, direct memory access, the national and international cipher algorithm (data encryption standard/3 data encryption standard, Rivest–Shamir–Adleman, HASH, SM1, SM2, SM3, SM4, SM7), PCIe and other communication interfaces with advanced extensible interface-advanced high-performance bus three-level bus architecture.

Findings

This paper presents a high-speed cryptographic chip that integrates several high-speed parallel processing algorithm units. The test results of post-silicon sample shows that the high-speed cryptographic chip can achieve Gbps-level speed. That means only one single chip can fully meet the requirements of cryptographic operation performance for most cryptographic applications.

Practical implications

The typical application in this work is PCIe encryption card. Besides server’s applications, it can also be applied in terminal products such as high-definition video encryption, security gateway, secure routing, cloud terminal devices and industrial real-time monitoring system, which require high performance on data encryption.

Social implications

It can be well applied on many other fields such as power, banking, insurance, transportation and e-commerce.

Originality/value

Compared with the current strategy of high-speed encryption card, which mostly uses hardware field-programmable gate arrays or several low-speed algorithm chips through parallel processing in one printed circuit board, this work has provided a new PCIe encryption card solution with high performance, high integration and low cost only in one chip.

Details

Circuit World, vol. 47 no. 2
Type: Research Article
ISSN: 0305-6120

Keywords

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Article
Publication date: 5 October 2015

Xiaoke Li, Haobo Qiu, Zhenzhong Chen, Liang Gao and Xinyu Shao

Kriging model has been widely adopted to reduce the high computational costs of simulations in Reliability-based design optimization (RBDO). To construct the Kriging model…

Abstract

Purpose

Kriging model has been widely adopted to reduce the high computational costs of simulations in Reliability-based design optimization (RBDO). To construct the Kriging model accurately and efficiently in the region of significance, a local sampling method with variable radius (LSVR) is proposed. The paper aims to discuss these issues.

Design/methodology/approach

In LSVR, the sequential sampling points are mainly selected within the local region around the current design point. The size of the local region is adaptively defined according to the target reliability and the nonlinearity of the probabilistic constraint. Every probabilistic constraint has its own local region instead of all constraints sharing one local region. In the local sampling region, the points located on the constraint boundary and the points with high uncertainty are considered simultaneously.

Findings

The computational capability of the proposed method is demonstrated using two mathematical problems, a reducer design and a box girder design of a super heavy machine tool. The comparison results show that the proposed method is very efficient and accurate.

Originality/value

The main contribution of this paper lies in: a new local sampling region computational criterion is proposed for Kriging. The originality of this paper is using expected feasible function (EFF) criterion and the shortest distance to the existing sample points instead of the other types of sequential sampling criterion to deal with the low efficiency problem.

Details

Engineering Computations, vol. 32 no. 7
Type: Research Article
ISSN: 0264-4401

Keywords

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Article
Publication date: 11 October 2018

Xu Han, Zhonghe Han, Wei Zeng, Peng Li and Jiangbo Qian

The purpose of this paper is to study the condensation flow of wet steam in the last stage of a steam turbine and to obtain the distribution of condensation parameters…

Abstract

Purpose

The purpose of this paper is to study the condensation flow of wet steam in the last stage of a steam turbine and to obtain the distribution of condensation parameters such as nucleation rate, Mach number and wetness.

Design/methodology/approach

Because of the sensitivity of the condensation parameter distribution, a double fluid numerical model and a realizable k-ε-kd turbulence model were applied in this study, and the numerical solution for the non-equilibrium condensation flow is provided.

Findings

The simulation results are consistent with the experimental results of the Bakhtar test. The calculation results indicate that the degree of departure from saturation has a significant impact on the wet steam transonic condensation flow. When the inlet steam deviates from the saturation state, shock wave interference and vortex mixing also have a great influence on the distribution of water droplets.

Originality/value

The research results can provide reference for steam turbine wetness losses evaluation and flow passage structure optimization design.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 28 no. 10
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 26 October 2018

Nour el Imane Harrat, Sabrine Louala, Fatima Bensalah, Fouad Affane, Hadjera Chekkal and Myriem Lamri-Senhadji

The purpose of this study was to investigate the effects of prickly pear (Opuntia ficus indica (OFI)) nopalitos on body weight, food consumption, arterial blood pressure…

Abstract

Purpose

The purpose of this study was to investigate the effects of prickly pear (Opuntia ficus indica (OFI)) nopalitos on body weight, food consumption, arterial blood pressure, glucidic homeostasis, cholesterol metabolic pathway and tissues redox status in type 2 diabetic (T2D) rats fed a high-fat diet (HFD).

Design/methodology/approach

Rats were fed by a HFD containing 30 per cent sheep fat for 10 weeks, after which they were rendered diabetic by an injection of a low dose of streptozotocin (STZ) (35 mg/kg). The diabetic rats were then divided into two groups. The first group consumed the HFD supplemented with 5 per cent (g/100 g diet) of freeze-dried OFI nopalitos (HFD-OFI), and the second group received the HFD without supplementation (HFD).

Findings

OFI nopalitos treatment decreased significantly arterial diastolic (−20%; p = 0.0001) and systolic (−16%; p = 0.0001) pressures, glycemia (−14%; p = 0.03), insulinemia (−50%; p = 0.04), glycated hemoglobin (−49%; p = 0.003), homeostasis model assessment insulin resistance (−67%; p = 0.03), cholesterolemia (−31%; p = 0.003), very-low and low-density lipoprotein cholesterol (−38%; p = 0.002 and −63% p = 0.0002, respectively); thiobarbituric acid reactive substances and lipid hydroperoxide contents, respectively, in liver (−26% p = 0.02, −20% p = 0.02), adipose tissue (−30% p = 0.002, −25% p = 0.001), muscle (−29% p = 0.003, −25% p = 0.008) and kidney (lipid hydroperoxides only (−28%; p = 0.001) but increased high-density lipoprotein (HDL2) cholesteryl esters (+61%; p = 0.0001), serum lecithin: cholesterol acyltransferase activity (+21%; p = 0.006) and antioxidant enzymes activities (superoxide dismutase, glutathione peroxidase and catalase) of some tissues (liver, adipose tissue, muscle and kidney).

Originality/value

Freeze-dried OFI nopalitos improves arterial blood pressure, glycemic control, metabolic pathway of cholesterol and redox status in T2D rats.

Details

Nutrition & Food Science, vol. 49 no. 3
Type: Research Article
ISSN: 0034-6659

Keywords

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