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Article
Publication date: 20 April 2012

Hur‐Li Lee

This study aims to understand the epistemic foundation of the classification applied in the first Chinese library catalogue, the Seven Epitomes (Qilue).

Abstract

Purpose

This study aims to understand the epistemic foundation of the classification applied in the first Chinese library catalogue, the Seven Epitomes (Qilue).

Design/methodology/approach

Originating from a theoretical stance that situates knowledge organization in its social context, the study applies a multifaceted framework pertaining to five categories of textual data: the Seven Epitomes; biographical information about the classificationist Liu Xin; and the relevant intellectual, political, and technological history.

Findings

The study discovers seven principles contributing to the epistemic foundation of the catalogue's classification: the Han imperial library collection imposed as the literary warrant; government functions considered for structuring texts; classicist morality determining the main classificatory structure; knowledge perceived and organized as a unity; objects, rather than subjects, of concern affecting categories at the main class level; correlative thinking connecting all text categories to a supreme knowledge embodied by the Six Classics; and classicist moral values resulting in both vertical and horizontal hierarchies among categories as well as texts.

Research limitations/implications

A major limitation of the study is its focus on the main classes, with limited attention to subclasses. Future research can extend the analysis to examine subclasses of the same scheme. Findings from these studies may lead to a comparison between the epistemic approach in the target classification and the analytic one common in today's bibliographic classification.

Originality/value

The study is the first to examine in depth the epistemic foundation of traditional Chinese bibliographic classification, anchoring the classification in its appropriate social and historical context.

Details

Journal of Documentation, vol. 68 no. 3
Type: Research Article
ISSN: 0022-0418

Keywords

Article
Publication date: 9 July 2020

Xin Liu, Junhui Wu, Yiyun Man, Xibao Xu and Jifeng Guo

With the continuous development of aerospace technology, space exploration missions have been increasing year by year, and higher requirements have been placed on the…

Abstract

Purpose

With the continuous development of aerospace technology, space exploration missions have been increasing year by year, and higher requirements have been placed on the upper level rocket. The purpose of this paper is to improve the ability to identify and detect potential targets for upper level rocket.

Design/methodology/approach

Aiming at the upper-level recognition of space satellites and core components, this paper proposes a deep learning-based spatial multi-target recognition method, which can simultaneously recognize space satellites and core components. First, the implementation framework of spatial multi-target recognition is given. Second, by comparing and analyzing convolutional neural networks, a convolutional neural network model based on YOLOv3 is designed. Finally, seven satellite scale models are constructed based on systems tool kit (STK) and Solidworks. Multi targets, such as nozzle, star sensor, solar,etc., are selected as the recognition objects.

Findings

By labeling, training and testing the image data set, the accuracy of the proposed method for spatial multi-target recognition is 90.17%, which is improved compared with the recognition accuracy and rate based on the YOLOv1 model, thereby effectively verifying the correctness of the proposed method.

Research limitations/implications

This paper only recognizes space multi-targets under ideal simulation conditions, but has not fully considered the space multi-target recognition under the more complex space lighting environment, nutation, precession, roll and other motion laws. In the later period, training and detection can be performed by simulating more realistic space lighting environment images or multi-target images taken by upper-level rocket to further verify the feasibility of multi-target recognition algorithms in complex space environments.

Practical implications

The research in this paper validates that the deep learning-based algorithm to recognize multiple targets in the space environment is feasible in terms of accuracy and rate.

Originality/value

The paper helps to set up an image data set containing six satellite models in STK and one digital satellite model that simulates spatial illumination changes and spins in Solidworks, and use the characteristics of spatial targets (such as rectangles, circles and lines) to provide prior values to the network convolutional layer.

Details

Aircraft Engineering and Aerospace Technology, vol. 92 no. 8
Type: Research Article
ISSN: 1748-8842

Keywords

Article
Publication date: 26 July 2021

Hongxing Zheng, Xin Liu, Junhui Wu, Yiyun Man, Xibao Xu and Jifeng Guo

The purpose of this paper is to improve the efficiency of on-orbit operations through the top-level task design based on DoDAF. Based on the existing upper stage rocket…

Abstract

Purpose

The purpose of this paper is to improve the efficiency of on-orbit operations through the top-level task design based on DoDAF. Based on the existing upper stage rocket technology, orbit transfer vehicles (OTVs) have developed rapidly in recent years. However, the lack of decision guidance based on overall task analysis requires integrating top-level analysis and bottom-level execution to achieve the smooth development of full-process tasks.

Design/methodology/approach

Using the Department of Defense Architecture Framework (DoDAF) as a reference, this paper performs the top-level mission analysis modeling of the on-orbit rendezvous and capture of the OTV. Moreover, the typical operational view products are obtained, and the cooperative relations among the mission requirements, the system requirements, and the functional requirements are also analyzed.

Findings

The results show that the attitude of the OTV changes violently during the maneuver and rendezvous phases. In addition, the view products can be optimized based on the results.

Originality/value

The proposed DoDAF-based on-orbit task integration analysis method achieves the effective fusion of high-level analysis and bottom-level execution of OTV on-orbit rendezvous and capture task through the top-level task modeling, operation view generation and task relationship analysis. According to the requirements and constraints of the on-orbit rendezvous and capture task, the control instructions of the vehicle are efficiently generated under the DoDAF framework.

Details

Aircraft Engineering and Aerospace Technology, vol. 93 no. 6
Type: Research Article
ISSN: 1748-8842

Keywords

Open Access
Article
Publication date: 1 August 2018

Jiandong Chen, Yinyin Wu, Chong Xu, Malin Song and Xin Liu

Non-fossil fuels are receiving increasing attention within the context of addressing global climate challenges. Based on a review of non-fossil fuel consumption in major…

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Abstract

Purpose

Non-fossil fuels are receiving increasing attention within the context of addressing global climate challenges. Based on a review of non-fossil fuel consumption in major countries worldwide from 1985 to 2015, the purpose of this paper is to analyze trends for global non-fossil fuel consumption, share of fuel consumption and inequality.

Design/methodology/approach

The similarities were obtained between the logarithmic mean divisia index and the mean-rate-of-change index decomposition analysis methods, and a method was proposed for complete decomposition of the incremental Gini coefficient.

Findings

Empirical analysis showed that: global non-fossil fuel consumption accounts for a small share of the total energy consumption, but presents an increasing trend; the level of global non-fossil fuel consumption inequality is high but has gradually declined, which is mainly attributed to the concentration effect; inequality in global non-fossil fuel consumption is mainly due to the difference between nuclear power and hydropower consumption, but the contributions of nuclear power and hydropower to per capita non-fossil fuel consumption are declining; and population has the greatest influence on global non-fossil fuel consumption during the sampling period.

Originality/value

The main contribution of this study is its analysis of global non-fossil fuel consumption trends, disparities and driving factors. In addition, a general formula for complete index decomposition is proposed and the incremental Gini coefficient is wholly decomposed.

Details

Management Decision, vol. 57 no. 4
Type: Research Article
ISSN: 0025-1747

Keywords

Article
Publication date: 14 August 2017

Xin Liu, Jing Hu and Bing Xu

The purpose of this study is to find out how electronic word of mouth (eWOM) may affect evaluations of products with different brand images. In particular, the study…

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Abstract

Purpose

The purpose of this study is to find out how electronic word of mouth (eWOM) may affect evaluations of products with different brand images. In particular, the study explores differential eWOM impacts across several brand types and extension categories.

Design/methodology/approach

An experiment with 2 (brand image: prestige/function) × 2 (category similarity: low/high) × 2 (eWOM message type: positive/negative) between-subjects design was used to examine the impacts of eWOM on different types of brand extensions. A total of 268 subjects from a public university in the Southwest participated in the study. Analysis of Variance (ANOVA) was used in analyzing the data.

Findings

The findings highlight the differential impact of eWOM on brand extension evaluations with different brand images. First, eWOM is more effective in influencing evaluations of functional brand extensions than prestige brand extensions. Second, whereas negative eWOM does equally bad on both high- and low-similarity brand extensions, positive eWOM is more effective in improving evaluations of high-similarity extensions than low-similarity extensions.

Originality/value

This study is the first to examine the impact of eWOM on products with different brand images. This is a critical issue for brand managers who allocate limited marketing resources to monitoring and managing vast amounts of eWOM activities. The findings provide important guidance for managing social media marketing communications.

Details

Journal of Research in Interactive Marketing, vol. 11 no. 3
Type: Research Article
ISSN: 2040-7122

Keywords

Article
Publication date: 12 June 2017

Liming Zhai, Yongyao Luo, Xin Liu, Funan Chen, Yexiang Xiao and Zhengwei Wang

The purpose of this paper is to analyze lubrication characteristics of a tilting pad thrust bearing considering the effect of the thermal elastic deformation of the pad and collar.

414

Abstract

Purpose

The purpose of this paper is to analyze lubrication characteristics of a tilting pad thrust bearing considering the effect of the thermal elastic deformation of the pad and collar.

Design/methodology/approach

This study used the fluid–solid interaction (FSI) technique to investigate the lubrication characteristics of a tilting pad thrust bearing for several typical operating conditions. The influences of the rotational speed, the thrust load and the oil supply temperature on the lubrication characteristics were analyzed.

Findings

The three-dimensional (3D) film model clearly shows that there is no pressure gradient but large temperature gradients across the film thickness. The wall heat transfer coefficients on the pad surfaces distribute in a very complex way and change within a large range. The rotational speed, the thrust load and the oil supply temperature have great but different influences on the lubrication characteristics.

Originality/value

This paper has preliminarily revealed the lubrication mechanism of the tilting-pad thrust bearings. The 3D FSI method is suggested to evaluate the thermal-elastic-hydrodynamic deformations of thrust bearings instead of the conventional method which iteratively solves the Reynolds equation, the energy equation, the heat conduction equation and the elastic equilibrium equation. Using FSI method, the heat transfer coefficients on the pad surfaces can be evaluated better.

Details

Engineering Computations, vol. 34 no. 4
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 30 September 2022

Guisheng Gan, Shiqi Chen, Liujie Jiang, Cong Liu, Tian Huang, Peng Ma, Dayong Cheng and Xin Liu

This study aims to research properties of Cu/SAC0307 mixed solder balls/Cu joints with different Zn-particles content at low-temperature under ultrasonic assisted.

Abstract

Purpose

This study aims to research properties of Cu/SAC0307 mixed solder balls/Cu joints with different Zn-particles content at low-temperature under ultrasonic assisted.

Design/methodology/approach

A new method that 1µm Zn particles and Sn-0.3Ag-0.7 (SAC0307) with a particle size of 25–38 µm were mixed to fill the joint and successfully achieved micro-joining of Cu/Cu under ultrasonic-assisted at low temperature.

Findings

The results showed that with a continuous increase in the Zn-particle content, the interfacial intermetallic compounds (IMCs) of the upper and lower interfaces of joints gradually changed from scallop-shaped Cu6Sn5 to wavy-shaped Cu5Zn8. Moreover, the IMC thickness of the upper/lower interface of joints first decreased and then increased with increasing Zn-particle content. The shear strengths of joints increased with Zn-particle content, the shear strength of joints went to a maximum of 29.76 MPa when the Zn-particle content was 40%, an increase of 62.6% compared to joints without Zn particles. However, as the Zn-particle content continued to increase, the shear strengths of the joints decreased. Additionally, when the Zn content increased to 50%, because the oxidation degree of Zn particles increased, the joints were mainly broken among Zn particles.

Originality/value

A new method that 1µm Zn particles and Sn-0.3Ag-0.7 (SAC0307) with a particle size of 25–38 µm were mixed to fill the Cu/Cu joint at 180°C.

Details

Soldering & Surface Mount Technology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0954-0911

Keywords

Article
Publication date: 24 January 2023

Guisheng Gan, Shi-qi Chen, Liujie Jiang, Cong Liu, Peng Ma, Tian Huang, Dayong Cheng and Xin Liu

This study aims to research properties of Cu/SAC0307 mixed solder balls/Al joints with different bonding temperature under ultrasonic-assisted.

Abstract

Purpose

This study aims to research properties of Cu/SAC0307 mixed solder balls/Al joints with different bonding temperature under ultrasonic-assisted.

Design/methodology/approach

A new method that 1 mm Zn particles and Sn-0.3Ag-0.7 (SAC0307) with a particle size of 25–38 mm were mixed to fill the joint and successfully achieved micro-joining of Cu/Al under ultrasonic-assisted.

Findings

The results indicated that when the bonding temperature was 180°C, there was only one layer of CuZn5 intermetallic compounds (IMCs) at the Cu interface. However, when the bonding temperature was 190°C, 200°C and 210°C, the Cu interface IMCs had two layers: for one layer, the IMCs near the Cu substrate were Cu5Zn8 and for another layer, the IMCs near the solder were CuZn5. In addition, the thickness of the Cu interfacial IMCs increased with the bonding temperature. In particular, the thickness of IMCs at the Cu interface of the Cu/Al joints soldered at 210°C was 4.6 µm, which increased by 139.6% compared with that of the Cu/Al joints soldered at 180°C. However, there was no IMC layer at the Al interface, but there might be a Zn–Al solid solution layer. The shear strength of Cu/Al joints soldered at 180°C was only 15.01 MPa, but as the soldering temperature continued to increase, the shear strength of the Cu/Al joints increased rapidly. When the soldering temperature was 200°C, the shear strength of the Cu/Al joints reached the maximum of 38.07 MPa, which was 153.6% higher than that at 180°C. When the soldering temperature was 180°C, the fracture of Cu/Al joints was mainly on the Al side. However, when soldering temperature was 190°C, 200°C and 210°C, the fracture of Cu/Al joints was mainly broken in the Zn particles layer.

Originality/value

A new method that 1 mm Zn particles and Sn-0.3Ag-0.7 (SAC0307) with a particle size of 25–38 mm were mixed to fill the Cu/Al joint at 210°C.

Details

Soldering & Surface Mount Technology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0954-0911

Keywords

Article
Publication date: 26 August 2022

Guisheng Gan, Shiqi Chen, Liujie Jiang, Zhaoqi Jiang, Cong Liu, Peng Ma, Dayong Cheng and Xin Liu

This study aims to evaluate the effect of thermal aging temperature on the properties of Cu/Cu joints.

Abstract

Purpose

This study aims to evaluate the effect of thermal aging temperature on the properties of Cu/Cu joints.

Design/methodology/approach

A new method that 1 um Zn-particles and Sn-0.3Ag-0.7Cu (SAC0307) with a particle size of 25–38 µm were mixed to fill the joint and successfully achieved the micro-joining of Cu/Cu under ultrasonic-assisted at low-temperature, and then the effect of thermal aging temperature on the properties of Cu/Cu joints was researched.

Findings

The composition of the intermetallic compounds (IMCs) on the upper and lower interfaces of Cu/SACZ/Cu joints remained unchanged, which was Cu5Zn8 in aging process, and the thickness of the IMCs on the upper and lower interfaces of the Cu/SACZ/Cu joints increased accordingly. Compared with the as-received joints, the thickness of the upper and lower interfaces IMCs of the soldering aged time for 24 h increased by 404.7% and 505.5% at 150ºC, respectively. The IMCs formation tendency and the IMCs growth rate of the lower interface are larger than those of the upper interface because the soldering seam near the IMCs at the upper and lower interfaces of the as-received joints were mostly white SAC0307 balls black Zn-particles, respectively. The growth activation energy of IMCs in the upper and lower interfaces is about 89.21 and 55.11 kJ/mol, respectively. Under the same aging time, with the increase of the aging temperature, the shear strength of Cu/SACZ/Cu joints did not change significantly at first before 150ºC. When the aging temperature reached 150ºC, the shear strength of the joints decreased significantly; the shear strength of the joints was the smallest at 150ºC for 24 h, which was 39.4% lower than that of the as-received joints because the oxidation degree of Zn particles in the joint with the increase of aging temperature and time.

Originality/value

Cu/Cu joints were successfully achieved under ultrasonic-assisted at low-temperature.

Details

Soldering & Surface Mount Technology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0954-0911

Keywords

Article
Publication date: 20 February 2019

Guisheng Gan, Da-quan Xia, Xin Liu, Cong Liu, Hanlin Cheng, Zhongzhen Ming, Haoyang Gao, Dong-hua Yang and Yi-ping Wu

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…

Abstract

Purpose

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.

Design/methodology/approach

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.

Findings

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 Cu3Sn 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.

Originality/value

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.

Details

Soldering & Surface Mount Technology, vol. 31 no. 2
Type: Research Article
ISSN: 0954-0911

Keywords

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