Rapid Process Modeling of the Aerosol Jet Printing Based on Gaussian Process Regression with Latin Hypercube Sampling

Haining Zhang,Seung Ki Moon,Teck Hui Ngo,Junjie Tou,Mohamed Ashrof Bin Mohamed Yusoff 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.21 No.1

Aerosol jet printing (AJP) technology is a relatively new 3D printing technology for producing customized microelectronic components due to its high design flexibility and fine feature deposition. However, complex interactions between machine, process parameters and materials will influence line morphology and remain a challenge on modeling effectively. And the system drift which induced by many changing and uncertain factors will affect the printing process significantly. Hence, it is necessary to develop a small data set based machine learning approach to model relationship between the process parameters and the line morphology. In this paper, we propose a rapid process modeling method for AJP process and consider sheath gas flow rate, carrier gas flow rate, stage speed as AJP process parameters, and line width and line roughness as the line morphology. Latin hypercube sampling is adopted to generate experimental points. And, Gaussian process regression (GPR) is used for modeling the AJP process because GPR has the capability of providing the prediction uncertainty in terms of variance. The experimental result shows that the proposed GPR model has competitive modeling accuracy comparing to the other regression models.

3D Printed Electronics of Non-contact Ink Writing Techniques: Status and Promise

Haining Zhang,Seung Ki Moon,Teck Hui Ngo 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.7 No.2

Non-contact ink writing techniques are a newly developed three-dimensional printing technology to fabricate customized and flexible electronic devices, while dramatically reducing chemical waste and lowering manufacturing costs. However, the use of non-contact ink writing technologies for fabricating electronics is still limited due to printing quality. To develop an electronic device with high performance, conductive lines should be printed with high controllability and excellent uniformity. Under such circumstances, many traditional optimization methods have been proposed to improve the printing quality. However, as the non-contact ink writing process is very sensitive to the system drifts and random variations, in situ process monitoring and online optimization technologies to optimize the printed line quality are in demand for practical printing. In this paper, we describe the processes of non-contact ink writing techniques based on inkjet printing (IJP) and aerosol jet printing (AJP). The key influencing factors in the non-contact ink writing processes are also discussed based on the three main printing stages. Then we analyze the advantages and disadvantages of the IJP and AJP techniques and review the state of art in quality optimization and precise control techniques that can be adopted in non-contact ink writing process. Additionally, to further develop a non-contact ink writing system, the major challenges and limitations of the current printing quality optimization technologies are also highlighted in this paper.

SBA-15 Templated Mesoporous Graphitic C3N4 for Remarkably Enhanced Photocatalytic Degradation of Organic Pollutants under Visible Light

Hongjin Liu,Haining Wu,Jun Lv,Guangqing Xu,Xing Chen,Xinyi Zhang,Yucheng Wu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.11

Organic pollutants in water have been threatening public and environmental health. Developing efficient and sustainable photocatalysts working for degradation of organic pollutants under visible light becomes a big challenge. In this paper, high-efficiency visible light driven catalyst ordered mesoporous graphite nitride carbon (mpg-C3N4) was prepared by using SBA-15 as template and dicyandiamide (C2H4N4) as precursor. The specific surface area of mpg-C3N4 can be increased remarkably as compared to that of the bulk graphite nitrite carbon (g-C3N4) by adjusting the ratio of SBA-15 to dicyandiamide. Photocatalytic performance of mpg-C3N4 were evaluated systematically by degradation of Rhodamine B (RhB), malachite green (MG) and tetracycline hydrochloride (TC) under visible light irradiation. The results showed that the mpg-C3N4 (1 : 0.5) has the highest photocatalytic activity and stability and the degradation rate is for RhB, MG and TC are all more than seven times that of bulk g-C3N4. After five recycling runs, the mpg-C3N4 (1 : 0.5) remains high photocatalytic activities for the degradation of MG (94%) and TC (81%), respectively. Additionally, radical trapping experiments certified that the main active species are ·O2 - and h+, while the role of ·OH is irrelevant in the reaction processes. This work provides a promising pathway to prepare metal-free photocatalyst for degradation of organic pollutants under visible light irradiation.

Failure Mechanism of Face for Slurry Shield-Driven Tunnel in Sand

Handong Liu,Yafeng Zhang,Haining Liu 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.10

To achieve the failure mechanism of face for slurry shield tunnel in sand stratum, a model test device for shield excavation with ideal slurry film was developed. The active failure processes of tunnel excavation face in dry sand stratum for different densities and cover depths were achieved through model test and two-dimensional particle flow code (PFC2D). Furthermore, soil deformation, failure mode and soil arching effect of tunnel excavation face were revealed. The results show that the face deformation can be divided into three stages in relation to the support pressure and the excavation face has been failed in third stage. The density of sand has a great influence on the failure mode of excavation face. The failure mode in dense condition is a combination of a wedge with slip arc and a prism chimney, while in loose condition it is a relatively dispersed “trumpet” shape failure zone. However, the cover depth has a negligible effect on the failure mode. In dense sand stratum, a loose failure zone was formed in front of the excavation face and a soil arch was formed above it. The soil arch developed continuously above the tunnel crown to the ground surface. The limit support pressure calculated by PFC2D (two-dimensional particle flow code) increases with the cover depth, which is consistent with the observations in model tests.

An Integrate RFID Traceability System for the Halal Supply Chain

Yang Haihong,Hu Xiaojian,Zhang Yanli,Ding Haining 보안공학연구지원센터 2016 International Journal of u- and e- Service, Scienc Vol.9 No.9

Expression and Clinicopathological Significance of CD9 in Gastrointestinal Stromal Tumor

Hongxin Yang,Chaoyong Shen,Bo Zhang,Haining Chen,Zhixin Chen,Jiaping Chen 대한의학회 2013 Journal of Korean medical science Vol.28 No.10

This study investigated the expression and clinicopathological significance of CD9 in gastrointestinal stromal tumor (GIST). Immunohistochemistry staining for CD9 was performed on tumor tissues from 74 GIST patients. The correlation with clinicopathological features, risk classification and prognosis was analyzed. CD9-positive staining comprised 59.5% (44/74) of the GIST patients. The CD9-positive expression rate of the sample was significantly associated with diameter (P=0.028), mitotic counts (P=0.035), risk classification (P=0.018) and three-year recurrence-free survival (RFS) (P<0.001). Cox proportional hazards regression (HR=0.352; P=0.015) showed that CD9 is an independent factor for post-operative RFS. The subgroup analysis showed that CD9 expression in gastric stromal tumor (GST) is significantly associated with diameter (P=0.031), risk classification (P=0.023) and three-year RFS (P=0.001). The Cox proportional hazards regression (HR=0.104; P=0.006) also showed that CD9 is an independent factor for RFS of GST. However, CD9 expression does not have a statistically significant correlation with clinicopathological features, risk classification, and prognosis in non-GST. In conclusion, CD9 expression in GIST appears to be associated with the recurrence and/or metastasis of GIST patients, especially in GST, which may indicate the important role of CD9 in the malignant biological behavior and prognosis of GST.

Comparison and Identification of Optimal Machine Learning Model for Rapid Optimization of Printed Line Characteristics of Aerosol Jet Printing Technology

Mingdong Li,Zhixin Liu,Shuai Yin,Joon Phil Choi,Haining Zhang 한국정밀공학회 2024 International Journal of Precision Engineering and Vol.11 No.1

Among the various direct-write (DW) techniques, aerosol jet printing (AJP) has the advantages of high resolution (~ 10 μm) and flexible working distance (2-5 mm). On this basis, it has emerged as a promising DW technology to precisely customize complex electrical functional devices. However, the micro-electronic devices fabricated using AJP suffer from low electrical performance because of inferior printed line geometric characteristics. Specifically, high edge roughness lines are detrimental to the uniformity of the formed electrical functional devices. In addition, the low controllability of the printed line width may induce overlap of narrowly spaced circuits or unnecessary intertrack voids, which will hinder the wide application of AJP technology in advanced electronic manufacturing industry. Therefore, ensuring high precision of the line width and low edge roughness is of primary importance for AJP technology. In this research, a machine learning framework is proposed for rapid optimization of printed line characteristics. In the proposed framework, SHGFR and CGFR were considered as input variables, and line width and line roughness were taken as the target responses. Three representative machine learning algorithms, tree-based random forest regression, kernel-based support vector machine, and Bayesian-based Gaussian process regression, were then adopted for model development. Subsequently, the identified optimal machine learning model was integrated with a NSGA-III for rapid optimization of printed line characteristics, and experiments validated the effectiveness of the adopted approach.