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Systematic characterization of cleanroom-free fabricated macrovalves,demonstrating pumps and mixers for automated fluid handling tuned for organ-on-chip applications

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Microsystems & Nanoengineering 2022年第3期8卷 163-176页

作者： Elsbeth G.B.M.Bossink Anke R.Vollertsen Joshua T.Loessberg-Zahl Andries D.van der Meer Loe l.Segerink Mathieu Odijk BIOs Lab on a Chip Group MESA+instituteTechnical Medical CenterMax Planck Institute for Complex Fluid DynamicsUniversity of TwenteEnschedeThe Netherlands Applied Stem Cell Technologies Group Technical Medical CenterUniversity of TwenteEnschedeThe Netherlands

Integrated valves enable automated control in microfuidic systems,as they can be applied for mixing,pumping and compartmentalization *** automation would be highly valuable for applications in organ-on-chip(OoC)***,OoC systems typically have channel dimensions in the range of hundreds of micrometers,which is an order of magnitude larger than those of typical microfluidic *** most-used fabrication process for integrated,normally open polydimethylsiloxane(PDMS)valves requires a reflow photoresist that limits the achievable channel *** addition,the low stroke volumes of these valves make it challenging to achieve flow rates of microliters per minute,which are typically required in OoC ***,we present a mechanical'macrovalve'fabricated by multilayer soft lithography using micromilled direct *** demonstrate that these valves can close off rounded channels of up to 700μm high and 1000μm ***,we used these macrovalves to create a peristaltic pump with a pumping rate of up to 48μL/min and a mixing and metering device that can achieve the complete mixing of a volume of 6.4μL within only 17 *** initial cell culture experiment demonstrated that a device with integrated macrovalves is biocompatible and allows the cell culture of endothelial cells over multiple days under continuous perfusion and automated medium refreshment.

关键词： pumping mixer pump

Effect of stress profile on microstructure evolution of cold-drawn commercially pure aluminum wire analyzed by finite element simulation

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Journal of Materials Science & Technology 2018年第7期34卷 1214-1221页

作者： Y.K.Zhu Q.Y.Chen Q.Wang H.Y.Yu R.Li J.P.Hou Z.J.Zhang G.P.Zhang Z.F.Zhang Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences National Quality Supervision & inspection center of Electrical Equipment Safety Performance Zhejiang Huadian Equipment Testing Institute

The evolution of microstructure in the drawing process of commercially pure aluminum wire （CPAW） does not only depend on the nature of materials, but also on the stress profile. In this study, the effect of stress profile on the texture evolution of the CPAW was systematically investigated by combining the numerical simulation and the microstructure observation. The results show that the tensile stress at the wire center promotes the formation of 〈111〉 texture, whereas the shear stress nearby the rim makes little contribution to the texture formation. Therefore, the 〈111 〉 texture at the wire center is stronger than that in the surface layer, which also results in a higher microhardness at the center of the CPAW under axial loading.2017 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science ＆ Technology.

关键词： Commercially pure aluminum wire Cold drawing Texture Finite element simulation Stress profile

Creep rupture behavior and microstructural evolution of modified 9Cr-1Mo heat-resistant steel

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Journal of Iron and Steel Research International 2018年第12期25卷 1303-1310页

作者： Fa-cai Ren He Wang Xiao-ying Tang Fei Chen Shanghai Institute of Special Equipment inspection and technical Research Shanghai 200062China Capital Aerospace Machinery Corporation Limited Beijing 100076China National Engineering Research Centre of Die &Mold CAD Shanghai Jiao Tong UniversityShanghai 200030China

High-temperature creep rupture behavior of modified 9Cr-lMo steel used for steam cooler was investigated at temperature of 838 and 923 K and stress ranging from 100 to 250 *** on the analysis of creep rate-time curves,it is found that the creep rupture life decreases with the increase in the applied stress and *** creep damage tolerance factor has been identified as a value of *** the normalized and tempered condition,the studied steel shows typical martensitic microstructure with Cr-rich M23C6 and Nb-or V-rich MX ***,the Laves phase has been found along the grain *** fracture morphology characterized by field emission scanning electron microscope is adopted to reveal the creep failure *** investigated results indicate the occurrence of the transgranular fracture under all the creep test conditions.

关键词： Creep rupture behavior Modified 9Cr-1Mo steel Microstructural evolution Fractography

Characterization and biodegradation kinetics of a new cold-adapted carbamazepine-degrading bacterium, Pseudomonas sp. CBZ-4

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Journal of Environmental Sciences 2013年第11期25卷 2281-2290页

作者： Ang Li Rui Cai Di Cui Tian Qiu Changlong Pang Jixian Yang Fang Ma Nanqi Ren State Key Laboratory of Urban Water Resource and Environment Harbin Institute of Technology National Supervision and inspection center of Environmental Protection Equipment Quality Yixing Urban Supervision andInspection Administration of Product Quality

Carbamazepine is frequently detected in waters and hardly eliminated during conventional wastewater treatment processes due to its complicated chemical structure and resistance to biodegradation. A carbamazepine-degrading bacterium named CBZ-4 was isolated at a low temperature （10℃） from activated sludge in a municipal wastewater treatment plant. Strain CBZ-4, which can use carbamazepine as its sole source of carbon and energy, was identified as Pseudomonas sp. by the 16S rRNA gene sequence. The composition and percentage of fatty acids, which can reveal the cold-adaptation mechanism of strain CBZ-4, were determined. Strain CBZ-4 can effectively degrade carbamazepine at optimal conditions： pH 7.0, 10℃, 150 r/min rotation speed, and 13% inoculation volume. The average removal rate of carbamazepine was 46.6% after 144 hr of incubation. The biodegradation kinetics of carbamazepine by CBZ-4 was fitted via the Monod model. Vmax and Ks were found to be 0.0094 hr^-1 and 32.5 mg/L, respectively.

关键词： carbamazepine low temperatures biodegradation kinetics Pseudomonas sp.

Automatic Malware Classification via PRICoLBP

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Chinese Journal of Electronics 2018年第4期27卷 852-859页

作者： YAN Hanbing ZHOU Hao ZHANG Honggang National Computer Network Emergency Response technical Team/Coordination center of China Beijing University of Posts and Telecommunications

Creating effective features is a critical issue in malware analysis. It requires a proper tradeoff between discriminative power and invariance. Previous studies have shown that it is fairly effective to design features based on the binary code. However, the current existing binary-based features seldom take into consideration the problem of obfuscation, such as relocated sections, incomplete code and redundant operations. In this paper, we propose a novel Pairwise rotation invariant co-occurrence local binary pattern(PRICo LBP) feature, and further extend it to incorporate the Term frequency-inverse document frequency(TFIDF) transform. Different from other static analysis techniques, our method not only achieves better linear separability, but also appears to be more resilient to obfuscation. In addition, we evaluate PRICo LBPTFIDF comprehensively on three datasets from different perspectives, e.g., classification performance, classifier selection and performance against obfuscation. What’s more,we compare our PRICoLBP-TFIDF method with other techniques, and demonstrate that PRICo LBP-TFIDF is quite an efficient and effective tradeoff between discriminative power and invariance.

关键词： Malware classification Pairwise rotation invariant co-occurrence local binary pattern Term frequency-inverse document frequency Texture classification Resilience to obfuscation

WAF-Based Chinese Character Recognition for Spam Image Filtering

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Chinese Journal of Electronics 2018年第5期27卷 1050-1055页

作者： LI Siyuan LI Ruiguang XU Yuan ZHOU Hao YAN Hanbing XU Bin ZHANG Honggang Beijing University of Posts and Telecommunication National Computer Network Emergency Response technical Team Coordination center of China

We address the problem of filtering image spam, a kind of rapidly spread spam in which the text is embedded into images to defeat text-based spam ***, we focus on image spam with Chinese text as "spam" which is a more challenging task. A popular way to detect image spam is by Optical character recognition(OCR) system, which detects and recognizes the embedded text, then followed by a text classifier that discriminate spam from ham. However, spammers start to obscure image text to prevent OCR system discovering the spam text. To compensate for the shortcomings of OCR system, a novel method which essentially is a keyword reconstruction algorithm based on Word activation force(WAF) model is proposed. It is effective on discovering keywords, hence is benefit for the later classification stage and notably improve the performance of image spam filtering. The experimental results on a personal data set of spam images(publicly available) validate the effectiveness of our approach that outperforms the original OCR system in practical usage with complex background in image spam.

关键词： Spam image Chinese character recognition Keyword reconstruction Word activation force

Identification of Salmonella and Listeria monocytogenes by Near-infrared Spectroscopy and PCA

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Meteorological and Environmental Research 2019年第4期10卷 77-80页

作者： Jiang Chuan Zhang Xiaohong Zou Xiaolong Lu Guangying Liu Yangchun Lishui Institute of Food and Drug & Quality and technical inspection

Near-infrared spectra of pathogenic bacteria (salmonella and Listeria monocytogenes ) were determined, and the spectral data were analyzed by the projection discriminant analysis based on principal component analysis (PCA). The expected results were obtained. The results showed that salmonella and L. monocytogenes could be distinguished from each other by the near-infrared spectroscopy of the whole cells, cell walls or cytoplasm.

关键词： Near-infrared spectroscopy Salmonella Listeria monocytogenes PCA Identification

Direct Yaw Moment Control for Distributed Drive Electric Vehicle Handling Performance Improvement

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Chinese Journal of Mechanical Engineering 2016年第3期29卷 486-497页

作者： YU Zhuoping LENG Bo XIONG Lu FENG Yuan SHI Fenmiao School of Automotive Studies Tongji University Pan Asia technical Automotive center Co. Ltd.

For a distributed drive electric vehicle（DDEV） driven by four in-wheel motors, advanced vehicle dynamic control methods can be realized easily because motors can be controlled independently, quickly and precisely. And direct yaw-moment control（DYC） has been widely studied and applied to vehicle stability control. Good vehicle handling performance： quick yaw rate transient response, small overshoot, high steady yaw rate gain, etc, is required by drivers under normal conditions, which is less concerned, however. Based on the hierarchical control methodology, a novel control system using direct yaw moment control for improving handling performance of a distributed drive electric vehicle especially under normal driving conditions has been proposed. The upper-loop control system consists of two parts： a state feedback controller, which aims to realize the ideal transient response of yaw rate, with a vehicle sideslip angle observer; and a steering wheel angle feedforward controller designed to achieve a desired yaw rate steady gain. Under the restriction of the effect of poles and zeros in the closed-loop transfer function on the system response and the capacity of in-wheel motors, the integrated time and absolute error（ITAE） function is utilized as the cost function in the optimal control to calculate the ideal eigen frequency and damper coefficient of the system and obtain optimal feedback matrix and feedforward matrix. Simulations and experiments with a DDEV under multiple maneuvers are carried out and show the effectiveness of the proposed method： yaw rate rising time is reduced, steady yaw rate gain is increased, vehicle steering characteristic is close to neutral steer and drivers burdens are also reduced. The control system improves vehicle handling performance under normal conditions in both transient and steady response. State feedback control instead of model following control is introduced in the control system so that the sense of control intervention to drive

关键词： direct yaw moment control distributed drive electric vehicle handling performance improvement state feedback control

Investigation on directional effects of Vrancea subcrustal earthquakes

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Earthquake Engineering and Engineering Vibration 2015年第3期14卷 399-410页

作者： Florin Pavel Radu Vacareanu Mircea Radulian Carmen Cioflan Seismic Risk Assessment center Technical University of Civil Engineering Bucharest National Institute for Earth Physics (INFP)

This paper evaluates possible directional effects from strong ground motions recorded during the last four significant subcrustal earthquakes produced in the Vrancea seismic zone（Romania） in August 1986（Mw=7.1）,May 1990（Mw=6.9 and 6.4） and October 2004（Mw=6.0）.Several measures of the horizontal component of the ground motion given in the literature（Boore et al.,2006;Boore,2010） are computed and are related to the geometric mean of the as-recorded horizontal *** method is applied in order to quantify the influence of the earthquake magnitude and of the soil class on some strong ground motion parameters（*** intensity,PGV/PGA,or mean period TM）.The study of the directional effects is performed using the distribution of IJMAand of the rotation angle corresponding to a measure of the horizontal component of the ground motion（RotD 100） and the results reveal a visible directional pattern for IJMA,while in the case of RotD100 the directional patterns are less visible.

关键词： response spectra horizontal ground motion directio