Development and testing of a XYZ scanner for atomic force microscope

Atomic force microscopy (AFM) is a widely used tool in nano measurement and manipulation techniques. However, a traditional AFM system suffers from the limitation of slow scanning rate, due to the low dynamic performance of piezoelectric positioners. As an important part of AFM system, scanner will have a significant impact the result of the scanning imaging and operation. It is well know that high-speed operation of an AFM are increasingly required, and it is also a challenge for the researchers. In this paper, we proposed a parallel kinematic high-speed piezoelectric actuator (PZT) XYZ scanner. The design is aimed at achieving high resonance frequencies and low cross-coupling. The developed stage consists of a parallel kinematic XY stage and a Z stage. The Z stage is mounted on the central moving platform of the XY stage. To achieve the design objective, several parallel leaf flexure hinge mechanisms, arranging symmetrically around the central moving platform of the XY stage, are utilized to provide large stiffness and reduce cross-coupling. For the Z stage, a symmetrical leaf flexure parallelogram mechanism is adopted to achieve high resonance frequencies and decoupling. Then, finite element analysis (FEA) is utilized to validate the characteristics of the XYZ scanner. Finally, extensive experiments are conducted, demonstrating feasibility of the proposed scanner

DCP-NAS: Discrepant Child-Parent Neural Architecture Search for 1-bit CNNs

Neural architecture search (NAS) proves to be among the effective approaches for many tasks by generating an application-adaptive neural architecture, which is still challenged by high computational cost and memory consumption. At the same time, 1-bit convolutional neural networks (CNNs) with binary weights and activations show their potential for resource-limited embedded devices. One natural approach is to use 1-bit CNNs to reduce the computation and memory cost of NAS by taking advantage of the strengths of each in a unified framework, while searching the 1-bit CNNs is more challenging due to the more complicated processes involved. In this paper, we introduce Discrepant Child-Parent Neural Architecture Search (DCP-NAS) to efficiently search 1-bit CNNs, based on a new framework of searching the 1-bit model (Child) under the supervision of a real-valued model (Parent). Particularly, we first utilize a Parent model to calculate a tangent direction, based on which the tangent propagation method is introduced to search the optimized 1-bit Child. We further observe a coupling relationship between the weights and architecture parameters existing in such differentiable frameworks. To address the issue, we propose a decoupled optimization method to search an optimized architecture. Extensive experiments demonstrate that our DCP-NAS achieves much better results than prior arts on both CIFAR-10 and ImageNet datasets. In particular, the backbones achieved by our DCP-NAS achieve strong generalization performance on person re-identification and object detection.Comment: Accepted by International Journal of Computer Visio

Integration of Preclinical and Clinical Data with Pharmacokinetic Modeling and Simulation to Evaluate Fexofenadine as a Probe for Hepatobiliary Transport Function

The suitability of fexofenadine as a probe substrate to assess hepatobiliary transport function in humans was evaluated by pharmacokinetic modeling/simulation and in vitro/in situ studies using chemical modulators

Analysis of Innovative Structural Design of Liyutuo Lounge Bridge in Dujiangyan

U projektu mosta Liyutuo Lounge višekatna okvirna konstrukcija kombinirana je s masivnom konstrukcijom mosta, te je tako projektirana jedinstvena građevina dvostruke namjene. Prometni dio rasponske konstrukcije mosta je prednapeti kruti betonski okvir, kruto spojen sa stupom, nosačem i poprečnim nosačem koji se odlikuju tipičnim značajkama prednapete betonske konstrukcije i okvirne konstrukcije. Pri projektiranju temelja stupa, primjenjeno je naknadno injektiranje te kombinacija uzdužnih veznih greda kako bi se riješili problemi malog promjera pilota i velikog opterećenja.According to its design, the Liyutuo Lounge Bridge combines a multilayer frame structure with a large bridge structure, offering a solution involving a unique dual-use structure. The transport layer of the superstructure is a prestressed concrete rigid frame, and the pier, girder, and cross girder, are rigidly connected, and have typical characteristics of a prestressed concrete bridge structure and frame structure. For the structural design of pier foundations, the post-grouting and a combination of longitudinal tie beams are used to solve the challenges associated with a small pile diameter and large loads

Impact of Basolateral Multidrug Resistance-Associated Protein (Mrp) 3 and Mrp4 on the Hepatobiliary Disposition of Fexofenadine in Perfused Mouse Livers

The disposition of fexofenadine, a commonly-used antihistamine drug, is governed primarily by active transport. Biliary excretion of the parent compound is the major route of systemic clearance. Previous studies demonstrated that fexofenadine hepatic uptake is mediated by organic anion transporting polypeptides. Recently, we showed that in mice fexofenadine is excreted into bile primarily by Mrp2 (Abcc2). In the present study, the role of Mrp3 (Abcc3) and Mrp4 (Abcc4) in the hepatobiliary disposition of fexofenadine was examined in knockout mice using in situ liver perfusion. Compared to wild-type mice, basolateral excretion of fexofenadine was impaired resulting in a ~50% decrease in perfusate recovery in Abcc3 ( − / − ) mice; in contrast, fexofenadine hepatobiliary disposition was unaltered in Abcc4 ( − / − ) mice. As expected, in Abcc2 ( − / − ) mice, fexofenadine was redirected from the canalicular to the basolateral membrane for excretion. In Abcc2 ( − / − )/Abcc3 ( − / − ) double knock-out mice, fexofenadine biliary excretion was impaired, but perfusate recovery was similar to wild-type mice, and more than 2-fold higher than in Abcc3 ( − / − ) mice, presumably due to compensatory basolateral transport mechanism(s). These results demonstrate that multiple transport proteins are involved in the hepatobiliary disposition of fexofenadine. In addition to Mrp2 and Mrp3, other transport proteins play an important role in the biliary and hepatic basolateral excretion of this zwitterionic drug

Reduced-Parameter YOLO-like Object Detector Oriented to Resource-Constrained Platform

Deep learning-based target detectors are in demand for a wide range of applications, often in areas such as robotics and the automotive industry. The high computational requirements of deep learning severely limit its ability to be deployed on resource-constrained and energy-first devices. To address this problem, we propose a class YOLO target detection algorithm and deploy it to an FPGA platform. Based on the FPGA platform, we can make full use of its computational features of parallel computing, and the computational units such as convolution, pooling and Concat layers in the model can be accelerated for inference.To enable our algorithm to run efficiently on FPGAs, we quantized the model and wrote the corresponding hardware operators based on the model units. The proposed object detection accelerator has been implemented and verified on the Xilinx ZYNQ platform. Experimental results show that the detection accuracy of the algorithm model is comparable to that of common algorithms, and the power consumption is much lower than that of the CPU and GPU. After deployment, the accelerator has a fast inference speed and is suitable for deployment on mobile devices to detect the surrounding environment