Enhanced 6D Measurement by Integrating an Inertial Measurement Unit (IMU) with a 6D Sensor Unit of a Laser Tracker

Six-degree-of-freedom (6D) sensors enhance the measurement capability of traditional three-degree-of-freedom (3D) laser trackers. However, the classical 6D measurement techniques still have shortcomings in actual use, such as the problem of line of sight and relatively low data acquisition rate. The proposed approach by integrating an Inertial Measurement Unit (IMU) with a 6D sensor unit of a laser tracker is effective to overcome these limitations. The error is corrected by the combination of a Kalman filter and a backward smoothing algorithm. The Kalman filter only works when the 6D sensor's data is being sent through, while the backward smoothing algorithm works during the whole process. The experiments are performed to compare the error in three positions and three rotational orientations between the proposed method and the Kalman filter and evaluate the effects of different rates and IMU frequencies on the algorithm. The simulations are also performed to estimate the maximum outage time. The results verify that the proposed method can solve the problem of line of sight and low data acquisition rate effectively.</p

Design and development of a ceiling-mounted workshop measurement positioning system for large-scale metrology

This paper presents a new ceiling-mounted workshop Measurement Positioning System (C-wMPS) compensating for many deficiencies shown by conventional metrology systems, especially on the possibility of task-oriented designing for coverage ability, measurement accuracy and efficiency. A hybrid calibration system consisting of a high-precision coordinate control field and standard lengths is developed and implemented for the C-wMPS, which can be designed concretely to provide both traceability and the ability of local accuracy enhancement. Layout optimization using a genetic algorithm based on grids is applied to design an appropriate layout of the system, therefore promotes the system’s performance and reduce cost. An experiment carried out at the Guidance, Navigation and Control laboratory (GNC lab, 40×30×12m) validates the prominent characteristic of C-wMPS and the fitness of the new calibration system and layout optimization method.<br/

Co-expression of apoptin (VP3) and antibacterial peptide cecropin B mutant (ABPS1) genes induce higher rate of apoptosis in HepG2 and A375 cell lines

The antibacterial peptide cecropin B mutant (ABPS1) gene has a broad range of antibacterial and  antiproliferative properties. Apoptin (VP3), a chicken anaemia virus-encoded protein is known to induce  apoptosis in human transformed cells. To explore drug combination in human tumor cells, apoptin and ABPS1 eukaryotic expression vector pIRES2-EGFP-apoptin and pIRES2-EGFP-ABPS1 were constructed and their expression effect individually and in combinations were studied in HepG2 and A375 cells. The vector pIRES2-EGFP-ABPS1 and pIRES2-EGFP-apoptin were transfected into tumor cells HepG2 and A375 by the  lipofectamine-mediated DNA transfection procedure. At 48 h post transfection, the apoptotic rate obtained by flow cytometry and the morphological changes under light and scanning electron microscope of tumor cells  were significant. In contrast, the microvilli on the surface of the control cells were disrupted, decreased and even disappeared. The cell membrane was injured and intracellular substances leaked out. Furthermore, our  results indicate that the apoptotic rates of apoptin (27.32% in HepG2 and 9.34% in A375 cells), were higher  than ABPS1 (23.79% in HepG2 and 8.33% in A375 cells). Moreover, the co-expression of Apoptin and ABPS1  showed higher apoptotic rates which were 27.66 and 10.33% in HepG2 and A375 cells respectively. However, the apoptotic rates obtained in HepG2 cells treated with apoptin and apoptin and ABPS1 together were closely  similar, but, not in A375 cells. Therefore, the results of the present study showed that the combination of  Apoptin and ABPS1 has synergistic effect in HepG2 and A375 cell lines.Keys words: Apoptin, ABPS1, apoptosis, co-expression, HepG2, A375

A polybenzimidazole/graphite oxide based three layer membrane for intermediate temperature polymer electrolyte membrane fuel cells

A three layer membrane (TLM) of polybenzimidazole/graphite oxide/polybenzimidazole (PBI/GO/PBI) has been fabricated as an electrolyte for intermediate temperature polymer exchange membrane fuel cells (IT-PEMFCs). The membrane is prepared by encapsulating a GO layer with two single PBI membranes via a layer-by-layer procedure and subsequently imbibed with phosphoric acid (PA). The TLM exhibits a lower swelling ratio than that of the pristine PBI membrane at the same PA loading time. The mechanical strength of the TLM could reach 28.6 MPa at 150 °C, significantly higher than that of a PBI membrane (12.2 MPa). The TLM is loaded with a PA amount of 2.23H3PO4 molecules per repeat unit (PRU), which provides a proton conductivity of 0.0138 S cm−1 at 150 °C. The three layer structure promotes a membrane for PEMFCs with lower PA leakage and material corrosion. The fuel cell performance based on TLM exhibits a peak power density of 210 mW cm−2 at 150 °C

Design of an omnidirectional single-point photodetector for large-scale spatial coordinate measurement

In high precision and large-scale coordinate measurement, one commonly used approach to determine the coordinate of a target point is to utilize the spatial trigonometric relationships between multiple laser transmitting stations and the target point. A light receiving device at target point is the key element in large-scale coordinate measurement systems. To ensure high-resolution and highly-sensitive spatial coordinate measurement, a high-performance and miniaturized omnidirectional single-point photodetector (OSPD) is highly desired. Here we report one design of OSPD using aspheric lens, which achieves enhanced reception angle of -5 to 45 degree in vertical and 360 degree in horizontal. As the heart of our OSPD, the aspheric lens is designed in geometric model and optimized by LightTools Software, which enables reflecting wide-angle incident light beam into the single-point photodiode. The performance of home-made OSPD is characterized with working distances from 1 m to 13 m and further analyzed utilizing established geometric model. The experimental and analytic results verify that our new device is highly suitable for large-scale coordinate metrology. The developed device also holds great potential in various applications such as omnidirectional vision sensor, indoor global positioning system, optical wireless communication systems

MXene (Ti3C2Tx) and Carbon Nanotube Hybrid-Supported Platinum Catalysts for the High-Performance Oxygen Reduction Reaction in PEMFC

The metal–support interaction offers electronic, compositional, and geometric effects that could enhance catalytic activity and stability. Herein, a high corrosion resistance and an excellent electrical conductivity MXene (Ti3C2Tx) hybrid with a carbon nanotube (CNT) composite material is developed as a support for Pt. Such a composite catalyst enhances durability and improved oxygen reduction reaction activity compared to the commercial Pt/C catalyst. The mass activity of Pt/CNT-MXene demonstrates a 3.4-fold improvement over that of Pt/C. The electrochemical surface area of Pt/CNT–Ti3C2Tx (1:1) catalysts shows only 6% drop with respect to that in Pt/C of 27% after 2000 cycle potential sweeping. Furthermore, the Pt/CNT–Ti3C2Tx (1:1) is used as a cathode catalyst for single cell and stack, and the maximum power density of the stack reaches 138 W. The structure distortion of the Pt cluster induced by MXene is disadvantageous to the desorption of O atoms. This issue can be solved by adding CNT on MXene to stabilize the Pt cluster. These remarkable catalytic performances could be attributed to the synergistic effect between Pt and CNT–Ti3C2Tx