Direct in situ synthesis of a 3D interlinked amorphous carbon nanotube/graphene/BaFe12O19 composite and its electromagnetic wave absorbing properties

2016-2017 > Academic research: refereed > Publication in refereed journalbcrcVersion of RecordPublishe

Portland Cement Hydration Behavior at Low Temperatures: Views from Calculation and Experimental Study

Environmental condition affects the property of construction materials. This study gives an initial understanding of Portland cement hydration under low temperatures from the views of laboratory experiments (including electrical resistivity, degree of hydration (DoH), and maturity) as well as thermodynamic calculation. The hydrates of Portland cement at the given period were detected with X-ray diffraction (XRD), and their microstructure was observed by scanning electron microscope (SEM). Experiment result (i.e., DoH and electrical resistivity) indicated that the hydration of Portland cement was delayed by low temperature without hydration stopping at −5°C. Based on a basic kinetics model, the thermodynamic calculation predicted that the final hydrate differs in dependence on environmental temperatures. The mechanical behavior trend of Portland cement paste affected by low temperatures potentially is linked to the appearing of aluminate compounds and reduction of portlandite

SPACEBORNE MULTIFUNCTIONAL DATA ACQUISITION SYETEM

International Telemetering Conference Proceedings / November 04-07, 1991 / Riviera Hotel and Convention Center, Las Vegas, NevadaThis paper introduces a multifunctional data acquisition system which has been developed. This system contains micro-computer and electronic memory, it adopts the method of hardware and software cooperation to control data acquisition, encoding, handling, storage and sending. It can acquire analog signal and digital signal, then output PCM data, and send data to transmitter after PSK modulation. It can real-time execute clock switching, changing of bit rate, writing data into memory or reading data from memory etc., according to the external command. The major handling function is data compression to reduce delayed data capacity. Basic characteristic of system, design consideration, data compression means and experiment result is represented in the paper, and emphasises on the handling means of independent subframe data inserted in digit form, and different design means of two electronic memory ( RAM and E PROM ) .International Foundation for TelemeteringProceedings from the International Telemetering Conference are made available by the International Foundation for Telemetering and the University of Arizona Libraries. Visit http://www.telemetry.org/index.php/contact-us if you have questions about items in this collection

Boosting efficiency of planar heterojunction perovskite solar cells by a low temperature TiCl4 treatment

It is well known that electron transport layer (ETL) plays an indispensable role in the planar heterojunction perovskite solar cells (PSCs). TiO2 is widely used as an ETL material due to its excellent transport properties, however, the presence of defects in the TiO2 layer diminishes the power conversion efficiency (PCE) of the devices. Herein, we introduce a method of low-temperature TiCl4 treatment to deposit a TiOx layer on the surface of TiO2 film, which can effectively passivate trap states at the TiO2 surface. Moreover, the treating process is optimized to be 30min using a 40mM TiCl4 aqueous solution. Benefiting from this, we obtain the champion device with the highest PCE of 18.47%, which is mainly due to the reduction of surface defects and the deposition of the well-crystallized perovskite films. Besides, the modified PSCs exhibit an average PCE of 17.59%, which is much better than the control devices

Estimating Soil Organic Carbon Using VIS/NIR Spectroscopy with SVMR and SPA Methods

With 298 heterogeneous soil samples from Yixing (Jiangsu Province), Zhongxiang and Honghu (Hubei Province), this study aimed to combine a successive projections algorithm (SPA) with a support vector machine regression (SVMR) model (SPA-SVMR model) to improve the estimation accuracy of soil organic carbon (SOC) contents using the laboratory-based visible and near-infrared (VIS/NIR, 350−2500 nm) spectroscopy of soils. The effects of eight spectra pre-processing methods, i.e., Log (1/R), Log (1/R) coupled with Savitzky-Golay (SG) smoothing (Log (1/R) + SG), first derivative with SG smoothing (FD), second derivative with SG smoothing (SD), SG, standard normal variate (SNV), mean center (MC) and multiplicative scatter correction (MSC), on SPA-based informative wavelength selection were explored. The SVMR model (i.e., SVMR without SPA) and SPA-PLSR model (i.e., SPA combined with partial least squares regression (PLSR)) were developed and compared with the SPA-SVMR model in order to evaluate the performance of SPA-SVMR. The results indicated that the variables selected by SPA and their distributions were strongly affected by different pre-processing methods, and SG was the optimal pre-processing method for SPA-SVMR model development; the SPA-SVMR model using SG pre-processing and 28 SPA-selected wavelengths obtained a better result (R2V = 0.73, RMSEV = 2.78 g∙kg−1 and RPDV = 1.89) and outperformed the SVMR model (R2V = 0.72, RMSEV = 2.83 g∙kg−1 and RPDV = 1.86) and the SPA-PLSR model (R2V = 0.62, RMSEV = 3.23 g∙kg−1 and RPDV = 1.63). Most of the spectral bands used by the SPA-SVMR model over the near-infrared region were important wavelengths for SOC content estimation. This study demonstrated that the combination of SPA and SVMR is feasible and reliable for estimating SOC content from the VIS/NIR spectra of soils in regions with multiple soil and land-use types

Germanium doping and impurities analysis on industrial scale mc-silicon ingot

Conference Name:2012 2nd International Conference on Mechanical Engineering, Industry and Manufacturing Engineering, MEIME 2012. Conference Address: Hefei, China. Time:June 23, 2012 - June 24, 2012.International Science and Education Researcher Association; Beijing Gireida Education Research Center; VIP-Information Conference CenterWith mc-silicon (multi-crystalline silicon) being the most favorable feedstock for solar cell, germanium was reported to be a promising dopant to improve the quality of silicon crystal growth. In this paper, we investigated the feasibility of germanium doping for industrial scale production. A homogeneously distribution of germanium across usable section is presented, and subsequently we optimized our recipe for better controlling it. Sopori etched pits were utilized to reveal dislocations in silicon wafers, and we found a reduced dislocations density in germanium doped samples. Carbon and oxygen are two inevitable significant impurities during silicon ingot casting. In this paper, experimental results showed the impact of carbon on minority charge carrier lifetime and on interstitial oxygen. In addition, Isostatic pressing method is proved to be very prospective for recycling quartz crucibles. 漏 (2012) Trans Tech Publications