Search

Additional file 1: Figure S1. Kaplan-Meier curves of PFS in patients with cervical cancer. (a): Number of births; (b): Adjuvant radiotherapy or chemotherapy; (c): P53; (d): Ki-67; (e): ER; (f): PR; (g): BMI; (h): HPV; (i): Pathological type; (j): Pathological differentiation degree. PFS, progression-free survival.

Static and dynamic mechanical properties of cement-asphalt composites with various contents of asphalt incorporated were studied. Uniaxial compressive stress-strain curves of different cement-asphalt mortars (CAMs) with cement mass ratio (A/C) in the range of 0.2 to 1.0 were obtained by the Materials Testing System (MTS) under different testing temperatures ranging from −40 to 80°C. Two typical CAMs, one with A/C of 0.2 denoted by LAC and the other with A/C of 0.9 denoted by HAC, were chosen to be tested at varied deformation rates over a range of 0.3 to 30 mm/min at room temperature. The correlation between mechanical properties, e.g., peak stress or elastic modulus, and temperature or loading rate was, respectively, acquired. As a result, temperature sensitivity and loading rate dependence for mechanical behavior of different CAMs were analyzed. Dynamic mechanical analysis (DMA) on three cement-asphalt binders (CABs) with A/Cs from 0.2 to 1.0 was carried out, and temperature spectra and frequenc...

The strength mechanisms of two kinds of cement-asphalt (CA) mortar, which vary principally in their strength and elastic modulus, were investigated by environmental scanning electron microscopy, calorimetry, and strength tests. The results showed that the asphalt emulsion delayed the early hydration of the cement and the asphalt membrane had a negative effect on the further hydration of the cement, to some extent. The cement products could impale the asphalt membrane, and the cement could hydrate adequately because of the sufficient water supply in the CA mortar. The framework formed by the hardened cement paste was the primary structure skeleton in the CA mortar with a high elastic modulus and the asphalt phase, exhibiting as a filling phase, increased the weak phase of the structure system. For CA mortar with a low elastic modulus, the asphalt phase exhibited as a dominant phase. Two weak structure skeletons, formed by the asphalt membrane and the hardened cement paste, respectively, were responsible fo...

This study focuses on the indoor location system based on radio fingerprinting, and a grid positioning method based on weighted Euclidean distance matching by RSSI statistic parameters is presented in this paper. We analyze the principle of location fingerprint system and study the signal intensity distribution characteristics in indoor environment. According to the unsteadiness problem of the indoor signal strength caused by environmental impact, the positioning parameter model based on distributed grid is given. Moreover, the grid matching location algorithm is put forward based on the RSSI statistic parameters fusion estimation. Attributed to the proposed two-dimensional grid model, the algorithm is fit for the rapid matching calculations in continuous positioning case. Simulation results show that the approach has better robustness and accuracy, and it can effectively solve the problem of location estimates stability in general RSSI location fingerprinting system.

According to indoor wireless environment and signal propagation model, an indoor location algorithm based on grid characteristics match by TDOA-RSSI combining is put forward in this paper, in which the RSSI and TDOA parameters are combined as grid characteristic parameters to calculate the weighted Euclidean distance. The location algorithm adopts KWNN algorithms for grid matching and location estimate. Simulation results show that this algorithm has better robustness and accuracy, and can effectively solve the problem of location estimates stability in general RSSI fingerprint location system.

The interface diffusion and chemical reaction between a PZT (PbZrxTi1-xO3) layer and a Si(111) substrate during the annealing treatment in air have been studied by using XPS (X-Ray Photoelectron Spectroscopy) and AES (Auger Electron Spectroscopy). The results indicate that the Ti element in the PZT precursor reacted with residual carbon and silicon, diffused from the Si substrate, to form TiCx, TiSix species in the PZT layer during the thermal treatment. A great interface diffusion and chemical reaction took place on the interface of PZT/Si also. The silicon atoms diffused from silicon substrate onto the surface of PZT layer. The oxygen atoms, which came from air, diffused into silicon substrate also and reacted with Si atoms to form a SiO2 interlayer between the PZT layer and the Si (111) substrate. The thickness of SiO2, interlayer was proportional to the square root of treatment time. The formation of the SiO2 interlayer was governed by the diffusion of oxygen in the PZT layer at low annealing temperature, and governed by the diffusion of oxygen in SiO2 interlayer at high annealing temperature. The apparent activation energy of the interface oxidation reaction was about 39.1 kJ/mol.

The effects of the Pt diffusion barrier layer on the interface diffusion and reaction, crystallization, dielectric and ferroelectric properties of the PZT/Si(111) sample have been studied using XPS, AES and XRD techniques. The results indicate that the Pt diffusion barrier layer between the PZT layer and the Si substrate prohibits the formation of TiCx, TiSix and SiO2 species in the PZT layer. The Pt barrier layer also completly interrupts the diffusion of Si from the Si substrate into the PZT layer and impedes the diffusion of oxygen from air to the Si substrate greatly. Although the Pt layer can not prevent completely the diffusion and reaction between oxygen and silicon, it can prevent the formation of a stable SiO2 interface layer on the interface of PZT/Si. The Pt layer reacts with silicon to form PtSix species on the interface of Pt/Si, which can intensify the chemical binding strength between the Pt layer and the Si substrate. To play a good role as a diffusion barrier layer, the Pt barrier layer must be not thinner than 140 nm. The existence of the Pt layer not only promotes the crystallization of PZT layer to form a perovskite phase but also improves dielectric and ferroelectric performances of the PZT layer.

The hydration products and microstructure of class G oil well cement and a newly developed plugging agent (YLD) slurries cured in the simulated temperature and pressure environment, which was of similar temperature and pressure with those at the bottom of oil well in a normal depth, were investigated using XRD, TG and SEM. Severe leakage is confirmed at the interface between hardened slurries and steel tube during the dynamically curing process, which induces the quick loss of cementing property of slurries. This should be the dominating cause of degradation of class G oil well cement slurry. A secondary hydration process can take place at the eroded interface of hardened YLD plugging agent slurry. Newly formed C-S-H gel has a self-healing effect to repair the damaged interface, which unceasingly maintains the cementing property of the YLD plugging agent slurry. Therefore, the effective using period of YLD plugging agent can be prolonged.

An algorithm was developed to Fourier-transform the measuring data of galvanostatic pulse method (GPM) from the time domain into the frequency domain. The polarization resistance and ohmic resistance are determined in the time domain; the impedance spectrum and disperse parameter are obtained in the frequency domain to characterize the corrosion status of reinforcement in concrete. Based on the investigation upon the different corrosion status of rebars in solution and in concrete, the criterions of depassivation are discussed.

In a downlink multiuser multi-input multi-output (MU-MIMO) communication system, a base station (BS) transmits to multiple mobile stations (MS) simultaneously over the same frequency band, thereby greatly increasing the channel capacity. However, in previous works, the multiuser spatial multiplexing system has no special strategies for selecting the multiuser channel. Although the exhaustive search algorithm can achieve optimal performance, its cost is large. In this paper, we propose a suboptimal user selection algorithm for the MU-MIMO system to save hardware resources and serve more users. The proposed selecting criterion bases on maximum total throughput by selecting the best channel of user. To reduce the complexity further more, we give out an iterative selection scheme. Compared with the optimal algorithm, the proposed algorithm achieves good sum capacity performance, has lower complexity, and is suitable for practical communication system. Simulation results show the performance of the proposed scheme.

The Location based services (LBS) are become increasingly important on telecommunication applications. Many LBS methods have been developed. Mobile station location technologies, including Cell-identification (CI), Enhanced Observed Time Difference (E-OTD), Observed Timed Difference of Arrival (OTDOA), and other third Generation (3G) location technologies, are evaluated in the paper. Above of all, the Assisted GNSS (A-GNSS) is analyzed to settle for emergency LBS. The technical advantages to widen AGPS to A-GNSS is developed to focus on the availability and accuracy of LBS. The architecture of software receiver for an integrated GNSS/UMTS is presented to meet the important requirements of seamless indoor/outdoor navigation and communication capability for emergency LBS. The principle platform of an integrated GNSS/GSM/CDMA based on the structure of " Single RF+PC" is implemented. By collecting and processing actual GPS data, the receiver is able to perform PVT calculations with high accuracy and rapid positioning.