Series of overlay flux-cored wires with different content of TiO2 were fabricated, and different claddings of high-manganese steel are welded by flux cored arc welding (FCAW). The influences of TiO2 ...addition on the electrochemical behaviour of the FCAW claddings over a high-manganese steel were studied. The results demonstrate that all the LPR values of the overlay welded claddings are higher than that of the base metal. However, the LPR values did not increase with the addition of TiO2. The EIS simulation results indicate that the addition of titanium dioxide improves the corrosion resistance of the high-manganese steel cladding, and the trends of the Rp values is highly consistent with the change of LRP value. At the same time, the grain refinement was achieved by the TiO2 addition. In conclusion, the proper content of the titanium dioxide in high-manganese steel cladding contributes to its high LRP and Rp values, in this paper, the suitable content of the TiO2 addition is 20g (0.2wt.%).
In order to explore the effect of addition of mixed rare earths (MRE) on the wetting behavior and interfacial reaction between Sn-0.70Cu-0.05Ni solder and amorphous Fe84.3Si10.3B5.4 alloy, 0.25 wt.% ...percentage of the MRE, which are mainly elements La and Ce, were added into the solder. Results show it can refine the microstructure of the solder alloy, and there is limited change of melting temperature with the addition of MRE in the solder. The wettability of the solder on amorphous substrate is improved by adding 0.25 wt.% percentage of the MRE into Sn-0.70Cu-0.05Ni solder. Moreover, research results indicate that, with the increase of wetting temperature, the final equilibrium wetting angles of Sn-0.70Cu-0.05Ni and Sn-0.70Cu-0.05Ni-0.25MRE on amorphous substrate decrease gradually, indicating the better wettability at the higher wetting temperature. In addition, with the increase of temperature, the distribution of intermetallic compound (IMC) FeSn2 formed at the interface between the two solders and amorphous substrate is changed from discontinuous state to continuous state. The thickness of the interfacial IMC layer between solder and amorphous substrates reduced with the addition of MRE, indicating that the presence of 0.25 wt.% percentage of the MRE is effective in suppressing the growth of IMC layer.
Tight sandstone gas reservoirs commonly contain water, so liquid loading often appears near wellbores, leading to production decline and even shutdown of gas wells. Therefore, the study on the change ...of water saturation near wellbores is of great significance to understanding the water production mechanisms of gas wells. In this paper, a set of physical simulation experiment procedures of identifying the change of water saturation near wellbores was designed according to the principle of radial well seepage of gas wells, and the production performance after vertical well fracturing in gas reservoirs was simulated by connecting tight cores with a diameter of 10.5 cm, 3.8 cm and 2.5 cm in series in a descending order of distance. According to the depressurizing production mode of gas wells, tubes with small diameters of 20, 30, 40 and 50 μm were used to simulate gas well tubing to control the gas production rate. And the change of water saturation near wellbore in the process of depletion production and its influencing factors were investigated. Finally, combined with actual data of production wells, the water saturation and water production of gas wells near wellbores and in different zones were calculated at the above four different small diameters of tubes and the changes thereof were also analyzed. The following results were obtained. First, each gas production rate corresponds to a critical water saturation. When the initial water saturation is lower than the critical value, the formation water flowing near the wellbore and in the middle zone can be carried out along with the production of gas and no liquid loading is formed. Second, when the initial water saturation is higher than the critical value, a large amount of formation water migrating from the far-wellbore zones accumulates near the wellbore, and thus liquid loading occurs at the bottom hole. Third, when the initial water saturation is equal to the critical value, the higher the gas production rate is, the more easily liquid loading tends to form near the wellbore. Fourth, for the same water saturation, water production increases and recovery factor decreases with the increase of gas production rate. In conclusion, the cumulative water production chart of a gas well generated by the physical simulation experiment method proposed in this paper agrees well with the water production behavior of the corresponding gas well. The research results are conducive to the effective prediction of gas well water production and can be used as guidance for the reasonable gas well water control. Keywords: Tight sandstone gas reservoir, Near the wellbore, Water saturation, Tube with a small diameter, Plane radial seepage, Physical simulation experiment, Water production rate of gas well, Gas production rate, Water control
β-Sialon based composites were produced using a vertical reactor by carbothermal reduction reaction under nitrogen using fly ash and lignite chars to examine the effects of mixing, carbon content, ...reaction temperature and sintering time. The influences of chars as a reductant were further investigated in comparison with graphite. The evolution of phase and morphology in samples were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM). Mechanical stirring was favored to mix fly ash and chars, while ball-milling shove the chars with porous structure due to collisions of agate balls, preventing N2 penetration to the inner parts of reactants. When excess carbon was increased to 100%, a higher combustion reactivity of low-temperature chars resulted in the production of SiC phase. The evolution of β-Sialon with increasing reaction temperature showed the samples mixed with chars were more sensitive to reaction temperature than that with graphite. β-Sialon phase increased gradually with increasing sintering time to 6 h and decreased thereafter due to the decomposition or conversion of β-Sialon. These changes were more significantly for samples adding lignite chars. The optimal operation has been determined and rod-like β-Sialon whiskers with high aspect ratio appeared after performing the operation. In the growth process of whiskers, bead-shape whiskers were observed, suggesting that the growth mechanism was different from the conventional vapor–liquid–solid (VLS) mechanism.
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empirical mode decomposition (EMD) is an effective random noise attenuation method for use with seismic profiles mainly containing horizontal events. However, when a seismic event ...is not horizontal, the use of
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EMD, this study proposes an improved denoising approach that retrieves lost useful signals by detecting effective signal points in a noise section using local similarity and then designing a weighting operator for retrieving signals. Compared with conventional
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predictive filtering, and
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empirical mode decomposition predictive filtering, the new approach can preserve more useful signals and obtain a relatively cleaner denoised image. Synthetic and field data examples are shown as test performances of the proposed approach, thereby verifying the effectiveness of this method.
Cancer stem cells (CSCs), which have been isolated from various malignancies, were closely correlated with the occurrence, progression, metastasis and recurrence of the malignant cancer. Little is ...known about the tumor stem-like cells (TSLCs) isolated from benign tumors. Here we want to explore the global expression profile of RNA of tumor stem-like cells isolated from MMQ rat prolactinoma cells.
In this study, total RNA was extracted from MMQ cells and MMQ tumor stem-like cells. RNA expression profiles were determined by Agilent Rat 8 × 60 K Microarray. Then we used the qRT-PCR to test the result of Microarray, and found VEGFA had a distinct pattern of expression in MMQ tumor stem-like cells. Then WB and ELISA were used to confirm the VEGFA protein level of tumor sphere cultured from both MMQ cell and human prolactinoma cell. Finally, CCK-8 was used to evaluate the reaction of MMQ tumor stem-like cells to small interfering RNAs intervention and bevacizumab treatment.
The results of Microarray showed that 566 known RNA were over-expressed and 532 known RNA were low-expressed in the MMQ tumor stem-like cells. These genes were mainly involved in 15 different signaling pathways. In pathway in cancer and cell cycle, Bcl2, VEGFA, PTEN, Jun, Fos, APC2 were up-regulated and Ccna2, Cdc25a, Mcm3, Mcm6, Ccnb2, Mcm5, Cdk1, Gadd45a, Myc were down-regulated in the MMQ tumor stem-like cells. The expression of VEGFA were high in tumor spheres cultured from both MMQ cell and human prolactinomas. Down-regulation of VEGFA by small interfering RNAs partially decreased cell viability of MMQ tumor stem-like cells in vitro. Bevacizumab partially suppressed the proliferation of MMQ tumor stem-like cells.
Our findings characterize the pattern of RNA expression of tumor stem-like cells isolated from MMQ cells. VEGFA may act as a potential therapeutic target for tumor stem-like cells of prolactinomas.
A SmallSat mission concept is formulated here to carry out Time-varying Optical Measurements of Clouds and Aerosol Transport (TOMCAT) from space while embracing low-cost opportunities enabled by the ...revolution in Earth science observation technologies. TOMCAT’s “around-the-clock” measurements will provide needed insights and strong synergy with existing Earth observation satellites to 1) statistically resolve diurnal and vertical variation of cirrus cloud properties (key to Earth’s radiation budget), 2) determine the impacts of regional and seasonal planetary boundary layer (PBL) diurnal variation on surface air quality and low-level cloud distributions, and 3) characterize smoke and dust emission processes impacting their long-range transport on the subseasonal to seasonal time scales. Clouds, aerosol particles, and the PBL play critical roles in Earth’s climate system at multiple spatiotemporal scales. Yet their vertical variations as a function of local time are poorly measured from space. Active sensors for profiling the atmosphere typically utilize sun-synchronous low-Earth orbits (LEO) with rather limited temporal and spatial coverage, inhibiting the characterization of spatiotemporal variability. Pairing compact active lidar and passive multiangle remote sensing technologies from an inclined LEO platform enables measurements of the diurnal and vertical variability of aerosols, clouds, and aerosol-mixing-layer (or PBL) height in tropical-to-midlatitude regions where most of the world’s population resides. TOMCAT is conceived to bring potential societal benefits by delivering its data products in near–real time and offering on-demand hazard-monitoring capabilities to profile fire injection of smoke particles, the frontal lofting of dust particles, and the eruptive rise of volcanic plumes.
Although many studies have evaluated the association between breast cancer (BC) and thyroid cancer (TC), this association has not been completely studied. In this study, we focused on the effect of ...BC as the first or second primary cancer on survival among women with TC. We present the following article in accordance with the STROBE reporting checklist.
Using the Surveillance, Epidemiology, and End Results (SEER) database, we performed a retrospective cohort analysis of 134,785 women with BC and TC between 1974 and 2016. The patients were divided into three subgroups, namely, TC only (TC group, n=128,888), BC after TC (TC2BC group, n=3,000), and BC before TC (BC2TC group, n=2,897). The curves for overall survival (OS) and cancer-specific survival (CSS) were evaluated, and Cox regression analyses were performed to examine the effect of BC as the first and second primary cancer on the CSS and OS of TC patients.
The CSS rates in the TC, TC2BC, and BC2TC groups were 96.96%, 98.70%, and 96.70%, respectively, and the OS rates were 91.17%, 77.13%, and 78.63%, respectively. Using the TC group as a reference, the hazard ratios (HRs) for the CSS of the TC2BC and BC2TC groups were 0.333 95% confidence interval (CI): 0.243-0.456, P<0.001 and 1.299 (95% CI: 1.062-1.589, P=0.011), respectively. The corresponding HRs for the OS were 1.544 (95% CI: 1.428-1.668, P<0.001) and 3.429 (95% CI: 3.158-3.724, P<0.001), respectively.
Among the female patients with TC, BC, as the second primary cancer, has a significant protective effect on the CSS of TC patients; however, when BC is the first primary cancer, it is a risk factor. Besides, BC is a risk factor for the OS of TC patients, especially for patients who develop TC after BC.
The spatial and angular emission patterns of artificial and natural light emitted, scattered, and reflected from the Earth at night are far more complex than those for scattered and reflected solar ...radiation during daytime. In this commentary, we use examples to show that there is additional information contained in the angular distribution of emitted light. We argue that this information could be used to improve existing remote sensing retrievals based on night lights, and in some cases could make entirely new remote sensing analyses possible. This work will be challenging, so we hope this article will encourage researchers and funding agencies to pursue further study of how multi‐angle views can be analyzed or acquired.
Plain Language Summary
When satellites take images of Earth, they usually do so from directly above (or as close to it as is reasonably possible). In this comment, we show that for studies that use imagery of Earth at night, it may be beneficial to take several images of the same area at different angles within a short period of time. For example, different types of lights shine in different directions (street lights usually shine down, while video advertisements shine sideways), and tall buildings can block the view of a street from some viewing angles. Additionally, since views from different directions pass through different amounts of air, imagery at multiple angles could be used to obtain information about Earth's atmosphere, and measure artificial and natural night sky brightness. The main point of the paper is to encourage researchers, funding agencies, and space agencies to think about what new possibilities could be achieved in the future with views of night lights at different angles.
Key Points
Remote sensing using the visible band at night is more complex than during the daytime, especially due to the variety of artificial lights
Views of night lights intentionally taken from multiple angles provide several advantages over near‐nadir or circumstantial view geometries
Night lights remote sensing would benefit from greater consideration of the role viewing geometry plays in the observed radiance
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