The surface modification of the equiatomic CoCrFeNi high-entropy alloy has been studied via solid carburization at 920 °C for 10 h. Microstructure, hardness and wear resistance were investigated by ...X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), microhardness and nanoindentation tester. Microstructure and phase analysis indicated that two types of nano-size carbide precipitates (M7C3 and M23C6) formed in the surface. The orientation relationship between the M7C3 precipitate and FCC matrix were (1(_)100)C1//(11(_)1)M and 0001C1//1(_)12M. The M23C6 precipitate possessed a cube-cube orientation relationship with the FCC matrix. Vickers hardness and nanoindentation testing results indicated that the carburized surface performed significant improvement of about 100% in hardness compared with the matrix. The strengthening mechanisms including solid-solution strengthening and precipitate strengthening were studied. Moreover, nano-scratch experiments have been conducted on the cross section of the carburized sample under a constant load mode to investigate the friction and wear behavior. The surface profile and depth of scratched tracks were examined using scanning probe microscopy (SPM) technology. The wear and deformation mechanisms at different distances from the surface have been discussed. The calculated values of the wear volume, wear rate, and wear resistance coefficient reveal that the carbide precipitates can improve the wear resistance of the carburized surface.
•The hard carbide coating was fabricated through solid carburization for CoCrFeNi HEA.•The surface hardness and wear resistance were enhanced significantly.•The carburized layer containing M7C3 and M23C6 carbide precipitates was detected.•The precipitation and solution hardening mechanism was studied.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
We show that magnetic response at terahertz frequencies can be achieved in a planar structure composed of nonmagnetic conductive resonant elements. The effect is realized over a large bandwidth and ...can be tuned throughout the terahertz frequency regime by scaling the dimensions of the structure. We suggest that artificial magnetic structures, or hybrid structures that combine natural and artificial magnetic materials, can play a key role in terahertz devices.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
This paper investigates why Chinese state-owned enterprises (SOEs) with strong political connections (i.e., politically connected firms) are more likely to list overseas than non-politically ...connected firms. We find that connected firms' post-overseas listing performance is worse than that of non-connected firms. This evidence suggests that connected firms' managers list their firms overseas for private (political) benefits. Consistent with this private benefits explanation, we further find that connected firms' managers are more likely to receive political media coverage or a promotion to a senior government position subsequent to overseas listing than domestic listing.
► Chinese SOEs with strong political connections are more likely to list overseas. ► Politically connected firms perform worse after overseas listing. ► Connected managers receive more private political benefits after overseas listing.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Abstract Diabetes mellitus (DM) adversely affects the number and function of circulating endothelial progenitor cells (EPCs). Consequently, there is also a reduction in the repair mechanism of these ...cells, which is a critical and initiating factor in the development of diabetic vascular disease. The aim of the present study was to analyze miR expression profiles in EPCs from patients with DM and choose the most significantly regulated miR to study its possible role on EPC dysfunction and elucidate its mechanism of action. EPCs were collected from subjects with Type II DM and non-diabetic control subjects. Total RNA was harvested from EPCs, and a total of 5 candidate miRNAs were identified by microarray screening and were quantified by TaqMan real-time PCR. Lentiviral vectors expressing miR-126 and miR-126 inhibitor (anti-miR-126) were transfected into EPCs, and the EPC colony-forming capacity, proliferation activity, migratory activity, differentiation capacity, and apoptotic susceptibility were determined and Western Blotting and mRNA real-time PCR analyses were performed. To study the mechanisms, lentiviral vectors expressing Spred-1 and a short interfering RNA (siRNA) targeting Spred-1 were prepared. Five miRs were aberrantly downregulated in EPCs from DM patients. These miRs included miR-126, miR-21, miR-27a, miR-27b and miR-130a. Anti-miR-126 inhibited EPC proliferation, migration, and enhanced apoptosis. Restored miR-126 expression in EPCs from DM promoted EPC proliferation, migration, and inhibited EPC apoptosis ability. Despite this, miR-126 had no effect on EPC differentiation. miR-126 overexpression significantly downregulated Spred-1 in EPCs. The knockdown of Spred-1 expression in EPCs from DM promoted proliferation, migration, and inhibited apoptosis of the cells. The signal pathway of miR-126 effecting on EPCs is partially mediated through Ras/ERK/VEGF and PI3K/Akt/eNOS regulation. This study provides the first evidence that miR-126 is downregulated in EPCs from diabetic patients, and impairs EPCs-mediated function via its target, Spred-1, and through Ras/ERK/VEGF and PI3K/Akt/eNOS signal pathway.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Substantial anthropogenic emissions from China have resulted in serious air pollution, and this has generated considerable academic and public concern. The physical transport of air pollutants in the ...atmosphere has been extensively investigated; however, understanding the mechanisms how the pollutant was transferred through economic and trade activities remains a challenge. For the first time, we quantified and tracked China's air pollutant emission flows embodied in interprovincial trade, using a multiregional input-output model framework. Trade relative emissions for four key air pollutants (primary fine particle matter, sulfur dioxide, nitrogen oxides and non-methane volatile organic compounds) were assessed for 2007 in each Chinese province. We found that emissions were significantly redistributed among provinces owing to interprovincial trade. Large amounts of emissions were embodied in the imports of eastern regions from northern and central regions, and these were determined by differences in regional economic status and environmental policy. It is suggested that measures should be introduced to reduce air pollution by integrating cross-regional consumers and producers within national agreements to encourage efficiency improvement in the supply chain and optimize consumption structure internationally. The consumption-based air pollutant emission inventory developed in this work can be further used to attribute pollution to various economic activities and final demand types with the aid of air quality models.
Generation of efficient light-induced charge separation inside the photocatalyst is an essential factor for a high catalytic efficiency. The usual immobilization of metal or metal oxide particles on ...semiconductor photocatalysts offers an uncontrolled assembly of active sites during the reaction. The introduction of single metal atoms on photocatalysts can lead to extremely high atomic utilization and precise active sites. However, this approach is limited because of the lack of suitable photosensitizers for single atom immobilization. Here, we have designed photocatalytic carbon quantum dots with anchoring sites for single cobalt atoms in a defined Co–N4 structure via facile pyrolysis of vitamin B12. Carbon dots functioned as both light-harvesting antenna and support for the cobalt atom with high atom loadings up to 3.27 wt %. This new photocatalytic material demonstrated enhanced visible light absorption, efficient charge separation, and reduced electrochemical impedance, while single Co atoms acted as the active site with strong oxidative ability. As a result, the photocatalysts showed excellent visible light-promoted photocatalytic efficiency with oxygen evolution rates up to 168 μmol h–1 g–1 via water oxidation, imine formation with high conversion (∼90%) and selectivity (>99%), and complete photodegradation of organic dyes.
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IJS, KILJ, NUK, PNG, UL, UM
CCUS technology has the potential to reduce emissions substantially from the whole lifecycle of traditional energy-intensive industry on a large-scale basis. A summary of the current status of CCUS ...in China is viewed as a necessary background and a starting point for the content of the following paper. Next, the positioning and analysis of China's future CCUS development are presented by answering the following questions "Why does China need CO sub(2) utilization?" and "How much of the CO sub(2) emission reductions which result from CCUS technology does China need to be responsible for?". Then, the important influential factors of China's CCUS development are summarized into three aspects (technology maturity, technology sustainability, and external impact factors). Finally, based on these findings, some important comments and suggestions are proposed for the future RD&D of CCUS technology in China.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Although entanglement is considered as an essential resource for quantum information processing, whether entanglement helps for energy conversion or output in the quantum regime is still lack of ...experimental witness. Here, we report on an energy-conversion device operating as a quantum engine with the working medium acted by two entangled ions confined in a harmonic potential. The two ions are entangled by virtually coupling to one of the vibrational modes shared by the two ions, and the quantum engine couples to a quantum load, which is another shared vibrational mode. We explore the energy conversion efficiency of the quantum engine and investigate the useful energy (i.e., the maximum extractable work) stored in the quantum load by tuning the two ions in different degrees of entanglement as well as detecting the change of the phonons in the load. Our observation provides, for the first time, quantitative evidence that entanglement fuels the useful energy produced by the quantum engine, but not helpful for the energy conversion efficiency. We consider that our results may be useful to the study of quantum batteries for which one of the most indexes is the maximum extractable energy.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UL, UM
The first searches for axions and axionlike particles with the Large Underground Xenon experiment are presented. Under the assumption of an axioelectric interaction in xenon, the coupling constant ...between axions and electrons g_{Ae} is tested using data collected in 2013 with an exposure totaling 95 live days ×118 kg. A double-sided, profile likelihood ratio statistic test excludes g_{Ae} larger than 3.5×10^{-12} (90% C.L.) for solar axions. Assuming the Dine-Fischler-Srednicki-Zhitnitsky theoretical description, the upper limit in coupling corresponds to an upper limit on axion mass of 0.12 eV/c^{2}, while for the Kim-Shifman-Vainshtein-Zhakharov description masses above 36.6 eV/c^{2} are excluded. For galactic axionlike particles, values of g_{Ae} larger than 4.2×10^{-13} are excluded for particle masses in the range 1-16 keV/c^{2}. These are the most stringent constraints to date for these interactions.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
Breast cancer is an extraordinarily hormone-dependent tumor. This study was to evaluate androgen receptor (AR) status and its significance in breast cancer in Chinese women.
Three hundred and ...thirty-five consecutive cases of invasive ductal breast carcinoma, 34 ductal carcinoma in situ (DCIS), and 82 DCIS adjacent to invasive tissues were involved in this study. The expression of AR was analyzed by immunohistochemistry and compared with patient outcome, and its implications were evaluated in five molecular subgroups of invasive ductal carcinoma (IDC) and in DCIS lesions.
AR expression was related to that of estrogen receptor (P < 0.001) and progesterone receptor (P = 0.035) but not correlated with the other conventional parameters. AR retained independent prognostic significance (hazard ratio 0.309, 95% confidence interval, 0.192–0.496; P < 0.001). The majority (61.0%) of basal-like breast cancers showed loss of AR expression (P < 0.001), which had poor prognosis. The percentage of AR-positive cases was significantly higher in DCIS adjacent to IDC group than in pure DCIS and IDC groups (93.9%, 79.4%, and 72.5%; P = 0.046 and P < 0.001, respectively).
Our data suggest that AR may provide another specific definition of breast cancer subtypes and reveal a potential role in DCIS progression. These findings may help develop new therapies.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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