An overview of Sun–Sky Radiometer Observation Network (SONET) measurements in China is presented. Based on observations at 16 distributed SONET sites in China, atmospheric aerosol parameters are ...acquired via standardization processes of operational measurement, maintenance, calibration, inversion, and quality control implemented since 2010. A climatology study is performed focusing on total columnar atmospheric aerosol characteristics, including optical (aerosol optical depth, ÅngstrÖm exponent, fine-mode fraction, single-scattering albedo), physical (volume particle size distribution), chemical composition (black carbon; brown carbon; fine-mode scattering component, coarse-mode component; and aerosol water), and radiative properties (aerosol radiative forcing and efficiency). Data analyses show that aerosol optical depth is low in the west but high in the east of China. Aerosol composition also shows significant spatial and temporal variations, leading to noticeable diversities in optical and physical property patterns. In west and north China, aerosols are generally affected by dust particles, while monsoon climate and human activities impose remarkable influences on aerosols in east and south China. Aerosols in China exhibit strong light-scattering capability and result in significant radiative cooling effects.
Two NiO products with different microstructures have been obtained using a traditional NaOH-induced aqueous-phase precipitation and a homogeneous precipitation in choline chloride/urea mixture-based ...deep eutectic solvent (DES), respectively. The synthesis processes play a key role in the structure construction of NiO precursors as well as the final NiO products, and possible formation mechanisms are proposed. The DES-based homogeneous precipitation method provides plentiful nucleation sites, moderate crystal growth process and possible template effect, which could conduce to the production of flower-like NiO with continuously self-supporting mesoporous structure assembled by tiny grains. The flower-like NiO electrode exhibits higher current density, faster charge-transfer process, better electrode accessibility, and improved stability for methanol electro-oxidation in an electrolyte of 0.1 M CH3OH + 0.005 M KOH than the disorderly aggregated NiO nanoparticles. We believe that the DES-based homogeneous precipitation method can provide an effective approach to fabricate advanced electrocatalyst materials with homogeneous and well-assembled microstructure.
•Synthesis of α-Ni(OH)2 nanostructure by a novel precipitation strategy in ionic liquid.•Annealing the flower-like α-Ni(OH)2 produces mesoporous NiO electrode.•Mesoporous structure of NiO is assembled by ∼5 nm sized grains.•Mesoporous structure is better than nanoparticulate for methanol electro-oxidation.
Leptomeningeal metastases (LM) are more frequent in non-small-cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) mutations. Due to limited access to leptomeningeal lesions, the ...purpose of this study was to explore the potential role of cerebrospinal fluid (CSF) as a source of liquid biopsy in patients with LM.
Primary tumor, CSF, and plasma in NSCLC with LM were tested by next-generation sequencing. In total, 45 patients with suspected LM underwent lumbar puncture, and those with EGFR mutations diagnosed with LM were enrolled.
A total of 28 patients were enrolled in this cohort; CSF and plasma were available in 26 patients, respectively. Driver genes were detected in 100% (26/26), 84.6% (22/26), and 73.1% (19/26) of samples comprising CSF cell-free DNA (cfDNA), CSF precipitates, and plasma, respectively; 92.3% (24/26) of patients had much higher allele fractions in CSF cfDNA than the other two media. Unique genetic profiles were captured in CSF cfDNA compared with those in plasma and primary tissue. Multiple copy number variations (CNVs) were mainly identified in CSF cfDNA, and MET copy number gain identified in 47.8% (11/23) of patients was the most frequent one, while other CNVs included ERBB2, KRAS, ALK, and MYC. Moreover, loss of heterozygosity (LOH) of TP53 was identified in 73.1% (19/26) CSF cfDNA, which was much higher than that in plasma (2/26, 7.7%; P<0.001). There was a trend towards a higher frequency of concomitant resistance mutations in patients with TP53 LOH than those without (70.6% versus 33.3%; P=0.162). EGFR T790M was identified in CSF cfDNA of 30.4% (7/23) of patients who experienced TKI progression.
CSF cfDNA could reveal the unique genetic profiles of LM and should be considered as the most representative liquid biopsy medium for LM in EGFR-mutant NSCLC.
Flexible thermoelectric (TE) materials have wide applications in fabricating portable/wearable devices owing to the advantages of being bendable, small size, and lightweight. Inorganic material–based ...flexible thin films have attracted much attention owing to their high TE performance. So far, developing high TE properties and environment friendly flexible thin films for practical applications is still a considerable challenge. Copper selenide (Cu2Se) is a non-toxic and low-cost material, providing relatively safe TE modules for thin film devices. In this work, Cu2Se-based thin films with single crystal phase have been fabricated successfully at a flexible substrate by an efficient layer-by-layer combination reaction method. By optimizing the composition, a high power factor of 5.3 μWcm−1K−2 and dimensionless figure of merit value of 0.35 with low thermal conductivity are achieved at room temperature. Through bending tests, it has been shown that the prepared thin films possess good flexibility and the designed flexible device displays stable output power, which demonstrates the potential of inorganic TE materials to be mountable on flexible/wearable substrates for energy harvesting and management devices.
The well-crystallized Cu2Se thermoelectric thin films have been synthesized via an efficient layer-by-layer combination reaction method, and the high power factor of 5.3 μWcm−1K−2 and ZT value of 0.35 with low thermal conductivity are achieved at room temperature by optimizing the composition. Cu2Se, copper selenide; ZT, dimensionless figure of merit. Display omitted
•The layer-by-layer combination reaction method was used for preparing high-performance copper selenide (Cu2Se) thin films.•The self-assembled growth of Cu2Se with single crystal phase was successfully realized.•A high power factor of 5.3 μWcm−1K−2 and dimensionless figure of merit value of 0.35 are achieved at room temperature.•The thin film possesses good flexibility, and the designed flexible device displays stable output power.
A non-classical third-order shear deformation plate model is developed using a modified couple stress theory and Hamilton’s principle. The equations of motion and boundary conditions are ...simultaneously obtained through a variational formulation. This newly developed plate model contains one material length scale parameter and can capture both the size effect and the quadratic variation of shear strains and shear stresses along the plate thickness direction. It is shown that the new third-order shear deformation plate model recovers the non-classical Reddy-Levinson beam model and Mindlin plate model based on the modified couple stress theory as special cases. Also, the current non-classical plate model reduces to the classical elasticity-based third-order shear deformation plate model when the material length scale parameter is taken to be zero. To illustrate the new model, analytical solutions for the static bending and free vibration problems of a simply supported plate are obtained by directly applying the general forms of the governing equations and boundary conditions of the model. The numerical results show that the deflection and rotations predicted by the new plate model are smaller than those predicted by its classical elasticity-based counterpart, while the natural frequency of the plate predicted by the former is higher than that by the latter. It is further seen that the differences between the two sets of predicted values are significant when the plate thickness is small, but they are diminishing with increasing plate thickness.
► In practice, many tunnels are shallow, and are subjected to supporting pressure. ► A new failure mechanism is proposed for shallow tunnels with the consideration of supporting pressure. ► The ...critical depth for classifying shallow and deep tunnels is established. ► The width of the failure block increases as the supporting pressure increases.
Collapse shape of shallow circular tunnel is derived using a new curved failure mechanism within the framework of upper bound theorem. Nonlinear Hoek–Brown failure criterion is adopted in the present analysis. With the consideration of supporting pressure, the energy dissipations of the new failure mechanism are calculated by employing integral technique. Equating the rate of energy dissipation to the external rate of work, the objective function is formulated, and is optimized with the variational approach. Numerical results are presented, and collapse mechanisms of shallow tunnel taking into account supporting pressure are obtained. The present results are compared with the previous solutions, and the agreement shows that the present method is valid. The effects of different parameters on the failure mechanisms are discussed, and a critical depth expression is proposed for classifying shallow and deep tunnels.
To retrospectively analyze the treatment status of tyrosine kinase inhibitors (TKI) in newly diagnosed patients with chronic myeloid leukemia (CML) in China.
Data of chronic phase (CP) and ...accelerated phase (AP) CML patients diagnosed from January 2006 to December 2022 from 77 centers, ≥18 years old, and receiving initial imatinib, nilotinib, dasatinib or flumatinib-therapy within 6 months after diagnosis in China with complete data were retrospectively interrogated. The choice of initial TKI, current TKI medications, treatment switch and reasons, treatment responses and outcomes as well as the variables associated with them were analyzed.
6 893 patients in CP (
=6 453, 93.6%) or AP (
=440, 6.4%) receiving initial imatinib (
=4 906, 71.2%), nilotinib (
=1 157, 16.8%), dasatinib (
=298, 4.3%) or flumatinib (
=532, 7.2%) -therapy. With the median follow-up of 43 (
22-75) months, 1 581 (22.9%) patients switched TKI due to resistance (
=1 055, 15.3%), intolerance (
=248, 3.6%), pursuit of better efficacy (
=168,
Observation of Weyl nodes in TaAs Lv, B. Q.; Xu, N.; Weng, H. M. ...
Nature physics,
09/2015, Letnik:
11, Številka:
9
Journal Article
Recenzirano
Odprti dostop
In 1929, H. Weyl proposed that the massless solution of the Dirac equation represents a pair of a new type of particles, the so-called Weyl fermions1. However, their existence in particle physics ...remains elusive after more than eight decades. Recently, significant advances in both topological insulators and topological semimetals have provided an alternative way to realize Weyl fermions in condensed matter, as an emergent phenomenon: when two non-degenerate bands in the three-dimensional momentum space cross in the vicinity of the Fermi energy (called Weyl nodes), the low-energy excitations behave exactly as Weyl fermions. Here we report the direct observation in TaAs of the long-sought-after Weyl nodes by performing bulk-sensitive soft X-ray angle-resolved photoemission spectroscopy measurements. The projected locations at the nodes on the (001) surface match well to the Fermi arcs, providing undisputable experimental evidence for the existence of Weyl fermionic quasiparticles in TaAs.
Two-dimensional topological insulators with a large bulk band gap are promising for experimental studies of quantum spin Hall effect and for spintronic device applications. Despite considerable ...theoretical efforts in predicting large-gap two-dimensional topological insulator candidates, none of them have been experimentally demonstrated to have a full gap, which is crucial for quantum spin Hall effect. Here, by combining scanning tunneling microscopy/spectroscopy and angle-resolved photoemission spectroscopy, we reveal that ZrTe5 crystal hosts a large full gap of ∼100meV on the surface and a nearly constant density of states within the entire gap at the monolayer step edge. These features are well reproduced by our first-principles calculations, which point to the topologically nontrivial nature of the edge states.
PDF
