Search

Fluorescence nanoscopy provides imaging techniques that overcome the diffraction-limited resolution barrier in light microscopy, thereby opening up a new area of research in biomedical imaging in fields such as neuroscience. Here, we review the foremost fluorescence nanoscopy techniques, including descriptions of their applications in elucidating protein architectures and mobility, the real-time determination of synaptic parameters involved in neural processes, three-dimensional imaging, and the tracking of nanoscale neural activity. We conclude by discussing the prospects of fluorescence nanoscopy, with a particular focus on its deployment in combination with related techniques (e.g., machine learning) in neuroscience.

Sinomenine (SIN) is commonly used as part of rheumatoid arthritis (RA) therapy in China, but there is still no published evidence of the efficacy of SIN monotherapy. This work investigates the efficacy and safety of SIN in treating RA patients and analyzes the correlation between ornithine level and the alleviation of disease activity in RA patients. In this 24 week, randomized, placebo-controlled, double-blind clinical trial, people with mild to moderate RA were randomly assigned (1:1:1, stratified by hospital) to receive SIN (120 mg, twice daily), methotrexate (MTX) (10 mg per week), or SIN + MTX therapy. The primary outcome was the proportion of patients who achieved a 50% improvement in the American College of Rheumatology (ACR) criteria at week 24 and who showed improvement according to the clinical disease activity index (CDAI). In this prospective subgroup analysis, we also assessed whether the 24 week alterations of disease activity in the treatment group were significantly correlated to the levels of blood ornithine. Of the 135 enrolled participants, 38, 39, and 36 patients were treated with SIN, MTX, and SIN + MTX, respectively. In the SIN-treated group, 52.63% of patients achieved ACR50 after 24 weeks of treatment, which was comparable to the results in the MTX-treated and SIN + MTX-treated groups. Hepatic and gastrointestinal disorders were the main adverse events; however, the ratio of patients suffering from hepatic disorder in the SIN group (1/38) was much lower than that in the MTX (10/39) and SIN + MTX (8/36) groups. A total of 221 serum samples were collected at the four follow-up time points in the three treatments, and the levels of ornithine, citrulline, and arginine were obtained through ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF/MS). The serum ornithine level decreased after the 24 week treatment along with a decrease in disease activity, and may reflect therapeutic responses with a sensitivity value of 80%. In conclusion, SIN revealed a comparable efficacy to MTX for treating RA patients, but with fewer side effects. In addition, the serum ornithine level was found for the first time to have a close correlation with the alleviation of RA, which shows the value of this measure as an assessment indicator of drugs in treating RA.

Welding deformation often brings about manufacturing problems such as dimensional inaccuracies during assembly and reduces fabrication efficiency. Prediction and controlling welding deformation can help to improve the quality of welded structures. In this paper, the welding deformation of propeller base structures is predicted by means of numerical approaches and mechanical constraints are proposed to control deformations in welding process. Thermal elasto-plastic finite element method (TEP FEM) is employed to simulate welding process of the base structure. Computed accuracy of welding deformation by TEP FEM analysis is verified by comparing with experimental data of tee joint welding. Results show that welding deformations of the base mainly comprise out-of-plane distortion of ring fringe and radial distortion of cylindrical plate. Exerting mechanical constraints of fixed points at fringe and rigid supports inside cylinder can decrease out-of-plane and radial distortions effectively. The numerical approach adopted in this article can serve as an effective tool to optimize welding process planning in integrated design method.

The diamondback moth (DBM), Plutella xylostella, is one of the most destructive insect pests on cruciferous plants, which causes huge economic losses annually across the world. Due to its resistance to all classes of insecticides, new effective management approaches are urgently needed. The innexin genes encode gap junction proteins in invertebrates, which play critical roles in cell-to-cell interactions for electrical currents, small molecules and ions. Zero population growth (zpg), one germline-specific innexin protein, is required for survival of differentiating early germ cells during gametogenesis in many insect species. In this study, nine innexin genes were identified from the P. xylostella genome, and named as Pxylinx1.1, Pxylinx1.2, Pxylinx2, Pxylinx3, Pxylinx4, Pxylinx7.1, Pxylinx7.2, PxylshakB.1 and PxylshakB.2. The expression profiles of P. xylostella innexin genes in different developmental stages and tissues were examined, revealing Pxylinx4 was specifically expressed in eggs and female ovaries, which is the candidate zpg gene in P. xylostella. RNA interference (RNAi) was utilized to investigate the functions of Pxylinx4 in egg-laying and egg-hatching. The results showed that RNAi treatment on Pxylinx4 in female P. xylostella, lead to the decrease of the egg-laying but not the egg-hatching. This study improves our understanding of P. xylostella innexin genes and provides a candidate molecular target (Pxylinx4) for developing new approaches to control this economically important pest.

Thermochemical two-step CO2 splitting is a potential approach that fixes the sustainable resource into transportable liquid fuels. However, the harsh CO2 splitting conditions, the limited oxygen release kinetics and capacity of metal oxides block further promoted the CO yield and solar-to-fuel energy efficiency. Here, we propose a different carbon cycle assisted by Ni/La2O3 via coupling methane decomposition with thermochemical CO2 splitting, replacing conventional metal oxides cycle. Superior performance was demonstrated with methane conversion reached around 94% with almost pure H2 generation. Encouragingly, CO2 conversion of 98% and CO yield of 6.9 mmol g−1 derived from CO2 were achieved, with peak CO evolution rate (402 mL min−1 g−1) of orders of magnitude higher than that in metal oxide process and outstanding thermodynamic solar-to-fuel energy efficiency (55.5% vs. 18.5%). This was relevant to the synergistic activation of La2O3 and Ni for CO2 in carbon cycle, thus improving CO2 splitting reaction with carbon species.

Owing to their high energy density, lithium-oxygen batteries (LOBs) have been drawn great attention as one of the promising electrochemical energy sources. However, the sluggish kinetics of oxygen reduction/evolution reaction (ORR/OER) hamper the widespread application of LOBs. Herein, an elaborate designed catalysts which are constructed by FeNx moieties dispersed on the network-like hollow dodecahedral carbon and then decorated with Ru nanoparticles (FeNx-HDC@Ru). Since the homogeneously dispersed FeNx moieties could promote ORR performance, and the Ru nanoparticles could facilitate OER capability, the FeNx-HDC@Ru nanocomposites used as cathode catalysts can significantly improve LOBs performance. A lower discharge and charge overpotentials of 0.15 V and 0.78 V can be detected in the first cycle, respectively, and an excellent cycle performance of 90 cycles at 200 mA g−1 and 89 cycles at 500 mA g−1 can be demonstrated. Herein, the charge transfer kinetics has been enhanced with the internal network-like hollow structure and a low impedance Li2O2/catalysts contact interface could be earned by the constructed Ru nanoparticles, these factors would lead to an efficient acceleration to the formation and decomposition of Li2O2 during discharge and charge process.

2Cr13 thin-wall part was additively deposited by robotic cold metal transfer (CMT) technology, and two traditionally manufactured counterparts in annealing (as-Aed) and quenching & tempering (as-QTed) conditions were adopted as comparison. The results show that only a strong texturing corresponding to α-Fe phase was detected for the wire-arc additively manufactured (WAAM) part, indicating an austenite-free structure. As-deposited microstructure was consisted of martensite laths and ferrite matrix, along with irregular δ-ferrite precipitation. The martensitic growth direction was non-oriented in the X–Y plane, but primarily parallel to the depositing direction in the X-Z and Y-Z planes along the maximum thermal gradient. Both nanohardness and ultimate tensile strength (UTS) for each WAAM sample were enhanced when compared with the as-Aed BM, while poorer than that of the as-QTed BM. Such mechanical evolution was a result of the intrinsic microstructural features, whereas the similar elastic modulus properties were mainly attributed to the similar 2Cr13 atomic bonding. A ductile tensile fracture behavior was dominant in the X-Z plane, while a mixed mode of ductile and brittle fracture occurred in the X–Y and Y-Z planes. The findings above reveal an isotropy in mechanical properties despite a slightly microstructural discrepancy in different planes for the as-deposited 2Cr13 WAAM part.

Transition metal chalcogenide quantum dots (TMCs QDs) constitute a crucial sector of semiconductors on account of large absorption coefficient for light harvesting, peculiar quantum confinement effect, and abundant active sites stemming from ultra-small size. However, elaborate and tunable modulation of anisotropic photoinduced charge carriers over TMCs QDs represents an enduring challenge in terms of sluggish charge transfer kinetic and ultra-short charge lifetime compared with nanoparticulate counterparts, thereby rendering maneuvering charge transfer of TMCs QDs a tough issue. We herein conceptually unlock the unanticipated charge transport capability of solid-state non-conductive poly(diallyl dimethylammonium chloride) (PDDA) for constructing cascade charge transfer pathway over self-assembled wide bandgap semiconductors (WBS)/PDDA/TMCs QDs multilayered heterostructures, by which unidirectional and accelerated electron transfer from TMCs QDs to WBS support mediums was spontaneously activated, markedly boosting the charge separation/migration efficiency. The integrated roles of such ultrathin insulating PDDA intermediate layer as simultaneous surface charge modifying agent and interfacial charge transfer mediator have been evidenced to be universal. The unexpected electron-withdrawing capability of ultrathin PDDA layer endows WBS (SnO 2, TiO2)@PDDA@TMCs (CdSe, CdS) QDs heterostructures with significantly enhanced net efficiency of photoactivities toward selective anaerobic reduction of nitroaromatics to amino derivatives under visible light irradiation. Our work would feature a promising scope for rational design of multifarious novel insulating polymers-based photosystems for solar energy conversion.

A pot experiment was conducted to investigate the effects of 0.5% and 1% alkaline, clay mineral and phosphorus amendments, as well as 2% and 5% organic amendments, on lead (Pb) soil bioavailability and Pb absorption by the low-Pb accumulator kumquat (Citrus japonica Thunb.) ‘Cuipi’ in two typical Pb-contaminated soils, Jiyuan and Yangshuo, from northern and southern China, respectively. The diethylenetriaminepentaacetic acid-extractable Pb soil concentration and Pb accumulation in kumquat significantly decreased with amendment additions. High amendment doses had greater inhibitory effects than low doses but no significant effects on the kumquat’s biomass in the two typical soils. Alkaline, but not clay mineral, amendments greatly increased the soil pH level. Organic amendments effectively reduced Pb accumulation owing to their strong adsorptive capacities. Thus, using organic amendments combined with a low-Pb accumulator kumquat forms a suitable farming practice for producing safe fruit in the two common types of Pb-contaminated soils in China.

Dephosphorylation that removes a phosphate group from substrates is an important reaction for living organisms and environmental protection. Although CeO2 has been shown to catalyze this reaction, cerium is low in natural abundance and has a narrow global distribution (>90 % of these reserves are located within six countries). It is thus imperative to find another element/material with high worldwide abundance that can also efficiently extract the phosphate out of agricultural waste for phosphorus recycle. Using para-nitrophenyl phosphate (p-NPP) as a model compound, we demonstrate that TiO2 with a F-modified (001) surface can activate p-NPP dephosphorylation at temperatures as low as 40 °C. By probe-assisted nuclear magnetic resonance (NMR), it was revealed that the strong electron-withdrawing effect of fluorine makes Ti atoms (the active sites) on the (001) surface very acidic. The bidentate adsorption of p-NPP on this surface further promotes its subsequent activation with a barrier ≈20 kJ mol-1 lower than that of the pristine (001) and (101) surfaces, allowing the activation of this reaction near room temperature (from >80 °C).

Heterogenization of organic-macrocyclic metal catalysts is one of the simplest and most efficient methods for effective separation of products and cyclic application of a catalyst. By using an environmentally friendly Mn-corrolazine catalyst as the building unit, which can directly oxidize organic substrates under oxygen atmosphere and mild conditions, we theoretically constructed a novel two-dimensional (2D) Mn-corrolazine nanocatalytic material with high catalytic activity. In this material, each Mn atom maintains its electronic configuration in the monomer and can directly activate O2 as the single-atom catalyst (SAC) center to form a radical-like [Mn]-O-O under mild visible-light irradiation conditions. The newly generated [Mn]–O–O can efficiently and selectively oxidize C–H bonds to form alcohol species through H-abstraction and the rebound reaction. Moreover, the catalytic reaction is easily regulated by an external electric field along its intrinsic Mn–O–O reaction axis. The current study provides a theoretical foundation for further experimental studies and practical applications of the Mn-corrolazine-based SAC.

A Cp*-Rh based D-shaped binuclear metallacycle and a template-free molecular Borromean ring (BR) were obtained in high yield using the semi-rigid thioether dipyridyl ligand 1,4-bis[(pyridin-4-ylthio)methyl]benzene (Bptmb). The topological transformation from a binuclear metallacycle and a BR to tetranuclear metallacycles was realized via the controlled oxidation of thioethers. The strategy used in this work can be regarded as a new form of stimuli-responsive post-synthesis modification (PSM).

Polyarylene ether nitrile (PEN) based composites combined MXene, Polydopamine (PDA) and barium titanate (BaTiO3, BT) with “core-shell”-like structure were developed successfully in this work, and then incorporating into the PEN matrix to form the PEN/MXene&PDA@BT nanocomposite films through the solution casting method. The novel MXene&PDA@BT nanoparticles were characterized by the Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). Then the structure and properties of the obtained PEN/MXene&PDA@BT nanocomposites are studied in detail. The results show that the modification of PDA improved the dispersibility of MXene nanosheets and BT nanoparticles in the PEN matrix, resulting in the enhancement of mechanical and dielectric properties. The research results reveal that when the content of MXene&PDA@BT is 1%, the tensile strength and modulus reached 114.15 MPa and 3015.74 MPa, respectively. Most important, the PEN based nanocomposites exhibit the outstanding frequency in dependent dielectric properties, including high dielectric constant (5.08 at 1 kHz) and low dielectric loss (0.0178 at 1 kHz). These results indicate that the PEN/MXene&PDA@BT composite films are greatly significant for using as the constructing high performance dielectric materials.

The North Qilian Orogenic Belt is surrounded by the Tarim Craton to the NW and the North China Craton to the NE. The Precambrian continental crust remnants that are distributed in the North Qilian Orogenic Belt are termed the North Qilian Block (NQB), and their tectonic evolution has profound implications for the evolution of the Columbia Supercontinent. Here we present major- and trace-element and Sr–Nd–Hf isotope data for (meta-) basalts from the Beidahe Group (BDHG) and Zhulongguan Group (ZLGG) in the western North Qilian Orogenic Belt, to investigate the tectonic evolution of the NQB during the Proterozoic Eon. The protoliths of Palaeoproterozoic amphibole gneisses and plagioclase amphibolites from the BDHG are calc-alkaline series basalts. These metabasalts show island-arc-basalt affinities with variable Nd and Hf isotopes (ϵNd(t) = −5.0–0.6 and 2.7–4.3;ϵHf(t) = −14.2–2.0 and 6.9–8.8) and were generated by partial melting of the asthenospheric mantle that was metasomatized by aqueous fluid and sediment melt in a continental-arc setting. The early Mesoproterozoic ZLGG basalts show features of shoshonite-series basalts and are geochemically similar to ocean-island basalts. These basalts show variable (87Sr/86Sr)i,ϵNd(t) andϵHf(t) values of 0.70464–0.70699, −1–2.6 and −1.5–5.7, and are products of mantle plume magmatism that participated with subducted oceanic crust in an intracontinental rift setting. This study suggests that the NQB underwent tectonic evolution from palaeo-oceanic subduction to intracontinental rifting during the Palaeoproterozoic–Mesoproterozoic eras. Furthermore, the above tectonomagmatic events were in response to convergence–splitting events of the Columbia Supercontinent during the Palaeoproterozoic–Mesoproterozoic eras.

Oxidized carbon foam (oxidized CF) was prepared by using a facile chemical oxidation treatment at relatively low temperature of 450 °C and applied to capture uranyl cation [U(VI)] from aqueous solutions. The effects of pH, contact time, initial U(VI) concentration, and temperature on the U(VI) absorption performance of oxidized CF were investigated by batch experiments. The oxidized CF was illustrated to exhibit fast sorption kinetics (92% removal within 15 min and 98% removal in 2 h) and high sorption capacity (305.77 mg g-1 at pH 5) toward U(VI). Integrated analyses combining energy-dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy were applied on the U(VI)-loaded oxidized CF, showing the introduction of carboxyl groups as U(VI) sorption sites on the surface of CF after oxidation treatment. Furthermore, extended X-ray absorption fine structure spectroscopy was employed to identify the binding modes of U(VI) indicating that each UO22+ cation is coordinated with one or two carboxyl groups on the equatorial plane. Notably, the low content of U(VI) in wastewater can be efficiently immobilized by the oxidized CF, and the immobilized U(VI) can be further concentrated and converted into Na2U2O7 or U3O8 by a simple sintering step. These findings presented in this work suggest the potential of using oxidized CF for further treatment of low concentration wastewater containing U(VI).

Radiation dosimeters displaying conspicuous response of irradiance are highly desirable, owing to the growing demand of monitoring high-energy radiation and environmental exposure. Herein, we present a case of dosimetry based on a discrete nanocluster, [Th6(OH)4(O)4(H2O)6](TPC)8(HCOO)4∙4DMF∙H2O (Th-SINAP-100), by judiciously incorporating heavy Th6 polynuclear centers as radiation attenuator and organic linkers as photo-responsive sensor. Interestingly, dual-module photochromic transitions upon multiple external stimuli including UV, β-ray, and γ-ray are integrated into this single material. The striking color change, and more significantly, the visible color transition of luminescence in response to accumulating radiation dose allow an on-site quantitative platform for naked-eye detection of ionization radiations over a broad range (1–80 kGy). Single crystal X-ray diffraction and density functional theory calculations reveal that the dual-module photochromism can be attributed to the π(TPC) → π*(TPC) intermolecular charge transfer driven by enhanced π-π stacking interaction between the adjacent TPC moieties upon irradiation., Radiation dosimeters that measure ionizing radiations over a broad range and allow for direct readout are desirable. Here, the authors present a dual-mode photochromic thorium-based metal-organic nanocluster that enables direct visible colorimetric dosimetry of UV, β-ray, and γ-ray radiation.

Single-atom catalysts (SACs) with complete dispersion of metal species on substrates provide the ultimate atom economy and opportunities for improved heterogenous catalysis or to develop more catal...

Phycoerythrobilin (PEB) is a special pigment in red algae and cyanobacteria that plays an important role in capturing light energy. As a natural non-toxic pigment with antioxidant properties, PEB is widely used in food and cosmetics industries. At present, the presence of other pigments in red algae and cyanobacteria, such as chlorophyll and phycocyanobilin, makes the preparation of PEB complicated and costly. In this study, the PEB synthesizing enzyme genes of hox1 from Synechocystis sp. PCC6803 and pebS from Nostoc sp. PCC 7120 were co-expressed in Escherichia coli to produce recombinant PEB. In addition, single-factor and response surface methods were used to enhance the yield of recombinant PEB. Under the conditions of lactose concentration at 4 mmol L−1, induction temperature at 27 °C, OD600 nm of 0.9, and induction time at 14 h, the concentration of PEB reached 20.37 mg L−1. In addition, a high-purity (purity > 70%) PEB was obtained through chloroform extraction, and the purified product was verified in UV spectrometry, high-performance liquid chromatography, and mass spectrometry.

It is important to develop an efficient noble-metal-based catalyst that has a wide work temperature window and good stability for CO preferential oxidation in H2 (CO-PROX), a key step to purify ind...

A zwitterionic ligand 3-(triethylammonio)propyne (TAP) has been employed to construct nine silver ethynide compounds for the first time. Single-crystal X-ray analyses reveal that compounds 1 and 2 are silver ethynide assemblies based on the Ag3 subunits and clusters 3-8 are small discrete clusters of Ag3, Ag6, Ag8, and Ag12, respectively, ligated by the bulky TAP ligand with different auxiliary ligands. In addition, upon acquiring the tripod-like tBuPO32-, a unprecedented 80 nuclei silver ethynide cluster was isolated and determined to be [(CF3CO2)5@Ag80(TAP)14(tBuPO3)16(CF3CO2)24]19+ by crystallography and thermogravimetric analysis. The C1 symmetry of Ag80 was deconstructed to be two [Ag40(TAP)7(tBuPO3)8(CF3CO2)12]12+ secondary building subunits arranged in a cross way, with five CF3CO2- trapped in the center. These results highlight that the elaborate selection of ethynide ligands is of great importance in the synthesis of novel silver ethynide clusters.

Currently, knowledge of the failure mechanisms of narrow backfills with retaining walls rotating about the top (RT mode) is still lacking which leads to inaccurate estimations of the earth pressure. Numerical simulations using finite element limit analysis find that under the effects of backfill geometries, interface strengths, and soil properties, the upper soil layer supported by soil arching retains its integrity and the lower soil layer is sheared by multiple curved sliding surfaces in the limit state. Based on the failure mechanisms of narrow backfills, a calculation model is established which considers the soil arching effect, curved sliding surface, and cohesive soils. Analytical solutions for the earth pressure of narrow cohesive backfills with retaining walls rotating about the top are derived by using the limit equilibrium horizontal slice method. Compared with previous studies, the present method predicts the earth pressure distribution with higher accuracy. Several extensive parametric studies have also been conducted. Thus, decreasing the aspect ratio of backfills, increasing the inclined angle of natural slopes, interface strengths, and soil cohesion are beneficial for maintaining backfill integrity and reducing earth pressure against retaining walls.

The controllable B-H bond activation of carboranes has long been a compelling challenge. However, as the symmetry of para-carborane places the same charge on all of its ten boron atoms, controlling the regiochemistry of B-H bond activation in these molecules has remained out of reach ever since their discovery. Herein, we describe how to use steric effects to achieve a regioselective process for B-H activation of para-carborane. In this strategy, B(2,8)-H or B(2,7)-H activation patterns were achieved by taking advantage of the π-π interactions between pyridine ligands. Interestingly, by employing host-guest interactions in metallacage compounds, B(2,8)-H bond activation could be avoided and exclusive B(2,9)-H bond activation can be achieved. Steric hindrance was also found to be beneficial for regioselective B(2,8)-H bond activation in metallacage species. In this work, we demonstrate that steric effects can be a promising driving force for controllable activation of the B-H bonds of carboranes and open new opportunities in this field.

In this protocol, the chemoselective defluoromethoxylation reactions of 2-trifluoromethyl-1,3-enynes were developed. The enynic and allenic orthoesters were selectively produced in good to excellent yields via multiple substitution processes under mild reaction conditions, respectively. The enynic orthoester products were proved capable of acting as efficient "platform molecules" to access various functionalized allenyl compounds.

Introduction of metallic nanoparticles into glasses can obviously improve the up-conversion luminescence efficiency through surface plasmon resonance (SPR). In this research, the Er3+/Yb3+ co-doped TeO2-ZnO-Bi2O3 glasses containing silver nanoparticles and nanocrystals were prepared by direct current(DC) electric field assisted heat treatment, to study the effect of silver nanoparticles on the up-conversion luminescence properties of Er3+. The results show that, although the introduction of AgNO3 will weaken the thermal stability of TZB-ErYb to some extent, the number and size of silver nanoparticles can be increased after DC electric field treated at 100°C for 10 minutes. Meanwhile, the nanocrystals do not grow too large to affect the up-conversion emission intensity of Er3+. The up-conversion emission intensity of Er3+ in TZB-ErYb-6AgNO3-100°C-150V-10min is 43 times stronger than that of TZB-ErYb. These results indicate that DC electric field assisted heat treatment can synergistically adjust the silver nanoparticles and nanocrystals and is a promising method to improve the luminescence properties of tellurite glasses.

The water inrush risk assessment of coal floor after coalbed methane (CBM) development is very important in the theoretical and practical study of safe coal mining. In this study, Chengzhuang coal mine is used as an example to evaluate the water inrush risk of the Ordovician aquifer in coal seam No.15 after the CBM development using the fractal-AHP-vulnerability index (VI) method. Using rock mechanics and geomechanics, a theoretical analysis of water inrush from the coal floor after CBM development is conducted, and two main control factors are added: minimum horizontal principal stress and rock fracture pressure of the hydrologic barrier. By fractal theory, instead of density, length, width and fault distance, the fractal dimension is used to quantify fault. Using the AHP-VI method, the water inrush risk of coal floor after CBM development is analyzed. The results show that there are 8 types of discrimination conditions and 6 main control factors for floor water inrush after CBM development. The fractal-AHP-VI method is more accurate than the traditional AHP-VI method. This method has reference value for the water inrush risk assessment of coal floor after CBM development.

An effective approach was developed for identifying and correcting ocean-bottom seismometer (OBS) time errors through improving ambient noise cross-correlation function (NCCF) analysis and combination with other methods. Significant improvements were illustrated through analyzing data from a passive-source seismic experiment in the southwestern sub-basin of the South China Sea. A novel method was first developed that can effectively identify errors in the sampling frequency of the OBS instruments. The traditional NCCF method was then expanded by increasing the analyzed data spectrum from a single-frequency band to dual-frequency band pairs, thus doubling the number of available data points and substantially improving the time correction quality. For data with relatively low signal-to-noise ratios, the average time errors were reduced from the original average values of 60–80 ms by the conventional methods to

Rational design and synthesis of new photochromic sensors have been active research areas of inquiry, particularly on how to predict and tailor their properties and functionalities. Herein, two thulium 2,2':6',2''-terpyridine-4'-carboxylate (TPC)-functionalized metal-organic hybrids, Tm(TPC)2(HCOO)(H2O) (TmTPC-1) and Tm(TPC)(HCOO)2 (TmTPC-2) with different photochromic response behaviors, have been successfully prepared, allowing for straightforward investigations of the structure-property correlation. Single-crystal X-ray diffraction and electron paramagnetic resonance analyses revealed that the incorporation of a unique dangling decorating TPC unit in TmTPC-1 offers a shorter and more accessible π-π interaction pathway between the adjacent TPC moieties than that in TmTPC-2. Such a structural feature leads to the production of radical species via a photoinduced intermolecular electron-transfer (IeMCT) process upon UV or X-ray irradiation, which ultimately endows TmTPC-1 with a rather unusual UV and X-ray dual photochromism. A linear relationship between the change of UV-vis absorbance intensity and X-ray dose was established, making TmTPC-1 a promising dosimeter for X-ray radiation with an extremely high energy threshold (30 kGy). To advance the development for real-world application, we have fabricated polyvinylidene fluoride (PVDF) membranes incorporating TmTPC-1 for functioning either as a UV imager or as an X-ray radiation indicator. Lastly, TmTPC-1 exhibits high thermal stability (up to 400 °C) and radioresistance (at least 900 kGy), and also excellent reversibility of photochromic transformation (at least 5 cycles).

n–i–p Type perovskite solar cells generally require air oxidation of the Spiro-OMeTAD layer to achieve high power conversion efficiency (PCE). However, the detailed oxidation mechanism is still not fully understood. In this paper, oxidation of Spiro-OMeTAD was demonstrated via a non-contact electrochemical route using UV-Vis absorption, laser beam induced current (LBIC) imaging and secondary ion mass spectrometry (SIMS) profiling of the Spiro-OMeTAD films. At the cathode, oxygen is reduced to form OH− with the help of H2O, while the anodic reaction is the oxidation of Spiro-OMeTAD to form Spiro-OMeTAD+. Diffusion of Li+ towards the surface of the Ag electrode completes the electrochemical cycle and increases the conductivity of the hole-transporting layer. SIMS analyses of the completed devices demonstrate that the oxidation of Spiro-OMeTAD also leads to migration of Li+ through the perovskite layer into SnO2, which supposedly leads to an increase of the built-in voltage. We verify these results by incorporation of the experimentally measured Li+ concentration into a numerical drift-diffusion simulation, to replicate solar cell J–V-curves. This work provides a new insight into the oxidation of Spiro-OMeTAD in perovskite solar cells, and demonstrates that Li+ migration is involved in the oxidation of Spiro-OMeTAD.

Flexible organic solar cells (OSCs) will be a promising energy harvest approach for portable and wearable electronics. However, the efficiency of flexible OSCs, particularly the efficiency of flexible devices with an area larger than 1 cm2, is still limited due to the lack of good flexible electrodes and the inhomogeneity of the large-area films. In this work, higher sensitivity of the performance to the interface contact for large-area devices (1 and 4 cm2) than small area devices (0.09 cm2) was found in flexible OSCs with different areas. To address this issue, a bilayer electron transporting layer (ETL) combining a lower sol–gel ZnO and an upper ZnO nanoparticle layer was developed for silver nanowire (AgNW) electrode involving large-area flexible OSCs. The use of the lower sol–gel ZnO layer effectively filled the network voids and modified the surface energy of the AgNWs, which enabled the homogeneous coverage of the upper ZnO nanoparticle layer and enhanced carrier collection. Due to the more homogeneous films and improved interface charge collection, the use of the sol–gel ZnO and ZnO NP bilayer ETL has lowered the performance decrease during upscaling. A record efficiency of 14.29% and 13.08% for the 1 and 4 cm2 flexible OSCs was achieved.

Titanium dioxide (TiO2) alone is rarely reported to have exciting performance towards heterogeneous hydrogenation reactions. In this work, we demonstrate via density functional theory (DFT) calculations that anatase TiO2 with oxygen vacancies (Ovs), which provides frustrated Lewis pairs (FLPs) from surface Ti and O atoms for the heterolytic dissociation of hydrogen, can effectively hydrogenate acetylene to ethylene. Meanwhile, the mechanisms of H2 activation and acetylene hydrogenation with several structure–reactivity correlations are well established, suggesting the potential catalytic reactivity in the presence of Ovs on anatase TiO2 surfaces. Then, the reactivity of anatase TiO2 towards acetylene hydrogenation is preliminarily confirmed by experimental studies which show that the existence of Ovs after reduction leads to higher reactivity. These results can provide important implications for the further development of selective hydrogenation catalysts based on earth-abundant materials.

We research the strong gravitational lensing for the quantum-modified Schwarzschild black hole which is derived from quantum Raychaudhuri equation. With the increase of quantum Raychaudhuri equation parameter η, we find that the distance between the black hole and the light passing by it becomes smaller; the deflection angle gets larger; the magnification of relativistic images is more similar; all of the relativistic images move towards the black hole while the images are farther to each other. These results, as we expect, will degenerate to the case of Schwarzschild black hole when $\eta \rightarrow 0$ .

By first applying a thorium-organic framework (Th-SINAP-2) as a radiation attenuator and by incorporating a terpyridine derivative (Htpbz) as a photo-responsive guest, selective photochromism in response to X-rays was achieved in the host-guest assembly of Htpbz@Th-SINAP-2. Such a combination endows the afforded material with the lowest detection limit of X-ray dose among all photochromic sensors and a brand-new function of X-ray dosimetry for thorium containing materials.

Two molecular metalla-knots containing over 500 non-hydrogen atoms (especially 16 RhIII ions) and one molecular Borromean ring were obtained in high yields facilitated by multiple intermolecular interactions between their components. The syntheses rely on the strategic selection of the nonlinear dipyridyl ligand 2,7-di(pyridin-4-yl)-9H-fluorene (L1) as precursor, and the structures of the assemblies were confirmed by detailed X-ray crystallographic analysis. Subsequently, replacing L1 with the bulkier ligand 4,4'-(9,9-dimethyl-9H-fluorene-2,7-diyl)dipyridine (L2) led to the formation of three tetranuclear metallocycles in high yields on account of the weakened π-π stacking interactions between the naphthacene/anthracene and fluorene moieties, which in turn confirmed the significance of stacking interactions in the construction of the molecular 818 metalla-knots and the molecular Borromean ring.

Five polyhydroxybenzophenones were synthesized, then their antitumor and antioxidant activities were evaluated. Compounds 1–3 and 5 exhibited obvious antitumor activity. Among them, compounds 1 and 2 exhibited stronger cytotoxicity against hepatocarcinoma SMMC-7721 cells than cisplatin, with half maximal inhibitory concentrations (IC50) of approximately 3.86 and 5.32 μM, respectively. Compounds 1, 2, and 3 exhibited stronger antioxidant activity than trolox, with IC50 values of 11.15, 10.15, and 8.91 μM, respectively, and the antioxidant mechanism and strength of all compounds were further verified using computational chemistry. These results demonstrated that compounds 1–3 and 5 were very promising leads for further structural modification.

Catalytic ethane dehydrogenation (EDH) to ethylene over Pt-based catalysts has received increasing interests in recent years as it is a potential alternative route to conventional steam cracking. However, the catalysts used in this reaction often suffer from rapid deactivation due to serious coke deposition and metal sintering. Herein, we reported the effects of Zn modification on the stability of Pt/Al2O3 for EDH. The Zn-modified sample (PtZn2/Al2O3) exhibits stable ethane conversion (20%) with over 95% ethylene selectivity. More importantly, it exhibits a significantly low deactivation rate of only 0.003 h−1 at 600 °C for 70 h, which surpasses most of previously reported catalysts. Detailed characterizations including in situ FT-IR, ethylene adsorption microcalorimetry, and HAADF-STEM etc. reveal that Zn modifier reduces the number of Lewis acid sites on the catalyst surface. Moreover, it could modify Pt sites and preferentially cover the step sites, which decrease surface energy and retard the sintering of Pt particle, then prohibiting the further dehydrogenation of ethylene to ethylidyne. Consequently, the good stability is realized due to anti-sintering and the decrease of coke formation on the PtZn2/Al2O3 catalyst.

Geosynthetic-reinforced structures are required for constructing roads in the presence of trench voids. In this study, we propose a novel method with respect to the geosynthetic-reinforced cohesive subgrade spanning trench or column voids. Using this method, we can estimate the geosynthetics deformation w and strain e by considering various load patterns, the upper interface friction of geosynthetics, the subgrade subsidence, and further investigate the effect of the soil cohesion and the filling in voids on the geosynthetics. Moreover, the node tension bar model was employed with respect to the geosynthetics in the subsided area and the settlement area. The present results were in good agreement with the previous experimental and numerical results. Extensive parametric studies have also been conducted. Thus, the invert parabolic load pattern is the most unfavourable load pattern. Affected by the soil-geosynthetic relative displacement and subgrade soils, w and e are off by at least 10%. With the loss of fillings in void, w and e are increased up to 590% and 300%. Reducing the stiffness of geosynthetics leads to increasing w and e by up to 55% and 250%. In addition, the larger void width results in maximum 260% and 150% increases in w and e .

Responsive soft materials capable of exhibiting various three-dimensional (3D) shapes under the same stimulus are desirable for promising applications including adaptive and reconfigurable soft robots. Here, we report a laser rewritable magnetic composite film, whose responsive shape-morphing behaviors induced by a magnetic field can be digitally and repeatedly reprogrammed by a facile method of direct laser writing. The composite film is made from an elastomer and magnetic particles encapsulated by a phase change polymer. Once the phase change polymer is temporarily melted by transient laser heating, the orientation of the magnetic particles can be re-aligned upon change of a programming magnetic field. By the digital laser writing on selective areas, magnetic anisotropies can be encoded in the composite film and then reprogrammed by repeating the same procedure, thus leading to multimodal 3D shaping under the same actuation magnetic field. Furthermore, we demonstrated their functional applications in assembling multistate 3D structures driven by the magnetic force-induced buckling, fabricating multistate electrical switches for electronics, and constructing reconfigurable magnetic soft robots with locomotion modes of peristalsis, crawling, and rolling., Responsive soft materials which can exhibit various three-dimensional (3D) shapes under the same stimulus are desirable for applications in adaptive and reconfigurable soft robots. Here, the authors report a laser rewritable magnetic composite film, whose responsive shape-morphing behaviors induced by a magnetic field can be digitally and repeatedly reprogrammed by a facile method of direct laser writing.

Expanding the family of f-element bearing molybdate iodates via hydrothermal reactions has yielded ten new rare-earth molybdate iodates with two distinct phases, Ln(MoO2)(IO3)4(OH) (LnMoIO-1, Ln = Ce and Pr) and Ln(Mo2O7)(IO3)(H2O)2 (LnMoIO-2, Ln = Gd-Yb, and Y), as well as the first thorium molybdate iodate, ThF(MO4)(IO3) (ThFMoIO). All three structures exhibit three dimensional frameworks and are exclusively built from lanthanide/actinide polyhedra bridged by molybdates and iodates. Furthermore, the coordination versatility of molybdates (octahedral, square pyramidal, and tetrahedral geometries) results in a diversity of structures. The effect of the lanthanide contraction on the compositions and structures is clearly observed, showing the increase in hydration from the early to late lanthanide analogues and the decrease in unit cell dimensions and the average Ln-O bonding distances across the same structure type. Single crystal X-ray diffraction studies reveal that LnMoIO-1 (Ln = Ce and Pr) crystalize in a noncentrosymmetric space group P21 and the second-harmonic generation (SHG) measurement shows a response of 5 × KDP for PrMoIO-1. In addition, CeMoIO-1 crystallizes as orange coloured tablets which are semiconducting in nature with a band gap of 2.41 eV.

The rigid pile composite foundation is widely used in highway projects in soft soil area as it can effectively increase the bearing capacity and stability of the foundation. While the research on the behavior and failure mode of rigid pile composite foundation under embankment is not enough, instability failure of rigid pile composite foundation often occurs in practical projects. This paper presents a centrifuge model test to investigate the load transfer mechanism, settlement characteristic and failure mode of rigid pile composite foundation under embankment. The test results show that: the soil displacement of different region in rigid pile composite foundation was different, obvious vertical displacement occurred in the soil under the center of embankment and the horizontal displacement was very small in this region; both vertical and horizontal displacement occurred in the soil under the shoulder of embankment; and obvious horizontal displacement occurred in the soil under the slope toe of embankment; moreover, ground heave also occurred near the slope toe of embankment. The soil displacement in rigid pile composite foundation had a large influence on the stress characteristic and failure mode of rigid piles, the compressive failure and bending failure would probably occur for the piles under the center and shoulder of the embankment, respectively, and the tension-bending failure would probably occur for the piles under the slope toe of embankment. The different failure modes of piles at different regions should be considered in the design of rigid pile composite foundation under embankment. The test results can be used to improve the design method for rigid pile composite foundation under embankment in practical projects.

Two-dimensional (2D) transition metal carbide, known as MXene, has recently received enduring attention for solar energy conversion by virtue of its pivotal role as efficient interfacial charge transfer mediator for photocatalysis. However, controllable design of MXene-based heterostructured photosystems is still in the infant stage and MXene-dominated photoredox mechanism in photoredox selective organic catalysis has so far not yet been unleashed. Herein, we conceptually report the rational construction of 2D/2D heterostructures by a facile electrostatic self-assembly approach utilizing oppositely charged transition metal chalcogenides (TMCs: CdIn2S4, CdS, Zn0.5Cd0.5S, ZnIn2S4) nanosheets (NSs) and Ti3C2Tx (MXene) as the building blocks for photocatalytic selective organic transformation. The peculiar face-to-face stacking mode between the building blocks and suitable energy level alignment synergistically endow the MXene-TMCs NSs heterostructures with markedly enhanced photoactivities toward multifarious photoredox catalysis including anaerobic selective photoreduction of nitroaromatics to amino derivatives and photoxidation of aromatic alcohols to aldehydes under the irradiation of visible light. The considerably enhanced photoactivities of MXene-TMCs NSs heterostructures are caused by the integrated merits of Ti3C2Tx (MXene) including: (i) abundant hydrophilic groups on the Ti3C2Tx (MXene) surface for affording substantial interaction with TMCs NSs, which benefits the charge migration; (ii) strong redox activities of surface Ti sites which promotes multiple electron reduction; (iii) electrons-withdrawing capability of Ti3C2Tx (MXene) to boost the electron transfer from TMCs NS to Ti3C2Tx (MXene), thereby enhancing the charge separation. This work would open a new frontier for constructing a host of MXene-based heterostructured photosystems and unveiling the charge transfer mechanism of MXene for solar energy conversion.

Design of materials with desired properties is currently laborious and heavily relies on intuition of researchers through a trial-and-error process. To tackle this challenge, we propose a novel regressional and conditional generative adversarial network (RCGAN) for inverse design of representative two-dimensional materials, the graphene and boron-nitride (BN) hybrids. RCGAN incorporates a supervised regressor network, thus overcoming the common technical barrier in the traditional unsupervised GANs, which cannot generate data when fed with continuous and quantitative labels. RCGAN can autonomously generate graphene/BN hybrids given any target bandgap values. These structures are distinguished from the ones used for training and exhibit high diversity for a given bandgap. Moreover, they exhibit high fidelity, yielding bandgaps within ∼10% MAEF of the desired bandgaps as validated by density functional theory (DFT) calculations. Analysis by the principle component analysis (PCA) and modified locally linear embedding (MLLE) reveals that the generator has successfully generated structures following the statistical distribution of the real structures. It implies the possibility of the RCGAN in recognizing physical rules hidden in the high-dimensional data. The novel strategy for designing regressional GAN architecture together with the successful application to inverse design of materials would inspire further exploration in research fields beyond materials.

Molecular figure-eight knot (notation: 41) is extremely rare and presents great synthetic challenge due to its essentially complicated entanglement. To solve this synthetic problem, a quadruple sta...

A copper-catalyzed anti-Markovnikov hydrosilylation of alkynes with PhSiH3 was reported. This reaction represents a notable and efficient example on copper-catalyzed hydrosilylatioin of alkynes, which shows excellent recognition between the terminal and internal triple bonds. Various (hetero)aromatic and aliphatic substituted terminal alkynes underwent this reaction to afford the (E)-vinylsilanes in high yields and with excellent regioselectivity.

Tuning CO2 hydrogenation selectivity to obtain targeted value-added chemicals and fuels has attracted great yet everincreasing attention. How ever, a fundamental understanding of the nature to control the selectivity is still lacking, posing a challenge in catalyst design and development. Here, w e report our new discovery in ambient pressure CO2 hydrogenation reaction where selectivity canbe completely reversed by simply changing the crystal phases of TiO2 support (anatase- or rutile-TiO2) or changing metal loadings on anatase-TiO2. Operando spectroscopy and NAP-XPS studies reveal the determining factor is dif ferent electron transfer from metal to support under reaction conditions most probably as a result of the different extents of hydrogen spillover, which changes the adsorption and activation of the intermediate of CO. Based on this new finding, we can not only regulate CO2 hydrogenation selectivity but also tune catalytic performance in other important reactions, thus opening up a door for efficient catalyst development by rational design. Fil: Li, Xiaoyu. University Of Chinese Academy Of Sciences; China. Dalian Institute Of Chemical Physics Chinese Academy Of Sciences; China Fil: Lin, Jian. Dalian Institute Of Chemical Physics Chinese Academy Of Sciences; China Fil: Li, Lin. Dalian Institute Of Chemical Physics Chinese Academy Of Sciences; China Fil: Huang, Yike. University Of Chinese Academy Of Sciences; China. Dalian Institute Of Chemical Physics Chinese Academy Of Sciences; China Fil: Pan, Xiaoli. Dalian Institute Of Chemical Physics Chinese Academy Of Sciences; China Fil: Collins, Sebastián Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina Fil: Ren, Yujing. University Of Chinese Academy Of Sciences; China. Dalian Institute Of Chemical Physics Chinese Academy Of Sciences; China Fil: Su, Yang. Dalian Institute Of Chemical Physics Chinese Academy Of Sciences; China Fil: Kang, Leilei. Dalian Institute Of Chemical Physics Chinese Academy Of Sciences; China Fil: Liu, Xiaoyan. Dalian Institute Of Chemical Physics Chinese Academy Of Sciences; China Fil: Zhou, Yanliang. University Of Chinese Academy Of Sciences; China. Dalian Institute Of Chemical Physics Chinese Academy Of Sciences; China Fil: Wang, Hua. Dalian Institute Of Chemical Physics Chinese Academy Of Sciences; China Fil: Wang, Aiqin. Dalian Institute Of Chemical Physics Chinese Academy Of Sciences; China Fil: Qiao, Botao. Dalian Institute Of Chemical Physics Chinese Academy Of Sciences; China Fil: Wang, Xiaodong. Dalian Institute Of Chemical Physics Chinese Academy Of Sciences; China Fil: Zhang, Tao. Dalian Institute Of Chemical Physics Chinese Academy Of Sciences; China

This study used clinopyroxene (cpx) compositions and zircon Hf-O isotopes of Eocene adakitic rocks (EARs) from the Qiangtang block to resolve the mechanism(s) responsible for the formation of the central Tibetan Plateau. The two leading and opposing hypotheses for the origin of these rocks are (1) partially molten foundered lower crust, and (2) partial melting of continentally subducted upper crust. The consensus is that some crustal sources within the mantle have reached eclogite facies, while evidence remains insufficient. Reverse zonation for cpx in high Mg# andesitic samples shows a low Mg# core with lower Sr and Sr/Y than the high Mg# rim, suggesting derivation of parent magma by interaction between some eclogite-derived felsic melts and mantle peridotite. Overall, the mantle-like zircon δ18O (mean value of ∼5.9‰) and εHf(t) (up to +6.7) values argue for a mafic source rather than buried upper-crustal rocks. Given the EARs were formed within a short time span after the end of crustal shortening, the original felsic melts were most likely derived from the foundered and eclogitized lower crust. The foundering process explains the early Eocene low-relief topography and the intermediate, eclogite-free modern crustal composition of central Tibet. Surface uplift as a response to lithosphere removal, however, was likely negligible, based on various lines of evidence, including sediment provenance, isotope paleoaltimetry, and thermochronology, perhaps because the central Tibetan crust was weak.

R-phycoerythrin and R-phycocyanin are the main light-harvesting pigment-protein complexes in Pyropia yezoensis. They have bright colors and a high degree of fluorescence, and are now widely used in biomedicine, food, and cosmetic industries. Therefore, membrane chromatography was used to isolate and purify phycobiliprotein from P. yezoensis. Algal cells were disrupted by repeated freeze-thaw cycles. Then ammonium sulfate was added into the crude phycobiliprotein extract, so that the saturation of ammonium sulfate in the solution reached 20%, 30%, and 40% in sequence. At 30% and 40% ammonium sulfate saturation, precipitates of R-phycoerythrin and R-phycocyanin mixture in different proportions were obtained. The precipitates were ultra-filtrated to remove the salt, and then, the retentate was taken for membrane chromatographic treatment. In the membrane chromatographic treatment, salt-sensitive PVDF (polyvinyl difluoride) membranes were used for the follow-up experiments. By adjusting the concentration of ammonium sulfate, the membrane system changed the binding strength of various proteins, and then separated different types of phycobiliproteins. The final products of R-phycoerythrin (Aλmax/A280 purity 4.25, yield 45%) and R-phycocyanin (two purity grades: purity 5.8, yield 14.70% and purity 4.18, yield 39.89%) were obtained and then characterized by spectrophotometric and fluorometric measurements and SDS-PAGE. However, the large-scale production of R-phycocyanin and R-phycoerythrin remains a bottleneck as the column chromatography is difficult to be applied for industrial production. This method avoids the problem of easy clogging of column chromatography and can be useful for mass-production of R-phycoerythrin and R-phycocyanin in the future based on the laboratory results.

Despite extensive research and several stunning breakthroughs in the synthesis of interlocked molecular species, [3]catenanes, Borromean rings and ring-in-ring complexes are exceedingly rare and their targeted synthesis remains a formidable challenge. Herein, a series of Cp*Rh-based homogeneous and heterogeneous interlocked structures have been prepared by coordination-driven self-assembly, not only including metalla[2]catenanes and molecular Borromean rings, but also linear metalla[3]catenanes and ring-in-ring complexes. The interlocked structures are all based on bithiophenyl groups. The bithiophenyl groups effectively enhance the strength of the inter-ring interactions and play a crucial role in the formation of these interlocked structures. By taking advantage of the strong interaction between π-donor (D) and π-acceptor (A) groups, the electron-deficient methylviologen cation was introduced into a cationic metallarectangle based on bithiophenyl groups. Taking inspiration from these results, a cationic metallarectangle based on A units was threaded into a metallarectangle based on D units, leading to a heterogeneous D–A ring-in-ring structure., A series of Cp*Rh-based homogeneous and heterogeneous interlocked structures have been prepared by coordination-driven self-assembly, not only including metalla[2]catenanes and molecular Borromean rings, but also linear metalla[3]catenanes and ring-in-ring complex.

Exclusive Pt species supported on inert substrates have not achieved satisfactory performance for cryogenic CO oxidation because of the constraint of the competitive Langmuir–Hinshelwood process in...

Acoustic waves enter a rock formation from a borehole and are reflected or scattered upon encountering a geologic structure. Consequently, we obtain the structure location represented by the azimuth and distance from the borehole using the acoustic reflection or scattering. Downhole acoustic measurements with the azimuthal resolution are realized using an azimuthal acoustic receiver sonde composed of several arcuate phased array receivers. Eight sensors distributed evenly across the arcuate phased array receiver can record acoustic waves independently; this allows us to adopt the beamforming method. We use a supporting logging tool to conduct the downhole test in two adjacent fluid-filled boreholes, for validating the evaluation of the geologic structure using scattered P-waves. The test results show the multi-azimuth images of the target borehole and the azimuthal variation in scattering amplitudes. Thus, we obtain the precise location of the target borehole. Furthermore, the measured values of the target borehole are consistent with the actual values, indicating that we can accurately evaluate a near-borehole geologic structure with scattered P-waves.

"Trees are known to provide various ecosystem services and disservices to urban communities, which can be quantified using models based on field and environmental data. It is often uncertain how tree structure and environmental variables impact model output. Here we perform a sensitivity analysis (SA) of i-Tree Eco, a common urban forest model, to analyze the relative impact of different model inputs on three module outputs: biogenic volatile organic compound (BVOC)(isoprene and monoterpenes) emissions, carbon storage and sequestration, and dry deposition of nitrogen dioxide, sulfur dioxide, and ozone. The SA methods included novel applications of the Morris one-at-a-time method and a variance-based decomposition method, which integrates Monte Carlo simulation with Latin hypercube sampling and Iman Conover analysis. A case study was performed in New York City, New York, USA, with field plot data collected in 2013. Genus has the largest influence on BVOC emissions by determining base emission rates and its high interactions with other input factors, and BVOC emissions are sensitive to leaf biomass in a concave manner and temperature in a convex manner, while isoprene emissions show a strong linear relationship with photosynthetically active radiation (PAR). Diameter at breast height plays the most important role for both carbon storage and sequestration estimators; crown light exposure and tree condition are also important for carbon sequestration. Dry deposition velocity is sensitive to leaf area index and relative humidity in a nearly linear way, while sensitive to temperature and PAR in a concave manner. The results provide guidance to facilitate future field plot campaigns and model development. The knowledge revealed by the SA is also beneficial for model uncertainty reduction, which in turn facilitates more effective urban forest management and decision-making.