Graphene-based electrodes and catalysts for electroreduction of CO_(2)to low-carbon alcohols

The electrochemical reduction of CO_(2)(CO_(2)ER)into the renewable and sustainable green fuels,such as low-carbon alcohols,is one of several workable strategies.CO_(2)ER can be combined with renewable electricity to transform intermittent energy sources(such as wind,hydro,and solar)into a fuel that can be stored until it is ready to be used.The intrinsic characteristics of the employed catalyst have a significant and substantial effect on the efficiency of CO_(2)ER and the ensuing economic viability.The paradigmatic multicarbon alcohol catalysts should increase the concentration of*CO in the reaction environment,stabilize the key intermediate products during the reaction,and facilitate the C-C coupling interaction.Since graphene has a large surface area and exceptional conductivity,it has been used as a support for active phases(nanoparticles or nanosheets).It is possible for graphene to enhance charge transport and accelerate CO_(2)conversion through its electronic and structural coupling effects.At the interface,a synergy can be produced that improves CO_(2)ER by increasing*CO adsorption,intermediate binding,and stability.This article focuses on recent advancements in graphene-based catalysts that promote CO_(2)ER to alcohols.Likewise,this paper also describes and discusses the key role graphene plays in catalyzing CO_(2)ER into alcohols.Finally,we hope to provide future ideas for the design of graphene-based electrocatalysts.

Multi-walled carbon nanotubes conjugated to tumor protein enhance the uptake of tumor antigens by human dendritic cells in vitro

Anti-tumor immunotherapy is an important form of adjuvant cancer treatment [1, 2]. While chemotherapy encounters the obstacles of drug toxicity and resistance, immunotherapy usually has limited adverse effects, good patient tolerance, and the potential to significantly improve the prognosis [1-4]. Some clinical trials of im- munotherapy generated promising results in treating malignancies such as malignant melanoma, glioblastoma multiforme, or renal cell carcinoma, which tend to re- spond poorly to chemotherapies [3-5]. Dendritic cells (DC) play a crucial role in generating specific immune reaction to antigens, which generally need to be ingested, processed and presented by DC, before triggering B cell- or T cell- mediated responses. This core immune mechanism has been utilized in designing DC-based anticancer immunotherapy, whereby a patient's DC are expanded with in vitro culture,

Pine wilt disease detection in high-resolution UAV images using object-oriented classification

Pine wilt disease(PWD)is currently one of the main causes of large-scale forest destruction.To control the spread of PWD,it is essential to detect affected pine trees quickly.This study investigated the feasibility of using the object-oriented multi-scale segmentation algorithm to identify trees discolored by PWD.We used an unmanned aerial vehicle(UAV)platform equipped with an RGB digital camera to obtain high spatial resolution images,and multiscale segmentation was applied to delineate the tree crown,coupling the use of object-oriented classification to classify trees discolored by PWD.Then,the optimal segmentation scale was implemented using the estimation of scale parameter(ESP2)plug-in.The feature space of the segmentation results was optimized,and appropriate features were selected for classification.The results showed that the optimal scale,shape,and compactness values of the tree crown segmentation algorithm were 56,0.5,and 0.8,respectively.The producer’s accuracy(PA),user’s accuracy(UA),and F1 score were 0.722,0.605,and 0.658,respectively.There were no significant classification errors in the final classification results,and the low accuracy was attributed to the low number of objects count caused by incorrect segmentation.The multi-scale segmentation and object-oriented classification method could accurately identify trees discolored by PWD with a straightforward and rapid processing.This study provides a technical method for monitoring the occurrence of PWD and identifying the discolored trees of disease using UAV-based high-resolution images.

A Frameless Network Architecture for the Way Forward of C-RAN

The key technologies involved in the evolution of the Cloud-based Radio Access Network(C-RAN) are discussed in this paper. Taking the Frameless Network Architecture(FNA) as a starting point, a cell-lessbased network topology for a multi-tier Heterogeneous Network(Het Net) and ultra-dense network is proposed. The FNA network topology modeling is researched with centralized processing and distributed antenna deployments. The Antenna Element(AE) is released as a new dimensional radio resource that is included in the centralized Radio Resource Management(RRM) processes. This contributes to the on-demand user-centric serving-set associations with cell-edge effect elimination. The Control Plane(CP) and User Plane(UP) separation and adaptation are introduced for energy efficiency improvements. The centralized RRM and different optimization goals are discussed for fully exploring the merits from the centralized computing of C-RAN. Considering the complexity, near-optimal approaches for specific users' Quality-of-Service(Qo S) requirements are addressed. Finally, based on the research highlighted above, the way forward of C-RAN evolution is discussed.

Variability in the climate-radial growth correlation of Pinus massoniana of different diameter classes

The physiological characteristics of trees change with age,suggesting that growth-related climate signals vary over time.This study aimed to clarify the impacts of different diameter classes on the chronological characteristics of Pinus massoniana Lamb.and its response to climatic factors.Chronologies of P inus massoniana were established in small diameter(14.1 cm),middle diameter(27.3 cm),and large diameter(34.6 cm)trees according to dendrochronology.The results show that:(1)radial growth of different diameter classes had varied characteristics and climate sensitivities;(2)radial growth of small diameter trees was affected by climatic factors of the previous and the current year,while large diameter trees were mainly affected by climatic factors of the current year;and(3)precipitation and temperature were key factors that restricted the radial growth of small and large diameter trees,respectively.

Sorption-enhanced chemical looping oxidative steam reforming of methanol for on-board hydrogen supply

Hydrogen is an indispensable energy carrier for the sustainable development of human society.Nevertheless,its storage,transportation,and in situ generation still face significant challenges.Methanol can be used as an intermediate carrier for hydrogen supplies,providing hydrogen energy through instant methanol conversion.In this study,a sorption-enhanced,chemical-looping,oxidative steam methanol-reforming(SECLOSRM)process is proposed using CuO–MgO for the on-board hydrogen supply,which could be a promising method for safe and efficient hydrogen production.Aspen Plus software was used for feasibility verification and parameter optimization of the SECL-OSRM process.The effects of CuO/CH_(3)OH,MgO/CH_(3)OH,and H_(2)O/CH_(3)OH mole ratios and of temperature on H_(2)production rate,H utilization efficiency,CH_(3)OH conversion,CO concentration,and system heat balance are discussed thoroughly.The results indicate that the system can be operated in autothermal conditions with high-purity hydrogen(99.50 vol%)and ultra-low-concentration CO(<50 ppm)generation,which confirms the possibility of integrating low-temperature proton-exchange membrane fuel cells(LT-PEFMCs)with the SECL-OSRM process.The simulation results indicate that the CO can be modulated in a lower concentration by reducing the temperature and by improving the H_(2)O/CH_(3)OH and MgO/CH_(3)OH mole ratios.

Non-sinusoidal transit timing variations for the exoplanet HAT-P-12b

Considering the importance of investigating the transit timing variations(TTVs)of transiting exoplanets,we present a follow-up study of HAT-P-12 b.We include six new light curves observed between2011 and 2015 from three different observatories,in association with 25 light curves taken from the published literature.The sample of the data used thus covers a time span of~10.2 years with a large coverage of epochs(1160)for the transiting events of the exoplanet HAT-P-12 b.The light curves are utilized to determine the orbital parameters and conduct an investigation of possible TTVs.The new linear ephemeris shows a large value of reducedχ^(2),i.e.X_(red)^(2)(23)=7.93,and the sinusoidal fitting using the prominent frequency coming from a periodogram shows a reducedχ^(2) around 4.Based on these values and the corresponding O-C diagrams,we suspect the presence of a possible non-sinusoidal TTV in this planetary system.Finally,we find that a scenario with an additional non-transiting exoplanet could explain this TTV with an even smaller reducedχ^(2) value of around 2.

Nanoimprint-induced strain engineering of two-dimensional materials

The high stretchability of two-dimensional(2D)materials has facilitated the possibility of using external strain to manipulate their properties.Hence,strain engineering has emerged as a promising technique for tailoring the performance of 2D materials by controlling the applied elastic strain field.Although various types of strain engineering methods have been proposed,deterministic and controllable generation of the strain in 2D materials remains a challenging task.Here,we report a nanoimprint-induced strain engineering(NISE)strategy for introducing controllable periodic strain profiles on 2D materials.A three-dimensional(3D)tunable strain is generated in a molybdenum disulfide(MoS_(2))sheet by pressing and conforming to the topography of an imprint mold.Different strain profiles generated in MoS_(2)are demonstrated and verified by Raman and photoluminescence(PL)spectroscopy.The strain modulation capability of NISE is investigated by changing the imprint pressure and the patterns of the imprint molds,which enables precise control of the strain magnitudes and distributions in MoS_(2).Furthermore,a finite element model is developed to simulate the NISE process and reveal the straining behavior of MoS_(2).This deterministic and effective strain engineering technique can be easily extended to other materials and is also compatible with common semiconductor fabrication processes;therefore,it provides prospects for advances in broad nanoelectronic and optoelectronic devices.

High-fidelity and clean nanotransfer lithography using structure-embedded and electrostatic-adhesive carriers

Metallic nanostructures are becoming increasingly important for both fundamental research and practical devices.Many emerging applications employing metallic nanostructures often involve unconventional substrates that are flexible or nonplanar,making direct lithographic fabrication very difficult.An alternative approach is to transfer prefabricated structures from a conventional substrate;however,it is still challenging to maintain high fidelity and a high yield in the transfer process.In this paper,we propose a high-fidelity,clean nanotransfer lithography method that addresses the above challenges by employing a polyvinyl acetate(PVA)film as the transferring carrier and promoting electrostatic adhesion through triboelectric charging.The PVA film embeds the transferred metallic nanostructures and maintains their spacing with a remarkably low variation of<1%.When separating the PVA film from the donor substrate,electrostatic charges are generated due to triboelectric charging and facilitate adhesion to the receiver substrate,resulting in a high large-area transfer yield of up to 99.93%.We successfully transferred the metallic structures of a variety of materials(Au,Cu,Pd,etc.)with different geometries with a<50-nm spacing,high aspect ratio(>2),and complex 3D structures.Moreover,the thin and flexible carrier film enables transfer on highly curved surfaces,such as a single-mode optical fiber with a curvature radius of 62.5μm.With this strategy,we demonstrate the transfer of metallic nanostructures for a compact spectrometer with Cu nanogratings transferred on a convex lens and for surface-enhanced Raman spectroscopy(SERS)characterization on graphene with reliable responsiveness.

Effects of synthetic site water on bentonite-concrete system for a potential nuclear waste repository

In high-level nuclear waste(HLW)repositories,concrete and compacted bentonite are designed to be employed as buffer materials,which may raise a problem of interactions between concrete and bentonite.These interactions would lead to mineralogy transformation and buffer performance decay of bentonite under the near field environment conditions in a repository.A small-scale experimental setup was established to simulate the concrete-bentonite-site water interaction system from a potential nuclear waste repository in China.Three types of mortars were prepared to correspond to the concrete at different degradation states.The results permit the determination of the following:(1)The macroproperties of Gaomiaozi(GMZ)bentonite(e.g.swelling pressure,permeability,the final dry density,and water content of reacted samples);(2)The composition evolution of fluids from the synthetic site water-concrete-bentonite interaction systems;(3)The sample characterization including Fourier transform infrared spectroscopy(FTIR)and X-ray powder diffraction(XRD).Under the infiltration of the synthesis Beishan site water(BSW),the swelling pressure of bentonite decreases slowly with time after reaching its second swelling peak.The flux decreases with time during the infiltrations,and it tends to be stable after more than 120 d.Due to the cation exchange reactions in the BSW-concrete-bentonite systems,the divalent cations(Ca and Mg)were consumed,and the monovalent cations(Na and K)were released.The dissolution of minerals in the bentonite such as albite causes Si increasing in the pore water.It was concluded that the hydro-mechanical property degradation of bentonite takes place when it comes into contact with concrete mortar,even under low-pH groundwater conditions.The soil dispersion,the uneven water content,and the uneven dry density in bentonite samples may partly contribute to the swelling decay of bentonite.Therefore,the direct contact with concrete has an obvious effect on the performance of bentonite.

Efficiency Analysis of Industrial Water Treatment in China Based on Two-stage Undesirable Fixed-sum Output DEA Model

China is a country with the most water consumption, so it is lack of water resources.Industry has brought serious water pollution while driving economic development, which leads to the destruction of ecological environment. With the improvement of environmental awareness, many scholars have shifted their research direction to how to improve the ecological environment. Most studies consider the whole system as a "black box", regardless of its internal structure. Therefore, a method to identify inefficiency is necessary and some suggestions for optimization are given. In this paper,a two-stage undesirable fixed-sum output data envelopment analysis(DEA) model is proposed. The industrial chemical oxygen demand(COD) emission during 2011–2015 are adjusted, and the efficiency values are calculated by heuristic search algorithm. The efficiency of 30 provinces and cities is divided into eastern, central and western regions. The model can identify the inefficient stage in industrial system, and find the source of low efficiency in the system. The analysis shows that the efficiency of eastern region is the highest, while the overall efficiency is inclined to the pollutant treatment stage.Finally, the paper puts forward some suggestions for the low efficiency areas, which can save water while ensuring economic benefits, and provide new direction for water pollution reduction and improve the ecological environment.

Spatial modulation of nanopattern dimensions by combining interference lithography and grayscale-patterned secondary exposure

Functional nanostructures are exploited for a variety of cutting-edge fields including plasmonics,metasurfaces,and biosensors,just to name a few.Some applications require nanostructures with uniform feature sizes while others rely on spatially varying morphologies.However,fine manipulation of the feature size over a large area remains a substantial challenge because mainstream approaches to precise nanopatterning are based on low-throughput pixel-by-pixel processing,such as those utilizing focused beams of photons,electrons,or ions.In this work,we provide a solution toward wafer-scale,arbitrary modulation of feature size distribution by introducing a lithographic portfolio combining interference lithography(IL)and grayscale-patterned secondary exposure(SE).Employed after the high-throughput IL,a SE with patterned intensity distribution spatially modulates the dimensions of photoresist nanostructures.Based on this approach,we successfully fabricated 4-inch wafer-scale nanogratings with uniform linewidths of<5%variation,using grayscale-patterned SE to compensate for the linewidth difference caused by the Gaussian distribution of the laser beams in the IL.Besides,we also demonstrated a wafer-scale structural color painting by spatially modulating the filling ratio to achieve gradient grayscale color using SE.

Estimating the number of Chinese cancer patients eligible for and benefit from immune checkpoint inhibitors

The total number of cancer patients who are eligible for and will benefit from immune checkpoint inhibitors(ICIs)in China has not been quantified.This cross-sectional study was conducted to estimate the number of Chinese cancer patients with eligibility and response to ICIs based on the 2015 Chinese cancer statistics and the immune checkpoint inhibitor clinical practice guideline of the Chinese Society of Clinical Oncology.A total of 11 ICIs were recommended for 17 cancer types.The estimated number of eligible patients annually was 1290156(55.18%),which included 888738 males(60.05%)and 400468 females(46.67%).The estimated number of responders annually was 448972(19.20%),which included 309023 males(20.88%)and 139764 females(16.29%).Gastric cancer(n=291000,12.45%),non-small-cell lung cancer(n=289629,12.39%),and hepatocellular carcinoma(n=277100,11.85%)were the top three cancer types with the highest number of eligible patients.Non-small-cell lung cancer(n=180022,7.70%),hepatocellular carcinoma(n=75648,3.24%),and small-cell lung cancer(n=64362,2.75%)were the top three cancer types with the highest number of responders.In conclusion,ICIs provide considerable benefit in Chinese cancer patients under optimal estimation.

A Refined Error Analysis for Fixed-Degree Polynomial Optimization over the Simplex

We consider the problem of minimizing a fixed-degree polynomial over the standard simplex.This problem is well known to be NP-hard,since it contains the maximum stable set problem in combinatorial optimization as a special case.In this paper,we revisit a known upper bound obtained by taking the minimum value on a regular grid,and a known lower bound based on Pólya’s representation theorem.More precisely,we consider the difference between these two bounds and we provide upper bounds for this difference in terms of the range of function values.Our results refine the known upper bounds in the quadratic and cubic cases,and they asymptotically refine the known upper bound in the general case.