Using the density functional theory calculations, we systematically investigate the structures and properties of silicene-like SiX and XSi3 (X = B, C, N, Al, P) hexagonal heterosheets. For the SiX ...systems, the SiP sheet favors a chairlike buckled structure akin to silicene, the SiB, SiN, and SiAl ones prefer the washboard-like buckling type, and the SiC sheet adopts the flat plane as graphene. The planarity is also favored in the XSi3 sheets with X = B, C, Al, while the rests with X = N and P prefer the chairlike buckled structures. The energetic stabilities and mechanical properties are also investigated for these SiX and XSi3 systems, and all the heterosheets are found to be stable. Unlike the semimetallic silicene, most of the SiX sheets are transformed to metals except for the SiC one with a wide band gap. For the XSi3 systems, they can be metals, semimetals, or narrow-band gap semiconductors depending on the X elements. The BSi3 and NSi3 sheets exhibit metallic behaviors, which behave like the p-type or n-type doping into silicene. On the other hand, the AlSi3 and PSi3 ones turn to semiconductors with narrow indirect band gaps, which are dominated by the Si–Si and Si–X bonding/antibonding states. Of particular interests, we find the CSi3 sheet maintains the zero-band gap semimetallicity of silicene, for which the p z orbitals of Si and C atoms contribute to the linear Dirac-like bands near the Fermi level. The dynamical stabilities of the CSi3, AlSi3, and PSi3 sheets are further examined by phonon calculations and ab initio molecular dynamics simulations, which confirm the robust stability of their free-standing states. Our studies demonstrate that the Si-related heterosheets have peculiar structures and properties, which have potential applications in the nanoelectronics and devices.
Arsenene and antimonene, i.e. two-dimensional (2D) As and Sb monolayers, are the recently proposed cousins of phosphorene (Angew. Chem. Int. Ed., 54, 3112 (2015)). Through first-principle ...calculations, we systematically investigate electronic and transport properties of the corresponding As and Sb nanoribbons, which are cut from the arsenene and antimonene nanosheets. We find that different from the 2D systems, band features of As and Sb nanoribbons are dependent on edge shapes. All armchair As/Sb nanoribbons keep the indirect band gap feature, while the zigzag ones transfer to direct semiconductors. Quantum confinement in nanoribbons enhances the gap sizes, for which both the armchair and zigzag ones have a gap scaling rule inversely proportional to the ribbon width. Comparing to phosphorene, the large deformation potential constants in the As and Sb nanoribbons cause small carrier mobilities in the orders of magnitude of 10
1
–10
2
cm
2
/Vs. Our study demonstrates that the nanostructures of group-Vb elements would possess different electronic properties for the P, As, and Sb ones, which have diverse potential applications for nanoelectronics and nanodevices.
In order to improve the effect of engineering safety management, this paper combines intelligent monitoring technology to construct a monitoring robot system. Moreover, this paper analyzes the ...characteristics of the digital impulse signal and analyzes the least square filtering and infinite impulse response filtering. At the same time, this paper detects the sample material on the detection test platform, obtains the digital pulse signal, and selects different filtering algorithms and filtering parameters. In addition, this paper uses a signal analysis and processing platform to establish a gamma energy spectrum and analyze the resolution of hydrogen peaks in the gamma energy spectrum. Finally, this paper compares and verifies the filtering algorithms and constructs an engineering safety management system based on robot intelligent monitoring. From the simulation monitoring test results, it can be seen that the engineering safety management system based on robot intelligent detection proposed in this paper has a good effect.
By first-principles calculations, the variations of band structures by strains are investigated for silicene and germanene nanosheets, i.e. the Si and Ge analogs of graphene. It is found that both ...systems exhibit a strain-induced self-doping phenomenon, which is closely related with their buckled structures and cannot arise in graphene. Under the compressive strain, the Dirac point is moved below the Fermi level, making the nanosheets behave as n-type doped. While under the tensile strain, the p-type doping is rendered by shifting the Dirac point above the Fermi level. Our studies demonstrate that the n-type/zero-band-gap/p-type semiconducting features can be switched for silicene and germanene by applying strains.
► A strain-induced self-doping phenomenon is found in the silicene/germanene. ► The compressive strains could induce n-type doping into the systems. ► The p-type doping would be rendered by applying tensile strains. ► The physical origins and advantages of such self-doping are discussed.
Display omitted
•A compact and adhesive CrxCy coating is successfully prepared on 316L steel.•The CrxCy coating is formed through the disproportionation reaction of chromium on a carbon coating in a ...molten salt.•The CrxCy coating shows good stability during long-term immersion in a molten FLiNaK environment.
Molten fluorides have been widely used in specific nuclear reprocessing and molten salt reactors due to their unique pyrophysical and pyrochemical properties. However, the severe corrosion of structural materials in highly corrosive molten fluorides at high temperatures limits their commercial use. In view of the high thermodynamic stability of chromium carbides in molten fluoride salts, and their good Cr-diffusion-blocking ability, it is proposed to develop a CrxCy coating, by electrodeposition coupled with a disproportionation reaction in molten salts, for application in molten fluorides A carbon coating is first prepared on 316L stainless steel by electrodeposition in molten LiCl-KCl-K2CO3, followed by a disproportionation reaction of Cr2+ on the carbon coating to obtain a CrxCy coating. Furthermore, the growth mechanism of the CrxCy coating and its corrosion resistance in molten fluorides are also investigated.
The catalytic hydrogenolysis of readily available glycerol to 1,2-propanediol (1,2-PD) and 1,3-propanediol (1,3-PD), which provides a new promising synthesis route to produce propanediols, has been ...extensively studied in the past decades. This study summarizes the most significant reports regarding glycerol hydrogenolysis into propanediols. Three reaction routes, including those working towards 1,2-PD production and the recently proposed one leading to 1,3-PD production, have been summarized. The catalysts used for this reaction have been classified into two categories according to the type of metal components: the transition metal catalysts taking Cu, Ni, and Co as representative metal components and the noble metal catalysts containing Ru, Pt, Ir, and Ag. Some inexpensive transition-metal catalysts exhibit high 1,2-PD selectivity and yield under mild reaction conditions, whereas several noble metal catalysts are promising in synthesizing the more valuable 1,3-PD. Efficient preparation methods and precise modulation techniques have been systematically developed to synthesize functionalized catalysts on the basis of the metal species in combination with acidic or basic compounds. Other technological aspects, such as hydrogen sources, reaction solvents, reactor types and feeding processes, are also summarized in this study. The focus of this review is on summarizing the preparation methods and the performance of various catalysts in glycerol hydrogenolysis.
This study summarizes the most significant reports regarding the catalytic hydrogenolysis of glycerol to propanediols.
A FRET‐based carbon nanodot (CDot) drug delivery platform has been developed. These CDots offer excellent biocompatibility, stable fluorescence, and efficient FRET between CDots and the attached ...fluorescent drug molecules, such as doxorubicin, enabling enhanced drug delivery, convenient cell imaging, and real‐time monitoring of drug release. Moreover, the FRET‐based two‐photon imaging and drug tracking in deep tissues are also demonstrated.
Atherosclerosis and its complications, such as myocardial infarction and stroke, are the major causes of morbidity and mortality, and development of effective therapies for both prevention and ...treatment of this disease is critically important. Currently, there are many drugs available for atherosclerotic disease, but the lipid-lowering drugs statins are still the first-choice for treatment of hypercholesterolemia, a major risk factor for atherosclerosis. On the other hand, traditional Chinese medicines, mainly Chinese herbal medicines (CHM), have been widely used in China and in other Asian countries for the treatment of atherosclerotic diseases. Although many CHMs have been reported to be effective for treating atherosclerotic diseases for more than two thousand years, there are still many difficulties for their use, such as lack of scientific evidence assessed by rigorous clinical trials, complicated components and unclear pharmacological mechanisms, which often hamper the widespread use of CHMs in Western countries. Due to these concerns, CHMs are usually considered as complimentary or alternative treatment for atherosclerotic diseases. In this review, we provide an overview of the pathophysiology of atherosclerosis viewed by Western and traditional Chinese medicine, summarize pros and cons on the efficacy of CHMs for atherosclerosis and discuss what is necessary for CHM use to spread to Western societies.
•The first review article to address whether Chinese herb medicines can treat atherosclerosis.•What is known and unknown about Chinese herb medicine for the treatment of atherosclerosis•Con and pro of Chinese herb medicine for atherosclerosis compared with Western medicine.
Size, shape, and protein corona play a key role in cellular uptake and removal mechanisms of gold nanoparticles (Au NPs). The 15 nm nanoparticles (NP1), the 45 nm nanoparticles (NP2), and the ...rod‐shaped nanoparticles (NR) enter into cells via a receptor‐mediated endocytosis (RME) pathway. The star‐shaped nanoparticles (NS) adopt not only clathrin‐mediated, but also caveolin‐mediated endocytosis pathways. However, the 80 nm nanoparitcles (NP3) mainly enter into the cells by macropinocytosis pathway due to the big size. Furthermore, the results indicate that the presence of protein corona can change the uptake mechanisms of Au NPs. The endocytosis pathway of NP1, NP2, and NS changes from RME to macropinocytosis pathway and NR changes from RME to clathrin and caveolin‐independent pathway under the non‐fetal bovine serun (FBS)‐coated condition. Both FBS‐coated and non‐FBS‐coated of five types of Au NPs are released out through the lysosomal exocytosis pathway. The size, shape, and protein corona have an effect on the exocytosis ratio and amount, but do not change the exocytosis mechanism. The systematic study of the endocytosis and exocytosis mechanism of Au NPs with different sizes and shapes will benefit the toxicology evaluation and nanomedicine application of Au NPs.
Size, shape, and protein corona play the key role in cellular uptake and removal mechanisms of gold nanoparticles (Au NPs). The uptake mechanisms of five types of Au NPs are different. Size, shape, and protein corona decrease the uptake amount and affect the endocytosis mechanism. However, all of them are released through the lysosomal exocytosis pathway.
PDF
