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Inorganic binder used in casting process has the advantages of low odor, labor-friendly conditions, and relatively low cost, which is one of the main development directions for casting molding materials in the future. However, compared to organic binders (such as resin binders), inorganic binders exhibit lower bonding strength and are more sensitive to environmental humidity. This sensitivity poses challenges, particularly in the reclamation of used sand, thus limiting their broader application. In this paper, the research and application status of inorganic binders (mainly silicate inorganic binders) and their curing methods are summarized. In addition, the research and application of phosphate inorganic binders and 3D printing inorganic binders that are being developed are introduced. Meanwhile, a detailed comparative analysis is conducted on the challenging issue of “reclamation for used sand” in the application of inorganic binders. Finally, the development direction of inorganic binders is clarified.

In this work, a new treatment method combining ultrasonic vibration with FeCoNiCrCu high entropy alloy (HEA) coating was used to prepared Al/Mg bimetal through the lost foam compound casting. The effects of composite treatment involving ultrasonic vibration and HEA coating on interfacial microstructure and mechanical properties of Al/Mg bimetal were studied. Results demonstrate that the interface thickness of the Al/Mg bimetal with composite treatment significantly decreases to only 26.99% of the thickness observed in the untreated Al/Mg bimetal. The HEA coating hinders the diffusion between Al and Mg, resulting the significant reduction in Al/Mg intermetallic compounds in the interface. The Al/Mg bimetal interface with composite treatment is composed of Al3Mg2and Mg2Si/AlxFeCoNiCrCu+FeCoNiCrCu/δ-Mg+Al12Mg17eutectic structures. The interface resulting from the composite treatment has a lower hardness than that without treatment. The acoustic cavitation and acoustic streaming effects generated by ultrasonic vibration promote the diffusion of Al elements within the HEA coating, resulting in a significant improvement in the metallurgical bonding quality on the Mg side. The fracture position shifts from the Mg side of the Al/Mg bimetal only with HEA coating to the Al side with composite treatment. The shear strength of the Al/Mg bimetal increases from 32.16 MPa without treatment to 63.44 MPa with ultrasonic vibration and HEA coating, increasing by 97.26%.

In this paper, we investigated the potential use of a new organic-inorganic hybrid crystal structure based on KNO3in ignition compositions. H2dabco[K(NO3)3] (DAN-2) with organic-inorganic hybrid crystal structure is synthesized through intermolecular assembly technology. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) were used to detect the crystal morphology, structure and molecular structure of DAN-2, which has a regular cubic structure. Experimental data were obtained using thermogravimetric/differential scanning calorimetry (TG-DSC), closed bomb test and high-speed photography, which were then used to study and analyze the thermal decomposition properties and combustion properties of DAN-2. The initial thermal decomposition temperature of DAN-2 was low (194 °C) and the activation energy of the thermal decomposition was 154 kJ/mol. Possible thermal decomposition mechanisms are further discussed and proposed. This research pushed forward the application of organic-inorganic hybrid crystal structure oxidant DAN-2 in ignition system.

Nitroalkanes serve as essential intermediates in the synthesis of pharmaceuticals, agrochemicals, and functional materials. To date, nitroalkanes are mainly prepared from homogeneous catalysts such as noble transition metal catalysts with poor recyclability. Herein, we propose a metal–organic framework-frustrated Lewis pair (MOF-FLP) heterogeneous catalyst for selectively reducing nitroolefins to nitroalkanes under moderate reaction conditions. MOF enrichment effect can significantly improve the catalytic efficiency compared to homogeneous FLP catalysts. Benefiting from the strong interaction between FLP and MOF, the MOF-FLP catalyst exhibits outstanding recyclability. This work not only provides a convenient route for nitroalkane synthesis but also showcases the potential of porous heterogeneous FLP catalysts, offering inspiration for future catalytic design strategies.

Microstructure, mechanical properties and phase transformation of a heat-resistant rare-earth (RE) Mg-16.1Gd-3.5Nd-0.38Zn-0.26Zr-0.15Y (wt.%) alloy were investigated. The as-cast alloy is composed of equiaxed α-Mg matrix, net-shaped Mg5RE and Zr-rich phases. According to aging hardening curves and tensile properties variation, the optimized condition of solution treatment at 520 °C for 8 h and subsequent aging at 204 °C for 12 h was selected. The continuous secondary Mg5RE phase predominantly formed at grain boundaries during solidification transforms to residual discontinuous β-Mg5RE phase and fine cuboid REH2particles after heat treatment. The annealed alloy exhibits good comprehensive tensile property at 350 °C, with ultimate tensile strength of 153 MPa and elongation to fracture of 6.9%. Segregation of RE elements and eventually RE-rich precipitation at grain boundaries are responsible for the high strength at elevated temperature.

Recent research has attracted considerable attention toward N-heterocyclic carbene-coordinated boranes (NHC-borane) and their B-substituted derivatives because of their unique characteristics. In the present work, we focused on the syntheses, structures, and reactivities of such types of amine complexes, [NHC·BH2NH3]X ((NHC = IPr (1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) and IMe (1,3-dimethylimidazol-2-ylidene); X = Cl, I, OTf). We have developed a synthetic method to access NHC·BH2NH2through the reaction of NaH with [IPr·BH2NH3]I, which was synthesized by the reaction of IPr·BH2I with NH3. As a Lewis base, NHC·BH2NH2could further react with HCl or HOTf to produce the corresponding salts of [IPr·BH2NH3]+. IPr·BH2NH2BH2X (X = Cl, I) were synthesized by the reaction of HCl/I2with IPr·BH2NH2BH3and then converted to [IPr·BH2NH2BH2·IPr]X (X = Cl, I) by reacting with IPr. The IMe-coordinated boranes reacted quite similarly. The preliminary results revealed that the introduction of the NHC molecule has a considerable impact on the solubility and reactivities of aminoboranes.

To overcome the disadvantages of inhomogeneous microstructures and poor mechanical properties of additively manufactured Ti-6Al-4V alloys, a novel technique of hybrid deposition and synchronous micro-rolling is proposed. The micro-rolling leads to equiaxed prior β grains, thin discontinuous intergranular α, and equiaxed primary α, in contrast to the coarse columnar prior β grains without the application of micro-rolling. The recrystallization by micro-rolling results in discontinuous intergranular α via the mechanism of strain and interface-induced grain boundary migration. The evolution of α globularization, driven by a solute concentration gradient, starts from the sub-boundary until the formation of equiaxed primary α. Simultaneous strengthening and toughening are achieved, which means an increase in yield strength, ultimate tensile strength, fracture elongation, and work hardening rate. The formation of α recrystallization leads to more fine grain boundaries to strengthen the yield strength, and the improvement of ductility is due to the better-coordinated deformation ability of discontinuous intergranular α and equiaxed primary α. As a result, the fracture mode in micro-rolling changes from intergranular type to transgranular type.

Cyclic GMP-AMP synthase (cGAS), a cytosolic DNA sensor, acts as a nucleotidyl transferase that catalyzes ATP and GTP to form cyclic GMP-AMP (cGAMP) and plays a critical role in innate immunity. Hyperactivation of cGAS-STING signaling contributes to hyperinflammatory responses. Therefore, cGAS is considered a promising target for the treatment of inflammatory diseases. Herein, we report the discovery and identification of several novel types of cGAS inhibitors by pyrophosphatase (PPiase)-coupled activity assays. Among these inhibitors, 1-(1-phenyl-3,4-dihydro-1H-pyrrolo[1,2-a]pyrazin-2-yl)prop-2-yn-1-one (compound 3) displayed the highest potency and selectivity at the cellular level. Compound 3exhibited better inhibitory activity and pathway selectivity than RU.521, which is a selective cGAS inhibitor with anti-inflammatory effects in vitro and in vivo. Thermostability analysis, nuclear magnetic resonance and isothermal titration calorimetry assays confirmed that compound 3directly binds to the cGAS protein. Mass spectrometry and mutation analysis revealed that compound 3covalently binds to Cys419 of cGAS. Notably, compound 3demonstrated promising therapeutic efficacy in a dextran sulfate sodium (DSS)-induced mouse colitis model. These results collectively suggest that compound 3will be useful for understanding the biological function of cGAS and has the potential to be further developed for inflammatory disease therapies.

The B-cell lymphoma 2 (BCL-2) protein family plays a pivotal role in regulating the apoptosis process. BCL-2, as an antiapoptotic protein in this family, mediates apoptosis resistance and is an ideal target for cell death strategies in cancer therapy. Traditional treatment modalities target BCL-2 by occupying the hydrophobic pocket formed by BCL-2 homology (BH) domains 1–3, while in recent years, the BH4 domain of BCL-2 has also been considered an attractive novel target. Herein, we describe the discovery and identification of DC-B01, a novel BCL-2 inhibitor targeting the BH4 domain, through virtual screening combined with biophysical and biochemical methods. Our results from surface plasmon resonance and cellular thermal shift assay confirmed that the BH4 domain is responsible for the interaction between BCL-2 and DC-B01. As evidenced by further cell-based experiments, DC-B01 induced cell killing in a BCL-2-dependent manner and triggered apoptosis via the mitochondria-mediated pathway. DC-B01 disrupted the BCL-2/c-Myc interaction and consequently suppressed the transcriptional activity of c-Myc. Moreover, DC-B01 inhibited tumor growth in vivo in a BCL‑2‑dependent manner. Collectively, these results indicate that DC-B01 is a promising BCL-2 BH4 domain inhibitor with the potential for further development.

The initiation of sex differentiation in insects is regulated by primary sex determination signals. In the Medfly Ceratitis capitataand other Tephritids, Maleness-on-the-Y(MoY) is the master gene for male sex determination. However, the primary signal in Zeugodacus cucurbitae(Coquillett), a very destructive Tephritid pest across the world, remains ambiguous. In this study, we have isolated and characterized the Medfly MoYhomolog in Z. cucurbitae, ZcMoY. ZcMOY protein shows high sequence conservation to its homologs in Bactroceraspecies. ZcMoYtranscription begins and peaks at very early embryonic stages and then becomes undetectable except the testes and heads of day 1 male adults. Silencing ZcMoYin early embryos by RNAi causes abnormal external genitalia and interior reproductive organs, giving rise to intersexes and feminization of XY individuals. The expression pattern and knockdown phenotypes of ZcMoYindicate that ZcMoYplays a key role in regulating sex determination of Z. cucurbitaemales. Our findings will help the understanding of sex determination in Z. cucurbitaeand facilitate the development of genetic sexing strains in its biological control.

This letter introduces a novel discrete fractional transform termed as pure number discrete fractional complex Hadamard transform (PN-FCHT). The proposed PN-FCHT offers three advantages over the traditional discrete fractional Hadamard transform (FHT). Firstly, the higher-order PN-FCHT matrix exhibits the Self-Kronecker product structure, which allows for the recursive generation from the $2\times 2$ core PN-FCHT matrix. Secondly, it possesses two important properties for computation, i.e. pure number property. Lastly, compared to existing state-of-the-art fast FHT algorithms, the PN-FCHT can reduce the transform multiplication computational complexity by up to 80% and this results in a more efficient hardware implementation.

Al/Mg bimetal was prepared by lost foam solid-liquid compound casting, and the effects of mechanical vibration on the filling and solidification behavior, microstructure and performance of the bimetal were investigated. Results show that the mechanical vibration has a remarkable influence on the filling and solidification processes. It is found that after mechanical vibration, the filling rate increases and the filling rate at different times is more uniform than that without vibration. In addition, the mechanical vibration also increases the wettability between liquid AZ91D and A356 inlays. The mechanical vibration reduces the horizontal and vertical temperature gradient of the casting and makes the temperature distribution of the whole casting more uniform. Compared to the Al/Mg bimetal without vibration, the shear strength is improved by 39.76% after the mechanical vibration is applied, due to the decrease of the inclusions and Al12Mg17dendrites, and the refinement and uniform distribution of the Mg2Si particles in the interface of the Al/Mg bimetal.

Efficient and stable expression of foreign genes in cells and transgenic animals is important for gain-of-function studies and the establishment of bioreactors. Safe harbor loci in the animal genome enable consistent overexpression of foreign genes, without side effects. However, relatively few safe harbor loci are available in pigs, a fact which has impeded the development of multi-transgenic pig research. We report a strategy for efficient transgene knock-in in the endogenous collagen type I alpha 1 chain (COL1A1) gene using the clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) system. After the knock-in of a 2A peptide-green fluorescence protein (2A-GFP) transgene in the last codon of COL1A1in multiple porcine cells, including porcine kidney epithelial (PK15), porcine embryonic fibroblast (PEF) and porcine intestinal epithelial (IPI-2I) cells, quantitative PCR (qPCR), Western blotting, RNA-seq and CCK8 assay were performed to assess the safety of COL1A1locus. The qPCR results showed that the GFPknock-in had no effect (P=0.29, P=0.66 and P=0.20 for PK15, PEF and IPI-2I cells, respectively) on the mRNA expression of COL1A1gene. Similarly, no significant differences (P=0.64, P=0.48 and P=0.80 for PK15, PEF and IPI-2I cells, respectively) were found between the GFPknock-in and wild type cells by Western blotting. RNA-seq results revealed that the transcriptome of GFPknock-in PEF cells had a significant positive correlation (P<2.2e–16) with that of the wild type cells, indicating that the GFPknock-in did not alter the global expression of endogenous genes. Furthermore, the CCK8 assay showed that the GFPknock-in events had no adverse effects (P24h=0.31, P48h=0.96, P72h=0.24, P96h=0.17, and P120h=0.38) on cell proliferation of PK15 cells. These results indicate that the COL1A1locus can be used as a safe harbor for foreign genes knock-in into the pig genome and can be broadly applied to farm animal breeding and biomedical model establishment.

Coordination of cellular metabolism is essential for optimal T cell responses. Here, we identify cytosolic acetyl-CoA production as an essential metabolic node for CD8 T cell function in vivo. We show that CD8 T cell responses to infection depend on acetyl-CoA derived from citrate via the enzyme ATP citrate lyase (ACLY). However, ablation of ACLY triggers an alternative, acetate-dependent pathway for acetyl-CoA production mediated by acyl-CoA synthetase short-chain family member 2 (ACSS2). Mechanistically, acetate fuels both the TCA cycle and cytosolic acetyl-CoA production, impacting T cell effector responses, acetate-dependent histone acetylation, and chromatin accessibility at effector gene loci. When ACLY is functional, ACSS2 is not required, suggesting acetate is not an obligate metabolic substrate for CD8 T cell function. However, loss of ACLY renders CD8 T cells dependent on acetate (via ACSS2) to maintain acetyl-CoA production and effector function. Together, ACLY and ACSS2 coordinate cytosolic acetyl-CoA production in CD8 T cells to maintain chromatin accessibility and T cell effector function.

To explore a new method to prepare B-doped silicon carbide, with B2O3 as a dopant, silicon dioxide and graphite as raw materials, B-doped silicon carbide (BxSi1-xC) was prepared using pressure-free sintering and self-spreading combustion methods. The material phase, microstructure, particle size, compressive strength and bulk density were characterized by the XRD, SEM, laser granularity tester, particle strength tester and powder comprehensive characteristic tester. The results show that the doping of B can inhibit the growth rate of the product, with the optimal ratio of SiO2:C:B2O3=60:120:150. At the same time, the crystal type of the generated product BxSi1-xC is relatively complete. The D50 is 17.3 μm, its bulk density is up to 1.08 g-1cm-3, and its single particle compression strength is second only to diamond, much higher than that of ordinary SiC.

The heat dissipation of electronic components is of great importance to the development of microelectronics industry. Polymer matrix composites have become a research hotspot due to their advantages in molding, insulation and cost. In this paper, the mechanism and influencing factors of thermal conductivity of polymer matrix composites are introduced, the research status of thermal network formation is reviewed, and the development trend of thermal conductivity composites is forecasted.

In the face of the requirement that nuclear fusion reactor materials exhibit more excellent thermal, mechanical and physical properties, a novel refractory high-entropy alloy, WTaHfTiZr was proposed. The constituent elements were selected in consideration of low activation, high melting point and high thermostability. The alloys were prepared by arc melting. The as-cast alloy shows a dendrite microstructure with two disordered BCC phases, which caused by the preferential nucleation of W and Ta with much higher melting points during solidification. It exhibits a high compressive yield strength of 1,900 MPa and fracture strain of 8.1% at room temperature, and its yield strengths are up to 612 MPa at 700 °C and 203 MPa at 1,000 °C, respectively. The high strengths are attributed mainly to solid solution strengthening and second phase strengthening. This alloy shows great promise as one of the next-generation nuclear fusion reactor materials.

The application of additive manufacturing technology is one of the main approaches to achieving the rapid casting. Additive manufacturing technology can directly prepare casting molds (cores) with no need of patterns, and quickly cast complex castings. The combination of additive manufacturing and traditional casting technology can break the constraint of traditional casting technology, improve casting flexibility, and ameliorate the working environment. Besides, additive manufacturing promotes the realization of “free casting”, greatly simplifying the processing procedures and shortening the manufacturing cycle. This paper summarizes the basic principle of additive manufacturing technology and its development situation domestically and overseas, mainly focusing on the development status of several main additive manufacturing technologies applicable to the foundry field, including three-dimensional printing, selective laser sintering, stereolithography, layered extrusion forming, etc. Finally, the future development trend of additive manufacturing technology in the foundry field is prospected.

Selective laser sintering (SLS), as a kind of additive manufacturing technology, which uses a laser beam to scan and heat powder material layer by layer to form parts (models), is widely used in the field of casting, mainly for preparing casting coated sand cores, investment casting patterns, etc. The SLS technique facilitates rapid casting and shortens the casting production periods by eliminating mold preparation. In this study, we reached conclusions for the basic principles and characteristics of SLS methods, and focused on the research status, key technology and development trend of SLS in the fields of forming coated sand-casting molds and investment casting patterns.

The lysosome-targeting carbon dots (CDs) with excellent water solubility and strong blue emission were synthesized through a one-step functional modification for long-term lysosome imaging in living cells. Based on the carboxyl-rich CDs synthesized by oxidizing carbon black in refluxing HNO3, then N,N-dimethylethylenediamine (DMEDA) was chemically linked onto the CDs through acylation reaction to obtain DMEDA modified carbon dots (M-CDs). The infrared spectrum of M-CDs showed the characteristic peak of acylamide (O=C–NH–) at 1658 cm−1, indicating the successful modification of DMEDA. The quantum yield of M-CDs was 15.6%, which was 27 times higher than the initial carboxyl rich CDs, meeting the requirement of cell imaging. The probe entered cells through the temperature-dependent endocytosis way and the co-localization experiment with commercial dye Lyso-Tracker red showed that the probe localized in lysosomes and could be used as a universal lysosome tracker in different cell lines. Moreover, compared to commercially available Lyso-Tracker blue, M-CDs were more photostable under UV light. The fluorescence of M-CDs was still brightness after time-lapsed imaging by confocal microscopy for 120 min with an interval of 5 min in living cells, implying that the M-CDs could be used for long-term imaging of lysosomes.

This paper presents experimental measurements by the time-resolved particle image velocimetry (TR-PIV) for the turbulent boundary layer (TBL) over the smooth surface, the superhydrophobic (SH) surface, and the superhydrophobic-riblets (SR) surface in an open-surface recirculating water channel. The Reynolds number based on the wall friction velocity and the thickness of the TBL over the smooth surface is 702. The SH surface and the SR surface are manufactured by the laser texturing method on the smooth surface and the riblets surface, respectively. By employing the (modified) Clauser method, a superior efficacy of the drag reduction of about 22.1% is obtained on the SR surface, while the drag reduction rate for the SH surface is about 18.7%. Comparing with the SH surface, the declining 2-order statistics in the near-wall region also indicates a significant drag reduction over the SR surface. The large-scale structure components extracted by the proper orthogonal decomposition are found to generate a majority of the Reynolds shear stress in the region y+> 40. The strength of the large-scale features over the rough surfaces (SH and SR surfaces) at disparate wall-normal positions is visualized by the Quadrant splitting method and the conditional averaging. The appearance of the large-scale structures such as the hairpin packets characterized by the two-point correlation shows an excellent consistency with the statistics profile. The hairpin packets over the SH surface seem always smaller and weaker than those over the smooth surface. Over the SR surface, the hairpin packets in the region 0.1 ≤ yδ < 0.3 are the smallest and weakest among those over the three surfaces, while the scale and the strength of the hairpin packets exceed those over the smooth surface in the region 0.3 < yδ < 0.6.

The genetic circuits that allow cancer cells to evade destruction by the host immune system remain poorly understood1–3. Here, to identify a phenotypically robust core set of genes and pathways that enable cancer cells to evade killing mediated by cytotoxic T lymphocytes (CTLs), we performed genome-wide CRISPR screens across a panel of genetically diverse mouse cancer cell lines that were cultured in the presence of CTLs. We identify a core set of 182 genes across these mouse cancer models, the individual perturbation of which increases either the sensitivity or the resistance of cancer cells to CTL-mediated toxicity. Systematic exploration of our dataset using genetic co-similarity reveals the hierarchical and coordinated manner in which genes and pathways act in cancer cells to orchestrate their evasion of CTLs, and shows that discrete functional modules that control the interferon response and tumour necrosis factor (TNF)-induced cytotoxicity are dominant sub-phenotypes. Our data establish a central role for genes that were previously identified as negative regulators of the type-II interferon response (for example, Ptpn2, Socs1and Adar1) in mediating CTL evasion, and show that the lipid-droplet-related gene Fitm2is required for maintaining cell fitness after exposure to interferon-γ (IFNγ). In addition, we identify the autophagy pathway as a conserved mediator of the evasion of CTLs by cancer cells, and show that this pathway is required to resist cytotoxicity induced by the cytokines IFNγ and TNF. Through the mapping of cytokine- and CTL-based genetic interactions, together with in vivo CRISPR screens, we show how the pleiotropic effects of autophagy control cancer-cell-intrinsic evasion of killing by CTLs and we highlight the importance of these effects within the tumour microenvironment. Collectively, these data expand our knowledge of the genetic circuits that are involved in the evasion of the immune system by cancer cells, and highlight genetic interactions that contribute to phenotypes associated with escape from killing by CTLs.

The properties of gray cast iron (GCI) are affected by density of matrix, size of flake graphite and primary austenite. In this paper, the Y-type specimen of GCI was prepared by lost foam casting (LFC) with and without vibration, and the influence of vibration frequency on the density of matrix, size of primary phase, and properties of the GCI was studied. The results show that the length of the flake graphite and the size of the primary austenite in GCI firstly decrease and then increase with the increase of the vibration frequency. With a vibration frequency of 35 Hz, the length of the flake graphite is the shortest, the primary austenite is the finest and the density of the matrix is the highest. In addition, the tensile strength, elongation and hardness of the GCI firstly increase and then decrease with the increase of the vibration frequency, due to the refinement of the primary phase and the increase of the matrix density. In order to analyze the refinement mechanism of the primary phase of the GCI fabricated by the LFC with vibration, the solidification temperature fields of the GCI fabricated by the LFC with the vibration frequency of 0 and 35 Hz were measured. The results show that the vibration reduces the eutectic point of the GCI and increases the supercooling degree during the eutectic transformation. As a result, the length of the flake graphite and the size of the primary austenite in GCI fabricated by LFC with the vibration frequency of 35 Hz decrease.

脓毒症的发展以免疫紊乱为特征, 这是继发感染和死亡率增加的主要因素.针刺可能是治疗脓毒症的一种潜在的补充替代疗法.在这篇综述中, 我们发现针刺确实对脓毒症免疫抑制有益.针刺可以改善脓毒症的免疫紊乱, 调节先天免疫细胞和适应性免疫细胞功能.针刺可以减少脓毒症中性粒细胞的数量, 促进巨噬细胞向M2型巨噬细胞极化, 减少小胶质细胞和星形胶质细胞的活化以缓解炎症.此外, 针刺还可以增加T细胞的百分比, 调节T细胞亚群的比例.针刺对脓毒症的免疫调节机制可能与平衡自主神经有关, 包括交感-肾上腺轴,迷走神经胆碱能通路和迷走神经-肾上腺轴的激活.除此之外, 针刺还可以通过保护肠道屏障功能和调节肠道微生物群来抑制炎症.临床研究也发现, 针刺可以提高外周自然杀伤细胞 (NK细胞) 和T细胞亚群的数量以及人类白细胞抗原DR (HLA-DR) 的表达水平, 降低白细胞与中性粒细胞的比例, 降低炎症因子水平.因此, 针刺具有改善脓毒症的免疫功能的潜力, 其作用机制的研究有望为针灸治疗脓毒症提供科学可靠的依据.

The vertical distribution of an emergent vegetation in wetlands and marshes is generally non-uniform due to the variations of the stem thickness and the leaf density. This study focuses on the effect of the varying vertical porosity on the hydrodynamic characteristics of the emergent vegetation flow. The new governing equation for the emergent vegetation flow with varying vertical porosity is established by applying the poroelastic media flow theory. According to the movement mechanism of the water flow in the porous media and the experimental data, the best fitted expression of the permeability is established for the emergent vegetation flow. The velocity distribution is obtained with the finite analytic method. Then, a flume experiment is performed using truncated cones to simulate the actual vegetation with varying vertical porosity. The calculated velocity distribution is compared with the measured data, which shows that the theoretical results are in good agreement with the experimental data. Finally, the influence of the vertical porosity distribution on the vegetation flow characteristics is analyzed graphically. The study can provide a useful reference and technical support for further study of the flow with a complex shape vegetation.

Wet reclamation of waste sodium silicate-bonded sand produces much alkaline sewage and causes pollution. Recycling water glass from wet reclamation sewage of the waste sodium silicate-bonded sand can solve pollution issues and generate economic benefits. In this work, the wet reclamation sewage was filtered, and the filtrate was causticized with a quicklime powder to produce a lye. The effects of causticization temperature, causticization time, and the amount of quicklime powder on the causticization rate were studied. The lye was used to dissolve the silica in the filtration residue to prepare a sodium silicate solution. The effects of the mass of filtration residue, dissolution temperature, and dissolution time on sodium silicate modulus were studied. Finally, the recycled water glass was obtained by concentrating the sodium silicate solution, and the bonding strength of the recycled water glass was tested. The results showed that the causticization rate could be improved by increasing the amount of quicklime powder, causticization temperature, and causticization time, and the highest causticization rate was above 92%. Amorphous silica in the filtration residue dissolved in the lye. Increasing the amount of the filtration residue, dissolution temperature, and dissolution time could improve the sodium silicate modulus. The bonding strength of the recycled water glass was close to that of commercial water glass. The recycled water glass could be used as a substitute for the commercial water glass.

In this paper, a kind of FeCrBSiMnMoW amorphous nanocrystalline composite coating was prepared on the steel matrix by arc spraying, and the microstructure and properties of the coating were studied. The results show that the coating owns compact structure and low porosity. The coating is composed of amorphous phase and α (Fe, Cr) nanocrystalline phase, and the nanocrystalline phase is uniformly distributed in the amorphous matrix. The initial crystallization temperature is above 587.5 °C, which indicates the coating has good thermal stability. The Vickers hardness of the coating is around HV0.3= 1150. The wear mechanism of the coating is abrasive wear with a friction coefficient of 0.434 and the wear loss rate of only 3.3×10-5 mm3/Nm, which shows excellent wear resistance of this kind of coating.

The Yellow River Plain (YRP), being regarded as the cradle of Chinese civilization, is traditionally thought to be the locale of the Great Flood, a hazardous flood (or floods) tamed by Yu who started China’s first “dynasty”, Xia, in ~ 2000 BC. However, by integrating published archaeological data, we propose that the Great Flood in fact impacted the Jianghan Plain (JHP) along the middle course of the Yangtze River. The arguments include: (1) around the era of the Great Flood, the most civilized and populated society in East Asia, named the Jianghan society, was located around the JHP (at that time, the habitation on the YRP remained limited); (2) the Jianghan society lived on river resources (shipping and rice growing) and was thus subject to flood risks (but not for the people inhabiting the YRP); (3) the people in the Jianghan society were experienced in dredging moats/ditches for shipping and irrigation; (4) unlike the floods on the YRP that were characterized by dynamic sedimentation and channel avulsion, those on the JHP typically occurred with slow-moving water manageable to ancient people; (5) the JHP has been associated with lake/wetland systems serving as detention basins during floods. Here, the recorded method for controlling the Great Flood, dredging channels to divert flood water to a “sea”, was feasible. Known speleothem paleo-rainfall data from multiple sites show that the climate of the JHP had been wet since the middle Holocene (earlier than the era of the Great Flood) and significantly turned dry after ~ 1850 BC (~ 150 years later than the Great Flood). Thus, the uniqueness of the Great Flood was likely to reflect an increase in land use on the JHP with the expansion of the Jianghan society, and the success in taming this flood was mainly due to the efforts of the society, not by luck.

In the present work, the Mg/Al bimetallic composites were successfully prepared by the lost foam casting (LFC) process, and the characteristics and formation mechanism of the interface of the Mg/Al bimetallic composites were investigated. The results show that a uniform and compact metallurgical interface with an average thickness of about 1400 μm was formed between magnesium alloy and aluminum alloy. The interface layer of the Mg/Al bimetallic composites was composed of three different reaction layers, namely the Al12Mg17+δ(Mg) eutectic layer adjacent to the magnesium matrix, the Al12Mg17+Mg2Si interlayer and the Al3Mg2+Mg2Si layer close to the aluminum matrix. The microhardnesses of the interface layer were remarkably higher than those of the magnesium and aluminum matrixes. The stress strength of the Mg/Al bimetallic composites was up to 47.67 MPa. The fractograph of the push out sample mainly showed a brittle fracture nature. The formation of the interface of the Mg/Al bimetallic composites was attributed to the fusion and diffusion bonding. With the variations of the concentrations of the different elements at the interface, the Al3Mg2 intermetallic phase first formed near to the aluminum matrix, and then the Al12Mg17 and Mg2Si successively generated toward the magnesium matrix, finally obtaining the interface layer of the Mg/Al bimetallic composites.

Few convenient/expeditious methods for identifying the species of shed snake skins in specific areas have been developed. The scales on shed snake skins are permeable to light and can be examined by light microscopy (LM), which is of higher availability—especially for wild animal researchers and citizen scientists—than conventional approach which examines the scale microstructures by scanning electron microscopy. We collected and examined a total of 801 shed samples or scale specimens from 53 snake species in Taiwan and adjacent islands, and developed the first guide to identify the fragmented or faded shed skins of most snake species by LM. Morphological characters of scales can be examined by LM include the apical notch, apical pits, apical lobes, keels, scale symmetry, unpigmented spots (mechanoreceptor-like organs), interscale follicles, cross/longitudinal micro-ridge, oberhautchen cells, rows of spines, light/tiny dots, and other microstructures. The microstructures on the scale specimens prepared by the stripped method and the impression method were similar to those on shed skins when examined by LM. We investigated the variations of scale morphology associated with ontogeny, body region, and position on scales, discussed the character evolution of snake scale morphology, and certified that the interscale follicles and the unpigmented spots could also be useful characters for shed skin identification. The methods and results of this study could be applied to identify squamate skins/sloughs and even fecal remnants. [ABSTRACT FROM AUTHOR]

Cast CrCoNiAlx(x=0–1.2) medium-entropy alloys (MEAs) were produced by arc melting and flip cast to investigate the alloying effect of Al addition on the microstructure, phase constituent and mechanical properties. The crystal structure changes from an initial face-centered cubic (FCC) to duplex FCC and body-centered cubic (BCC) and finally a single BCC with increasing Al content. In the duplex region, FCC and BCC phases form under a eutectic reaction in the interdendrite region. In the single BCC region, the dendrites transform to ordered B2 and disordered A2 BCC phases resulting from spinodal decomposition. Corresponding to their phase constituents, yield strength increases accompanied with an elongation reduction with increasing Al addition. A very interesting phenomenon of very weak ordered FCC (001) spots appearing in Al-0.4 alloy was observed, indicating a local ordering of FCC phase. The changes of fracture surfaces after the tensile deformation are also corresponding to the variations in mechanical properties.

A method was developed for the separation and detection of morpholinium ionic liquid cations by hydrophilic interaction column combined with indirect ultraviolet detection using imidazolium ionic liquids as ultraviolet absorbents in high‐performance liquid chromatography. The effects of the ultraviolet absorbents, organic solvents, and the pH value of the aqueous solution in the mobile phase for the determination of morpholinium cations were investigated by using a hydrophilic column with carbamoyl group as the analytical column. The retention and detection behavior of morpholinium cations was discussed. The suitable chromatographic conditions were 0.8 mmol/L 1‐ethyl‐3‐methyl‐imidazolium tetrafluoroborate aqueous solution (pH 3.5 adjusted with acetic acid)/acetonitrile (45/55, v/v) as the mobile phase and a detection wavelength of 210 nm. Under these conditions, the baseline separation of N‐methyl‐N‐ethyl‐morpholinium cation ([MEMo]+) and N‐methyl‐N‐propyl‐morpholinium cation ([MPMo]+) was successfully achieved in 15 min. The detection limits of [MEMo]+and [MPMo]+were 0.595 and 0.531 mg/L, respectively. Relative standard deviations were less than 0.2%. This method has been successfully applied to the analysis of morpholinium ionic liquid samples synthesized in chemical laboratories, which is simple, reliable, and practical. The separation and detection of N‐methyl‐N‐ethyl‐morpholinium cation and N‐methyl‐N‐propyl‐morpholinium cation by hydrophilic interaction column combined with indirect ultraviolet detection using imidazolium ionic liquids as ultraviolet absorbents in high‐performance liquid chromatography.

In this study, an analytical method of hydrophilic interaction liquid chromatography combined with indirect ultraviolet detection for the determination of alkyl ammonium ionic liquid cations was developed, and it was combined with the sample pretreatment technique of solid phase extraction in order to be applied to analysis of alkyl ammonium ionic liquid cations in environmental water. The retention behavior of alkyl ammonium cations on the hydrophilic interaction column had the typical characteristics of hydrophilic interaction liquid chromatography, and their retention followed the carbon number rule. The separation and detection of tetraethyl ammonium cations, tetrapropyl ammonium cations and tetrabutyl ammonium cations were achieved in 20 min by using 1.0 mM 1-ethyl-3-methyl imidazolium trifluoroacetate aqueous solution/acetonitrile (40/60, v/v) as the mobile phase. The detection limits were 0.093, 0.096 and 0.253 mg L−1, respectively. The relative standard deviations of the retention time and the peak area were less than 0.5% from seven determinations. The reversed phase ion-pair solid phase extraction method was realized by using sodium octanesulfonate as the ion-pair reagent and 90% acetonitrile (v/v) solution as the eluent. Alkyl ammonium cations in Songhua River water and Hulan River water were analyzed. The results showed that the recoveries and enrichment effect of tetraethyl ammonium cations and tetrapropyl ammonium cations were all good. The method is simple and reliable, which can provide a reference for the analysis of alkyl ammonium cations in environmental water.

In this research, the effects of main parameters such as speed of agitator, concentration and redium change ratio on the grinding effect were studied by the method of wet-grinding. The powder was characterized and analyzed by means of particle size analysis and scanning electron microscope. The results show that the mechanical grinding method can effectively prepare micro-nanosilicon carbide powder with particle size of about 130nm, the optimum parameter is the rotational speed 1000r/min, the concentration is 30%, the medium change ratio is 75%.

Because of the poor stereocomplex (sc) crystallization and low melt strength, stereocomplexed polylactide (sc-PLA) is yet to fulfill its promise as a heat-resistant green foam. Herein, the strategy of dynamic PLA is proposed to promote sc crystallization and improve the melt strength of sc-PLA simultaneously. Maleic anhydride-grafted poly(l-lactide) (PLLA) and poly(d-lactide) (PDLA) were first blended to form sc crystallites, ensuring that the interchain cross-linking between PLLA and PDLA pairs occurred based on epoxy–anhydride chemistry. The prepared dynamic cross-linked sc-PLA enabled by Zn(II)-catalyzed transesterification can form exclusive sc crystallites during nonisothermal and isothermal crystallization, facilitated by the increased nucleation density and growth rate for sc crystallization. The inhibited separation of chains by interchain linking of PLLA and PDLA pairs and compatibilization induced by dynamic cross-linking due to the produced grafted multiblock copolymers of PLLA and PDLA by interchain cross-links shorten the diffusion path to form enantiomer chain pairs, reducing the kinetic hindrance of sc crystallization. The high viscosity of dynamic cross-linked sc-PLA at low frequencies indicates a significant improvement in melt strength, enabling the foamability with an expansion ratio of 5.9-fold by the supercritical carbon dioxide foaming technique. The obtained highly crystalline foam with exclusive sc crystallites can withstand temperatures up to 200 °C. The promoted sc crystallization and increased melt strength are realized simultaneously through dynamic cross-linking of PLLA and PDLA chains, opening up a new path for creating heat-resistant green foams.

Fe/N-based biomass porous carbon composite (Fe/N-pCarbon) was prepared by a facile high-temperature carbonization method from biomass, and the effect of Fe/N-pCarbon on the thermal decomposition of energetic molecular perovskite-based material DAP-4 was studied. Biomass porous carbonaceous materials was considered as the micro/nano support layers for in situ deposition of Fe/N precursors. Fe/N-pCarbon was prepared simply by the high-temperature carbonization method. It was found that it showed the inherent catalysis properties for thermal decomposition of DAP-4. The heat release of DAP-4/Fe/N-pCarbon by DSC curves tested had increased slightly, compared from DAP-4/Fe/N-pCarbon-0. The decomposition temperature peak of DAP-4 at the presence of Fe/N-pCarbon had reduced by 79°C from 384.4°C (pure DAP-4) to 305.4°C (DAP-4/Fe/N-pCarbon-3). The apparent activation energy of DAP-4 thermal decomposition also had decreased by 29.1 J/mol. The possible catalytic decomposition mechanism of DAP-4 with Fe/N-pCarbon was proposed.

Although aberrant metabolism in tumors has been well described, the identification of cancer subsets with particular metabolic vulnerabilities has remained challenging. Here, we conducted an siRNA screen focusing on enzymes involved in the tricarboxylic acid (TCA) cycle and uncovered a striking range of cancer cell dependencies on OGDH, the E1 subunit of the alpha-ketoglutarate dehydrogenase complex. Using an integrative metabolomics approach, we identified differential aspartate utilization, via the malate-aspartate shuttle, as a predictor of whether OGDH is required for proliferation in 3D culture assays and for the growth of xenograft tumors. These findings highlight an anaplerotic role of aspartate and, more broadly, suggest that differential nutrient utilization patterns can identify subsets of cancers with distinct metabolic dependencies for potential pharmacological intervention.

In this study, we describe the 3D chromosome regulatory landscape of human naive and primed embryonic stem cells. To devise this map, we identified transcriptional enhancers and insulators in these cells and placed them within the context of cohesin-associated CTCF-CTCF loops using cohesin ChIA-PET data. The CTCF-CTCF loops we identified form a chromosomal framework of insulated neighborhoods, which in turn form topologically associating domains (TADs) that are largely preserved during the transition between the naive and primed states. Regulatory changes in enhancer-promoter interactions occur within insulated neighborhoods during cell state transition. The CTCF anchor regions we identified are conserved across species, influence gene expression, and are a frequent site of mutations in cancer cells, underscoring their functional importance in cellular regulation. These 3D regulatory maps of human pluripotent cells therefore provide a foundation for future interrogation of the relationships between chromosome structure and gene control in development and disease.

In this article, we study one fractional (p, q)-Laplacian equations with subcritical or critical Hardy exponents. We obtain some existence results using variational methods and Nehari manifold under two different cases.

In this paper, a matrix based feature extraction and measurement method, i.e.: multi-column principle component analysis (MCPCA) is used to directly and effectively extract features from the matrix. We analyze the advantages of MCPCA over the conventional principal component analysis (PCA) and two-dimensional PCA (2DPCA), and we have successfully applied it into face image recognition. Extensive face recognition experiments illustrate that the proposed method obtains high accuracy, and it is more robust than previous conventional face recognition methods.

To understand the oil and gas accumulation rules and main controlling factors of H Basin at different phases, approaches such as reservoir dissection and analysis on the spatial allocation of reservoir accumulation conditions are adopted to divide the reservoir of the main fault depression zones of central H Basin into early and late phases. The widely-spread oil and gas at early phase are obviously more than that of the late phase. The main controlling factors of reservoir accumulation at early phase include source rocks area, antithetic faults - tilted upheavals and sand body of fan delta front subfacies while that of the late phase include sources rocks area, inverted structure and long-term developed fractures. The achievement of the study expounded in this paper is significantly important to correctly understand the oil and gas accumulation rules of complicated faulted-block fields and guide the oil and gas exploration activities.

Using high quality carbon raw material,high quality silica raw material , the β-SiC powder are prepared by high-temperature vacuum smelting method. The effects of different materials and electrical power to the product of β-SiC quality has been studied. The microstructure and phase analysis of β-SiC powder samples were observed by Scanning Electron Microscopy and X-ray diffraction. The result shows that the raw materials are better, the product quality are better. In addition, the result also indicates that the β-SiC powder have better quality when the power are 3000W.

Anthracite and bitumite were processed respectively at 1400°C,1700°C, 2000°C, 2200°C, 2400°C and 2600°C,and their chemical composition,resistivity,microstructure, phase composition,and the internal migration of molecular functional group were tested and characterized. The results indicate that moisture, ash and volatile in coal have gradually shifted and lost with the elevation of heat treatment temperature, while the higher temperature, the quicker and completer phase change. Heat treatment can make the coal transform from approximately insulative phase to conductive phase,. Furthermore, as the temperature increases, the conductive phase transformation effect is better. The higher the heat treatment temperature of coal, the more amorphous carbon transforming into crystalline carbon completely, but the less types of phases .

In this paper, reporting a new way to directly prepare quality of carbon materials such as artificial graphite, like-graphitization carburant and senior carbonaceous reductant et al ,which is prepared from anthracite under ultra-high temperature without any other additional process and catalyst. The chemical composition of carbon materials was analysed ; the electrical resistivity was tested; the composition of phase and the graphitization degree was tested by XRD; the microstructure was characterized by SEM and the degree of crystallization and crystal defect was characterized by the Raman diffraction spectrum. At the same time, the graphitization method was discussed during ultra-high temperature. The results show that good carburant and carbonaceous reductant can be prepared by anthracite which was graphitization under ultra-high temperature ;The microstructure of carbon materials which was prepared by anthracite that was graphitization during ultra-high temperature is more ordered than that of raw anthracite, its graphitization degree also increase significantly; When the ultra-high graphitization temperature is above 2600 °C, carbon materials which is like to pure graphite have a small amount of structural defects and distortion; the high quality carbon materials prepared by graphitization method under ultra-high temperature ,it is a simple process with low cost and high added value, and its prospects of application is broad.

This paper summarized the basic properties and preparation methods of ultrafine powder, introduced the present situation and progress of ultrafine powder classification technology at home and abroad, also pointed out the application of ultra-fine powder material in the mold manufacturing, biomedical, electronic information, fine ceramics, food industry and coatings.

The microstructures and mechanical properties of the ductile cast iron (Dl) specimens obtained by lost foam casting (LFC) with and without vibration were investigated. The results indicate that the number of the graphite nodule increases from 173 mm−2of the specimens produced by LFC without vibration to 334 mm−2of the specimens produced by LFC with vibration, and the thickness of the ferrite shell increases. Meanwhile, the amount of the carbides decreases in the specimens produced by LFC with vibration and the granule structure then forms. These are mainly attributed to the “crystal shower” caused by the vibration. In addition, the tensile strength and elongation of DI specimens produced by LFC with vibration are improved due to the dispersion-strengthening of refined carbide and pearlite colony, uniform distribution of the graphite nodule, and increase of the amount of dimples and tearing edges.

The microstructures and mechanical properties of the ductile cast iron (DI) specimens obtained by lost foam casting ( LFC) with and without vibration were investigated. The results indicate that the number of the graphite nodule increases from 175 mm−2of the specimens produced by LFC without vibration to 334 mm−2of the specimens produced by LFC with vibration, and the thickness of the ferrite shell increases. Meanwhile, the amount of the carbides decreases in the specimens produced by LFC with vibration and the granule structure then forms. These are mainly attributed to the “crystal shower” caused by the vibration. In addition, the tensile strength and elongation of DI specimens produced by LFC with vibration are improved due to the dispersion-strengthening of refined carbide and pearlite colony, uniform distribution of the graphite nodule, and increase of the amount of dimples and tearing edges.

Three-dimensional printing has been used as a rapid freeform fabrication process to fabricate a wider range of green ceramic components with complex structures difficult to obtain using traditional ceramic fabrication process. In this study, calcia-based ceramic core composites were fabricated by three dimensional printing and sintering operation. The green bodies were printed using a CaO/TiO2 powder mixture as a precursor material and ethylene glycol as a binder. They were sintered at 1400-1500 °C for 2 h. The phases and microstructures of these samples were characterized by X-ray diffraction and scanning electron microscopy. The effect of TiO2 content and the sintering temperature on the density, hydration resistance and bending strength of the sintered bodies was investigated. It was found that increment of TiO2 content and sintering temperature would result in an increase of density of the sintered bodies and then increase of hydration resistance and bending strength.

In order to improve the mechanical properties of A356 aluminum alloy in lost form casting (LFC), vibration and pressure were applied to solidification process of LFC, and the microstructures and the mechanical properties of the castings were compared with that of the castings in LFC without vibration and pressure. The results indicated that the grains of A356 alloy with vibration pressure in LFC became finer, and the dendrites decreased, and the equiaxed grains increased. At the same time, the porosities of the castings were significantly reduced. Compared with conventional LFC, the tensile strength, elongation, and hardness of A356 alloy with vibration pressure in LFC were all increased by 10% or above.

Embryonic stem cells (ESCs) of mice and humans have distinct molecular and biological characteristics, raising the question of whether an earlier, “naive” state of pluripotency may exist in humans. Here we took a systematic approach to identify small molecules that support self-renewal of naive human ESCs based on maintenance of endogenous OCT4 distal enhancer activity, a molecular signature of ground state pluripotency. Iterative chemical screening identified a combination of five kinase inhibitors that induces and maintains OCT4distal enhancer activity when applied directly to conventional human ESCs. These inhibitors generate human pluripotent cells in which transcription factors associated with the ground state of pluripotency are highly upregulated and bivalent chromatin domains are depleted. Comparison with previously reported naive human ESCs indicates that our conditions capture a distinct pluripotent state in humans that closely resembles that of mouse ESCs. This study presents a framework for defining the culture requirements of naive human pluripotent cells.