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A quantitative kinetic model for the supercritical water partial oxidation of the mixture of acetic acid, naphthalene and phenol at 560 °C, 25 MPa was established. The model consisted a group of pathways that included two kind of compounds, which could be classified as stable cyclic compound (Int.1) and unstable ring-opening products (Int.2). The model was validated with the experimental data at oxygen ratio (OR) of 0 and 0.2, respectively. Results showed that the model could accurately predict the influences of reactants time on gas yields and intermediates concentrations. Reaction rate analysis indicated that the general trends of reaction rate at OR = 0 and OR = 0.2 were similar. The decomposition and steam reforming reactions of Int.2 were the main pathways for gas production. The oxygen during the gasification played a positive role in promoting the ring-opening reactions, which induced higher Int.2 production and increasing of steam reforming and decomposition rates, and finally increased the H2 production.

This paper focuses on the relationship between the world oil price and China's coke price, particularly with respect to extreme movements in the world oil price. Based on a daily sample from 2009 to 2015 and the ARJI-GARCH models and copulas, our empirical results show that China's coke price and the world oil price are characterized by GARCH volatility and jump behaviors. Specifically, negative oil price shocks lead to falls in China's coke returns on the following day while positive oil prices have no significant effects. In addition, current coke returns positively respond to the very recent oil price jump intensity, and a time-varying and volatile lower tail dependence is found between the world oil price and China's coke price. Our results are expected to have implications for coke producers and users and policy makers.

Random invariant manifolds are considered for a stochastic Swift-Hohenberg equation with multiplicative noise in the Stratonovich sense. Using a stochastic transformation and a technique of cut-off function, existence of random invariant manifolds and attracting property of the corresponding random dynamical system are obtained by Lyaponov-Perron method. Then in the sense of large probability, an approximation of invariant manifolds has been investigated and this is further used to describe the geometric shape of the invariant manifolds.

We report systematic magneto-transport measurements and ab initio calculations on single-crystalline TaP2, a new member of the transition-metal dipnictides. We observed unsaturated magnetoresistance (MR) reaching ~ 700% at a magnetic field (B) of 9 T at 2 K along with striking Shubnikov-de Hass (SdH) oscillations. Our analysis on the SdH oscillations reveals nonzero Berry phase, indicating nontrivial band topology. The analysis also uncovers three fundamental magnetic oscillation frequencies of 72 T, 237 T, and 356 T, consistent with the theoretical calculations which reveal one hole pocket and two electron pockets at the L point and one electron pocket at the Z point of the Brillouin zone. We also found negative longitudinal MR (n-MR) within a narrow window of the angles between B and the electric current (I). The n-MR could be fitted with the Adler-Bell-Jackiw chiral anomaly equation but the origin remains yet ambiguous. The ab inito calculations suggest TaP2 as a weak topological insulator with the Z2 indices of (0; 111), which exhibits topological surface states on the (001) surface., 22 pages, 6 figures, 1 table

We report a systematic NMR study on [Sr4Sc2O6]Fe-2(As1-xPx)(2), for which the local lattice parameters of the iron-pnictogen (FePn) layer are similar to those of the series LaFe(As1-x'Px')O, which exhibits two segregated antiferromagnetic (AFM) order phases, AFM1 at x' = 0 - 0.2 and AFM2 at x' = 0.4 - 0.7. Our results reveal that the parent AFM1 phase at x = 0 disappears at x = 0.3 - 0.4, corresponding to a pnictogen height (h(pn)) from the Fe plane of 1.3-1.32 angstrom, which is similar to that of LaFe(As1-x'Px')O and various parent Fe pnictides. By contrast, the AFM2 order reported for LaFe(As0.4P0.6)O does not appear at x similar to 0.8, although the local lattice parameters of the FePn layer and the microscopic electronic states are quite similar. Despite the absence of the static AFM2 order, reemergent dynamical AFM spin fluctuations were observed at approximately x similar to 0.8, which can be attributed to the instability of the AFM2 phase. We suggest this re-enhancement of AFM spin fluctuations plays a significant role in enhancing the T-c to 17 K for x = 0.8 - 1. Finally, we discuss the universality and diversity of the complicated magnetic ground states from a microscopic point of view, including the difference in the origins of the AFM1 and AFM2 phases, and their relations with the high superconducting transitions in Fe pnictides.

Two-dimensional (2D) materials with narrow band gaps (∼0.3 eV) are of great importance for realizing ambipolar transistors and mid-infrared (MIR) detections. However, most of the 2D materials studied to date have band gaps that are too large. A few of the materials with suitable band gaps are not stable under ambient conditions. In this study, the layered Nb

The recent discovery of intrinsic ferromagnetic order in the atomically thin van der Waals crystal CrXTe_{3} (X=Si, Ge) stimulates intensive studies on the nature of low-dimensional magnetism because the presence of long-range magnetic order in two-dimensional systems with continuous symmetry is strictly prohibited by thermal fluctuations. By combining advanced many-body calculations with angle-resolved photoemission spectroscopy we investigate CrSiTe_{3} single crystals and unveil the pivotal role played by the strong electronic correlations at both high- and low-temperature regimes. Above the Curie temperature (T_{c}), Coulomb repulsion (U) drives the system into a charge transfer insulating phase. In contrast, below T_{c} the crystal field arranges the Cr-3d orbitals such that the ferromagnetic superexchange profits, giving rise to the bulk ferromagnetic ground state with which the electronic correlations compete. The excellent agreement between theory and experiment establishes CrSiTe_{3} as a prototype low-dimensional crystal with the cooperation and interplay of electronic correlation and ferromagnetism.

We present AC and DC magnetometry, heat capacity, muon spin relaxation ($\ensuremath{\mu}\mathrm{SR}$), and resonant inelastic x-ray scattering (RIXS) studies of the pyrochlore osmate ${\mathrm{Y}}_{2}{\mathrm{Os}}_{2}{\mathrm{O}}_{7}$. Consistent with previous results, we observe a small Curie-Weiss effective moment of approximately 0.4 ${\ensuremath{\mu}}_{\mathrm{B}}$ and spin freezing at a temperature ${T}_{f}\ensuremath{\simeq}5\phantom{\rule{0.16em}{0ex}}\mathrm{K}$. On the other hand, our analysis of the RIXS spectra with single-ion energy-level calculations implies a nonmagnetic ${J}_{\mathrm{eff}}=0$ ground state on the ${\mathrm{Os}}^{4+}$ sites, with the spin-orbit interaction, Hund's coupling, and trigonal distortion of ${\mathrm{OsO}}_{6}$ octahedra, all important in modeling the observed spectra. From high-field magnetization data, we show that the paramagnetic moment is most likely due to large moments ${\ensuremath{\mu}}_{\mathrm{eff}}\ensuremath{\simeq}3\phantom{\rule{0.16em}{0ex}}{\ensuremath{\mu}}_{\mathrm{B}}$ on only a small fraction $f\ensuremath{\simeq}0.02$ of Os sites. We suggest disorder-related effects, such as oxygen nonstoichiometry or site interchange between Os and Y ions, as the most likely explanation for the magnetic response of this material.

Magnetic Weyl semimetals (WSMs) bearing long-time pursuing are still very rare. We herein identified magnetic exchange induced Weyl state in EuCd2Sb2, a semimetal in type IV magnetic space group, via performing high magnetic field (B) magneto-transport measurements and ab initio calculations. For the A-type antiferromagnetic (AFM) structure of EuCd2Sb2, external B larger than 3.2 T can align Eu spins to be fully polarized along the c-axis and consequently drive the system into a ferromagnetic (FM) state. Measurements up to B ~ 55 T revealed a striking Shubnikov-de Hass oscillation imposed by a nontrivial Berry phase. We unveiled a phase transition from a small-gap AFM topological insulator into a FM WSM in which Weyl points emerged along the {\Gamma}-Z path. Fermi arcs on (100) and (010) surfaces are also revealed. The results pave a way towards realization of various topological states in a single material through magnetic exchange manipulation., Comment: 31 papges,10 figures, 2 tables

The finite dimension estimates of Hausdorff dimension and fractal dimension of the attractor of the dissipative quantum Zakharov equations are mainly studied by using the estimates of the Lyapunov exponents. The main results on the attractor are obtained through studying the linear system $\operatorname{DS}(t)$ , which is the differential system of solution operator $S(t)$ for the dissipative quantum Zakharov equations at the initial value $(m_{0},n_{0},E_{0})$ .

The extremely large magnetoresistance (XMR) in nonmagnetic semimetals has inspired growing interest owing to both intriguing physics and potential applications. We report results of synchrotron X-ray diffraction (SXRD) and electrical transport measurements on TaAs2 under pressure up to ~ 37 GPa, which revealed an anisotropic compression of the unit cell, formation of unusual As-As bonds above 9.5 GPa, and enhancement of metallicity. Interestingly, the MR of TaAs2 under pressure changed gently, which at 1.7 GPa is 96.6% and at 36.6 GPa is still 36.7%. The almost robust MR under pressure could be related to the nearly stable electronic structure unveiled by the ab initio calculations. The discovery would expand the potential use of XMR even under high pressure., Comment: 15 pages, 7 figures including those in supporting information

In this paper, the existence of random attractors for nonautonomous stochastic reversible Selkov system with multiplicative noise has been proved through Ornstein-Uhlenbeck transformation. Furthermore, the upper semicontinuity of random attractors is discussed when the intensity of noise approaches zero. The main difficulty is to prove the asymptotic compactness for establishing the existence of tempered pullback random attractor.

Weyl semimetals exhibit exceptional quantum electronic transport due to the presence of topologically-protected band crossings called Weyl nodes. The nodes come in pairs with opposite chirality, but their number and location in momentum space is otherwise material specific. Following the initial discoveries there is now a need for better material realizations, ideally comprising a single pair of Weyl nodes located at or very close to the Fermi level and in an energy window free from other overlapping bands. Here we propose the layered intermetallic EuCd$_2$As$_2$ to be such a system. We show that Weyl nodes in EuCd$_2$As$_2$ are magnetically-induced via exchange coupling, emerging when the Eu spins are aligned by a small external magnetic field. The identification of EuCd$_2$As$_2$ as a model magnetic Weyl semimetal, evidenced here by ab initio calculations, photoemission spectroscopy, quantum oscillations and anomalous Hall transport measurements, opens the door to fundamental tests of Weyl physics.

We reveal the electronic structure in YbCd2Sb2, a thermoelectric material, by angle-resolved photoemission spectroscopy (ARPES) and time-resolved ARPES (trARPES). Specifically, three bulk bands at the vicinity of the Fermi level are evidenced near the Brillouin zone center, consistent with the density functional theory (DFT) calculation. It is interesting that the spin-unpolarized bulk bands respond unexpectedly to right- and left-handed circularly polarized probe. In addition, a hole band of surface states, which is not sensitive to the polarization of the probe beam and is not expected from the DFT calculation, is identified. We find that the non-equilibrium quasiparticle recovery rate is much smaller in the surface states than that of the bulk states. Our results demonstrate that the surface states can be distinguished from the bulk ones from a view of time scale in the nonequilibrium physics.

Van der Waals (vdW) ferromagnetic materials have attracted considerable attention in the nanomaterial community, which could provide a unique platform to study magnetism at the nanoscale. Along this direction, many interesting results have been reported, including the electric field control of magnetism and topological spin textures. In this report, we present a rapid and spatially resolved imaging method to study the dimensionality-dependent magnetic properties of Fe3GeTe2 (FGT) nanoflakes. Our method is named as polar magneto-optical Kerr imaging microscopy magnetometry (p-MIMM), which is made possible by analyzing the intensity evolution of wide-field polar magneto-optical Kerr effect (MOKE) images that were collected by varying magnetic fields, thicknesses, and temperatures. In particular, spatially resolved MOKE hysteresis loops can be acquired in the FGT nanoflakes with a submicrometer resolution. By analyzing the evolution of the relative (saturated) MOKE intensity as a function of temperature, we further study the critical exponent and universality class and its dependence on the FGT nanoflake thickness. Combining the polar MOKE images with the calculated MOKE hysteresis loops, a detailed magnetic phase diagram summarizing an evolution of the stripe domain, single domain, and paramagnetic state is further validated. Our results suggest that the wide-field p-MIMM can be conveniently used for rapidly examining the magnetic properties of versatile vdW magnetic materials.

A mixture of phenol, acetic acid, and naphthalene was partially oxidized in supercritical water in order to produce hydrogen. The effects of temperature, oxidation ratio (OR), reaction time, and reactant concentrations on gaseous distributions, gasification efficiencies, and reactants removal efficiencies were investigated. Furthermore, the effects of oxygen on the main intermediate products were analyzed, and possible degradation pathways were proposed. Results indicated that higher temperatures significantly promoted the H 2 yield. In addition, small amounts of oxygen (OR 2 and CH 4 . The maximum H 2 gasification efficiency (240.25%) and H 2 yield (70.16 mmol g −1 ) were obtained at 560 °C, 25 MPa, reaction time of 20 s and OR of 0.2. Longer reaction time enhanced the gasification efficiencies in 10 s, while the effect was little when reaction times longer than 10 s. The concentrations of the reactants did not significantly influence the gasification efficiencies.

A plasma jet, driven by an active helium atom supplied with an atmospheric and room temperature plasma (ARTP) biological breeding system, was used as a novel method to breed L-arginine high-yielding strains. A mutant with resistance to L-homoarginine and 8-azaguaine, ARG 3-15 (L-HA(r), 8-AG(r), L-His(-)), was screened after several rounds of screening. The L-arginine production of these mutants was more than that of the original strain, increased by 43.79% for ARG 3-15. Moreover, N-acetyl-L-glutamate synthase activity of these mutants was also increased. After a series of passages, the hereditary properties of these mutants were found to be stable. Interestingly, beet molasses was utilized in a co-feeding fermentation and benefited to increase the productivity by 5.88%. Moreover, the fermentation with 1.0 g/L betaine could produce 9.33% more L-arginine than without betaine. In fed-batch fermentation, C. glutamicum ARG 3-15 began to produce L-arginine at the initial of logarithmic phase, and continuously increased over 24 hr to a final titer of 45.36 ± 0.42 g/L. The L-arginine productivity was 0.571 g/L/hr and the conversion of glucose (α) was 32.4% after 96 hr. These results indicated that C. glutamicum ARG 3-15 is a promising industrial producer.

Characterization of Fermi surface of the BaSn3 superconductor (T c ∼ 4.4 K) by de Haas–van Alphen (dHvA) effect measurement reveals its non-trivial topological properties. Analysis of non-zero Berry phase is supported by the ab initio calculations, which reveals a type-II Dirac point setting and tilting along the high symmetric K–H line of the Brillouin zone, about 0.13 eV above the Fermi level, and other two type-I Dirac points on the high symmetric Γ–A direction, but slightly far below the Fermi level. The results demonstrate BaSn3 as an excellent example hosting multiple Dirac fermions and an outstanding platform for studying the interplay between nontrivial topological states and superconductivity.

We have used the de Hass-van Alphen (dHvA) effect to investigate the Fermi surface of high-quality crystalline TiSb2, which unveiled a nontrivial topologic nature by analyzing the dHvA quantum oscillations. Moreover, our analysis on the quantum oscillation frequencies associated with nonzero Berry phase when the magnetic field is parallel to both of the ab-plane and c-axis of TiSb2 finds that the Fermi surface topology has a three-dimensional (3D) feature. The results are supported by the first-principle calculations which revealed a symmetry-protected Dirac point appeared along the {\Gamma}-Z high symmetry line near the Fermi level. On the (001) surface, the bulk Dirac points are found to project onto the -{\Gamma} point with nontrivial surface states. Our finding will substantially enrich the family of 3D Dirac semimetals which are useful for topological applications., Comment: 14 pages, including main text + SI, 5 figures

Materials with giant spin splitting are desired for spintronic applications. The fabrications of spintronic devices from half metals with one spin direction are often hampered, however, by stray magnetic fields, domain walls, short spin coherence times, scattering on magnetic atoms or magnetically active interfaces, and other characteristics that come along with the magnetism. The surfaces of topological insulators, or Dirac/Weyl semimetals, could be an alternative, but production of high-quality thin films without the presence of the bulk states at the Fermi energy remains very challenging. Here, by utilizing angle-resolved photoemission spectroscopy, a record-high Dresselhaus spin-orbit splitting of the bulk state in the nonmagnetic IrBiSe is found. The band structure calculations indicate that the splitting band is fully spin-polarized with 3D chiral spin texture. As a source of spin-polarized electrons, lightly doped IrBiSe is expected to generate electric-field-controlled spin-polarized currents, free from back scattering, and could host triplet and Fulde-Ferrel-Larkin-Ovchinnikov (FFLO) superconductivity.

Half-metals are a class of materials that are metallic only for one spin direction, and are essential for spintronics applications where one needs to read, write, store and transfer spin-data. This spin sensitivity appears to restrict them to be magnetic, and the known examples indeed are. The fabrication of real spintronic devices from such materials is often hampered, however, by stray magnetic fields, domain walls, short spin coherence times, scattering on magnetic atoms or magnetically active interfaces, and other characteristics that come along with the magnetism. The surfaces of topological insulators, or Dirac or Weyl semimetals, could be an alternative, but production of high-quality thin films without the presence of the bulk states at the Fermi level remains very challenging. Here we introduce non-magnetic half-metals and demonstrate that this state is realized in IrBiSe. Using angle-resolved photoemission spectroscopy and band structure calculations we find a record-high Dresselhaus spin-orbit splitting, fully spin-polarized remnant Fermi surfaces and a chiral 3D spin-texture, all with no magnetism present. Promising applications include using IrBiSe as a source of spin-polarized electrons, and lightly doped IrBiSe is expected to generate electric-field-controlled spin-polarized currents, free from back scattering, and could host triplet superconductivity.

The layered Cr2Ge2Te6 (CrGT) has captured vast attentions because it is capable of retaining the long-range ferromagnetic order even in its monolayer form, thus offering potential applications in spintronic devices. We report herein the Raman spectra of CrGT under pressure up to 35.1 GPa at room temperature. We observed a structural phase transition at ∼14 GPa as was revealed by a change in pressure derivate frequencies of the E g 3 and A g 1 modes. Both of the two peaks became broad and the A g 1 mode eventually disappeared with further increasing the pressure. Raman modes above 26.4 GPa could not be experimentally observed, suggesting that the CrGT was pressed into the amorphous phase. Interestingly, a pressure-induced soft phonon mode is identified in CrGT at ∼23 GPa by dynamical property calculation. The phonon instability at the Brillouin zone boundary T point is suggested as the driving force for the experimentally observed crystalline-to-crystalline phase transition at ∼ 18 GPa. The appearance of soft phonon might indicate the possibility of superconductivity induced by much higher pressure.

Vanadium diselenide (VSe2) is a van der Waals layered transitional metal dichalcogenide, which has attracted intensive attention due to the coexistence of charge density wave (CDW) transition and magnetic property down to two-dimension limit. We apply Spin- and angle-resolved photoemission spectroscopy measurement to explore the evolution of the valence eletronic states of VSe2 accompanied with the CDW transition. The V 3d-derived-band in the vicinity of Fermi energy shows negligible spin polarization both below and above the CDW transition temperature. Furthermore, a sizable spin polarization of Se 4p electronic states has been clearly observed, indicating an atomic-layer-dependent spin polarization in VSe2. Our results provide new clues to understand the spin polarized electronic states in transitional metal dichalcogenides.

Considering the slight deformation of the paper honeycomb sandwich plate in the vibration, the stiffness coefficient of the paper honeycomb sandwich plate was equivalent to the elasticity. The analytical model of natural frequency related to the structural and material parameters of the paper honeycomb sandwich plate and mass of block was derived. Subsequently, 5 different paper honeycomb sandwich plates and 3 different blocks were chosen to modify the analytical model by finite element method and verify it by experiment. The results show that the modifying factorl is 0.606 and the error between analytical and experimental results is less than 10%. In the future, the analytical model can be used to predict the natural frequency of paper honeycomb sandwich plate with different structural parameters under different blocks. Therefore, it provides the necessary theoretical reference for the optimization design of paper honeycomb sandwich plate.

We use resonant elastic x-ray scattering to determine the evolution of magnetic order in EuCd$_2$As$_2$ below $T_\textrm{N}=9.5$\,K, as a function of temperature and applied magnetic field. We find an A-type antiferromagneticstructure with in-plane magnetic moments, and observe dramatic magnetoresistive effects associated with field-induced changes in the magnetic structure and domain populations. Our \textit{ab initio} electronic structure calculations indicate that the Dirac dispersion found in the nonmagnetic Dirac semimetal Cd$_3$As$_2$ is also present in EuCd$_2$As$_2$, but is gapped for $T < T_\textrm{N}$ due to the breaking of $C_3$ symmetry by the magnetic structure., Supplemental information attached to preprint

Different two-dimensional (2D) materials, when combined together to form heterostructures, can exhibit exciting properties that do not exist in individual components. Therefore, intensive research efforts have been devoted to their fabrication and characterization. Previously, vertical and in-plane 2D heterostructures have been formed by mechanical stacking and chemical vapor deposition. Here, we report a new material system that can form in-plane p-n junctions by thermal conversion of n-type SnSe

LiOsO$_3$ is the first example of a new class of material called a ferroelectric metal. We performed zero-field and longitudinal-field $\mu$SR, along with a combination of electronic structure and dipole field calculations, to determine the magnetic ground state of LiOsO$_3$. We find that the sample contains both static Li nuclear moments and dynamic Os electronic moments. Below $\approx 0.7\,$K, the fluctuations of the Os moments slow down, though remain dynamic down to 0.08$\,$K. We expect this could result in a frozen-out, disordered ground state at even lower temperatures., Comment: 6 pages, 1 figure

Different two-dimensional materials, when combined together to form heterostructures, can exhibit exciting properties that do not exist in individual components. Therefore, intensive research efforts have been devoted to their fabrication and characterization. Previously, vertical and in-plane two-dimensional heterostructures have been formed by mechanical stacking and chemical vapor deposition. Here we report a new material system that can form in-plane p-n junctions by thermal conversion of n-type SnSe2 to p-type SnSe. Through scanning tunneling microscopy and density functional theory studies, we find that these two distinctively different lattices can form atomically sharp interfaces and have a type II to nearly type III band alignment. We also demonstrate that this method can be used to create micron sized in-plane p-n junctions at predefined locations. These findings pave the way for further exploration of the intriguing properties of the SnSe2-SnSe heterostructure., Comment: 30 pages, 6 figures

Experiments show that TaAs is a three-dimensional topological Weyl semimetal. Three-dimensional (3D) topologicalWeyl semimetals (TWSs) represent a state of quantum matter with unusual electronic structures that resemble both a ‘3D graphene’ and a topological insulator. Their electronic structure displays pairs of Weyl points (through which the electronic bands disperse linearly along all three momentum directions) connected by topological surface states, forming a unique arc-like Fermi surface (FS). Each Weyl point is chiral and contains half the degrees of freedom of a Dirac point, and can be viewed as a magnetic monopole in momentum space. By performing angle-resolved photoemission spectroscopy on the non-centrosymmetric compound TaAs, here we report its complete band structure, including the unique Fermi-arc FS and linear bulk band dispersion across the Weyl points, in agreement with the theoretical calculations1,2. This discovery not only confirms TaAs as a 3DTWS, but also provides an ideal platform for realizing exotic physical phenomena (for example, negative magnetoresistance, chiral magnetic effects and the quantum anomalous Hall effect) which may also lead to novel future applications.

Acetohydroxy acid synthase (AHAS) controls carbon flux through the branch point and determines the relative rates of the synthesis of isoleucine, valine and leucine, respectively. However, it is strongly regulated by its end products. In this study, we characterized AHAS variants from five branched-chain amino acids-producing strains. Amino acid substitution occurred in both catalytic subunit and regulatory subunit. Interestingly, AHAS variants reduced sensitivity to feedback inhibition by branched-chain amino acids (BCAAs). Although AHAS with amino acid substitution in regulatory subunit showed higher resistance, amino acid substitution in catalytic subunit could also endow AHAS with resistance to feedback inhibition. In addition, AHAS variants from V2 and L5 displayed about 1.4-fold higher specific activity compared to other AHAS variants. On the other hand, AHAS variant from V1 exhibited the highest resistance to BCAAs, 87% of original activity left even in the presence of 10mM BCAAs. Recombinant Corynebacteriumglutamicum strains were further constructed to investigate the effects of expressing AHAS variants on the synthesis of BCAAs and alanine (main by-product) in C. glutamicum. BCAAs production was increased with the increase of resistance to feedback inhibition, although valine showed a significant increase. For instance, C. g-1BN could accumulate 9.51g/l valine, 0.450g/l leucine and 0.180g/l isoleucine, and alanine was reduced to 0.477g/l. These AHAS variants are important for further improving performance of BCAAs-producing strain.

The aspartate aminotransferase (AAT) and aspartate ammonia-lyase (AAL) catalyzes respectively the reversible reaction of oxaloacetate (OAA) and fumarate to form l -aspartate. However, the effects of AAT and AAL on metabolite variations have not been clearly elucidated as yet. Now, the effects of AAT and AAL on metabolite variations in genetically defined l -lysine producing strains were studied by genetically modifying AAT gene aspB and AAL gene aspA . AAL was not detected in Corynebacterium glutamicum Lys1 but increased in aspB -deleted strain. Inversely, AAT exhibited high activity in Lys1, but it was not detected in aspB -deleted strains. Moreover, the deletion of aspB was bad for cell growth and metabolites production. The expression of Escherichia coli aspA in aspB -deleted strain not only restored cell growth and l -lysine production, but also accumulated some metabolites. However, the over-expression of aspB or aspA in aspB -natural strain did not affect cell growth and metabolites production except l -aspartate production. Although E. coli AAL could used to restore cell growth and metabolites accumulation in aspB -deleted strain, the effect on l -lysine production was significantly worse than that of AAT. Results indicates that native AAT is both necessary and sufficient for cell growth and l -lysine production, and deepens our understanding of the role of native aspB and E. coli aspA on cell growth and metabolites productions.

We present our study on the mechanical and electronic properties of two-dimensional phthalocyanines (2D-Pc) under external strain using first principles and pz-orbital tight-binding model calculations. The Poisson's ratio and in-plane stiffness calculated in the harmonic elastic strain range are found to be 0.43 and 73.41 J m−2, indicating that 2D-Pc is much softer than graphene. The 2D-Pc can bear the same critical uniform strain as pristine graphene, which reduces the hopping integrals of π-electrons and narrows the width of the bands near the Fermi level. Consequently, the band gap and effective masses of carriers undergo ascending trends as the strain increases. The present study provides meaningful insight into the strain induced variation of electronic transport performance in 2D-Pc and other 2D tetrapyrrole macrocyles.

This article focuses on the effects of glycine betaine on preventing caramelization, and increasing DCW and L-lysine production. The additional glycine betaine not only decreased the browning intensity (decreased 4 times), and the concentrations of 5-hydroxymethylfurfural (decreased 7.8 times) and furfural (decreased 12 times), but also increased the availability of glucose (increased 17.5%) for L-lysine production. The DCW and L-lysine production were increased by adding no more than 20 mM glycine betaine, whereas the DCW and L-lysine production were decreased with the reduction of pH values, although pH had a better response to prevent caramelization than did glycine betaine. For L-lysine production, the highest increase (40%) was observed on the media with 20 mM glycine betaine. The crucial enzymes in glycolysis and L-lysine biosynthesis pathway were investigated. The results indicated that additional glycine betaine increases the activity of enzymes in glycolysis, in contrast to the effect of pH. All the results indicated that glycine betaine can be used to prevent caramelization and increase the L-lysine production. By applying this strategy, glucose would not be have to be separated from the culture media during autoclaving so that factories can save production costs and shorten the fermentation period.

In this paper, we investigate a global random attractor for a stochastic local modified Swift-Hohenberg equation with multiplicative noise in Stratonovich sense. Through the Ornstein-Uhlenbeck (O-U) transformation, we obtain the random dynamical system associated with the stochastic local modified Swift-Hohenberg equation. Using the properties of the O-U process, we derive the specific uniform a priori estimates, using which we prove the existence of global random attractor for the corresponding random dynamical system.

In Corynebacterium glutamicum, acetohydroxy acid synthase (AHAS, encoded by ilvBN) is regulated by the end products in biosynthesis pathway, which catalyzes the first common reaction in the biosynthesis of branched-chain amino acids (BCAAs). In this study, conserved A42, A89 and K136 residues in AHAS regulatory subunit were chosen for site-directed mutagenesis, and the resulting mutations A42V, A89V and K136E exhibited higher resistance to inhibition by BCAAs than wild type AHAS. Furthermore, double-mutation was carried out on A42V, A89V and K136E mutations. Expectedly, A42V-A89V mutation exhibited nearly complete resistance to inhibition by all three BCAAs, which retained above 93% enzyme activity even at 10 mM. Strains were further studied to investigate the effects of over-expressing different mutant ilvBN on the biosynthesis of BCAAs. It was found that production of BCAAs was increased with the increase of resistance to BCAAs. However, the increase of isoleucine and leucine was slower than valine which showed a significant increase (up to 86.30 mM). Furthermore, strains harboring plasmids with different mutant ilvBN could significantly decrease production of alanine (main byproduct). This work gives additional understanding of roles of A42, A89 and K136 residues and makes the A42V, A89V, K136E and A42V-A89V mutations a good starting point for further development by protein engineering.

The experiments presented here were based on the conclusions of our previous results. In order to avoid introduction of expression plasmid and to balance the NADH/NAD ratio, the NADH biosynthetic enzyme, i.e., NAD-dependent glyceraldehyde-3-phosphate dehydrogenase (GADPH), was replaced by NADP-dependent GADPH, which was used to biosynthesize NADPH rather than NADH. The results indicated that the NADH/NAD ratio significantly decreased, and glucose consumption and L-lysine production drastically improved. Moreover, increasing the flux through L-lysine biosynthetic pathway and disruption of ilvN and hom, which involve in the branched amino acid and L-methionine biosynthesis, further improved L-lysine production by Corynebacterium glutamicum. Compared to the original strain C. glutamicum Lys5, the L-lysine production and glucose conversion efficiency (α) were enhanced to 81.0 ± 6.59 mM and 36.45% by the resulting strain C. glutamicum Lys5-8 in shake flask. In addition, the by-products (i.e., L-threonine, L-methionine and L-valine) were significantly decreased as results of genetic modification in homoserine dehydrogenase (HSD) and acetohydroxyacid synthase (AHAS). In fed-batch fermentation, C. glutamicum Lys5-8 began to produce L-lysine at post-exponential growth phase and continuously increased over 36 h to a final titer of 896 ± 33.41 mM. The L-lysine productivity was 2.73 g l(-1) h(-1) and the α was 47.06% after 48 h. However, the attenuation of MurE was not beneficial to increase the L-lysine production because of decreasing the cell growth. Based on the above-mentioned results, we get the following conclusions: cofactor NADPH, precursor, the flux through L-lysine biosynthetic pathway and DCW are beneficial to improve L-lysine production in C. glutamicum.

Fructose-1,6-bisphosphatase (FBPase), which is mainly used to supply NADPH, has an important role in increasing L-lysine production by Corynebacterium glutamicum. However, C. glutamicum FBPase is negatively regulated at the metabolic level. Strains that overexpressed Escherichia coli fructose-1,6-bisphosphatase in C. glutamicum were constructed, and the effects of heterologous FBPase on cell growth and L-lysine production during growth on glucose, fructose, and sucrose were evaluated. The heterologous fructose-1,6-bisphosphatase is insensitive to fructose 1-phosphate and fructose 2,6-bisphosphate, whereas the homologous fructose-1,6-bisphosphatase is inhibited by fructose 1-phosphate and fructose 2,6-bisphosphate. The relative enzyme activity of heterologous fructose-1,6-bisphosphatase is 90.8% and 89.1% during supplement with 3 mM fructose 1-phosphate and fructose 2,6-bisphosphate, respectively. Phosphoenolpyruvate is an activator of heterologous fructose-1,6-bisphosphatase, whereas the homologous fructose-1,6-bisphosphatase is very sensitive to phosphoenolpyruvate. Overexpression of the heterologous fbp in wild-type C. glutamicum has no effect on L-lysine production, but fructose-1,6-bisphosphatase activities are increased 9- to 13-fold. Overexpression of the heterologous fructose-1,6-bisphosphatase increases L-lysine production in C. glutamicum lysC(T311I) by 57.3% on fructose, 48.7% on sucrose, and 43% on glucose. The dry cell weight (DCW) and maximal specific growth rate (μ) are increased by overexpression of heterologous fbp. A "funnel-cask" diagram is first proposed to explain the synergy between precursors supply and NADPH supply. These results lay a definite theoretical foundation for breeding high L-lysine producers via molecular target.

LaZnAsO has been studied mainly in the thin film form that was indicated as a wide-gap insulator with the gap size of ∼2.3 eV. We herein report the synthesis of polycrystalline bulk LaZnAsO compound for the first time under a high pressure of 6 GPa. Effect of oxygen deficiency on the electric and magnetic properties of the compound was also investigated by synchrotron X-ray diffraction and measurements of electrical resistivity, magnetic susceptibility, isothermal magnetization, and specific heat. The bulk LaZnAsO crystallized into the ZrCuSiAs-type structure with the space group P 4/ nmm , isostructural with the layered LaFeAsO . It is semiconducting with a thermal activation energy of ∼0.8 eV, and the semiconductivity was highly robust against oxygen deficiency up to 25 at.%. The virtue will benefit the development of a diluted magnetic semiconductor.

This study documents the return and volatility spillover effect between the stock prices of Chinese new energy and fossil fuel companies using the asymmetric BEKK model. Based on daily samples taken from August 30, 2006 to September 11, 2012, the dynamics of new energy/fossil fuel stock spillover are found to be significant and asymmetric. Compared with positive news, negative news about new energy and fossil fuel stock returns leads to larger return changes in their counter assets. News about both new energy and fossil fuel stock returns spills over into variances of their counter assets, and the volatility spillovers depend complexly on the respective signs of the return shocks of each asset. The empirical results demonstrate that new energy and fossil fuel stocks are generally viewed as competing assets, that positive news about new energy stocks could affect the attractiveness of fossil fuel stocks and that new energy stock investment is more speculative and riskier than fossil fuel stock investment. These results have potential implications for asset allocation, financial risk management and energy policymaking.

Plasma treatment is a powerful tool to tune the properties of two-dimensional materials. Previous studies have utilized various plasma treatments on two-dimensional materials. We find a new effect of plasma treatment. After controlled oxygen-plasma treatment on field-effect transistors based on two-dimensional SnSe 2 , the capacitive coupling between the silicon back gate and the channel through the 300nm SiO 2 dielectric can be dramatically enhanced by about two orders of magnitude (from 11 nF/cm 2 to 880 nF/cm 2 ), reaching good efficiency of ion-liquid gating. At the same time, plasma treated devices show large hysteresis in the gate sweep demonstrating memory behavior. We reveal that this spontaneous ion gating and hysteresis are achieved with the assistance of a thin layer of water film automatically formed on the sample surface with water molecules from the ambient air, due to the change in hydrophilicity of the plasma treated samples. The water film acts as the ion liquid to couple the back gate and the channel. Thanks to the rich carrier dynamics in plasma-treated two-dimensional transistors, synaptic functions are realized to demonstrate short- and long-term memories in a single device. This work provides a new perspective on the effects of plasma treatment and a facile route for realizing neuromorphic devices.

The maximum vibration transmissibility of paper honeycomb sandwich structures with different sizes of honeycomb core under various static stresses was investigated using the sine frequency sweep test. The effects of the cell length of the honeycomb, the thickness of the sandwich structure, and the static stress on the maximum vibration transmissibility were evaluated and a linear polynomial equation for evaluating the maximum vibration transmissibility was obtained. The results show that the maximum vibration transmissibility increases steadily with the increase in the cell length of the honeycomb, the thickness of the sandwich structure, and the static stress. The proposed equation for the maximum vibration transmissibility is suitable for predicting the maximum vibration transmissibility of paper honeycomb sandwich structures. In addition, the fitted three-dimensional diagrams of the effects of the factors on the maximum vibration transmissibility derived from the evaluation equation were shown to be in good agreement with the experimental results.

For electronic and photoelectronic devices based on GeSe, an emergent two dimensional monochalcogenide with many exciting properties predicted, good electrical contacts are of great importance for achieving high device performances and exploring the intrinsic physics of GeSe. In this article, we use temperature-dependent transport measurements and thermionic emission theory to systematic investigate the contact-barrier heights between GeSe and six common electrode metals, Al, Ag, Ti, Au, Pt and Pd. These metals cover a wide range of work functions (from ~ 3.6 eV to ~ 5.7 eV). Our study indicates that Au forms the best contact to the valence band of GeSe, even though Au does not possess the highest work function among the metals studied. This behavior clearly deviates from the expectation of Schottky-Mott theory and indicates the importance of the details at the interfaces between metals and GeSe., 10 pages, 4 figures

BACKGROUND Corynebacterium glutamicum was engineered for improvement of L-lysine production and minimization of by-products synthesis by genetically engineering. RESULTS The most promising recombinant strain C. glutamicum Lys9 produced 62.1 mmol L-1 L-lysine with substrate-specific yield (YP/S) of 0.28 mol per mol of glucose in shake flasks fermentation, whereas parental strain showed more than four times lower L-lysine production and more than 10 times lower biomass-specific yield (YP/X) than that of C. glutamicum Lys9. L-lysine production and cell growth were drastically decreased by isocitrate dehydrogenase (ICD) attenuation in aceE deletion strains, indicating that down-regulation of ICD activity in aceE deletion strains adversely affects L-lysine production. In fed-batch fermentation, C. glutamicum Lys9 produced 526 mmol L-1 L-lysine, i.e. 96.8 g L-1 L-lysine-HCl with high yield of 0.422 mol per mol of glucose and productivity of 2.69 g L-1 h-1. Corynebacterium glutamicum Lys9 was devoid of any detectable L-alanine and L-lactate synthesis. CONCLUSION Superior to classical producers to some degree, C. glutamicum Lys9 is more adaptable for industrial L-lysine production. In addition to L-lysine, pyruvate, oxaloacetate (OAA) and L-valine were produced by C. glutamicum Lys9, suggesting further optimization to improve L-lysine production by engineering the L-lysine and/or NADPH biosynthetic pathway. © 2013 Society of Chemical Industry