Kinetics of C2(a3Πu) radical reactions with NO, N2O, O2, H2 and NH3

Pulsed laser photolysis/laser-induced fluorescence (LP-LIF) is utilized to measure rate constants for C₂(a³Π_u) reactions with NO, N₂O, O₂, H₂ and NH₃. Multiphoton dissociation of C₂Cl₄ at 266 nm is employed for the generation of C₂(a³Π_u) radicals. The C₂(a³Π_u) concentration is monitored by the fluorescence of the (0, 0) band of the (d³Π_g&#8596;a³Π_u) transition at 516.5 nm. C₂(a³Π_u) removal rate constants for the reactions are determined as k_NO = (5.46 ± 0.10) × 10^-11 cm³ molecule^-1 s^-1 , k_N2O = (1.63 ± 0.20) × 10^-13 cm³ molecule^-1 s^-1 , k_N2O = (1.58 ± 0.16) × 10^-11 cm³ molecule^-1 s^-1, k_O2 = (5.92 ± 1.00) × 10^-14 cm³ molecule^-1 s^-1, k_H2< 1.0× 10^-14 cm³ molecule^-1 s^-1. Based on the data analysis and theoretical calculation, we suggest that the C₂(a³Π_u) reactions with H₂ and NH₃ proceed via the hydrogen abstraction mechanism, barriers exist at the entrance channel of the reactions of C₂(a³Π_u) with H₂ and NH₃.     

Determination of crystal structure of omphacite

The chemical formula of omphacite was expressed with (MⅡ MⅠ ) (Si, AI)2O6. Cations that occupied the MⅡ site were large cations such as Ca or Na, and (Na/(Na+Ca)) ratio ranged from 0.2 to 0.8; the 6-coordinated MⅠ site accommodated cations such as Mg, Fe2+, Al, Fe3+ ,and(AI/(AI+Fe3+)) ratio was more than 0.5. Omphacite space groups reported were C2/ c, P2, P2/n, P2/c, cell parameters are α0 = 0.9600-0.9630 nm,b0 = 0.8750-0.8830 nm,c0 = 0.5230-0.5290 nm,β = 106°40′-107°10'. The sample was picked up from the eclogites in Zhucheng County, Shangdong Province. The intensity data were collected with the RIGAKU RASA Ⅱ -S four-circle single crystal diffractometer.The correct structure model was obtained by using the Patterson method and Fourier synthesis, SHELX-76 program, structure refinement with 905 independent diffraction points (| F0 |> 3σ |F0 |). After the structure parameter refinement, the R-factor reduced to 0.0515. The crystal structure analysis indicates that omphacite has a new space group-Pn space group.     

求解对流扩散方程的一类AGE方法

结合Crank-Nicolson格式和第二类Saul’yev非对称格式,设计求解对流扩散方程的交替分组显式方法.得到求解对流扩散方程的交替分组显式方法为该方法是绝对稳定的,且使用方便,适合并行计算,具有较好的精度.     

The concentration quenching characteristics of 5D3-7FJ and 5D4-7FJ (J=0―6) transitions of Tb3+ in YBO3:Tb3+ phosphor

The photoluminescence quenching behaviors of ^5D3-^7Fj and ^5D4-^7Fj （J = 0—6） transitions of Tb^3＋ in YBO3：Tb under 130—290 nm excitation were systematically investigated. The results revealed that the quenching concentrations of both ^5D3-^7Fj and ^5D4-^7Fj transitions of Tb^3＋ in YBO3：Tb were mainly dependent on excitation wavelength. Particularly, the quenching concentrations of ^5D4-^7Fj transitions of Tb^3＋ under 130—290 nm excitation were correlated with excitation bands of YBO3：Tb. The quenching concentrations of ^5D3-^7Fj transitions remained at low concentration （2%） under 186—290 nm excitation and then increased gradually with energy of incoming excitation photon when excited at 130—186 nm. This dependence should be involved in their excitation mechanisms and quenching pathway in particular excitation region.[第一段]     

Molecule modification andmass deposition induced bythe implantation of lowenergy Fe+ ion beamsinto amino acids

Fe+ ion beams with the energy of 110 keV were implanted into films of L(+)-cysteine (HSCH2CH(NH2)COOH). One of the single crystals grown in hydrochloric acid solution with the implanted samples through slow evaporation was structurally characterized by the X-ray crystallography. The crystal is monoclinic, space group C2, with a = 1.8534(4) nm, b = 0.5234(1) nm, c = 0.7212(1) nm, β= 103.72°, V = 0.67965(3) nm3, Z = 4, F(000) = 144.0, Dclac = 1.763 g@cm-3, μ(MoKα) = 1.06 mm-1, T = 293(2) K. R = 0.0379, wR = 0.0835 for 660 observed reflections (I > 2σ(I)). The structural formula of the crystal compound is (CH2CH(NH2)NO2)ClFe (Mr = 180.38 u). Products of heavy ion beam irradiation were purified and it was directly confirmed that the implanted Fe+ ions had been deposited in the novel molecules. The same doses of Fe+ ion beams of the same energy were implanted into films of L(+)-cysteine hydrochloride monohydrate. FTIR spectroscopy of the implanted samples proved that some of the original molecules were seriously damaged and significant modifications were induced.     

Nitric oxide suppresses stomatal opening by inhibiting inward-rectifying K<Stack><Subscript>in</Subscript><Superscript>+</Superscript></Stack> channels in <Emphasis Type="Italic">Arabidopsis</Emphasis> guard cells

We explore nitric oxide （NO） effect on K^＋in, channels in Arabidopsis guard cells. We observed NO inhibited K^＋in, currents when Ca^2＋ chelator EGTA （Ethylene glycol-bis（2-aminoethylether）-N,N,N′,N;tetraacetic acid） was not added in the pipette solution; K^＋in currents were not sensitive to NO when cytosolic Ca^2＋ was chelated by EGTA. NO inhibited the Arabidopsis stomatal opening, but when EGTA was added in the bath solution, inhibition effect of NO on stomatal opening vanished. Thus, it implies that NO elevates cytosolic Ca^2＋ by activating plasma membrane Ca^2＋ channels firstly, then inactivates K^＋in, chartnels, resulting in stomatal opening suppressed subsequently.     

Characterization of type<Emphasis Type="Italic">p</Emphasis> Banach spaces by the weak law of large numbers

For weighted sums of the form where {a _nj , 1 ⩽j⩽k _n ↑∞,n⩾1} is a real constant array and {X _aj , 1≤j≤k _{n, n}≥1} is a rowwise independent, zero mean, random element array in a real separable Banach space of typep, we establishL ^r convergence theorem and a general weak law of large numbers respectively, conversely, we characterize Banach spaces of typep in terms of convergence inr-th mean and probability for such weighted sums. Foundation item: Supported by the National Natural Science Foundation of China (No. 10071058) Biography: Gan Shi-xin (1939-), male, Professor, research direction: martingale theory, probability limiting theory and Banach space geometry theory.     

Theoretical study of partial oxidation of ethylene by vanadium trioxide cluster cation

Density functional theory （DFT） study of reaction between vanadium trioxide cluster cation （VO3^＋） and ethylene （C2H4） to yield VO2^＋ ＋ CH3CHO （acetaldehyde） and VO2CH2^＋ ＋ HCHO （formaldehyde） is carried out. Structures of all reactants, products, intermediates, and transition state in the reaction have been optimized and characterized. The results show unexpected barriers in the reaction due to the existence of a η^2-O2 moiety in the ground state structure of VO3^＋. The initial reaction steps combining ethylene adsorption, C=C activation and O-O cleavage are proposed as rate limiting processes. Comparison of reactions of VO3^＋ ＋ C2H4 with VO3 ＋ C2H4 and VO2^＋ ＋ C2H4 in the previous studies is made in detail. The results of this work may shed light on the understanding of C=C bond cleavage in related heterogeneous catalysis.     

Effect of fatty acids on polyamine contents and Na+/H+ antiport activity in PM vesicles isolated from roots of barley under salt stress

With 200 mmol/L NaCl treatment on barley cultivar “Jian 4” (Hordeum vulgare L. cv. J4) seedlings for 6 d, the contents of covalently and noncovalently conjugated polyamines (PAs) and activities of H⁺-ATPase in plasma membrane (PM) vesicles isolated from the roots decreased remarkably. Moreover, the activity of Na⁺/H⁺ antiport was detected first in PM vesicles. The results showed that the decrease in the contents of membrane phospholipid, noncovalently conjugated PAs and activity of H⁺-ATPase caused by NaCl could be restored partially by application of 1 mmol/L stearie acid (C_16:0) and linoleic acid (C_18:2), and C_18:2 was more effective than C_16:0 In addition, a reduction in the contents of covalently conjugated PAs was only reversed partially in the presence of C_18:2 Furthermore, Na⁺/H⁺ antiport activity was strengthened by exogenous C_16:0 and C_18:2 and C_18:2 was more effective than C_16:0. The correlative analysis suggested that, after application of C_16:0 and C_18:2 under salt stress, there was a significant positive correlation existing among phospholipid content, noncovalently conjugated PA levels, H⁺-ATPase activities and Na⁺/H⁺ antiport activities, indicating that one of the mitigative mechanisms of exogenous fatty acids on salt injury was to improve membrane phospholipid and PA contents, leading to an enhance in membrane integrity and a change in charge status of PM vesicles, so the activity of membrane-associated enzyme H⁺-ATPase was increased and synthesis of Na⁺/H⁺ antiport protein was activated.     

Multi-parameter infinite-dimensional (r,δ)-OU process

The definition of n-parameter infinite-dimensional (r,δ) -Ornstein-Uhlenbeck process {xt (·) } ((r, δ)-OUPn∞ for short) is given. The absolute continuity of distribution μt of Xt(·) and the limit of Xt(·) when |t| →∞ is discussed.     

Magnetoelectric and converse magnetoelectric res ponses in TbxDy1-xFe2-y alloy ＆ Pb（Mg1/3Nb2/3）（1-x）TixO3 crystal laminated composites

Measured results of magnetoelectric （ME） and converse magnetoelectric （CME） effects of TbxDy1-xFe2-y/ Pb（Mg1/3Nb2/3）（1-x）TixO3/TbxDy1-xFe2-y （TD/PMNT/TD） and PMNT/TD/PMNT laminated composites are presented. ME effect was determined by measuring laminate voltage output under a Helmholtz-generated AC field biased by a DC field （0-1 kOe） （1Oe = 79.58 A/m）. The CME effect was measured by recording the voltage induced in a solenoid encompassing the ME sample while exposed to a DC bias field and PMNT layer driven by a 10 V AC source. The ME and CME responses in the two laminated structure are linear. The highest values of ME coefficients in TD/PMNT/TD and PMNT/TD/PMNT composites are 384 mV/Oe and 158 mV/Oe, respectively, while the highest values of CME coefficients in the two composites are 118 mG/V and 162 mG/V （1 G=10^-4 T）, respectively.     

Kinetic studies of the decomposition reaction of adducts of dinuclear Fe(Ⅱ)/O2

Kinetic studies of the decomposition reaction of dinuclear Fe(Ⅱ) adducts [Fe₂(N-Et-HPTB){O₂P(OPh)₂}](Cl- O₄)₂ (1) and [Fe₂(N-Et-HPTB) {O₂P(Ph)₂}] (ClO₄)₂ (2) with O₂ have been carried out at low temperature using UV-vis spectra. The decomposition reaction of Fe(Ⅱ)/O₂ adducts was first-order in the experimental conditions, and the activation parameters were obtained. ?H^¹ = 85.62 kJ·mol^-1, ?S¹ = 19.43 J·mol^-1·K^-1 for compound (1) and ?H^¹ = 97.97 kJ·mol^-1, ?S^¹ = 55.68 J·mol^-1·K^-1 for compound (2). These results are similar to those of dioxygen adducts of other metals complexes and natural enzymes such as methane mono- oxygenase (MMOH).     

A possible configuration of H 5 + cluster

On the basis of our previous work, a configuration of H ₅ ⁺ has been presented that is a square center structure, and the energy for the structure of H ₅ ⁺ has been obtained by IACQM. The result showed that there is an extreme energy E_e: −2.45981 [2 Ry] atR = 2.50a ₀. It indicates that the square center structure of H ₅ ⁺ system has the certain stability, which is a possible configuration of H ₅ ⁺ .     

The short C-terminal hydrophilic domain of NhaH Na^＋/H^＋ antiporter from Halobacillus dabanensis with roles in resistance to salt and in pH sensing

The Na^＋/H^＋ antiporter plays key roles in maintaining low cytoplasmic NaNa^＋ level and pH homeostasis, while little is known about the Carboxyl-terminal hydrophilic tails of prokaryotic antiporters. In our previous study, the first Na^＋/H^＋ antiporter gene nhaH from moderate halophiles was cloned from Halobacillus dabanensis D-8 by functional complementation. A topological model suggested that only nine amino acid residues （^395PLIKKLGMI403） existed in the hydrophilic C-terminal domain of NhaH. The C-terminal truncated mutant of NhaH was constructed by PCR strategy and designated as nhaH△C. Salt tolerance experiment demonstrated that the deletion of hydrophilic C-terminal nine amino acid residues significantly inhibited the complementation ability of E. coil KNabc, in which three main Na^＋/H^＋ antiporters nhaA, nhaB and chaA were deleted. Everted membrane vesicles prepared from E. coil KNabc/nhaHAC decreased both Na^＋/H^＋ and Li^＋/H^＋ exchange activities of NhaH, and also resulted in an acidic shift of its pH profile for Na^＋, indicating a critical role of the short C-terminal domain of NhaH antiporter in alkali cation binding/translocation and pH sensing.     

Synthesis of layered LiMnO2 byin situ oxidation-intercalation and a study of the reaction mechanism and electrochemical performance

Using Mn(OH)₂ as precursor, LiOH as lithiating agent and (NH₄)₂S₂O₈ as oxidant, layeredo-LiMnO₂ was obtained by a novel method—in situ oxidation-intercalation under mild conditions (80 °C). The product was characterized by XRD, ICP, TEM and⁷Li-NMR. The results reveal that orthorhombic LiMnO₂ with high purity and good crystallinity can be obtained by this method. During electrochemical tests, a LiMnO₂/Li cell shows an initial reversible capacity of 208 mAh · g⁻¹ and a reversible capacity of 180 mAh · g⁻¹ after 30 cycles at room temperature.     

Chemical states of the atoms in magnetic multilayers Ta/NiO x /Ni81Fe19/Ta and Co/AlO x /Co

Ta/NiO _x /Ni₈₁Fe₁₉/Ta and Co/AlO _x /Co multilayers were prepared by rf reactive and dc magnetron sputtering. The exchange coupling field (H _ex) and the coercivity (H _c) of NiO _x /Ni₈₁Fe₁₉ as a function of the ratio of Ar to O₂ during the deposition process were studied. The composition and chemical states at the interface region of NiO _x /NiFe were also investigated using the X-ray photoelectron spectroscopy (XPS) and peak decomposition technique. The results show that when the ratio of Ar to O₂ is equal to 7 and the argon sputtering pressure is 0.57 Pa, the x value is approximately 1 and the valence of nickel is +2. At this point, NiO _x is antiferromagnetic NiO and the corresponding H_ex is the largest. As the ratio of Ar/O₂ deviates from 7, the H _ex will decrease due to the presence of magnetic impurities such as Ni⁺³ or metallic Ni at the interface region of NiO _x /NiFe, while the H _c will increase due to the metallic Ni. Al layers in Co/AlO _x /Co multilayers were also studied by angle-resolved XPS. Our finding is that the bottom Co could be completely covered by depositing an Al layer about 1.8 nm. The thickness of AlO _x was 1.2 nm.     

The fourier transformations of positive distributions on lorentz groupSO (3, 1)

With the aid of Plancherel-Godement Theorem, we prove that every positive distributionT onSO (3, 1) which is bi-invariant underSO(3) corresponds to a measure μ on ω=∝σC|s(2-s)>=0∝, and μ can be decomposed intoμ=μ ₁+μ ₂, whereμ ₁ is a bounded measure on 0<=s<=2 andμ ₂ is slowly increasing measure on (sχC|Re(s)=1)} Foundation item: Supported by the National Natural Science Foundation of China (19871065) and Hua Cheng Mathematics Science Foundation. Biography: Zhu Li (1976-), male, Graduate student, research interest: partial differential equation     

A sufficient condition fork′(z)(k(z)∈H q,q≥1) to be ofH 1

We proved ifk(z)∈H ^q (q≥1),g(z) is analytic on |z|=1, , thenk′(z)∈H ¹, especially, ifq=1, thenk(z) is an analytic function on the closed unit disk |z|≤1. Peng Zhigang: born in June 1970, Ph. D     

H-ATPase in the plasma membrane of Arabidopsis pollen cells is involved in extracellular calmodulin-promoted pollen germination

In this paper, the role of the plasma membrane (PM) H⁺-ATPase in extracellular calmodulin (CaM)-promoted pollen germination and in tube growth of Arabidopsis thaliana was investigated. Pollen germination, pollen tube growth rate, free cytosolic Ca²⁺ concentration ([Ca²⁺]_cyt) and Ca²⁺ channel activity in the PM of pollen cells were measured. In response to fusicoccin or CaM treatment, in vitro pollen germination and pollen tube growth rate, [Ca²⁺]_cyt and activity of a hyperpolarization-activated Ca²⁺-permeable channel increased. Sodium vanadate inhibited the promotion of these parameters by extracellular CaM. The results suggest that H⁺-ATPase may be involved in extracellular CaM-regulated pollen germination and in tube growth by modulation of the hyperpolarization-activated Ca²⁺ channel in the PM of A. thaliana pollen cells.