S2分子电离能的多参考方法计算

应用多组态准简并微扰理论, 计算了S₂分子基态和S⁺₂分子离子基态与激发态的绝热势能曲线, 并拟合光谱参数,  得到了S₂分子9~16 eV的3p电子电离的绝热电离能和垂直电离能. 计算结果表明, S₂分子的第一绝热电离能为9.34 eV, 与实验值(9.356±0.002)eV相符. 比较了其他电离谱带绝热和垂直电离能的理论计算值与实验值, 并分析了误差产生因素,  结合计算结果对S⁺₂(A²Π_u)和S⁺₂(B²Σ^-_g)电离谱带进行了确认.     

四阶矩阵环的一类半交换Armendariz子环

考虑四阶矩阵环M₄(R)的子环S₄(R)的半交换性和Armendariz性质, 证明了如果R是reduced环, α₁,α₂,α₃,α₄是R的相容自同态, 则S₄(R)是半交换Armendariz环.     

层状化合物K0.81Li0.27Ti1.73O4的合成

研究以K₂CO₃,Li₂CO₃和TiO₂为反应原料合成层状钛酸盐K_0.81Li_0.27Ti_1.73O₄过程中合成条件对产物的影响. 结果表明: 反应温度在
1 000~1 200 ℃, 反应原料配比为n(K₂CO₃) ∶n(Li₂CO₃) ∶n(TiO₂)=(0.405~0.42) ∶(0.135~0.165) ∶1.73时, 均可以得到产物K_0.81Li_0.27Ti_1.73O₄, 延长反应时间及升高反应温度均有利于产物的生成; 在1 200 ℃高温条件下, 使用刚玉坩埚为反应容
器时, 最佳的反应条件是： 反应温度为1 100 ℃, 反应原料配比为n(K₂CO₃) ∶n(Li₂CO₃) ∶n(TiO₂)=0.405 ∶0.135 ∶1.73, 反应24 h.     

重叠和分组函数的分配性方程求解

运用区间值模糊集的方法和原理, 通过引入可表示的区间值重叠函数和分组函数的概念, 结合乘法生成元对生成的重叠和分组函数, 在边界条件下给出方程I(G(x,y),z)=O(I(x,z),I(y,z))和 I(x,O₁(y,z))=O₂(I(x,y),I(x,z))的解, 并讨论重叠和分组函数的相关性质.     

重叠和分组函数的分配性方程求解

运用区间值模糊集的方法和原理, 通过引入可表示的区间值重叠函数和分组函数的概念, 结合乘法生成元对生成的重叠和分组函数, 在边界条件下给出方程I(G(x,y),z)=O(I(x,z),I(y,z))和 I(x,O₁(y,z))=O₂(I(x,y),I(x,z))的解, 并讨论重叠和分组函数的相关性质.     

Loewner型方程组极小范数最小二乘解的快速算法

通过构造特殊分块矩阵及其三角分解给出了求秩为n 的m×n阶Loewner型矩阵为系数阵的线性方程组极小范数最小二乘解的快速算法, 该算法的计算复杂度为O(mn)+O(n²), 而一般方法的计算复杂度为O(mn²)+O(n³) .     

集值 L1 极限鞅的 Riesz 分解

假定（X,‖·‖）为可分的Banach空间, X^*为其对偶空间,X^*可分. 设(Ω,B,P)为完备的概率空间, {B_n,n≥1}为B的上升子σ-域族, 且B=∨B_n. 讨论集值L¹极限鞅的一些性质, 并利用支撑函数及实值L¹ 极限鞅的Riesz分解定理, 给出了集值L¹极限鞅可Riesz分解的一个充要条件.     

γ′-Fe4N薄膜的制备及其磁性

采用直流磁控溅射方法, 以Ar/N₂为放电气体（N₂/(Ar+N₂)=10％）, 在玻璃和NaCl(100)单晶片上分别沉积获得Fe-N薄膜样品. 利用X射线衍射(XRD)、 原子力显微镜(AFM)和超导量子干涉仪(SQUID)对样品的结构、 形貌和磁性能进行分析, 研究基片和基片温度等条件对薄膜的影响. 结果表明, 以NaCl单晶为基片获得单相γ′-Fe₄N薄膜, 与玻璃基片相比可降低其生成的基片温度并可扩大形成温度的范围, 且比饱和磁化强度略有增大.      

添加元素对Mg-基非晶合金非晶形成能力和热稳定性的影响

研究Mg₆₀Ni₂₅Gd_15-xNd_x（x=0,7.5,15）和(Mg₆₀Ni₂₅Gd₁₅)_100-xM_x(M=Fe或Co)（x=0,3,5）非晶态合金快淬甩带样品的非晶形成能力(GFA)及热稳定性随成分的变化关系. 结果表明, 用Nd替代Gd可提高Mg₆₀Ni₂₅Gd_15-xNd_x（x=0,7.5,15）合金的GFA和热稳定性, Fe或Co与主元素间的正混合热降低了(Mg₆₀Ni₂₅Gd₁₅)_100-xM_x(M=Fe或Co)合金的GFA和热稳定性.      

用Fenton技术去除水中盐酸左氧氟沙星

研究Fenton高级氧化技术对水中抗生素盐酸左氧氟沙星的去除效果, 并考察n(H₂O₂)∶n(Fe²⁺)、 H₂O₂投加量、 溶液初始pH值、 反应时间和初始质量浓度对去除效果的影响. 结果表明: 当n(H₂O₂)∶n(Fe²⁺)=5~25时, 盐酸左氧氟沙星、 化学需氧量(K₂Cr₂O₇法, COD_Cr）和总有机碳(TOC)的去除率随二者物质的量比的增加先增加后降低; 当H₂O₂投加量为15 mL/L时, 盐酸左氧氟沙星、 COD_Cr和TOC去除率分别为88.40%,5952%,3380%; 当pH=3时, 盐酸左氧氟沙星、 COD_Cr和TOC的去除率分别为9240%,5952%,3451%; 盐酸左氧氟沙星、 COD_Cr和TOC的去除率随反应时间呈逐渐增加的趋势, 去除率随初始质量浓度的升高而下降; 当反应时间为3 h时, 去除过程基本完成. 在pH=3, 温度为20 ℃, H₂O₂投加量为15 mL/L, n(H₂O₂)∶n(Fe²⁺)=10的条件下, Fenton高级氧化技术对水中盐酸左氧氟沙星的去除效果最好, 达9640%.     

Monitoring the concentration of N2O in the Fildes Peninsula, maritime Antarctica

Gases in the marine boundary layer in Fildes Peninsula, maritime Antarctica were sampled and analyzed for the first time. Sampling sites included areas covered by moss and lichen growth, penguin colonies and an area where scientific research stations are located. A total of 211 samples were analyzed for N₂O concentrations, with an average of (321.33±3.07) nL/L. This is above the global average value of 314 nL/L. It is found that the N₂O concentrations evidently increase during the summer months. Concentrations around the research stations are higher than at remote areas, indicating a potential source from human activities on the island. N₂O concentrations at a large penguin colony on Barton Peninsula are the highest among the sampled areas. This may explain why N₂O concentrations in Fildes Peninsula are higher than the global average. Our preliminary conclusions are that human activities and emissions from penguin dropping-amended soil and vegetation soil constitute the major sources of N₂O in the maritime Antarctic atmosphere.     

The impact of HS radicals on the measured rate constant of H<Subscript>2</Subscript>S with OH radicals

The rate constant for the reaction of OH radicals and hydrogen sulfide (H₂S) was studied in different bath gases (including N₂, air, O₂ and He) by using relative technique at 298 K. The small difference of the measured rate constants between N₂ and those with the presence of O₂ suggested possible influence of HS self reaction. Further experiments with NO_x presence for scavenging HS demonstrated this assumption. The rate constant of (5.48±0.12) ×10^–12 cm³ molecule^–1 s^–1 obtained with 4.09 ×10^–4 mol m₃ NO presence may be accurate for estimating the atmospheric lifetime of H2S. The results provided circumstantial evidence that the rapid reaction of HS with N₂O is suspected.     

羧基富勒烯增强g-C3N4材料的制备及光降解罗丹明B的研究

富勒烯具有合适的能带间隙,能够实现快速的光诱导电荷分离和相对缓慢的电荷重组,被认为是一类增强半导体光催化活性的优良材料。本研究中通过Prato反应在富勒烯表面引入羧基制得衍生物C₆₀-(COOH),采用可见-近红外光谱、傅里叶变换红外光谱（FT-IR）和质谱对合成的产物进行表征,表明了合成的羧基富勒烯衍生物是1到4加成的羧基化衍生物。通过液相沉淀法制备C₆₀/g-C₃N₄和C₆₀-(COOH)/g-C₃N₄复合材料,采用X射线衍射、紫外-可见漫反射等分析手段表征复合材料的性质,并使用合成的复合材料在可见光下对罗丹明B进行光催化降解实验,实验表明C₆₀-(COOH)/g-C₃N₄复合材料具有最高的光催化活性,其光催化降解罗丹明的速率为C₆₀/g-C₃N₄复合材料的1.3倍,是g-C₃N₄复合材料的1.6倍。此外还对g-C₃N₄、C₆₀-(COOH)/g-C₃N₄、C₆₀/g-C₃N₄复合材料做了回收实验。实验结果表明C₆₀-(COOH)/g-C₃N₄复合材料仍可以降解49.4%的罗丹明B,是g-C₃N₄复合材料的1.2倍,是C₆₀/g-C₃N₄复合材料的1.7倍。上述实验结果表明,羧基化的富勒烯是比富勒烯更高效的增强光催化活性物质,由此制备的半导体复合材料是一种有应用前途和非常有效的光催化剂,能够有效地降解有机污染物。     

The effect of biomass pyrolysis gas reburning on N<Subscript>2</Subscript>O emission in a coal-fired fluidized bed boiler

The fossil fuel consumption and pollutant emissions in a coal fired fluidized bed boiler could be reduced by biomass pyrolysis gas reburning. The influence of three kinds of biomass pyrolysis gases on the emission of N₂O in a laboratory scale fluidized bed was investigated using the mechanism of GRI3.0 in this paper. The results showed that: the effect of sawdust pyrolysis gas reburning on N₂O was more significant than that of rice husk and orange peel under the same conditions; the increase of initial oxygen content from 1% to 8% in flue gas would restrain the decomposition of N₂O; the N₂O decomposition was enhanced by increasing reaction temperature from 1073.15 K to 1323.15 K, and the decomposition rate may reach 99% at 1223.15 K.     

聚三嗪亚胺的合成及从水溶液中吸附铀

利用熔盐法合成了聚三嗪亚胺(polytriazineimide,PTI),并用来吸附水中的U(VI)。在常温下,PTI对铀的最大饱和吸附量达到了135.5 mg/g,与g-C₃N₄相比,是g-C₃N₄饱和吸附量的54.2倍。通过对动力学与吸附等温线模型的探究,发现PTI对U(VI)的吸附符合准一级动力学模型,说明PTI吸附U(VI)属于物理吸附。同时,Langmuir吸附等温线模型能更好地拟合PTI对U(VI)的吸附过程,说明U(VI)在PTI上属于单层吸附。通过对吸附铀后的材料进行XPS表征,发现铀在吸附后的价态没有改变,仍为U(VI)。     

Fluxes of CO2, N2O and CH4 from a typical temperate grassland in Inner Mongolia and its daily variation

Using a dark enclosed chamber technique, the fluxes of CO₂, N₂O and CH₄ from nature and disturbed grassland were measured on the spot in Inner Mongolian Temperate Grassland along the annual rainfall gradient section ranging from 450 to 200 mm. The results showed that the measured mean fluxes of CO₂, N₂O and CH₄ were (1 180.4 ± 308.7), (0.010 ± 0.004) and (−0.039 ± 0.016) mg · m⁻²/h, respectively. The decrease of the fluxes of CO₂, N₂O and CH₄ follows with that of annual rainfall gradient in the measurement area. Human activities, such as grazing and reclamation are also critical factors to affect the fluxes of these gases from grassland. Daily continuous measurement of CO₂, N₂O and CH₄ fluxes showed a strong diurnal variation with higher emission in the daytime. A good relationship between the fluxes of CO₂, N₂O, CH₄ and temperature was exposed in this study.     

Simulation for the primary electronic donor of photosystem IIin vitro

Histidine coordinated to Chi a is a distinct characteristic of Chl ain vivo. By using histidine analogue of 1-methylimidazole (C₄H₆N₂2) and measuring the UV/vis absorption, CD and MCD spectra of the interaction between C₄H₆N₂ and Chl a in CCI₄, we have obtained that: (i) In pure CCl₄ solvent, Chl a molecule is in five-coordinate state, and two Chl a molecules form an asymmetric compact-dimer with strong coupling interaction. We propose that the two Chl a molecules are connected by two unequally coordinated Mg-O bonds (the two oxygen atoms come from the C=O of C13¹ keto and C17 ester, respectively); (ii) when the molar ratio of C₄H₆N₂/Chl a is 0.5 or 1 (corresponding to 2Chl a · 1C₄H₆N₂ and 2Chl a · 2C₄H₆N₂, respectively), significant changes have been observed in the absorption, CD and MCD spectra, which indicate that the Chl a remains in dimer form, but the coupling interaction between them reduces greatly. We postulate that C₄H₆N₂ replaces the ligation of C=O of C17 ester and C13¹ keto to Mg atoms sequentially. The two Chl a molecules linked by two weakly interacted Mg…O bonds form a relaxed-dimer. The structure of the model is essentially similar to that of the primary electronic donor, P₆₈₀, of photosystem II in high plants and algae.     

Effects of acetylene at low concentrations on nitrification, mineralization and microbial biomass nitrogen concentrations in forest soils

Temperate forest surface soils at the varying distances from main trunks (e.g., Pinus koraiensis and Quercus mongolica) were used to study the effects of acetylene (C₂H₂) at low concentrations on nitrification, mineralization and microbial biomass N concentrations of the soils, and to assess the contribution of heterotrophic nitrification to nitrous oxide (N₂O) emissions from soils. The use of acetylene at partial pressures within a range from 10 to 100 Pa C₂H₂ in headspace gas gave a significant decrease in N₂O emission at soil moisture of c. 45% water-filled porosity space, and the decrease was almost the same in each soil after exposure of C₂H₂ at low concentrations. Heterotrophic nitrification could account for 21%―48% of total N₂O emission from each soil; the contribution would increase with increasing distances from the Pinus koraiensis trunks rather than from the Quercus mongolica trunks. Under the experimental conditions, the use of C₂H₂ at low concentrations showed no significant influence on soil microbial biomass N, net N mineralization and microbial respiration. However, 100 Pa C₂H₂ in headspace gas could reduce carbon dioxide (CO₂) emissions from soils. According to the rapid consumption of 10 Pa C₂H₂ by forest soils and convenience for laboratory incubations, 50 Pa C₂H₂ in headspace gas can be used to study the origin of N₂O emissions from forest soils under aerobic conditions and the key associated driving mechanisms. The N₂O and CO₂ emissions from the soils at the same distances from the Quercus mongolica trunks were larger than those from the Pinus koraiensis trunks, and both emissions decreased as the distances from trunks increased. The stepwise regression analysis showed that 95% of the variability in soil CO₂ emissions could be accounted for by the concentrations of soil total C and water soluble organic C and soil pH, and that 72% of the variability in soil N₂O emissions could be accounted for by the concentrations of soil total N, exchangeable NH⁺₄-N and microbial biomass N and 25% of the variability in heterotrophic nitrification by the soil microbial biomass N concentration. The emissions of N₂O and CO₂ from forest soils after exposure of C₂H₂ at low concentrations were positively related to the net nitrification of the soils.     

Structure and magnetism of carboxylate/EO-azido-mixed-ligands bridged CuII systems

Using two structurally related benzoates bearing different H-bond acceptors as co-ligands, three new azido-Cu^Ⅱ compounds, [Cu（L^1）（N3）（H2O）]n（1）, [Cu（L^1）（N3）（MeOH）]n （2）, and [CuL^2HL^2（N3）3（H2O）]n（3） （HL^1 = 4-nitrobenzoic acid; HL^2= 2-phenyl-4-quinolinecarboxylic acid）, have been synthesized and structurally characterized. 1 is a carboxylate/EO-azido bridged copper chain, forming 3D structure by H-bonds, and 2 has a similar chain structure as 1 but forming a 2D structure by H-bonds, while 3 is a 3D supramolecular network with ternary center H-bonds. Magnetic study indicates that domain ferromagnetic coupling interactions were found to exist in complexes 1 and 3.     

Phase analysis and thermal conductivity of in situ O′-sialon/β-Si3N4 composites

Typical O??-sialon-based ceramics, with a formula of Si_2?x Al _x O_1+x N_2?x , where x was set as 0.25, were fabricated by in-situ synthesis. Si₃N₄, Al₂O₃, and SiO₂ powders were used as raw materials, and MgO and Y₂O₃ were added as sintering additives. All the samples were sintered at different temperatures under a nitrogen pressure of 0.25?C0.30 MPa, and their microstructure, phase content, and thermal conductivity were evaluated. The effects of O??-sialon and ??-Si₃N₄ on the thermal conductivity were analyzed by numerical calculation in detail. In the case of the similar porosity, the thermal conductivity of O??-sialon-based ceramics decreased with the ratio of O??-sialon/??-Si₃N₄ increasing. When the ratio was 12, the thermal conductivity of O??-sialon ceramics sintered at 1360°C was 1.197 W·m^?1·K^?1.