燃气-蒸汽联合循环余热回收系统性能研究

燃气发电是我国城市供电的主要形式之一,针对LNG接收站一体的电厂发电模式进行研究,提出一种新型燃气-蒸汽联合循环热电联供系统,利用超临界CO2布雷顿循环结合有机朗肯循环(ORC)辅助发电,将LNG作为冷源,对烟气余热进行三级利用.通过构建热力学和经济模型,以Aspen Plus软件模拟值为基础,结果表明:在消耗燃料1....     

类锂等电子系列高位三激发态2p2np4So能量和到1s2pmp4P态的辐射跃迁

利用多组态相互作用方法及Rayleigh-Ritz变分法,计算了类锂离子2p²np⁴S^o(n=2—4)和1s2pmp⁴P(m=2,3)的能量.运用截断变分方法得到能量的改进量.计算了相对论修正、质量极化效应,从而获得了高精度的能量计算值.同时还计算了该系统之间的辐射跃迁波长、振子强度和辐射跃迁率.计算结果与实验符合得很好. 关键词： 三激发态 类锂离子 振子强度 辐射跃迁     

Polysulfonylamine. CLXIII [1] Kristallstrukturen von Metall‐di(methansulfonyl)amiden. 12 [1] Das orthorhombische Doppelsalz Na2Cs2[(CH3SO2)2N]4·3H2O: Ein dreidimensionales Koordinationspolymer aus (Caesium‐Anion‐Wasser)‐Schichten und intercalierten Natriumionen

Polysulfonylamines. CLXIII. Crystal Structures of Metal Di(methanesulfonyl)amides. 12. The Orthorhombic Double Salt Na₂Cs₂[(CH₃SO₂)₂N]₄·3H₂O: A Three‐Dimensional Coordination Polymer Built up from Cesium‐Anion‐Water Layers and Intercalated Sodium Ions The packing arrangement of the three‐dimensional coordination polymer Na₂Cs₂[(MeSO₂)₂N]₄·3H₂O (orthorhombic, space group Pna2₁, Z′ = 1) is in some respects similar to that of the previously reported sodium‐potassium double salt Na₂K₂[(MeSO₂)₂N]₄·4H₂O (tetragonal, P4₃2₁2, Z′ = 1/2). In the present structure, four multidentately coordinating independent anions, three independent aquo ligands and two types of cesium cation form monolayer substructures that are associated in pairs to form double layers via a Cs(1)—H₂O—Cs(2) motif, thus conferring upon each Cs⁺ an irregular O₈N₂ environment drawn from two N, O‐chelating anions, two O, O‐chelating anions and two water molecules. Half of the sodium ions occupy pseudo‐inversion centres situated between the double layers and have an octahedral O₆ coordination built up from four anions and two water molecules, whereas the remaining Na⁺ are intercalated within the double layers in a square‐pyramidal and pseudo‐C₂ symmetric O₅ environment provided by four anions and the water molecule of the Cs—H₂O—Cs motif. The net effect is that each of the four independent anions forms bonds to two Cs⁺ and two Na⁺, two independent water molecules are involved in Cs—H₂O—Na motifs, and the third water molecule acts as a μ₃‐bridging ligand for two Cs⁺ and one Na⁺. The crystal cohesion is reinforced by a three‐dimensional network of conventional O—H···O=S and weak C—H···O=S/N hydrogen bonds.     

Synthesis,Structure and Magnetic Phase Transitions of the Manganese Succinate Hybrid Framework,Mn(C4H4O4)

An anhydrous manganese succinate, Mn(C₄H₄O₄), has been synthesised hydrothermally and studied by single‐crystal X‐ray diffraction. It adopts a succinate pillared structure in which layers of corner‐sharing MnO₆ octahedra alternate with sheets that contain chains of edge‐sharing octahedra. This unique 3D framework structure contains highly distorted MnO₆ octahedra, which are made possible by the lack of ligand field stabilisation energy for the high‐spin Mn²⁺ ion. Attempts to dope the structure with other divalent transition‐metal ions were accordingly unsuccessful. Magnetic susceptibility and heat capacity measurements indicate that Mn(C₄H₄O₄) undergoes antiferromagnetic ordering below 12 K, with a second antiferromagnetic transition at approximately 6 K. These two antiferromagnetic phases undergo further transitions in applied fields, underlining the subtle magnetic behaviour that is possible in inorganic–organic frameworks of this structural complexity.     

Volume dependence of thermal conductivity and bulk modulus for poly(propylene glycol)

The thermal conductivity λ and heat capacity per unit volume of poly(propylene glycol) PPG (0.4 and 4.0 kg·mol⁻¹ in number-average molecular weight) have been measured in the temperature range 150–295 K at pressures up to 2 GPa using the transient hot-wire method. At 295 K and atmospheric pressure, λ = 0.147 W m⁻¹K⁻¹ for PPG (0.4 kg·mol⁻¹) and λ = 0.151 W m⁻¹K⁻¹ for PPG (4.0 kg·mol⁻¹). The temperature dependence of λ is less than 4 × 10⁻⁴ W m⁻¹K⁻² for both molecular weights. The bulk modulus has been measured in the temperature range 215–295 K up to 1.1 GPa. At atmospheric pressure, the room temperature bulk moduli are 1.97 GPa for PPG (0.4 kg·mol⁻¹) and 1.75 GPa for PPG (4.0 kg·mol⁻¹). These data were used to calculate the volume dependence of $ \lambda ,g\, = - \left( {\frac{{\partial \lambda /\lambda }}{{\partial V/V}}} \right)_T $. At room temperature and atmospheric pressure (liquid phase) we find g = 2.79 for PPG (0.4 kg·mol⁻¹) and g = 2.15 for PPG (4.0 kg·mol⁻¹). The volume dependence of g, (∂g/∂ log V)_T varies between −19 to −10 for both molecular weights. Under isochoric conditions, g is nearly independent of temperature. The difference in g between the glassy state and liquid phase is small and just outside the inaccuracy of g of about 8%. The theoretical model for λ by Horrocks and McLaughlin yields an overestimate of g by up to 120%. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36 : 345–355, 1998     

钝感炸药圆筒试验与爆轰产物JWL状态方程研究

 对以TATB为主的钝感炸药JB-9014进行了25 mm和50 mm两种装药直径的圆筒试验，测试了TU1圆筒在爆轰产物驱动下的膨胀过程R(t)关系。对圆筒试验进行了综合分析和二维数值模拟计算，综合评估了JB-9014的作功能力和圆筒试验的相似性。通过二维流体动力学数值模拟，确定得到了JB-9014炸药爆轰产物JWL状态方程参数。经对JB-9014二维平面滑移爆轰驱动试验的数值模拟检验，证明确定的JWL状态方程参数是可靠的，具有较高的精度和普适性。     

Er3+单掺、Er3+/Yb3+共掺杂Ca12Al14O32F2的 制备及上转换发光性质

利用高温固相法成功制备了Er~(3+)单掺、Er~(3+)/Yb~(3+)共掺杂Ca_(12)Al_(14)O_(32)F_2上转换发光样品。在980 nm激光激发下,Er~(3+)单掺和Er~(3+)/Yb~(3+)共掺杂样品均呈现出较强的绿光(528,549 nm)和较弱的红光(655 nm)发射,分别归因于Er~(3+)离子的~2H_(11/2),~4S_(3/2)→~4I_(15/2)和~4F_(9/2)→~4I_(15/2)能级跃迁。随着Er离子浓度的增加,单掺杂样品上转换发光强度先增大后减小,最佳掺杂浓度为0.8%。共掺杂Yb~(3+)后,Er~(3+)的发光强度明显增大。还原气氛下合成的样品上转换发光强度增大约两倍,可能和笼中阴离子基团变化有关。发光强度和激发光功率的关系表明所得上转换发射为双光子吸收过程,借助Er~(3+)-Yb~(3+)体系能级结构详细讨论了上转换发射的跃迁机制。     

Ergodicity of transition semigroups for stochastic fast diffusion equations

In this paper, we first show the uniqueness of invariant measures for the stochastic fast diffusion equation, which follows from an obtained new decay estimate. Then we establish the Harnack inequality for the stochastic fast diffusion equation with nonlinear perturbation in the drift and derive the heat kernel estimate and ultrabounded property for the associated transition semigroup. Moreover, the exponential ergodicity and the existence of a spectral gap are also investigated.     

Fractional extensions of some boundary value problems in oil strata

In the present paper, we solve three boundary value problems related to the temperature field in oil strata — the fractional extensions of the incomplete lumped formulation and lumped formulation in the linear case and the fractional generalization of the incomplete lumped formulation in the radial case. By using the Caputo differintegral operator and the Laplace transform, the solutions are obtained in integral forms where the integrand is expressed in terms of the convolution of some auxiliary functions of Wright function type. A generalization of the Laplace transform convolution theorem, known as Efros’ theorem is widely used.     

Adsorption of carbon dioxide on microporous carbon adsorbent PAU-10

Carbon dioxide adsorption on the microporous carbon adsorbent PAU-10 within the 177.8—423 K temperature and 0.1—5.13·10⁶ Pa pressure intervals was studied. The isosteres of absolute adsorption are well approximated by straight lines, which do not change their slope on going to temperatures higher than the critical temperature of CO₂. An increase in the differential molar isosteric heat of adsorption (q _st) at 0 < a < 1 mmol g^–1 is explained by the influence of the endothermic effect of adsorption expansion of the adsorbent. In the region of high pressures and nonideal gas phase, q _st is temperature-dependent.