夏热冬冷区机场顶棚太阳能优化吸收设计模型

针对机场顶棚面积巨大由于设计不合理导致的资源浪费状况,提出一种夏热冬冷区机场顶棚太阳能优化吸收设计模型,通过对太阳辐射角和太阳辐射量的计算,获取到达机场顶棚表面单位面积、单位时间内太阳辐射量的大小,设计出夏热冬冷区机场顶棚太阳能优化吸收控制流程图,依据获取的差值控制机场顶棚的转向,计算出连续时间控制率,对其进行离散化处理,将规定时间内太阳能传感器输出电压信号的平均值作为目标函数,对PID参数进行调整,从而增加太阳能传感器输出信号的可调范围。仿真实验结果验证了所提方法的有效性。

多循环CCRs法在分离燃煤锅炉尾部烟气中CO_2方面的应用

随着温室效应和全球变暖的加剧,煤燃烧所排出的CO2作为引起温室效应的主要气体而引起人们的密切关注。由于燃煤锅炉所排放的尾气中所含的CO2的体积份额低、排放量大,而且处于微负压状态,因此目前控制和分离吸收CO2的方法,包括各类吸收法、吸附法、膜分离法和O2/CO2燃烧技术等,能够经济可行地适用于电力工业燃煤锅炉尾部烟气中CO2分离的方法非常少。与上述各类方法相比,钙基吸收剂CCR s(calc ination/carbonation reactions)法是一种新兴的经济可行的分离燃煤锅炉尾部烟气中CO2的方法。对采用该法时,吸收剂的选择、吸收剂在多次CCR s过程中结构特点的变化、提高吸收剂对CO2的吸收容量以及防止吸收剂反应性的衰减等方面进行了详细的阐述。

化工工艺中提高丙烯收率的有效途径

本篇文章着重针对气分装置所涉及到的化工工艺流程进行了全面深入的分析,同时对于其中其中导致丙烯收率被影响的因素加以研究,以期通过提升操作形式以及优化系统吸收稳定性的方式,来直接促使气分装置表现出的丙烯收率得以提升。

Optimization design of an electroabsorption modulator integrated with spot-size converter

A novel 1.55 μm spot-size converter integrated with electroabsorption modulator is designed and fabricated with conventional photolithography and chemical wet etching process.For the modulator,we employed a deeply-etched ridge waveguide structure with polyimide on each side of its walls.For the spot-size converter,we employed a buried double-core structure in which a ridge-based passive waveguide is incorporated.The wide and thin passive waveguide is optically combined with a laterally tapered active waveguide to control the mode size.By simulation,the figure of merit is 4.17(dB/V/(100 μm)) and the beam divergence angles in the horizontal and vertical directions are as small as 11.2°×13.0°,respectively.

Contrastive analysis and crashworthiness optimization of two composite thin-walled structures

For the safety protection of passengers when train crashes occur, special structures are crucially needed as a kind of indispensable energy absorbing device. With the help of the structures, crash kinetic-energy can be completely absorbed or dissipated for the aim of safety. Two composite structures(circumscribed circle structure and inscribed circle structure) were constructed. In addition, comparison and optimization of the crashworthy characteristic of the two structures were carried out based on the method of explicit finite element analysis(FEA) and Kriging surrogate model. According to the result of Kriging surrogate model, conclusions can be safely drawn that the specific energy absorption(SEA) and ratio of specific energy absorption to initial peak force(REAF) of circumscribed circle structure are lager than those of inscribed circle structure under the same design parameters. In other words, circumscribed circle structure has better performances with higher energy-absorbing ability and lower initial peak force. Besides, error analysis was adopted and the result of which indicates that the Kriging surrogate model has high nonlinear fitting precision. What is more, the SEA and REAF optimum values of the two structures have been obtained through analysis, and the crushing results have been illustrated when the two structures reach optimum SEA and REAF.

Multidisciplinary Design Optimization of Crash Box with Negative Poisson’s Ratio Structure

To improve the crashworthiness and energy absorption performance,a novel crash box negative Poisson’s ratio(NPR)structure is proposed according to the characteristics of low speed collision of bumper system.Taking the peak collision force and the average collision force as two subsystems,a multidisciplinary collaborative optimization design is carried out,and its optimization results are compared with the ones optimized by NSGA-II algorithm.Simulation results show that the crashworthiness and energy absorption performance of the novel crash box is improved effectively based on the multidisciplinary optimization method.

Optimizing crashworthiness design of square honeycomb structure

To provide theoretical basis for square honeycombs used as crashworthy structures, energy-absorption properties of metal square honeycombs and the size optimization were performed. Specific energy absorption(SEA) was defined as the energy absorbed by the honeycomb structure per unit volume. This parameter was often used for determining the crashworthiness of thin-walled structures. In order to find the most optimized metal square honeycomb structure with the maximum SEA and the lowest peak stress, the cell length and the foil thickness of the metal honeycombs were optimized, with a low peak stress and a high SEA set as the two primary objectives. The pre-processing software Patran was used to build FE models, and the explicit solver LS-DYNA was employed to perform the crashworthiness analyses. The results show that the square honeycomb exhibits good energy absorption performance in some cases. The geometry is effective using 16.8% less buffer structure volume than the hexagonal honeycombs with a peak stress limitation of 1.21 MPa.

Study on the prediction of visible absorption maxima of azobenzene compounds

The geometries of azobenzene compounds are optimized with B3LYP/6-311G* method, and analyzed with nature bond orbital, then their visible absorption maxima are calculated with TD-DFT method and ZINDO/S method respectively. The results agree well with the observed values. It was found that for the calculation of visible absorption using ZINDO/S method could rapidly yield better results by adjusting OWFπ-π (the relationship between π-π overlap weighting factor) value than by the TD-DFT method. The method of regression showing the linear relationship between OWFπ-π and BLN-N (nitrogen-nitrogen bond lengths) as OWFπ-π=?8.1537+6.5638BLN-N, can be explained in terms of quantum theory, and also be used for prediction of visible absorption maxima of other azobenzne dyes in the same series. This study on molecules’ orbital geometry indicates that their visible ab- sorption maxima correspond to the electron transition from HOMO (the highest occupied molecular orbital) to LUMO (the lowest unoccupied molecular orbital).

Optimal transmission lines assignment with maximal reliabilities in multi-source multi-sink multi-state computer network

The optimal transmission lines assignment with maximal reliabilities (OTLAMR) in the multi-source multi-sink multi-state computer network (MMMCN) was investigated. The OTLAMR problem contains two sub-problems: the MMMCN reliabilities evaluation and multi-objective transmission lines assignment optimization. First, a reliability evaluation with a transmission line assignment (RETLA) algorithm is proposed to calculate the MMMCN reliabilities under the cost constraint for a certain transmission lines configuration. Second, the non-dominated sorting genetic algorithm II (NSGA-II) is adopted to find the non-dominated set of the transmission lines assignments based on the reliabilities obtained from the RETLA algorithm. By combining the RETLA and the NSGA-II algorithms together, the RETLA-NSGA II algorithm is proposed to solve the OTLAMR problem. The experiments result show that the RETLA-NSGA II algorithm can provide efficient solutions in a reasonable time, from which the decision makers can choose the best solution based on their preferences and experiences.

调制转移光谱的最佳吸收程

调制转移光外差光谱信号的信噪比(SNR)和中心斜率与吸收程等有关.采用吸收程微元叠加法———把吸收程分成n段,计算出每一段产生的调制转移光谱信号元,再对n求和得到总的调制转移光谱信号.利用该方法,理论上研究了调制转移光谱信号相对强度及中心斜率随吸收程的变化,得到最佳吸收程.实验上比较了碘池温度为-15℃时一倍程(40 cm),二倍程(80 cm),三倍程(120 cm)和四倍程(160 cm)的光谱信号信噪比和谱线中心斜率,得到三倍程时信号信噪比和谱线中心斜率为最大,估算得到相应的激光稳频精度为9×10-14(1 s积分时间).通过吸收程优化过程获得的调制转移光谱信号用于激光频率稳定控制,有望获得更高的稳频精度.

Optimal Initialization of a Quantum System for an Efficient Coherent Energy Transfer

For an energy transfer network, the irreversible depletion of excited electron energy occurs through either an efficient flow into an outer energy sink or an inefficient decay. With a small decay rate, the energy transfer efficiency is quantitatively reflected by the average life time of excitation energy before being trapped in the sink where the decay process is omitted. In the weak dissipation regime, the trapping time is analyzed within the exciton population subspace based on the secular Redfield equation. The requirement of the noise-enhanced energy transfer is obtained, where the trapping time follows an exact or approximate 1/F- scaling of the dissipation strength F. On the opposite side, optimal initial system states are conceptually constructed to suppress the 1/F-scaling of the trapping time and maximize the coherent transfer efficiency. Our theory is numerically testified in four models, including a biased two-site system, a symmetric three-site branching system, a homogeneous one- dimensional chain, and an 8-chromophore FMO protein complex.

炼厂气胺法脱硫设计优化问题探讨

对炼厂脱硫技术优化的目的在于稳定各种设备的操作,在脱硫的过程中提高对硫化氢的选择性,保证脱硫的效果,有效的提高产品质量。然而,不同原材料和产品,对于脱硫率的要求也不尽相同,所以,需要从多方面分析,提出有针对性的优化方法。本文主要在现场操作的数据以及模拟比较真实的计算结果上,对炼厂气胺法脱硫设计过程中的一些问题进行探讨,从而提出一些有针对性的解决方案。

A chlorinated low-bandgap small-molecule acceptor for organic solar cells with 14.1% efficiency and low energy loss

A new acceptor-donor-acceptor(A-D-A) type small-molecule acceptor NCBDT-4 Cl using chlorinated end groups is reported.This new-designed molecule demonstrates wide and efficient absorption ability in the range of 600–900 nm with a narrow optical bandgap of 1.40 eV. The device based on PBDB-T-SF:NCBDT-4 Cl shows a power conversion efficiency(PCE) of 13.1%without any post-treatment, which represents the best result for all as-cast organic solar cells(OSCs) to date. After device optimizations, the PCE was further enhanced to over 14% with a high short-circuit current density(Jsc) of 22.35 m A cm-2 and a fill-factor(FF) of 74.3%. The improved performance was attributed to the more efficient photo-electron conversion process in the optimal device. To our knowledge, this outstanding efficiency of 14.1% with an energy loss as low as 0.55 eV is among the best results for all single-junction OSCs.

Optimization of the Doped Ablator Layers for the Plastic Ignition Capsule

The paper investigates theoretically the optimization of the doped ablator layers for the plastic ignition capsule. The high-resolved one-dimensional implosion simulations show that the inner pure CFI layer of the Si-doped design is excessively preheated by the hard x-ray, leading to the unstable ablator-fuel interface compared to the Ge-doped capsule. This is because that the Si K-shell absorption edge （1.8 keV） is higher than the Ge L-edge （1.3 keV）, and Si dopant makes more hard x-ray penetrate through the doped ablator layers to preheat the inner pure CH layer. So an optimization of the doped ablator layers （called ＂Si/Ge capsule＂） is performed： an Si-doped CH layer is placed next to the outer pure CH layer to keep the high implosion velocity; next to the Si-doped layer is a thin Ge-doped layer, in order to absorb the hard x-ray and protect the inner undoped CH-layer from excessively preheating. The simulations show that the Si/Ge capsule can effectively improve hydrodynamic stability at the ablator-fuel interface while keeping the high implosion velocity.