Discrete time model and algorithms for container yard crane scheduling

Container terminal (CT) operations are often bottlenecked by slow YC (yard crane) movements. PM (prime mover) queues in front of the YCs are common. Hence, efficient YC scheduling to reduce the PM waiting time is critical in increasing a CT’s throughput. We develop an efficient model for YC scheduling by taking into account realistic operational constraints such as inter-crane interference, fixed YC separation distances and simultaneous container storage/retrievals. Among them, only inter-crane interference has ever been considered in the literature. The model requires far fewer integer variables than the literature by using bi-index decision variables. We show how the model can be solved quickly using heuristics and rolling-horizon algorithm, yielding close to optimal solutions in seconds. The solution quality and solution time are both better than the literature even with additional constraints considered. The proposed formulations and algorithms can be extended to other problems with time windows and space constraints.     

强震条件下双面坡变形破坏机理的振动台物理模拟试验研究

5·12汶川地震引发了数以万计的崩塌、滑坡、泥石流等地质灾害。为了研究双面坡在强震条件下的动力响应规律,本文在大量野外调查的基础上,采用振动台物理模拟试验手段,设计完成了四类11个模型试验,从改变模型的坡度和坡顶宽度、软岩硬岩结合、阶梯状坡形等角度,较系统地研究了双面坡在强震作用下的响应规律。试验结果显示：强震条件下地震水平惯性力是导致边坡破坏的主要原因; 在地震情况下边坡变形破坏表现出明显的初动破坏效应; 振动过程中双坡具有明显的共剪效应,坡面为阶梯状时其共剪效应更明显; 坡体结构为上软下硬时下部硬岩对振动具有一定的放大效应,上硬下软时坡体易整体偏移产生变形破坏。试验结论与实际情况基本符合。     

扩展腔对方波型微混合器混合性能的影响研究

微混合器凭借节约试剂、混合强度高和易于集成等优点,在材料合成、医药制备和生化检测等领域中具有广泛的应用. 为了进一步提高混合性能,保证混合过程的安全性及生化反应结果的准确性,设计了一种带扩展腔的新型方波型微混合器. 在综合考虑混合强度和压降的前提下,通过实验研究和数值模拟分析了窄缝宽度、窄缝长度和扩展腔高度对微混合器混合性能的影响并得到了不同雷诺数\mathit{Re}条件下的最优结构参数. 与方波型微混合器的混合性能进行比较,发现\mathit{Re}=20时,带扩展腔的方波型微混合器的混合强度更高,其中\mathit{Re}时两者混合强度相差最多,可达12%. 在相同\mathit{Re}下,带扩展腔的方波型微混合器的压降要低于方波型微混合器. 对带扩展腔的方波型微混合器进行内部流场分析,发现扩展腔结构能在流体层流状态的基础上引入涡流,使通道中流体的流动状态发生改变、对流增强,进而混合性能提高.      

Second to tenth order susceptibilities of conserved charges within a modified Nambu-Jona-Lasinio model

We discuss the sign and energy dependence of second to tenth order susceptibilities of the baryon number,charge number, and strangeness for the analysis of critical conditions in heavy ion collisions in the LHC and RHIC by applying a modified Nambu-Jona-Lasinio model. This model is fitted to the quark condensate of the lattice QCD result at finite temperature and zero baryon chemical potential. The presence of a critical point made these susceptibilities deviate considerably from a Hadron-Resonance-Gas model that shows no criticality. The sign, magnitude, and energy dependence of these higher order fluctuations hint towards the existence and location of a critical point that could be discovered in future heavy ion collision experiments.     

两种比色法检测水体中微量氨含量的比较研究

氨氮含量的高低是衡量湖泊和水库水体富营养化的指标之一,水体中的氮元素极易诱发水体富营养化。目前,国标中通过比色法来检测氨氮含量的方法主要有靛酚蓝分光光度法和纳氏试剂分光光度法。根据高等教育国家标准中对于培养大学生的创新实践、科研意识、实验动手能力的要求,依照检测水体中氨氮含量的国家标准,检测了济南市区内三大名泉(趵突泉、黑虎泉、五龙潭)、大明湖、聊城东昌湖以及天津海河的水体样品中的氨氮浓度,并把山东师范大学的生活自来水作为对比样品,比较了比色法检测水体中氨氮含量的两种检测方法的差异。更重要的是,学生从检测过程中的得失领悟到了采用比色法检测、分析样品的方法技巧。结果表明,通过不断地完善检测方案,两种方法的标准曲线相关系数均达到0.9999以上。在实验操作中,由于操作过程和操作手法的不同(例如显色剂浓度、标准溶液的取用技巧以及各溶剂混合之后放置时间的长短等),获得了不同的实验结果,对实验结果的异常现象出现的原因进行了分析,同时讨论了两种检测方法的不同。     

Knoevenagel condensation catalyzed by novel Nmm-based ionic liquids in water

A series of novel N-methyl morpholine (Nmm) based ionic liquids with 1,2-propanediol group were synthesized and used as catalysts for Knoevenagel condensation at room temperature in water. Under the effect of the catalyst, various aldehydes or aliphatic ketones could react with a wide range of activated methylene compounds well, including malononitrile, alkyl cyanoacetate, cyanoacetamide, β-diketone, barbituric acid, 2-arylacetonitrile and thiazolidinedione. Furthermore, most of the products could be separated just by filtrating and washing with water. Additionally, the catalyst is recyclable and applicable for the large-scale synthesis.     

Side-chain modification of polyethylene glycol on conjugated polymers for ternary blend all-polymer solar cells with efficiency up to 9.27%

With the rapid progress achieved by all-polymer solar cells (all-PSCs), wide-bandgap copolymers have attracted intensive attention for their unique advantage of constructing complementary absorption profiles with conventional narrow-bandgap copolymers. In this work, we designed and synthesized a wide bandgap ternary copolymer PEG-2% which has the benzodithiophene-alt-difluorobenzotriazole as the backbone and the polyethylene glycol (PEG) modified side chain. The PBTA-PEG-2%:N2200 can be processed with a non-chlorinated solvent of 2-methyl-tetrahydrofuran (MeTHF) for the binary all-PSC, which exhibits a moderate photovoltaic performance. In particular, the ternary all-PSCs that consisting an additional narrow bandgap polymer donor PTB7-Th can also be processed with MeTHF, resulting in an unprecedented power conversion efficiency (PCE) of 9.27%, and a high PCE of 8.05% can be achieved with active layer thickness of 240 nm, both of which are the highest values so far reported from all-PSCs. Detailed investigations revealed that the dramatically improved device performances are attributable to the well-extended absorption band in the photoactive layer. Hence, developing novel copolymers with tailored side chains, and introducing additional polymeric components, can broaden the horizon for high-performance all-PSCs.     

8.0% Efficient all-polymer solar cells based on novel starburst polymer acceptors

The polymer N2200, with its π-conjugated backbone composed of alternating naphthalene diimide(NDI) and bithiophene(DT)units, has been widely used as an acceptor for all-polymer solar cells(all-PSCs) owing to its high electron mobility and suitable ionization potential and electron affinity. Here, we developed two naphthalene diimide derivatives by modifying the molecular geometry of N2200 through the incorporation of a truxene unit as the core and NDI-DTas the branches. These starburst polymers exhibited absorption spectra and molecular orbital energy levels that were comparable to N2200. These copolymers were paired with the wide-bandgap polymer donor PTz BI-O to fabricate all-polymer solar cells(all-PSCs), which displayed impressive power conversion efficiencies up to 8.00%. The improved photovoltaic performances of all-PSCs based on these newly developed starburst acceptors can be ascribed to the combination of increased charge carrier mobilities, reduced bimolecular recombination, and formation of more favorable film morphology. These findings demonstrate that the construction of starburst polymer acceptors is a feasible strategy for the fabrication of high-performance all-PSCs.     

Highly efficient removal of uranium(VI) from aqueous solutions by poly(acrylic acid-co-acrylamide) hydrogels

In this study, poly(acrylic acid-co-acrylamide) (PAAAM) hydrogels were used to remove uranium (VI) ions in wastewater and characterized by FTIR, SEM, EDX. The effects of pH value, coexistence of ionic strength, contact time, initial U (VI) ion concentration and adsorption temperature were also studied. Adsorption data fitted well with pseudo-second-order, intra-particle diffusion model and Langmuir isotherm mode, the maximum adsorption capacity of U(VI) was 713.24 mg g^?1. Thermodynamic analysis shows that the adsorption of U(VI) is spontaneous endothermic. PAAAM hydrogel has excellent regeneration performance, after five time adsorption–desorption cycles, the adsorbent still maintained 99.24% adsorption capacity.