Nonlinear transport of Bose-Einstein condensates in a double barrier potential

The stable nonlinear transport of the Bose-Einstein condensates through a double barrier potential in a waveguide is studied. By using the direct perturbation method we have obtained a perturbed solution of Cross-Pitaevskii equation. Theoretical analysis reveals that this perturbed solution is a stable periodic solution, which shows that the transport of Bose-Einstein condensed atoms in this system is a stable nonlinear transport. The corresponding numerical results are in good agreement with the theoretical analytical results.

Nonlinear Intestinal Absorption of Fluorescein Isothiocyanate Dextran 4, 000 Caused by Absorptive and Secretory Transporting System

The mechanism of the nonlinear concentration dependence of the intestinal absorption of fluorescein isothiocyanate dextran 4,000 (FD-4) was studied using in situ rat intestinal loops and the in vitro Ussing-type chamber method. The intestinal absorption rate constant of FD-4, as evaluated by the intestinal loop method, increased significantly in a nonlinear fashion as the FD-4 concentration increased up to 0.2 mM and tended to decrease at concentrations higher than 0.2 mM. The mucosal-to-serosal permeation of FD-4 across rat ileal sheets, as evaluated by the in vitro Ussing-type chamber method, also increased in a nonlinear fashion in the low concentration range (0.01 - 0.02 mM), before decreasing as the concentration increased further, whereas serosal-to-mucosal permeation decreased in a concentration-dependent manner. In addition, mucosal-to-serosal flux and serosal-to-mucosal flux were increased and reduced in the presence of the metabolic inhibitor 2, 4-dinitrophenol, respectively. These results suggest that FD-4 is predominantly secreted into the intestinal lumen by an efflux transport system.

The Nonlinear Electronic Transport in Multilayer Graphene on Silicon-on-Insulator Substrates

We conduct a study on the superlinear transport of multilayer graphene channels that partially or completely locate on silicon which is pre-etched by inductively coupled plasma （ICP）. By fabricating a multilayer-graphene field-effect transistor on a Si/SiO2 substrate, we obtain that the superlinearity results from the interaction between the multilayer graphene sheet and the ICP-etched silicon, In addition, the observed superlinear transport of the device is found to be consistent with the prediction of Schwinger＇s mechanism. In the high bias regime, the values of a increase draxnatically from 1.02 to 1.40. The strength of the electric field corresponding to the on-start of electron-hole pair production is calculated to be 5 × 10^4 Vim. Our work provides an experimental observation of the nonlinear transport of the multilayer graphene.

A Quantum Chemical Screening of Two Imidazole-Chalcone Hybrid Ligands and Their Pd, Pt and Zn Complexes for Charge Transport and Nonlinear Optical (NLO) Properties: A DFT Study

A quantum chemical screening of two imidazole-based chalcone ligands: 2- [1-(3-(1H-imidazol-1-yl)propylimino)-3-(phenylallyl)]phenol and 2-[1-(3-(1H- imidazol-1-yl)propylimino)-3-4-nitrophenylallyl]phenol (hereinafter referred to as HL1 and HL2 respectively) and their Pd, Pt and Zn chelates for charge transport and nonlinear optical (NLO) properties, is reported via dispersion- corrected density functional theory (DFT-D3) and time-dependent DFT (TD- DFT) methods. From our results, Pd and Pt complexes have been observed to show excellent hole-transport properties, owing to their very small reorganization energies. The light extraction efficiency of the HL1-Pt complex was deduced to be particularly impressive, thus suitable for the manufacture of hole transport layer in violet light emitting diodes (LEDs). Moreover, redox potentials and chemical stability studies have enabled us to validate the greater stability in moisture (towards oxidation), of HL2 complexes compared to their HL1 counterparts. The first and second hyperpolarizabilities of both ligands and their complexes have been found to be outstandingly higher than those of the push-pull prototypical, para-nitroaniline by factors of up to 12 in the case of HL2. These compounds, with the exception of the HL2-Pt complex, are thus interesting candidates having wide transparency tradeoffs for NLO efficiency in the manufacture of optoelectronic and photonic devices capable of second and third-order NLO response. Finally, metal chelation has been established to enhance the NLO response of all the chalcone-based imidazole ligands investigated as a result of metal-ligand charge transfer and ligand- metal charge transfer electronic transitions identified in the resulting complexes with the exception of the zinc complexes.

Expert System for the Transport Operator of Accelerator Single-Freedom Nonlinear Components

An expert system by Arity Prolog is developed for the transport operator of accelera-tor single-freedom nonlinear components. It automatically yields any order transport operatorand its inverse transport operator for various accelerator single-freedom nonlinear components.As an example, the fifth order inverse transport operator derived by the expert system is given.

Transport Operator of Accelerator Single-Freedom Nonlinear Components

For accelerator single-freedom nonlinear components,the general theory of nonlinear transportis developed,and the algorithm for the inverse transport operator is given,based on which an expert sys-tem can be built to automatically yield any order transport operator and its inverse transport operator forvarious accelerator single-freedom nonlinear components.

Using Nuclear Transport Theory to Study Nonlinear Effects Between the Different Strands in DNA

A dynamic model of DNA molecules which takes into account the interaction of the nearestbase pairs between the different strands is presented.The nonlinear effect and phase transition aresimulated by the nuclear transport theory and the method of fractorial moment in high energy physics,re-spectively.The results show that the nonlinear interaction of the nearest base pairs between the differentstrands may play a rule in DNA molecules.

Nonlinear Accelerator Beam Transport Operator

This paper deals with the theory of nonlinear accelerator beam transport op-erator.For nonautonomous accelerator dynamics,a theorem of finding the inversenonlinear beam transport operator is developed.Several concrete examples are workedout in detail to show the practical applications of this theory.

车辆制动载荷下包装件非线性摇摆响应分析

车辆制动产生纵向半正弦冲击载荷,浮放包装件在运输过程中制动条件下的摇摆特性及倾覆风险研究对于确保运输安全至关重要。研究浮放包装件非线性摇摆响应(α>15°),构建循环神经网络模拟包装件非线性受迫摇摆响应,应用雅可比椭圆函数构建包装件非线性自由响应分析表达式,根据能量守恒原则构建包装件在自由响应阶段倾覆边界条件。根据包装件非线性摇摆响应分析方法,构建包装件倾覆边界条件。分析结果表明,在半正弦冲击激励下,包装件在受迫响应阶段和自由响应阶段均可能绕O点逆时针旋转倾覆,导致包装件自由响应倾覆的冲击幅值较导致包装件受迫响应倾覆的冲击幅值小,这表明,包装件更容易在自由响应阶段倾覆。

天然气水合物试采多相输送的弯管段防护研究

天然气水合物浆液中混杂的泥砂颗粒在低流速管段容易产生堆积阻塞,在高流速管段经常发生冲蚀磨损,目前国内外针对以液体为连续相流动的气液固多相流冲蚀研究较少。为此,以欧拉(Euler)气泡流模型与离散相模型(DPM)耦合的多相流数学模型为理论基础,对多相流中气液相间分布及管壁冲蚀磨损进行了数值模拟,开展了冲蚀磨损试验并提出耐磨防护方案。研究结果表明:可以从减弱弯管段湍流剪切作用、颗粒对弯管内壁的直接碰撞及减少动能传递进行防护设计;15°楔形垫层对应的最大冲蚀速率减幅74.55%,在1.0~2.2 m/s的流速范围内防护效果更明显;陶瓷涂垫层防护对冲蚀-腐蚀交互作用有明显的抑制效果。研究结论可为管道输送工程防护措施的制定提供技术参考。

城市小汽车用户公交使用的影响因素分析

引导小汽车用户使用公交有助于缓解城市交通拥堵和推动交通领域节能减排。采用昆明市小汽车用户出行调查数据,基于随机森林模型探究建成环境、公交服务质量、个人社会经济属性对小汽车用户公交使用的影响。研究表明:建成环境是影响小汽车用户公交使用的最重要因素,相对重要性之和为53.7%,路网密度、土地利用混合度、居住区位、公交站点数量与小汽车用户公交使用密切相关;个人社会经济属性相对重要性之和为24.9%,家庭年收入变量相对重要性最高(5.2%);公交服务质量相对重要性之和为21.4%,分别为便利性(5.8%)、舒适性(5.6%)、可靠性(5.2%)、安全性(4.8%);建成环境对小汽车用户公交使用具有非线性影响且非线性影响在不同收入水平的小汽车用户之间存在差异。研究结果有助于更好理解小汽车用户的公交使用行为,从而采取针对性策略促进小汽车用户使用公交。

铁路枢纽双编组站静态配流协同优化研究

枢纽内跨编组站进行协同配流有助于优化枢纽内的车流接续,提高全局配流质量。引入跨编组站协同配流思想,构建铁路枢纽双编组站静态配流协同优化模型,以最小化双编组站的配流总代价、最大化双编组站的总满轴列车数为优化目标,考虑车流量约束、列车到解编发作业与枢纽小运转列车走行的接续时间约束、出发列车满轴与不违编约束、调机资源使用约束。以列车等级、编组去向数及出发时刻排序作为配流代价。设计理想点算法将多目标转化为单目标进行求解,最后运用算例对模型及算法的有效性进行验证。结果表明,双编组站联合配流相较于两编组站单独配流,可使满轴列车总数增加1列、站存车总数减少13辆、配流总代价降低5.4%,从而达到更佳的配流效果。

考虑负外部性成本的铁矿石航线配船多目标优化

针对实际铁矿石航运过程中所存在的船舶运营导致负外部性内部化问题,综合考虑船舶海上运输所造成的环境影响、港口拥堵以及交通事故等负外部性要素,并对其进行量化评估。通过分析铁矿石海上运输活动,将负外部性问题与航线配船相结合考虑,以负外部性成本最低与营运利润最大为目标,建立了铁矿石航线配船双目标优化模型,采用改进遗传算法进行求解与验证。以从巴西经过好望角到中国的3条铁矿石航线为例,对模型进行求解验证,并对船型和燃油价格进行灵敏度分析。结果表明:负外部性成本在航运企业运营收益中是不容忽略的,合理的船型运力配比在运输过程中会显著地减少负外部性成本。随着燃油价格上涨,会导致负外部成本大幅增加。可为航运相关企业提出优化建议,并为政府宏观调控运力和航运企业制定运输计划提供参考。

Thermal Transport in One-Dimensional FPU-FK Lattices

<正> Thermal transport in the FPU model with FK on-site potential is studied by using fourth-order Runge-Kuttaalgorithm.The heat flux,local temperature profile,and heat conductivity are simulated and analyzed.It is foundthat temperature gradient scales behave as N-1 linearly.The divergence of heat conductivity κ with system size N isin term of κα N~α with α=0.44.It is shown that thermal transport is mainly dependent on the FPU nonlinear andthe FK interactions.

3D contaminant migration model with consolidation dependent transport coefficients

Soil consolidation would induce variations of its transport coefficients such as hydraulic conductivity and diffusion coefficient. This paper presents a study of the influence of barrier consolidation on transport coefficients, and a 3D transport model based on mixture theory is proposed for describing the liners that involve circular defects in the geomembrane. The elastoplastic ALPHA model is revised by using the spatially mobilized plane （SMP） criterion for simulating the deformation of the soils. Then, the 3D model coupling the nonlinear consolidation and contaminant advection-diffusion is solved using the finite element software ABAQUS. The results show that the importance of reducing the defect size in the geomembrane and the liner porosity to control the contaminant concentration increase

阶梯式碳税下煤炭海铁联运网络调运优化研究

在大规模海铁联运网络背景下,考虑铁路年运输能力和煤炭港口年吞吐量限制的基础上,引入阶梯式碳税量化碳排放成本,建立考虑碳排放的煤炭海铁联运网络调运方案非线性优化模型。模型以大规模海铁联运网络每条可行路径的年煤炭运输量为决策变量,根据模型特性设计了一种组合式求解算法(Combinatorial Algorithm,CA),外层迭代算法采用增广拉格朗日乘子法,内层迭代算法采用可行方向法,将非线性规划模型转化为标准Hitchcock模型。采用国家能源集团煤炭海铁联运业务相关数据进行实例分析,并运用CA进行求解。在实例分析的基础上进一步对固定碳税和阶梯式碳税进行了敏感性分析,结果表明,阶梯式碳税上下限在合理度范围内时,采用其得到的最优调运方案在企业总效益和减排效果2个方面优于固定碳税,但当其上下限超出合理范围后,会对企业效益及企业减排积极性产生打击。

基于客流博弈均衡的旅客列车双层开行方案优化

为提高旅客列车运行效益及旅客出行满意度,以铁路运营部门净收益、列车空座位走行公里最小化为上层0-1规划模型,以旅客出行满意度最大化为下层客流均衡模型,构建了纯整数非线性高速铁路旅客列车开行方案双层规划模型。针对下层客流均衡模型,通过划分博弈环境和分析旅客乘车出行选择行为,选取旅客同质群体作为局中人,构造各局中人合理赢得函数,对每个博弈环境均运用非合作博弈理论进行客流均衡分配。基于构建的模型特征分析,采用NSGA-Ⅱ算法求解上层停站方案模型,运用QPSO算法求解下层客流博弈均衡模型,并以兰新高速铁路为例验证了模型及算法的可行性。结果表明:该算法可获得使铁路运营部门与旅客双方均满意的Nash均衡解,由此得到的开行方案铁路旅客损失率为0%。

基于最小油耗的货车车速与信号配时协同优化模型

为解决货车受信号灯影响频繁停和启而造成油耗过高的问题,本文建立货车车速与信号配时协同优化的整数非线性规划模型。模型的目标函数是基于弗吉尼亚理工大学综合油耗模型的货车行程油耗,包括路段行驶油耗、交叉口停车油耗以及速度恢复油耗。将路段划分为加速区、匀速区和减速区;考虑货车多档渐变的加速过程,货车每个挡位设定加速度以及换挡时间的上下限;采用交通波理论分析下游路口的排队消散过程,建立货车的时空轨迹约束。优化变量包括货车各挡位加速度、加速时间、匀速区速度、匀速行驶时间、减速度、减速时间、交叉口绿灯延长时间和红灯早断时间。以均匀间隔生成的10种货车到达情形为例进行分析,结果表明:与无车速引导相比,本模型行程油耗最高减少29.9%,最低减少3.9%,平均减少13.7%;货车停车次数减少5次(降低71.4%),总停车时间减少174 s(降低89.2%)。模型有效减少了货车通过交叉口的燃油消耗和停车次数。

考虑力学-化学荷载下压实黏土垫层中一维非线性固结与污染物运移耦合模型

针对力学-化学荷载下压实黏土垫层中一维固结与污染物运移耦合过程,考虑了土体压缩性和渗透性的非线性变化,建立了相应的耦合模型,并利用有限差分法对该模型进行了求解。通过与有限元软件COMSOL Multiphysics计算结果和已有解析解计算结果展开对比分析,对所建耦合模型正确性进行了验证。基于所建模型,比较研究了两种假定情况下力学荷载pu和渗滤液中污染物浓度Cb对耦合过程的影响。结果表明:当忽略非线性压缩和渗透特性时,力学荷载pu的增大会使污染物运移速率降低;但当考虑非线性压缩和渗透特性时,pu的增大会使污染物运移速率增大,这主要是由于污染物运移过程会受对流和扩散作用的综合影响。污染物浓度Cb的增大会使沉降量增大,超孔隙水压力值减小,也会使得污染物运移速率降低;相比于忽略非线性的情况,考虑非线性情况下Cb对沉降量、超孔隙水压力和污染物运移速率的影响会减弱。

弹性转子油气混输泵的非线性动力学研究

为了研究弹性体转子外表面橡胶非线性变形对弹性体转子泵的影响,采用非线性单向流固耦合方法,建立转子啮合接触有限元模型,将非定常计算结果内流压力载荷施加到转子表面,研究圆弧转子型线和宽头刮边转子型线在不同的橡胶壁厚和出口压力下,对转子泵效率和启动扭矩的影响.结果表明,无论采用哪种型线,压差对橡胶剪应力和变形量影响较大,而转动角度对剪应力峰值影响较小;剪应力较大值主要出现在转子与衬套、转子与转子接触点附近靠高压区侧的圆弧区;壁厚与最大剪应力和橡胶变形呈正相关.设计的螺杆转子和得到的数据可用于弹性转子油气混输泵的设计和优化,延长弹性体转子油气混输泵在深海环境下的使用寿命,并大大节省了维护成本.