基于一步水热合成荧光碳点的水样中亚硝酸根离子的检测研究

碳基荧光纳米点是一类新型的碳纳米材料,由于具有低毒性、生物兼容性优异、成本低、原料丰富等特点,而被广泛的应用于生物标记、荧光分析、防伪等多方面并具有巨大的应用前景。亚硝酸盐可导致人类高铁血红蛋白血症,有潜在的致癌性。通过盐酸多巴胺、邻苯二胺为原料一步水热法制备,提纯分离后得到目标产物——荧光发射波长为535 nm的黄绿色碳点。实验结果表明,该碳点溶液对亚硝酸根离子具有特异性响应,碳点的荧光被turn-off,检测范围为0～12μg·mL^-1,检出限为0.116 6μg·mL^-1(S/N=3,n=3)。此外,通过三种水样加标实验,回收率在93.9%～97.2%之间(RSD范围为0.03%～0.29%,n=3)。该荧光碳点合成方法快速简便,在污染物检测尤其是有毒亚硝酸盐污染物检测中有着较大的应用潜力,可作为水源地监测的重要补充手段。     

实现3-2译码及2-3编码的射极根合逻辑电路

本文运用作者最近提出的适用于射极藕合逻辑电路(ECL)设计的代数系统进行了3-2译码器及2-3编码器的ECL电路设计.它们不仅结构简单,而且适用于做成全译码电路及通用编码电路.     

周期性需求的供应商配送排程优化研究

在供应商管理库存(VMI)模式中,从提高供应商服务水平的视角,研究零售商具有周期性需求,供应商采用直接配送策略情形下以最小化缺货损失为目标的供应商配送日程安排问题。根据零售商最大需求周期的特点,设计了R倍放大(RTE)策略,分别针对实际中的边际缺货损失费率、固定缺货损失费率和递增缺货损失费率,证明了RTE策略在配送周期满足不同条件下对应的近似比。通过近似比的比较和算例分析,发现RTE策略在边际缺货损失费率下表现最好,某些情形下可以达到最优。研究结果对面对周期性需求的供应商配送排程具有一定的指导意义。     

二维三温辐射流体力学拉氏计算中的子网格压力方法

研究对应于电子压、离子压、光子压的扰动隅角力的计算方法,提出二维三温辐射流体力学拉氏计算中的两种子网格压力方法,即基于状态方程和基于几何的方法.数值试验表明,这两种方法均能很好地抑制二维三温辐射流体力学拉氏计算中出现的网格非物理畸变.     

Stimulated supercontinuum-radiation generation of carbon disulfide by all-trans-β-carotene fluorescence enhancement effect in liquid core optical fibre

We demonstrate stimulated supercontinuum-radiation of carbon disulfide (CS₂) influenced by biological molecules all-trans-β -carotene in liquid core optical fibre (LCOF). By virtue of the broad fluorescence characteristics and large third-order optical nonlinearities of all-{trans}-β-carotene,the high-order Stokes lines of stimulated Raman scattering (SRS) and the multi-order Stokes lines of stimulated Brillouin scattering (SBS) excitated by SRS are observed at low input-laser energies. The results indicate that the fluorescence not only enhances the SRS, but also the SBS. These Stokes lines generate the SRS--SBS supercontinuum radiation (RBSR). A flat-amplitude bandwidth of 110 nm from 515nm to 625nm is observed when a frequency-doubled Nd:YAG laser at 532nm with an energy of 0.86mJ is used. This result is expected to be useful for the multi-wavelength fibre laser.     

Influence of pressure effect on Fermi resonance in binary solution

The Fermi resonance behaviours of the two groups of binary solutions --- pyridine and methanol, benzene and carbon tetrachloride, under different pressures are investigated according to their Raman spectra. The effect of pressure on Fermi resonance in binary solution differs significantly from that in pure liquid. In a binary solution, with the intermolecular distance shortening, the intermolecular interaction potential increases, the shift rates of the Raman spectral lines increase, the spectral line splitting occurs ahead of that in pure liquid, and the wavenumber separation Δ₀ between the unperturbed harmonic levels shifts more quickly, too. The Fermi resonance parameters, the coupling coefficient W and the intensity ratio R of the two Raman bands, decrease rapidly with pressure increasing, and the pressure at which Fermi resonance phenomenon disappears is much lower than that in pure liquid, especially in the solution whose molecules are of the same polarity. This article is valuable in the identification and the assignment of spectral lines under high pressure, as well as the study of high pressure effect, intermolecular interaction, and solvent effects in different cases, etc.     

多边形交错网格的守恒重映算法

提出基于细分和数值积分思想的一种离散的守恒重映方法——质点重映方法.密度分布可采用一阶精度的分片常数分布,或二阶精度的分片线性分布.分片线性密度分布函数采用面平均方法构造.重映过程中,借助四边形辅助网格,实现了交错网格节点量的重映.质点重映方法既适用于结构网格,也适用于非结构网格,且不要求新旧网格之间一一对应.数值结果表明,一阶精度重映算法健壮性好,但会产生较大的扩散效应;二阶精度重映算法可较好地保持密度分布的特性,但存在单调性问题.为改善二阶精度重映方法单调性,将结构网格质量守恒调整算法推广到非结构网格上,以限制新网格的质量密度.给出了一些重映的例子,并进行了误差分析.     

典型模式下网络平台与食品生产经营者的相关决策

针对网络食品安全问题,分别构建网络平台与食品生产经营者合作一体化与各自独立时的经济利益优化模型,比较他们食品安全的相关决策,并在网络平台与食品生产经营者各自独立模式下对两者的行为策略进行博弈分析.结果表明:相比于各自独立,在合作一体化模式下网络平台设定的食品质量安全标准更低,食品生产经营者的食品供给量更大;在各自独立模式下,平台预期利润受食品安全问题负面影响更显著;网络平台与食品生产经营者合作一体化时,质量安全标准对两者合作的预期总利润影响相对较小.在各自独立模式下,若食品生产经营者供给不安全食品的"机会收益"不高于"机会损失",供给安全食品与严格监管是食品生产经营者与网络平台的最优策略组合.     

Jet Radius and Momentum Splitting Fraction with Dynamical Grooming in Heavy-Ion Collisions

We investigate the medium modifications of momentum splitting fraction and groomed jet radius with both dynamical grooming and soft drop algorithms in heavy-ion collisions.In the calculation,the partonic spectrum of initial hard scattering in p+p collisions is provided by the event generator PYTHIA8,and the energy loss of fast parton traversing in a hot/dense quantum-chromodynamic medium is simulated with the linear Boltzmann transport model.We predict the normalized distributions of the groomed...