气相色谱-质谱监测1-溴-2,4-二氟苯的合成条件、贡献及纯度

采用气相色谱-质谱（GC—MS）法对1,3-二氟苯溴化产物定性分析,采用了峰面积归一化法对产物进行定量分析,并通过正交设计结合多指标综合评价法优化合成条件。结果表明,通过GC—MS监测,对正交实验Z值结果分析得到最佳制备工艺：四氯化碳为溶剂,反应摩尔比（间二氟苯与液态溴）2：1,5℃下反应12h。产物纯度高于99．50％     

Preservation of Linear Constraints in Approximation of Tensors

For an arbitrary tensor (multi-index array) with linear constraints at each direction, it is proved that the factors of any minimal canonical tensor approximation to this tensor satisfy the same linear constraints for the corresponding directions.     

Comments on the theory of Bessel functions with more than one index

We present an outline of the theory of Bessel-like functions with more than one index and one or more variables. Their link with other types of functions is discussed and their use in applications is touched on.     

Polyhedral combinatorics of multi-index axial transportation problems

This paper studies integer points (IP) and integer vertices (IV) of the p-index axial transportation polytope (p  -ATP) of order _n1×_n2×?×_np$n_1\times n_2\times ?\times n_p$, _n1,_n2,…,_np?2$n_1\text{,}{n}_2\text{,}\dots \text{,}{n}_p?2$, p?2$p?2$, defined by integer vectors, as well as noninteger vertices of the 3-ATP. In particular, for the p  -ATP, we establish criteria for the minimum and maximum number of IPs and describe the class of polytopes for which the number of IPs coincides with the number of IVs. For the 3-ATP of order n×n×n$n\times n\times n$, we prove the theorem on the exponential growth of denominators of fractional components of the polytope vertices. Three conjectures are stated regarding the maximum number of vertices of the p-ATP, the maximum number of IVs, and the structure of the nondegenerate polytopes with the maximum number of IPs.     

基于近红外光谱特征的三文鱼品质多指标快速检测

三文鱼肉质鲜美、营养丰富，尽管价格昂贵，却深受广大消费者喜爱，2017年我国三文鱼进口额达3.5亿美元。近年来不法商贩为追求高额利润导致三文鱼消费市场“以假乱真”、“以次充好”的问题日益突出，主要表现为：(1)以价格低廉、外观相似的淡水虹鳟、大马哈鱼、太平洋鲑鱼等冒充价格高、消费者认可度高的挪威三文鱼；(2)将低成本、低品质的冰冻三文鱼(-18 ℃储运、保质期长、组织结构被冰晶破坏、口感风味破坏严重)化冻后冒充高成本、高品质的冰鲜三文鱼(0～4 ℃储运、保质期短、无冰晶产生、口感风味最大限度保持)；(3)将次新鲜的三文鱼冒充新鲜三文鱼。针对三文鱼品质感官检测误差大、理化检测耗时费力的不足，拟研究一种基于近红外光谱(NIRs)特征的真品/伪品三文鱼、冰鲜/冻融三文鱼、新鲜/次新鲜三文鱼快速鉴别方法。首先采集真品(挪威三文鱼)/伪品(淡水虹鳟、大马哈鱼和太平洋鲑鱼)三文鱼、冰鲜(冰鲜1，3和5 d)/冻融(冰冻15，30和45 d并化冻)三文鱼和新鲜/次新鲜(冰鲜保藏0，2，4，6和8 d)三文鱼样品的NIRs信息，并将不同储藏天数的冰鲜三文鱼以国标法测定其TVB-N含量。原始光谱经标准正态变量变换(SNV)等方法预处理后，分别使用主成分分析(PCA)和遗传算法(GA)进行光谱数据降维及特征波长筛选。最后，结合K-最近邻法(KNN)和最小二乘支持向量机(LS-SVM)对真品/伪品三文鱼和冰鲜/冻融三文鱼构建识别模型；结合联合区间偏最小二乘法(Si-PLS)对新鲜/次新鲜三文鱼构建TVB-N预测模型。建模结果表明：真品/伪品三文鱼LS-SVM定性识别模型对应的测试集识别率达97.50%，冰鲜/冻融三文鱼LS-SVM定性识别模型对应的测试集识别率达98.89%；TVB-N对应的Si-PLS定量检测模型的预测集相关系数为0.864 1，基于TVB-N预测值建立的三文鱼新鲜度定性鉴别模型对应的测试集准确率为90.00%。研究结果表明，利用近红外光谱特征结合化学计量学方法能够快速、无损检测真品/伪品三文鱼、冰鲜/冻融三文鱼和新鲜/次新鲜三文鱼，实现三文鱼品质多指标快速检测。     

Multi-index evaluation learning-based computation offloading optimization for power internet of things

Cloud–edge-device collaborative computation offloading can provide flexible and real-time data processing services for massive resource-constrained devices in power internet of things (PIoT). However, the computation offloading optimization in PIoT still faces several challenges such as high computation offloading delay caused by uncertain information, coupling between task offloading and computation resource allocation, and degraded optimization performance due to the lack of multi-index consideration. To address the above challenges, we formulate a joint optimization problem of task offloading and computation resource allocation to minimize the average computation offloading delay. Specifically, a multi-index evaluation learning-based two-stage computation offloading (MINCO) algorithm is proposed to decouple the joint optimization problem into two-stage subproblems and solve them with evaluation and learning of multiple indexes including data flow characteristic, service priority, empirical average computation offloading delay, and empirical arm selection times. Simulation results show that compared with the baseline 1 and baseline 2 algorithms, MINCO improves the average computation offloading delay by 14.67% and 30.71%. Moreover, MINCO can evaluate different service priorities and data flow characteristics to meet different requirements of computation offloading delay.     

Clique facets of the axial and planar assignment polytopes

The (k,s) assignment problem sets a unified framework for studying the facial structure of families of assignment polytopes. Through this framework, we derive classes of clique facets for all axial and planar assignment polytopes. For each of these classes, a polynomial-time separation procedure is described. Furthermore, we provide computational experience illustrating the efficiency of these facet-defining inequalities when applied as cutting planes.