改进的屏蔽氢离子模型中量子修正Δ_nl的推算

此文用等电子系列实验抛物线关系推算出了改进的屏蔽氢离子模型中量子修正Δnl的值,从而提高了屏蔽氢离子模型计算离子能量的精度     

抗坏血酸自加速的圆二色谱电化学研究

以现场长光程薄层圆二色光谱电化学方法研究了抗坏血酸在玻碳电极上的电极反应过程,通过双对数法和非线性回归的方法处理了薄层圆二色光谱电化学实验数据,结果表明抗坏血酸在ＰＨ７．０的缓冲溶液中玻碳电极上为２个电子转移的不可逆电化学氧化,氧化产物在电极上发生了强吸附,吸附层对抗坏血酸的电化学氧化反应有自加速作用,并获得了抗坏血酸在裸电极和在吸附电极上的式电位分别为Ｅ＝０．０９Ｖ,Ｅｎ＝０．２６Ｖ;电子转移数     

EFFECT OF ADSORPTION ON THE VISCOSITY OF DILUTE POLYMER SOLUTION*

Careful measurements of the dilute solution viscosities of polyethylene glycol and polyvinylalcohol in water were carried out. The reduced viscosities of both polymer solutions plot upward curves atextremely dilute concentration levels similar to the phenomena observed for many polymer solutions in theearly 1950's. Upon observation of the changes of the flow times of pure water in and the wall surfacewettability of the viscometer after measuring solution viscosity, a view was formed that the observed viscosityabnormality at extremely dilute concentration regions is solely due to the effect of adsorption of polymerchains onto the wall surface of viscometer. A theory of adsorption effect based on the Langmuir isothermswas proposed and a mathematical analysis for data treatment was performed. The theory could adequatelydescribe the existing viscosity data. It seems necessary to correct the viscosity result of dilute polymersolutions measured by glass capillary viscometer by taking into account the effect of adsorption in all cases.     

激光金等离子体谱中3d-5f、3p-5s跃迁子阵计算

 激光等离子体M带0.346～0.372nm范围内精细结构谱,是金等离子体的类Co、类Ni、类Cu、类Zn离子的3d-5f、3p-5s跃迁子阵形成的。在自旋轨道劈裂阵模型下, 对平均波长在该范围内的各子阵的主要特征参数如平均波长、半高宽和总跃迁强度进行详细计算,得到与实验测量基本一致的结果,可用于等离子体的精确诊断。     

Efficient entanglement purification in quantum repeaters

We present an efficient entanglement purification protocol(EPP) with controlled-not(CNOT) gates and linear optics.With the CNOT gates,our EPP can reach a higher fidelity than the conventional one.Moreover,it does not require the fidelity of the initial mixed state to satisfy F > 1/2.If the initial state is not entangled,it still can be purified.With the linear optics,this protocol can get pure maximally entangled pairs with some probabilities.Meanwhile,it can be used to purify the entanglement between the atomic ensembles in distant locations.This protocol may be useful in long-distance quantum communication.     

TSCL-SQL: Two-Stage Curriculum Learning Framework for Text-to-SQL

Text-to-SQL is the task of translating a natural language query into a structured query language. Existing text-to-SQL approaches focus on improving the model’s architecture while ignoring the relationship between queries and table schemas and the differences in difficulty between examples in the dataset. To tackle these challenges, a two-stage curriculum learning framework for text-to-SQL(TSCL-SQL) is proposed in this paper. To exploit the relationship between the queries and the table schemas,...     

空化水动力学非定常特性研究进展及展望

空化作为一种重要的复杂水动力学现象,具有明显的三维流动特征与剧烈的非定常特性,在水力机械、船舶推进器、水利工程中广泛存在,且通常会带来不利的影响,长期以来一直是水动力学领域研究的重点与难点课题之一.本文首先从实验测量和数值模拟两个角度,综述了空化水动力学非定常特性研究的发展概况, 分析了当前存在的问题.在空化实验研究中,主要介绍了空化水洞、空化流场测量以及多物理场同步测量等方面所取得的进展.在数值模拟方法中, 对目前的空化模型和湍流模型进行了分类介绍,并重点讨论了大涡模拟、验证和确认等在空化流模拟中的应用.之后以附着型空化为主, 同时兼顾云状空泡、空蚀、涡空化等,梳理了其研究中存在的几个关键科学问题,包括空化演变、空化流动的三维结构、失稳机制、空化不稳定性及其与低频压力脉动的联系、空化与旋涡的相互作用、空化与弹性水翼的流固耦合、空化对尾流场影响等.最后展望了空化水动力学的研究方向和未来发展趋势.      

基于合作博弈的网格资源分配

针对网格资源分配中的竞争问题,提出了一种合作博弈的方法,通过建立用户的评估函数,使得竞争同一资源的多个用户能够结成联盟来增加整体效用,其中用户分得的资源份额取决于出价水平.着重研究了联盟中用户的评估函数并证明了其满足非联盟评估函数的性质,因此在资源竞争中联盟成为有效的参与者.分析表明,该方法不仅可产生惟一的纳什均衡,而且能够为联盟用户带来更多的收益,从而实现帕累托改进.     

环己酮肟在改性氧化锆催化剂上的Beckmann重排反应Ⅲ．B_2O_3对ZrO_2的改性效应

采用ＩＲ和ＸＲＤ技术研究了Ｂ２Ｏ３／ＺｒＯ２催化剂的结构性质，用ＩＣＰ－ＭＳ测定了样品中Ｂ２Ｏ３的含量，通过Ｈａｍｍｅｔ指示剂正丁胺滴定法测定了Ｂ２Ｏ３／ＺｒＯ２系列催化剂的表面酸性；研究了载体预处理温度对样品表面酸性和结构的影响，以及Ｂ２Ｏ３含量对样品催化性能的影响；比较了Ｂ２Ｏ３负载于ＺｒＯ２，Ａｌ２Ｏ３，ＳｉＯ２，ＴｉＯ２，ＭｇＯ和ＨＺＳＭ－５上催化活性和目的产物选择性的差异，讨论了Ｂ２Ｏ３／ＺｒＯ２催化剂在气固相Ｂｅｃｋｍａｎｎ重排反应中的作用特点     

近红外光谱分析原油中水分和硫含量模型的建立及验证

取原油样品120个,分别按照GB/T 11133-2015和GB/T 17040-2008中所述方法测定了上述原油样品中的水分和硫的含量。通过优化的近红外光谱(NIRS)条件采集了上述原油样品的NIR光谱图。采用杠杆值算法剔除4个异常样品。在建立水分含量分析模型时,采用的条件为:用Savitzky-Golay法对光谱进行滤波预处理,建模光谱区间为6 200～8 200cm-1,主成分数为6,用偏最小二乘回归法(PLS)交叉验证建立分析模型。硫含量分析模型的建立条件为:采用二阶导数-Norris Derivative对光谱进行预处理,建模光谱区间为4 400～4 700cm-1,主成分数为6,用PLS交叉验证建立分析模型。水分和硫含量模型的预测值与测定值的相关性较好。水分模型的决定系数(R2c)为0.989 9,校正标准偏差(RMSEC)为0.084 2,说明其预测效果较好,可用于原油中水分含量的预测。硫含量模型的R2c为0.996 3,RESEC为0.069 6,说明此模型的预测效果也较好,可用原油中硫含量的预测。应用所建立的两个模型对10个未知原油样品中水分和硫含量进行了预测,并与其测定值比较,结果表明两者之间的相对偏差均小于10%。