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Investigation of Vacuum Ultraviolet Photoionization of Methylcyclohexane in Energy Region of 9$ - $15.5 eV
Hang Zhang, Li Yan-bo, Zhu Long, Chen Jun, Yu Ye-peng, Li Zhao-hui, Lin Xuan, Shan Xiao-bin, Liu Fu-yi, Sheng Liu-si
2020, 33(3): 296-302. doi: 10.1063/1674-0068/cjcp1905095
摘要:
Tuning Structural, Electronic, and Magnetic Properties of Black-AsP Monolayer by Adatom Adsorptions: A First Principles Study
Xin Liu, Yu-xiang Ni, Hong-yan Wang, Hui Wang
2020, 33(3): 311-318. doi: 10.1063/1674-0068/cjcp1907136
摘要:
Six-Dimensional $ab$ $ initio$ Potential Energy Surface and Bound States for He-H$ _\textbf{2} $S Complex
Chao-ying Han, Ting Jiang, Hua Zhu, Hong-jun Fan
2020, 33(3): 319-326. doi: 10.1063/1674-0068/cjcp1907145
摘要:
Electronic Stability of Bimetallic Au$ _{\textbf{2}} $@Cu$ _{\textbf{6}} $ Nanocluster: Closed-Shell Interaction and Multicenter Bonding
Ying-ying Ma, Yuan-qin Yu, Long-jiu Cheng
2020, 33(3): 327-333. doi: 10.1063/1674-0068/cjcp1912200
摘要:
Metallophilic interaction is a unique type of weak intermolecular interaction, where the electronic configuration of two metal atoms is closed shell. Despite its significance in multidisciplinary fields, the nature of metallophilic interaction is still not well understood. In this work, we investigated the electronic structures and bonding characteristic of bimetallic Au$ _{2} $@Cu$ _{6} $ nanocluster through density functional theory method, which was reported in experiments recently [Angew. Chem. Int. Ed. 55 , 3611 (2016)]. In general thinking, interaction between two moieties of (CuSH)$ _{6} $ ring and (Au$ _{2} $PH$ _{3} $)$ _{2} $ in the Au$ _{2} $@Cu$ _{6} $ nanocluster can be viewed as a d$ ^{10} $-$ \sigma $ closed-shell interaction. However, chemical bonding analysis shows that there is a ten center-two electron (10c-2e) multicenter bonding between two moieties. Further comparative studies on other bimetallic nanocluster M$ _{2} $@Cu$ _{6} $ (M = Ag, Cu, Zn, Cd, Hg) also revealed that multicenter bonding is the origin of electronic stability of the complexes besides the d$ ^{10} $-$ \sigma $ closed-shell interaction. This will provide valuable insights into the understanding of closed-shell interactions.
Principles of Surface Potential Estimation in Mixed Electrolyte Solutions:Taking into Account Dielectric Saturation
Wen-xin Zou, Jing Peng, Wei-ning Xiu, Xin-min Liu
2020, 33(3): 334-342. doi: 10.1063/1674-0068/cjcp1907132
摘要:
The dielectric properties between in-particle/water interface and bulk solution are significantly different, which are ignored in the theories of surface potential estimation. The analytical expressions of surface potential considering the dielectric saturation were derived in mixed electrolytes based on the nonlinear Poisson-Boltzmann equation. The surface potentials calculated from the approximate analytical and exact numerical solutions agreed with each other for a wide range of surface charge densities and ion concentrations. The effects of dielectric saturation became important for surface charge densities larger than 0.30 C/m$ ^2 $. The analytical models of surface potential in different mixed electrolytes were valid based on original Poisson-Boltzmann equation for surface charge densities smaller than 0.30 C/m$ ^2 $. The analytical model of surface potential considering the dielectric saturation for low surface charge density can return to the result of classical Poisson-Boltzmann theory. The obtained surface potential in this study can correctly predict the adsorption selectivity between monovalent and bivalent counterions.
Interaction of CO and O$ _\textbf{2} $ with Supported Pt Single-Atoms on TiO$ _\textbf{2} $(110)
Shi-hui Dong, Wang Ao-lei, Zhao Jin, Shi-jing Tan, Bing Wang
2020, 33(3): 349-356. doi: 10.1063/1674-0068/cjcp1911198
摘要:
In view of the high activity of Pt single atoms in the low-temperature oxidation of CO, we investigate the adsorption behavior of Pt single atoms on reduced rutile TiO$ _2 $(110) surface and their interaction with CO and O$ _2 $ molecules using scanning tunneling microscopy and density function theory calculations. Pt single atoms were prepared on the TiO$ _2 $(110) surface at 80 K, showing their preferred adsorption sites at the oxygen vacancies. We characterized the adsorption configurations of CO and O$ _2 $ molecules separately to the TiO$ _2 $-supported Pt single atom samples at 80 K. It is found that the Pt single atoms tend to capture one CO to form Pt-CO complexes, with the CO molecule bonding to the fivefold coordinated Ti (Ti$ _{5 \rm{c}} $) atom at the next nearest neighbor site. After annealing the sample from 80 K to 100 K, CO molecules may diffuse, forming another type of complexes, Pt-(CO)$ _2 $. For O$ _2 $ adsorption, each Pt single atom may also capture one O$ _2 $ molecule, forming Pt-O$ _2 $ complexes with O$ _2 $ molecule bonding to either the nearest or the next nearest neighboring Ti$ _{5 \rm{c}} $ sites. Our study provides the single-molecule-level knowledge of the interaction of CO and O$ _2 $ with Pt single atoms, which represent the important initial states of the reaction between CO and O$ _2 $.
Fabrication of Melamine/Tb\begin{document}$ ^{\textbf{3+}} $\end{document}-Intercalated Polydiacetylene Nanosheets and Their Thermochromic Reversibility Test
Qing Wang, Gang Wang, Xia-yun Huang, Dao-yong Chen
2020, 33(3): 357-364. doi: 10.1063/1674-0068/cjcp1907143
摘要:

Polydiacetylene (PDA) is one kind of the conjugated polymer with layered structure, which can serve as a host to accommodate the guest components through intercalation. In these intercalated PDAs, some of them were reported to have a nearly perfect organized structure and perform completely reversible thermochromism. Till now, these reported intercalated PDAs were made by only introducing a single component for intercalation. Here, we chose 10, 12-pentacosadiynoic acid (PCDA) as the monomer, of which the carboxyl-terminal groups can interact with either Tb

\begin{document}$ ^{3+} $\end{document}

ions or melamines (MAs). When the feeding molar ratio of PCDA, MA, and Tb

\begin{document}$ ^{3+} $\end{document}

ion was 3:267:1, only Tb

$ ^{3+} $

ions were intercalated though excess MAs existed. Such Tb

$ ^{3+} $

-intercalated poly-PCDA exhibited completely reversible thermochromism, where almost all the carboxyl groups interacted with Tb

$ ^{3+} $

ions to form the nearly perfect structure. When the feeding molar ratio of PCDA, MA, and Tb

$ ^{3+} $

ion was 3:267:0.6, both Tb

$ ^{3+} $

ions and MAs were intercalated. There existed some defects in the imperfect MA-intercalated domains and at the domain boundaries. The MA/Tb

$ ^{3+} $

-intercalated poly-PCDA exhibits partially reversible thermochromism, where the backbones near the defects are hard to return the initial conformation, while the rest, those at nearly perfect organized domains, are still able to restore the initial conformation.

Highly Sensitive Flexible Pressure Sensors based on Graphene/Graphene Scrolls Multilayer Hybrid Films
Yi-heng Zhai, Tao Wang, Zhi-kai Qi, Xiang-hua Kong, Hang-xun Xu, Heng-xing Ji
2020, 33(3): 365-370. doi: 10.1063/1674-0068/cjcp1907146
摘要:
In recent years, flexible pressure sensors have attracted much attention owing to their potential applications in motion detection and wearable electronics. As a result, important innovations have been reported in both conductive materials and the underlying substrates, which are the two crucial components of a pressure sensor. 1D materials like nanowires are being widely used as the conductive materials in flexible pressure sensors, but such sensors usually exhibit low performances mainly due to the lack of strong interfacial interactions between the substrates and 1D materials. In this paper, we report the use of graphene/graphene scrolls hybrid multilayers films as the conductive material and a micro-structured polydimethylsiloxane substrate using Epipremnum aureum leaf as the template to fabricate highly sensitive pressure sensors. The 2D structure of graphene allows to strongly anchor the scrolls to ensure the improved adhesion between the highly conductive hybrid films and the patterned substrate. We attribute the increased sensitivity (3.5 kPa$ ^{-1} $), fast response time ($ < $50 ms), and the good reproducibility during 1000 loading-unloading cycles of the pressure sensor to the synergistic effect between the 1D scrolls and 2D graphene films. Test results demonstrate that these sensors are promising for electronic skins and motion detection applications.
Facile Green Synthesis of Magnetic Fe$ _\textbf{3} $C@C Nanocomposite using Natural Magnetite
Ju-wen Gu, Yong Bai, Song-bai Qiu, Qian Zhang, Tie-jun Wang
2020, 33(3): 371-375. doi: 10.1063/1674-0068/cjcp1907142
摘要:
One simple and environmental friendly synthesis strategy for preparing low-cost magnetic Fe$ _3 $C@C materials has been facilely developed using a modified sol-gel approach, wherein natural magnetite acted as the iron source. A chelating polycarboxylic acid such as citric acid (CA) was employed as the carbon source, and it dissolved Fe very effectively, Fe$ _3 $O$ _4 $ and natural magnetite to composite an iron-citrate complex with the assistance of ammonium hydroxide. The core-shell structure of the as-prepared nanocomposites was formed directly by high-temperature pyrolysis. The Fe$ _3 $C@C materials exhibited superparamagnetic properties (38.09 emu/mg), suggesting potential applications in biomedicine, environment, absorption, catalysis, etc.
Magnetic Nano-Amorphous-Iron-Oxide-Based Drug Delivery System with Dual Therapeutic Mechanisms
Shan Lei, Li-an Wang, Fu-xing Lin, Kun Zeng, Mo-zhen Wang
2020, 33(3): 376-384. doi: 10.1063/1674-0068/cjcp1906123
摘要:
Smart nanoparticles that respond to pathophysiological parameters, such as pH, GSH, and H$ _2 $O$ _2 $, have been developed with the huge and urgent demand for the high-efficient drug delivery systems (DDS) for cancer therapy. Herein, cubic poly(ethylene glycol) (PEG)-modified mesoporous amorphous iron oxide (AFe) nanoparticles (AFe-PEG) have been successfully prepared as pH-stimulated drug carriers, which can combine doxorubicin (DOX) with a high loading capacity of 948 mg/g, forming a novel multifunctional AFe-PEG/DOX nanoparticulate DDS. In an acidic microenvironment, the AFe-PEG/DOX nanoparticles will not only release DOX efficiently, but also release Fe ions to catalyze the transformation of H$ _2 $O$ _2 $ to $ \cdot $OH, acting as fenton reagents. In vitro experimental results proved that the AFe-PEG/DOX nanoparticles can achieve combination of chemotherapeutic (CTT) and chemodynamic therapeutic (CDT) effects on Hela tumor cells. Furthermore, the intrinsic magnetism of AFe-PEG/DOX makes its cellular internalization efficiency be improved under an external magnetic field. Therefore, this work develops a new and promising magnetically targeted delivery and dual CTT/CDT therapeutic nano-medicine platform based on amorphous iron oxide.
1956—2018年中国江河径流演变及其变化特征
张建云, 王国庆, 金君良, 贺瑞敏, 刘翠善
2020, 31(2): 153-161. doi: 10.14042/j.cnki.32.1309.2020.02.001
摘要:
地表水资源是维系区域生态平衡和促进经济社会发展的制约性要素, 河川径流是地表水资源的主要形式, 二者的丰枯变化均直接影响流域水资源管理。基于江河实测径流量资料和水资源公报资料, 初步分析了1956—2018年中国主要江河实测径流量和中国十大水资源区地表水资源的变化和演变特征。结果表明:①除长江大通站外, 中国主要江河代表性水文站实测年径流量均呈现下降趋势。②黄河上游唐乃亥站实测年径流量为非显著性减少趋势, 黄河花园口站实测径流量呈现显著性减少趋势; 1980—2000年和2001—2018年唐乃亥站实测径流量较基准期1956—1979年分别变化1.8%和-5.9%, 而同时期花园口站实测径流量分别减少26.7%和41.0%。③地理分布上, 黄河是中国南北地区径流变化的分水岭, 黄河以南地区江河径流量为非显著性变化, 黄河以北江河径流量为显著性减少趋势, 特别是海河流域, 实测径流量减少最为显著; 21世纪以来, 黄河以北河流实测径流量较1980年之前减少幅度超过25%, 海河减幅高达80%以上。④ 1956—2018年全国地表水资源量约为27 266亿m3, 较第二次全国水资源评价结果偏少122亿m3。21世纪以来, 海河、黄河、辽河地表水资源明显减少, 进一步加重了区域水资源供需矛盾。
基于水位流量关系的流量估算不确定性分析
邱江潮, 刘丙军, 杨子博, 彭为
2020, 31(2): 214-223. doi: 10.14042/j.cnki.32.1309.2020.02.007
摘要:
针对现有水位流量关系线型物理机制不强及流量估算不确定性来源考虑不充分问题, 以北江流域石角水文站为例, 推导该测站水位流量关系, 基于BaRatin模型评估流量测量误差及率定样本选取对估算流量不确定性的影响。发现河槽控制宽浅矩形断面水位流量关系为幂函数, 其系数可用糙率、河宽、比降表达, 指数为定值5/3;考虑流量测量误差后高水估算流量总不确定性减小32%;率定数据增加1倍、3倍, 高水估算流量总不确定性减小12%、34%。结果表明:①水位流量关系模型建立方法可推广至多类型测站; ②高水测量误差对率定精度影响较大, 建议提高高水流量测量精度; ③现有实测水位与流量数据存在信息冗余, 主要存在于低水数据中, 本方法可减少率定数据使用, 降低整编成本。
基于信息熵的水文站网优化准则的应用与评价
李禾澍, 王栋, 王远坤
2020, 31(2): 224-231. doi: 10.14042/j.cnki.32.1309.2020.02.008
摘要:
将基于信息熵的四类水文站网优化准则, 即熵-互信息(H-T)准则、联合熵-总相关(H-C)准则、联合熵-互信息-总相关(H-T1-C/H-T2-C)准则以及信息传递指数(TI)准则, 应用于太湖西南山丘区雨量站网, 对四类准则进行对比和评价。以2007—2016年日降水序列为样本, 根据各优化准则, 分别采用3种数值离散化方法计算站点秩次, 分析秩次相关性、对多目标准则中指标权重的敏感性以及秩次年际变化。结果表明, H-C准则对应秩次的代表性最好, 对指标权重的敏感度最低, 秩次年际变化小; H-T2-C准则对指标权重最敏感, 秩次年际变化显著。H-C准则有利于反映基于信息熵的基本优化原则(增大信息量和降低冗余度), 而H-T2-C准则有利于体现决策偏好。
床面粗糙度和底床渗透率对泥-水界面物质交换特性的影响
樊靖郁, 陈春燕, 赵亮, 王岱峰, 王道增
2020, 31(2): 232-239. doi: 10.14042/j.cnki.32.1309.2020.02.009
摘要:
泥-水界面物质交换过程对自然水体中污染物的迁移转化起重要作用, 粗糙底床界面物质交换过程涉及到床面粗糙度和底床渗透率的影响。通过实验室环形水槽实验测量得到水力粗糙砂质底床条件下界面物质交换通量的定量数据和变化特征, 采用参数化方法分析有效扩散系数与其主要影响参数之间的依赖关系。实验结果表明, 在实验参数变化范围内, 受上覆水平均流速、床面粗糙度和底床渗透率的共同作用, 有效扩散系数从水力光滑区、过渡粗糙区至完全粗糙区呈现较为明显的分段变化特征, 采用渗透率雷诺数可将有效扩散系数与其主要影响参数的依赖关系进行较为一致的描述。基于双参数(粗糙雷诺数和渗透率雷诺数)分析, 确定了不同流动区域的相应阈值以合理表征床面粗糙度和底床渗透率对界面物质交换特性的综合影响。
小浪底水库淤积形态数值模拟
假冬冬, 王远见, 江恩惠, 邵学军, 张幸农
2020, 31(2): 240-248. doi: 10.14042/j.cnki.32.1309.2020.02.010
摘要:
水库淤积形态是影响库容分布、水库排沙的一项重要因素。小浪底水库近坝段淤积泥沙粒径极细, 具有流动性, 针对其细颗粒泥沙淤积特点, 揭示了水库细颗粒淤积物的流变特性与流型特征; 通过引入水、淤积物、床面之间的界面受力分析, 构建了细颗粒淤积物失稳流动描述模式, 并与水沙输移模型相耦合, 建立了考虑细颗粒淤积物流动特性的水库淤积形态模拟方法, 在此基础上对小浪底水库淤积形态进行了验证分析。研究结果表明:低密度细颗粒淤积物为宾汉型流体, 淤积平衡坡降较小, 当其密度大于1.25 g/cm3后, 流动性快速减弱; 考虑细颗粒淤积物流动特征的水库淤积形态模拟结果与实测结果吻合较好。研究成果可为水库淤积形态形成机理及其对水沙调控的响应研究提供技术支撑。
生产堤溃口展宽过程的概化模型试验研究
果鹏, 夏军强, 周美蓉, 张晓雷
2020, 31(2): 249-259. doi: 10.14042/j.cnki.32.1309.2020.02.011
摘要:
为研究生产堤溃口横向展宽过程的发展规律, 以黄河下游生产堤土体为材料, 开展概化模型试验, 分析溃口处水深、流速、流量以及溃口宽度的变化。试验结果显示, 溃口横向展宽的机理主要表现为水流冲刷堤身下层土体伴随上层悬臂土体发生绕轴崩塌; 随着溃口展宽, 堤前水深持续下降但下降速率逐渐减小, 溃口流速呈先增大后减小的趋势, 流速峰值约为1.1 m/s; 随着主槽流量增加, 溃口宽度发展至0.7 m时, 溃口的水深、泄流流量、流速、展宽速率均有所增加。基于对溃口展宽的影响因素分析, 提出溃口横向展宽速率的计算关系式, 计算溃口展宽过程与实测值符合较好。研究结果不仅有助于生产堤展宽机理及发展规律的研究, 还可为数学模型的建立与验证提供参考资料。
挑坎体型对下游雾化影响的试验研究
练继建, 冉聃颉, 何军龄, 张紫畅
2020, 31(2): 260-269. doi: 10.14042/j.cnki.32.1309.2020.02.012
摘要:
以解决挑流消能工在泄洪期间为提高消能率而加重下游雾化问题为目标, 探究不同体型挑坎的下游雾化特性。通过水力学模型试验, 对典型的非对称舌型坎、标准舌型坎、扭面贴坎和连续坎的下游水舌风分布、下游溅水雨强和不同液滴体积分布以及挑流水舌水力特性与冲刷特性进行了研究。研究表明:①各种工况下, 非对称舌型坎、标准舌型坎、扭面贴坎的下游水舌风风速均大于连续坎。②对于非对称舌型坎, 其溢洪道轴线左侧溅水强度大于右侧, 其雨强左右两侧峰值差值最大为5.625 g/(m2·min); 对于扭面贴坎, 其溢洪道轴线右侧溅水强度更大, 其雨强左右两侧峰值差值最大为45.125 g/(m2·min)。③随着距离水舌入水点长度增大, 大粒径水滴数量和体积占比均剧烈下降; 连续坎和舌型坎的挑宽均随着角度的增加而增加; 冲坑深度随着角度的减小而增大。④在挑坎合适边墙侧设置扭面贴角能改善下游雾化危害, 同时适当增加挑角可以减弱下游冲刷破坏。
水平圆柱强迫振荡水动力特性的数值模拟
毛鸿飞, 袁剑平, 庞建华, 贾宝柱
2020, 31(2): 278-286. doi: 10.14042/j.cnki.32.1309.2020.02.014
摘要:
为了研究处于自由面以下完全淹没状态的水平圆柱在强迫振荡运动时的水动力特性, 采用基于黏性流理论建立的二维两相流数值波浪水槽模型, 对不同液相黏性条件下强迫振荡水平圆柱的受力进行计算, 并对压力、黏性切力和圆柱运动之间的相位关系特征进行对比和分析, 进而结合流场分析解释黏性影响机理。结果表明:黏性切力和涡旋压力对流体作用力的贡献差别是导致不同流体黏性下流体作用力结果差异的主要原因; 涡旋运动相对圆柱振荡运动的滞后性受流体黏性影响显著, 导致不同流体黏性下压力之间有相位差; 流体水质点相对于圆柱的滞后运动在大黏性流体中更为显著, 这导致了其黏性切力的相位超前现象。
溶蚀丘陵型岩溶流域概念性水文模型
陈晓宏, 颜依寒, 李诚, 危润初
2020, 31(1): 1-9. doi: 10.14042/j.cnki.32.1309.2020.01.001
摘要:
为弥补传统概念性水文模型在岩溶水文模拟上的缺陷,基于三水源新安江模型,采用多个线性水库表达岩溶地下系统的异质性,同时引入流域虚拟面积系数修正岩溶流域的非闭合性。将改进的概念性水文模型应用于湘中南典型溶蚀丘陵型岩溶流域,并在此基础上探讨岩溶流域非闭合性的动态变化。研究结果表明:①改进模型的日径流模拟精度提高11.21%,水量平衡误差及低水误差分别降低23.29%、27.64%;②岩溶地下汇流系统的多向性导致流域非闭合状态具有双重性;③地下汇流面积与时段降雨量呈正相关,然而受地下饱和程度的制约,地下汇流面积的变化率随时段降雨量的增大而减小;④由于岩溶地貌的蓄水滞水作用,地下流域受外侧补给的过程存在滞后性。模型的改进与拓展研究可为岩溶水文模拟提供新思路。
融合出版视角下的内容标引体系构建
赵宏源
2020, 0(0): 1-7. doi: 10.19619/j.issn.1007-1938.2020.00.021
摘要:
在融合出版背景下,内容标引作为出版物内容传播的基础,作用更加突出,从知识关联、智能化推荐、搜索引擎优化到内容交付都有赖于完整的内容标引体系。文章根据融合出版内容运营的特征,提出构建包含知识元标引、社会标引、隐性知识标引在内的标引体系,及基于内容交互的标引动态更新,以满足用户不同场景的使用需求。
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