135 results on '"Xiang, Kai"'
Search Results
2. A Novel Organometallic Coordination Polymer as a Heterogeneous Catalyst for C−C Bond Formation
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Xiang‐Kai Yang, Ji‐Hong Hu, Wei‐Te Lee, Yu‐Hsiang Liu, Yung‐Sheng Yen, Tsun‐Ren Chen, and Jhy‐Der Chen
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Inorganic Chemistry - Published
- 2022
3. A structural equation model-based study on the status and influencing factors of acute exacerbation readmission of elderly patients with chronic obstructive pulmonary disease within 30 days
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Hong-Yan, Lu, Rui, Zhang, Yan, Chang, Xiao-Na, Zhang, Jie, Zhao, Xin-Dan, Li, and Xiang-Kai, Feng
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Pulmonary and Respiratory Medicine ,Pulmonary Disease, Chronic Obstructive ,Activities of Daily Living ,Disease Progression ,Humans ,Patient Readmission ,Patient Discharge ,Aged ,Retrospective Studies - Abstract
Objective To investigate the circumstances that lead to acute exacerbation readmission of elderly patients with chronic obstructive pulmonary disease (COPD) within 30 days and to explore the influencing factors of readmission using a structural equation model to provide evidence for medical staff so that effective intervention measures can be taken. Methods The convenience sampling method was used to select 1120 elderly patients with COPD from the respiratory departments of thirteen general hospitals in the Ningxia region, China, from April 2019 to August 2020, who then completed a survey questionnaire. The survey questionnaire contained a general data questionnaire and the modified Medical Research Council, activities of daily living, geriatric depression scale and COPD assessment test scales. Results The readmission rate of patients with COPD presenting with acute exacerbation within 30 days was determined to be 21.52%. Therefore, the modified model measures data accurately. The results showed that seasonal factors, family rehabilitation, age factors and overall health status were direct factors in the acute exacerbation readmission of patients with COPD within 30 days of hospital discharge. Smoking is not only a direct factor for acute exacerbation readmission within 30 days but also an indirect factor through disease status; disease status and chronic disease are not only direct factors for acute exacerbation readmission within 30 days but also indirect factors through the patient’s overall health status. Conclusions The rate of patients with COPD presenting with acute exacerbation within 30 days is high; while taking measures to prevent readmission based on influencing factors that directly impact admission rates, attention should also be paid to the interaction between these factors.
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- 2022
4. Vibration for enhancement of electrochemical analysis of biomolecules in a droplet on the rough surface of a disposable working electrode
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Ya-Hong Wang, Xiang-Yun Lin, Ye Cheng, Hua Wang, Wu Liu, Xiang-Kai Zhuge, Xiao-Lei Huo, and Ning Bao
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Environmental Chemistry ,Biochemistry ,Spectroscopy ,Analytical Chemistry - Published
- 2023
5. A Structural Equation Model-Based Study on The Status and Influencing Factors of Acute Exacerbation Readmission in Elderly Patients with Chronic Obstructive Pulmonary Disease within 30 Days
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Hong-Yan Lu, Rui Zhang, Yan Chang, Xiao-Na Zhang, Jie Zhao, Xin-Dan Li, and Xiang-Kai Feng
- Abstract
Objective To investigate the situation of acute exacerbation readmission in elderly patients with Chronic Obstructive Pulmonary Disease (COPD) within 30 days, and to explore the influencing factors of readmission by structural equation model, so as to provide evidence for medical staff to take effective intervention measures. Methods Convenience sampling method was used to select 1120 elderly COPD patients from respiratory department of 13 general hospitals in Ningxia region from April 2019 to August 2020 for questionnaire survey. The participants completed the questionnaire containing general data questionnaire, Modified Medical Research Council (mMRC), Activities of Daily Living (ADL), the Geriatric Depression Scale (GDS), and COPD Assessment Test (CAT) scale. Results The readmission rate of acute exacerbation within 30 days in elderly COPD patients was 21.52%; The modified model fits well. Fitting results showed that seasonal factors, family rehabilitation, age factors and overall status were the direct influencing factors of acute exacerbation readmission in elderly COPD patients within 30 days. Smoking status is not only a direct factor for acute exacerbation of readmission within 30 days, but also an indirect effect through disease status; Disease status and chronic disease are not only direct factors for acute exacerbation of readmission within 30 days, but also indirectly through overall status. Conclusions The rate of acute exacerbation readmission within 30 days in elderly patients with COPD is high, While taking measures to prevent readmission based on direct influencing factors, attention should be paid to the interaction between factors.
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- 2022
6. Zn(<scp>ii</scp>) and Cd(<scp>ii</scp>) coordination polymers with a new angular bis-pyridyl-bis-amide: synthesis, structures and sensing properties
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Xiang-Kai Yang, Ji-Hong Hu, Wei-Te Lee, and Jhy-Der Chen
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chemistry.chemical_classification ,Quenching (fluorescence) ,Ligand ,Metal ions in aqueous solution ,General Chemistry ,Polymer ,Condensed Matter Physics ,Ion ,chemistry.chemical_compound ,Crystallography ,chemistry ,Amide ,General Materials Science ,Benzamide ,Luminescence - Abstract
Zn(II) and Cd(II) coordination polymers constructed from a new angular bis-pyridyl-bis-amide ligand and naphthalene-1,4-dicarboxylic acid (1,4-H2NDC), {[Zn2(L)(1,4-NDC)2]·2H2O} [L = 4,4′-oxybis(N-(pyridin-3-ylmethyl)benzamide)], 1, and {[Cd2(L)(1,4-NDC)2]·EtOH}, 2, have been solvothermally synthesized and structurally characterized by using single-crystal X-ray diffraction. While complex 1 displays a 2D double layer with the rare (46·64)-5 L4 topology, complex 2 shows a 3D framework with a new (4·5·6)(45·55·69·7·8) topology. Both complexes 1 and 2 display luminescence properties and 2 exhibits a high sensitivity toward the detection of Fe3+ ions with a Ksv value of 1.9 × 104 M−1. The quenching effect can most probably be ascribed to the interactions between the metal ions and the amide carbonyl oxygen atoms.
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- 2021
7. Lewis acid mediated cyclization: synthesis of 2 spirocyclohexylindolines
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Jing-Feng Zhao, Hongbin Zhang, Wen Chen, Xiang Zhi, Xue-Ling Meng, Xiang-Kai Kong, and Zhi-Min Xiong
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Stereochemistry ,Chemistry ,Organic Chemistry ,Lewis acids and bases ,Physical and Theoretical Chemistry ,Biochemistry - Abstract
Herein, we report the synthesis of 2-spirocyclohexylindolines based on a Lewis acid mediated cyclization. This diastereoselective procedure provides the target structures in a straightforward way via dual activation.
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- 2021
8. Structural Transformations of Cobalt(II) Coordination Polymers Constructed from N,N′-Di-3-pyridyladipoamide and Tetracarboxylic Acids: Disentanglement upon Water Coordination
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Jhy-Der Chen, Yen-Fu Liu, Ji-Hong Hu, Wei-Te Lee, and Xiang-Kai Yang
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chemistry.chemical_classification ,chemistry ,Polymer chemistry ,chemistry.chemical_element ,General Materials Science ,General Chemistry ,Polymer ,Condensed Matter Physics ,Cobalt ,Hydrothermal circulation - Abstract
Hydrothermal reactions of N,N′-di-3-pyridyladipoamide (L) with 1,2,4,5-benzenetetracarboxylic acid (1,2,4,5-H2btec) in water without and with NaOH afforded [Co(L)(1,2,4,5-btec)0.5]n, 1, and [Co(L)(...
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- 2020
9. Characterizing robust optimal solution sets for nonconvex uncertain semi-infinite programming problems involving tangential subdifferentials
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Juan Liu, Xian-Jun Long, and Xiang-Kai Sun
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Control and Optimization ,Applied Mathematics ,Business, Management and Accounting (miscellaneous) ,Management Science and Operations Research ,Computer Science Applications - Published
- 2022
10. Investigation and analysis of 62 organic solvents in 110 liquid pesticide formulations
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TANG Xiang-kai, FENG De-jian, XU Yang, WU Wei, SHI Xie-fei, and LI Huai-ping
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Environmental sciences ,Agriculture (General) ,GE1-350 ,gas chromatography-mass spectrometry(gc-ms) ,organic solvents ,pesticide formulations ,pesticide adjuvants ,S1-972 - Abstract
The aim of this study was to investigate and analyze the content of 62 organic solvents in 110 liquid pesticide formulations. The study would provide a basis and reference for the promulgation of the relevant limits of organic solvents in pesticide formulations. The pesticide formulation was diluted with solvent, and the supernatant was filtered through a 0.22 μm membrane. After separation on a VF-1701 MS column, the analytes were detected by gas chromatography-mass spectrometry (GC-MS) in the selected ion monitoring (SIM) mode and quantified using the external standard method. A total of 110 pesticide formulation samples were analyzed. The results showed that 28 kinds of organic solvents, including xylene, N,N-dimethylformamide, methanol, methylbenzene, naphthalene, and ethylbenzene, were detected in 108 samples with content ranging from 0.07% to 77.23%. Among the 94 emulsifiable concentrate (EC) samples in which organic solvents had been detected, 76 violated the relevant state regulations on the limits of organic solvents in pesticide formulations. Liquid pesticide formulations generally contained high concentration of organic solvents and had great safety risks. We suggest that government departments should promulgate relevant standard on organic solvents in pesticide formulations as soon as possible.
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- 2020
11. One-dimensional chains based on linear tetranuclear copper(<scp>i</scp>) units: reversible structural transformation and luminescence change
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Tsun-Ren Chen, Chih-Tung Yang, Xiang-Kai Yang, Chih-Chieh Wang, Jhy-Der Chen, Wei-Te Lee, and Ji-Hong Hu
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Ligand ,Halide ,chemistry.chemical_element ,General Chemistry ,Condensed Matter Physics ,Copper ,Solvent ,Metal ,chemistry.chemical_compound ,Crystallography ,chemistry ,Sodium hydroxide ,visual_art ,visual_art.visual_art_medium ,Dimethylformamide ,General Materials Science ,Luminescence - Abstract
One-pot solvothermal reactions of 2-aminopyridine, triethylorthoformate and sodium hydroxide with CuX (X = Br, and I) in dimethylformamide (DMF) and methanol (MeOH) afforded extended metal chains based on the linear tetracopper units, {[Cu4Br2(Dpyf)2]·DMF}n, 1, and [Cu4I2(Dpyf)2]n, 2, which were structurally identified by X-ray crystallography. Complexes 1 and 2 present closed-shell Cu(I)–Cu(I) interactions that are supported by formamidinate ligands, resulting in a face-to-side configuration and a face-to-face configuration, respectively, for the tetranuclear units. Complexes 1 and 2 represent the first example of one-dimensional (1D) coordination polymers that are based on linear tetracopper units. Moreover, complexes 1 and 2 can be regarded as copper(I) halide aggregates with the unique Cu4Br22+ and Cu4I22+ cations extending into a 1D zigzag chain and a looped chain, respectively. Complexes 1 and 2 show broad emissions at 570 and 549 nm, respectively, which can most probably be ascribed to 3d(Cu) → π* metal to ligand charge transfer. Reversible crystal-to-crystal transformation and luminescence change were observed for complex 1 upon solvent exchange, which can be regarded as a potential luminescent sensor for selective detection of water and methanol.
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- 2020
12. Syntheses, structures and adsorption properties of two-dimensional Cd(II) coordination polymers
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Jhy-Der Chen, Pradhumna Mahat Chhetri, and Xiang-Kai Yang
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Thermogravimetric analysis ,010405 organic chemistry ,Ligand ,Type (model theory) ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Inorganic Chemistry ,chemistry.chemical_compound ,Crystallography ,Adsorption ,chemistry ,Materials Chemistry ,Physical and Theoretical Chemistry ,Selectivity ,Acetamide ,Topology (chemistry) ,Benzoic acid - Abstract
Solvothermal reactions of Cd(CH3COO)2 and 2,2′-(1,3-phenylene)-bis(N-pyridin-3-yl)acetamide (1,3-pbpa) with 1,3-phenylenediacetic acid (1,3-H2PDA), 4,4′-oxybis(benzoic acid) (4,4′-H2OBA) and 1,4-benzenedicarboxylic acid (1,4-H2BDC) afforded [Cd(1,3-pbpa)(1,3-PDA)]n, 1, [Cd(1,3-pbpa)(OBA)·2H2O]n, 2, and [Cd(1,3-pbpa)(1,4-BDC)(H2O)·EtOH·H2O]n, 3, respectively, which were structurally characterized as two-dimensional (2D) coordination polymers. Complexes 1 and 2 show the rare {84·122}{8}2-2,4L2 topology, whereas complex 3 adopts a new topology with a point symbol of {12}{4·125}{4}, which can be further simplified as the 44-sql topology and the 63-hcb topology, respectively. Desolvated product of 2 shows a moderate uptake of CO2 and a good selectivity over N2, which also exhibits a better H2 and CO2 sorption compared to the activated product of 1, indicating the effect of ligand type on the adsorption properties of 2D complexes with the 44-sql topology. Thermal gravimetric analysis (TGA) and the solid state luminescence properties of 1–3 have also been investigated.
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- 2019
13. Eight-Fold Interpenetrating Diamondoid Coordination Polymers for Sensing Volatile Organic Compounds and Metal Ions
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Jhy Der Chen, Yi Ting Lai, Chia Her Lin, Manivannan Govindaraj, Xiang Kai Yang, and Venkatesan Lakshmanan
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chemistry.chemical_classification ,Aqueous solution ,Polymers and Plastics ,Coordination polymer ,Metal ions in aqueous solution ,Organic chemistry ,General Chemistry ,Polymer ,crystal structure analysis ,Diamondoid ,Article ,chemistry.chemical_compound ,coordination polymer ,QD241-441 ,chemistry ,Polymer chemistry ,luminescence ,Molecule ,Luminescence ,entanglement ,Mesitylene - Abstract
Reactions of divalent metal salts with 4,4-oxybis(N-(pyridine-4-yl)-benzamide), L, and naphthalene-1,4-dicarboxylic acid (1,4-H2NDC) in various solvents gave [Zn(L)(1,4-NDC)·H2O]n, 1, [Cd(L)(1,4-NDC)(H2O)·MeOH]n, 2, and [Co(L)(1,4-NDC)(H2O)0.5·MeOH]n, 3, which have been structurally characterized. Complexes 1–3 show eight-fold interpenetrating frameworks with the dia topology, which exhibit porosities substantiated by CO2 adsorption, whereas 1 and 2 manifest stability in aqueous environments and show high selectivity toward sensing of mesitylene molecules and Fe3+ ions with low detection limits and good reusability up to five cycles.
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- 2021
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14. An efficient strategy for digging protein-protein interactions for rational drug design - A case study with HIF-1α/VHL
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Yue Zhong, Hai-Qing Zhang, Juan Ji, Wen-Yu Wu, Xiao Yang, Ji-Bo Kang, Nan Li, Liang Chang, Xiang-Kai Meng, Shao-Peng Yu, Xiao-Long Wang, Shan-Liang Sun, Nian-Guang Li, and Xin Xue
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Cell Survival ,Mutagenesis (molecular biology technique) ,Drug design ,Molecular Dynamics Simulation ,urologic and male genital diseases ,Protein–protein interaction ,HeLa ,Structure-Activity Relationship ,Ubiquitin ,Drug Discovery ,Humans ,Site-directed mutagenesis ,Pharmacology ,biology ,Dose-Response Relationship, Drug ,Molecular Structure ,Chemistry ,Organic Chemistry ,General Medicine ,Alanine scanning ,biology.organism_classification ,Hypoxia-Inducible Factor 1, alpha Subunit ,Ubiquitin ligase ,Cell biology ,Hydroxyproline ,Von Hippel-Lindau Tumor Suppressor Protein ,Drug Design ,biology.protein ,HeLa Cells ,Protein Binding - Abstract
The ubiquitination of the hypoxia-inducible factor-1α (HIF-1α) is mediated by interacting with the von Hippel-Lindau protein (VHL), and is associated with cancer, chronic anemia, and ischemia. VHL, an E3 ligase, has been reported to degrade HIF-1 for decades, however, there are few successful inhibitors currently. Poor understanding of the binding pocket and a lack of in-depth exploration of the interactions between two proteins are the main reasons. Hence, we developed an effective strategy to identify and design new inhibitors for protein-protein interaction targets. The hydroxyproline (Hyp564) of HIF-1α contributed the key interaction between HIF-1α and VHL. In this study, detailed information of the binding pocket were explored by alanine scanning, site-directed mutagenesis and molecular dynamics simulations. Interestingly, we found the interaction(s) between Y565 and H110 played a key role in the binding of VHL/HIF-1α. Based on the interactions, 8 derivates of VH032, 16a-h, were synthesized by introducing various groups bounded to H110. Further assay on protein and cellular level exhibited that 16a-h accessed higher binding affinity to VHL and markable or modest improvement in stabilization of HIF-1α or HIF-1α-OH in HeLa cells. Our work provides a new orientation for the modification or design of VHL/HIF-1α protein-protein interaction inhibitors.
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- 2021
15. Entanglement and Irreversible Structural Transformation in Co(II) Coordination Polymers Based on Isomeric Bis-pyridyl-bis-amide Ligands
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Wei-Chun Huang, Chih-Tung Yang, Pradhumna Mahat Chhetri, Xiang-Kai Yang, Chih-Hsun Hsu, and Jhy-Der Chen
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chemistry.chemical_classification ,010405 organic chemistry ,Chemistry ,Structural diversity ,General Chemistry ,Quantum entanglement ,Polymer ,010402 general chemistry ,Condensed Matter Physics ,01 natural sciences ,Structural transformation ,0104 chemical sciences ,Crystallography ,chemistry.chemical_compound ,Amide ,Atom ,General Materials Science ,Single crystal ,Topology (chemistry) - Abstract
Four coordination polymers constructed from the flexible isomeric bis-pyridyl-bis-amide (bpba) ligands, N,N′-di(3-pyridyl)suberoamide (L1) and N,N′-di(4-pyridyl)suberoamide (L2), and the auxiliary 1,4-naphthalenedicarboxylic acid (1,4-H2NDC), including [Co(L1)1.5(1,4-NDC)(H2O)]n, 1, [Co3(L1)1.5(1,4-NDC)3(EtOH)]n, 2, {[Co(L2)1.5(1,4-NDC)]·H2O}n, 3, and {[Co(L2)0.5(1,4-NDC)]·EtOH}n, 4, have been synthesized and structurally characterized by using single crystal X-ray crystallography. Complex 1 forms a two-dimensional layer with double edges and 2 exhibits a unique three-dimensional (3D) self-catenated framework with the (48.66.8)-6T60 topology, while 3 displays a 3D framework with the highest 5-fold interpenetration for the bnn topology and 4 shows a 3D 2-fold interpenetrated framework with the pcu topology. The donor atom positions of the L1 and L2 ligands and the identity of the solvents play important roles in determining the structural diversity. Moreover, irreversible structural transformation from 2 t...
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- 2019
16. Uniformly valid asymptotic solutions of rod eutectic growth in directional solidification for liquid-solid interface slopes of small order
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Xiang-Ming Li, Fei Xu, and Xiang-Kai Chen
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Inorganic Chemistry ,Work (thermodynamics) ,Materials science ,Phase (matter) ,Thermal ,Materials Chemistry ,Order (ring theory) ,Mechanics ,Condensed Matter Physics ,Asymptotic expansion ,Supercooling ,Eutectic system ,Directional solidification - Abstract
Recently, uniformly valid asymptotic solutions of rod eutectic growth for liquid-solid interface slopes at triple phase junction being the normal order have been presented in reference (Li and Xu, 2017). In this work, analytical calculations of rod eutectic growth during directional solidification for liquid-solid interface of small order are performed. The purpose is to study the liquid-solid interfacial shape and average undercooling of rod eutectic growth. We give the mathematical formulation of rod eutectic growth for the general case. The steady solutions of rod eutectic growth are obtained by using asymptotic expansion method and matching method. The relationship of the overall average interfacial undercooling with the rod eutectic spacing is presented. The overall average interfacial undercooling always exists a minimum value at the minimum-undercooling spacing, and the minimum-undercooling spacing is slightly smaller than one given by Jackson and Hunt. We also analyze the effect of pulling speeds and thermal gradients on the interfacial shapes for the case of the minimum-undercooling spacing.
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- 2019
17. Crystal-to-crystal transformation and linker exchange in Cd(<scp>ii</scp>) coordination polymers based on flexible bis-pyridyl-bis-amide and 1,4-naphthalenedicarboxylate
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Xiang-Kai Yang and Jhy-Der Chen
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Crystal transformation ,chemistry.chemical_classification ,Coordination polymer ,Ligand ,General Chemistry ,Polymer ,Condensed Matter Physics ,Crystal ,chemistry.chemical_compound ,Crystallography ,Oxygen atom ,chemistry ,Amide ,General Materials Science ,Linker - Abstract
Solvothermal reactions of Cd(II) salts and naphthalene-1,4-dicarboxylic acid (1,4-H2NDC) with bis(N-pyrid-3-ylmethyl)adipoamide, L1, and bis(N-pyrid-3-ylmethyl)suberoamide, L2, afforded three Cd(II) coordination polymers, {[Cd(L1)(1,4-NDC)(H2O)]·H2O}n, 1, {[Cd(L2)(1,4-NDC)]·2H2O}n, 2, and {[Cd2(L2)(1,4-NDC)2]·3H2O}n, 3, which have been structurally characterized using single-crystal X-ray crystallography. Complex 1 forms a 2D layer with 44-sql topology, whereas 2 and 3 are 3D frameworks with rare {32·62·72}{32·65·73}2-4,5T61 and unique {32·54}{34·46·58·66·74}-sqc776 topologies, respectively. Complex 2 undergoes reversible crystal-to-crystal transformation to 3, while irreversible structural transformations from 1 to 2 and 3 to 1 can be carried out by linker exchange. Reorientation of the amide oxygen atoms that results in the change of the ligand conformation is proposed for the initiation of the crystal-to-crystal transformation. Complex 3 represents a unique example of a coordination polymer that is able to undergo both crystal-to-crystal transformation and linker exchange.
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- 2019
18. Synthesis, crystal structures and thermal properties of six Co(II) and Ni(II) coordination polymers with mixed ligands: Formation of a quadruple-strained helical nanotube
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Chih-Tung Yang, Miao-Ning Chang, Jhy-Der Chen, Meng-Lun Wu, Jo-Feng Hsing, Chih-Hsun Hsu, and Xiang-Kai Yang
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chemistry.chemical_classification ,Nanotube ,Ligand ,Chemistry ,Hydrogen bond ,Organic Chemistry ,02 engineering and technology ,Crystal structure ,Polymer ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Analytical Chemistry ,Inorganic Chemistry ,Isophthalic acid ,Metal ,Crystallography ,chemistry.chemical_compound ,visual_art ,visual_art.visual_art_medium ,0210 nano-technology ,Spectroscopy ,Topology (chemistry) - Abstract
The syntheses, structures and thermal properties of six coordination polymers based on semi-rigid N,N′-bis(3-pyridinyl)terephthalamide (L1), flexible N,N′-di(3-pyridyl)adipoamide (L2) and N,N′-di(3-pyridyl)suberoamide (L3) and auxiliary dicarboxylate ligands, [M(L1)(AIPA)·2H2O]n, (M = Ni, 1; Co, 2; H2AIPA = 5-acetamido isophthalic acid), [Ni(L2)(AIPA)(H2O)2]n, 3, [Co(L2)0.5(AIPA)(H2O)]n, 4, [Co(L3)(2,4-PDC)(H2O)]n (2,4-H2PDC = 2,4-pyridinedicarboxylic acid), 5, and [Co(L3)(5-Br-IPA)(H2O)]n (5-Br H2IPA = 5-bromoisophthalic acid), 6, are reported, which have been structurally characterized by X-ray crystallography. Complexes 1 and 2 are isomorphous, forming 3D nets with the new (4⋅6⋅8)(4⋅64⋅85) topology, which can be further simplified as self-catenated networks with the (424⋅64)-8T2 topology, while 3 is a 1D looped chain and 4 and 6 show 2D layers with the (42⋅63⋅8)(42⋅6)-3,4L83 and (44⋅62)-sql topologies, respectively. Moreover, complex 5 shows quadruple-strained helices formed by cobalt ions and L3 ligands, which are supported by 2,4-PDC2- anions to construct the rare single-walled metal-organic nanotubes that are supported by extensive N H --O and O H --O hydrogen bonds. The roles of ligand flexibility and the identity of the metal ion in the formation of 1–6 as well as their thermal properties are discussed.
- Published
- 2018
19. Au(I) and Ag(I) formamidinate tetranuclear complexes and coordination polymers: Synthesis, structures and luminescent properties
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Shi-Jie Lin, Jhy-Der Chen, Wayne Hsu, Yu-Sian Li, Tsun-Ren Chen, Pradhumna Mahat Chhetri, and Xiang-Kai Yang
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chemistry.chemical_classification ,010405 organic chemistry ,Phosphor ,Polymer ,010402 general chemistry ,01 natural sciences ,Fluorescence ,Aurophilicity ,0104 chemical sciences ,Inorganic Chemistry ,Crystallography ,chemistry ,Intramolecular force ,Materials Chemistry ,Physical and Theoretical Chemistry ,Luminescence - Abstract
Reactions of AuClS(CH3)2 and Ag(I) salts (AgSCN, AgOAc and AgSbF6) with the lithiated formamidines afforded the tetranuclear complexes [Au4(4-pyf)4]·4CH3OH [4-Hpyf = N,N’-bis(pyridine-4-yl)formamidine], 1, [Au4(pmf)4] [Hpmf = N,N’-bis(pyrimidine-2-yl)formamidine], 2, and [Ag4(pmf)4], 3, and the coordination polymers [Ag2(OAc)(4-pyf)]n, 4, and {[Ag2(4-pyf)2]·THF}n, 5, which have been structurally characterized by X-ray crystallography. The intramolecular Au⋯Au separations in 1 and 2 are in the range 2.8832(2)–3.3338(10) A and the Ag⋯Ag separations in 3–5 are 2.7927(3)–2.9819(19) A, indicating the existence of aurophilicity and argentophilicity, respectively. Complex 3 is a unique tetranuclear complex of the type Ag4(form)4 in which “form” represents the formamidinate ligands. The short lifetimes of 1.06–49.15 ns for 1–5 indicate that the emissions belong to fluorescence. Moreover, complex 4 emits white luminescence in the solid-state and the CIE coordinate appears at (0.30, 0.38), which represents the first single-emitting component white phosphor in the class of formamidinate coordination polymers.
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- 2018
20. α-Benzoyloxylation of β-Dicarbonyl Compounds Involving Cyclic Trivalent Iodine Reagents
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Zhu Daoyong, Zhang Yating, Xu Xuetao, Xiang Kai, and Gao Zhupeng
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Organic Chemistry - Published
- 2022
21. Testing the nature of h1(1380) resonance in χcJ→ϕK*K¯, ϕh1 (1380)
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Wei-Hong Liang, Xiang-Kai Luo, Sheng-Juan Jiang, S. Sakai, and Eulogi Oset
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Physics ,Nuclear magnetic resonance ,Resonance - Published
- 2020
22. Impact of Isomeric Dicarboxylate Ligands on the Formation of One-Dimensional Coordination Polymers and Metallocycles: A Novel cis→trans Isomerization
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Xiang-Kai Yang, Ji-Hong Hu, Jhy-Der Chen, and Kuan-Ting Chen
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chemistry.chemical_classification ,Polymers and Plastics ,Coordination polymer ,Supramolecular chemistry ,General Chemistry ,Polymer ,structural transformation ,dinuclear metallocycle ,Article ,Cis trans isomerization ,lcsh:QD241-441 ,Crystallography ,chemistry.chemical_compound ,coordination polymer ,Zigzag ,chemistry ,lcsh:Organic chemistry ,X-ray structure ,Single crystal ,Isomerization ,Cis–trans isomerism - Abstract
A series of Co(II), Ni(II) and Cu(II) coordination polymers and dinuclear metallocycles containing 4-aminopyridine (4-ampy) and benzenedicarboxylate ligands, {[M(4-ampy)2(1,4-BDC)]·, H2O·, CH3CH2OH}n (M = Ni, 1a, Co, 1b, 1,4-H2BDC = benzene-1,4-dicarboxylic acid), {[Ni2(4-ampy)4(1,3-BDC)2]·, CH3CH2OH}n (1,3-H2BDC = benzene-1,3-dicarboxylic acid), 2, [M2(4-ampy)4(1,2-BDC)2] (M = Ni, 3a, Co, 3b, 1,2-H2BDC = benzene-1,2-dicarboxylic acid), [Co(4-ampy)2(1,3-BDC)]n, 4, {[Cu(4-ampy)2(1,4-BDC)] CH3CH2OH}n, 5a, and {[Cu(4-ampy)2(1,4-BDC)]·, H2O}n, 5b·, H2O, are reported, which were hydrothermally prepared and structurally characterized by using single crystal X-ray diffraction. Complexes 1a and 1b are isomorphous 1D zigzag chains, while 2 displays a concave&ndash, convex chain and 3a and 3b are dinuclear metallocycles that differ in the boding modes of the 1,2-BDC2&minus, ligands, forming a 3D and a 2D supramolecular structures with the pcu and sql topologies, respectively. Complex 4 exhibit a 1D helical chain and complexes 5a and 5b·, H2O are 1D linear and zigzag chains, in which the Cu2-1,4-BDC2&minus, units adopt the cis and trans configurations, respectively. A novel irreversible structural transformation due to cis&rarr, trans isomerization of the Cu2-1,4-BDC2&minus, units was observed in 5b&sdot, H2O and 5a upon water adsorption of the desolvated product of 5b·, H2O.
- Published
- 2020
23. Coronavirus Disease 2019 (COVID-19)
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Xiang, Kai Yan, Zu, Zi Yue, Lu, Guang Ming, and Zhang, Long Jiang
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Pulmonary and Respiratory Medicine ,Radiology Nuclear Medicine and imaging - Published
- 2020
- Full Text
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24. Several Turán-Type Inequalities for the Generalized Mittag-Leffler Function
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Xiu-Li Lin, Li Yin, and Xiang Kai Dou
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Pure mathematics ,Inequality ,Article Subject ,media_common.quotation_subject ,010102 general mathematics ,010103 numerical & computational mathematics ,Function (mathematics) ,Type (model theory) ,01 natural sciences ,symbols.namesake ,Mittag-Leffler function ,symbols ,QA1-939 ,0101 mathematics ,Analysis ,Mathematics ,media_common - Abstract
In this paper, several Turán-type inequalities for the more generalized Mittag-Leffler function are proved. In addition, we also gave affirmative answers to two open problems posed by Mehrez and Sitnik.
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- 2020
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25. Co(II) coordination polymers exhibiting reversible structural transformation and color change: A comparative analysis with Ni(II) analogue
- Author
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Kedar Bahadur Thapa, Tsun-Ren Chen, Jhy-Der Chen, Ming-Hao Wu, and Xiang-Kai Yang
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Diffraction ,chemistry.chemical_classification ,02 engineering and technology ,Polymer ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Net (mathematics) ,01 natural sciences ,Structural transformation ,0104 chemical sciences ,Inorganic Chemistry ,Crystallography ,chemistry ,Materials Chemistry ,Physical and Theoretical Chemistry ,0210 nano-technology ,Single crystal ,Topology (chemistry) - Abstract
By employing the flexible ligands, bis(3,5-dicarboxyphenyl)adipoamide, H4L1; bis(N-pyrid-3-ylmethyl)adipoamide, L2; and bis(N-pyrid-3-ylmethyl) suberoamide, L3, four coordination polymers of the types {[M(L1)0.5(L2)(H2O)2]·H2O}n (M = Co, 1; Ni, 2) and {[M2(L1)(L3)2(H2O)4]·3H2O}n (M = Co, 3; Ni, 4) have been hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction. Complexes 1–4 are topologically identical coordination polymers having the 2-fold interpenetrating 3D net with the mog topology. Additionally, the Co(II) complexes exhibit the reversible structural transformation with color change on dehydration/rehydration but Ni(II) complexes are unable to show such a behavior. All four complexes display good photo-degradation performance and the Co(II) complexes show slightly higher efficiencies than the Ni(II) ones.
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- 2018
26. Two Turán Type Inequalities Related to the Q-exponential Functions
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Li Yin, Chun Fang Liu, and Xiang Kai Dou
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Combinatorics ,q-exponential ,Monotonic function ,General Medicine ,Type (model theory) ,Mathematics - Published
- 2018
27. Mercury halide coordination polymers exhibiting reversible structural transformation
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Jhy-Der Chen, Pradhumna Mahat Chhetri, and Xiang-Kai Yang
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chemistry.chemical_classification ,010405 organic chemistry ,Chemistry ,Halide ,General Chemistry ,Polymer ,010402 general chemistry ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Solvent ,chemistry.chemical_compound ,Crystallography ,Amide ,General Materials Science ,Isostructural ,Luminescence ,Acetonitrile ,Acetamide - Abstract
Solvothermal reactions of HgX2 salts with the new bis-pyridyl-bis-amide ligand 2,2′-(1,3-phenylene)-bis(N-(pyridin-3-yl)acetamide) (1,3-pbpa) in acetonitrile afforded the complexes [Hg(1,3-pbpa)X2]n (X = Cl, 1; Br, 2; I, 3), while the complexes [Hg(1,3-pbpa)X2·MeCN]n (X = Br, 4; I, 5) were obtained by layering solutions of HgX2 and 1,3-pbpa at room temperature. Complexes 1 and 2 are isostructural one-dimensional (1D) helical chains different from the 1D helical chain 3 in spans, which are 18.0, 18.3 and 29.1 A, respectively. Upon solvent adoption and removal, complexes 2 and 3 undergo reversible structural transformation into the 1D mesohelical chains 4 and 5 with spans of 29.1 and 29.9 A, respectively. Pyridyl ring rotation and amide group reorientation are proposed for the structural transformation accompanied by a simultaneous change in luminescence. The structural transformation in 2 and 4 represents a unique example of elastic 1D helical chains that show stretching during the process. The roles of halide anions in the structural changes and the luminescence properties of 1–5 are also discussed.
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- 2018
28. Isostructural Hg(II) halide coordination polymers: A comparison of powder XRD, IR, emission and Hirshfeld Surface Analysis
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Pradhumna Mahat Chhetri, Xiang-Kai Yang, and Jhy-Der Chen
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chemistry.chemical_classification ,Bromine ,010405 organic chemistry ,Organic Chemistry ,Halide ,chemistry.chemical_element ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Analytical Chemistry ,Inorganic Chemistry ,Solvent ,Crystallography ,chemistry ,Molecule ,Non-covalent interactions ,Isostructural ,Luminescence ,Spectroscopy ,Powder diffraction - Abstract
Three isomorphous mercury(II) halide coordination polymers [Hg(dpndc)X2]n (X = Cl, 1; Br, 2; I, 3) have been synthesized by the reactions of HgX2 salts with the semi-rigid N,N’-di(pyridin-3-yl)naphthalene-1,4-dicarboxamide (dpndc), which form one-dimensional (1D) helical chains. Stuctural comparisons with the other similar CPs indicate that their structural diversity is governed by the co-crystallized solvent molecules and the identity of the spacer ligands, whereas the role of the halide anions is not significant. Hirshfeld Surface Analysis revels that chlorine atom contributes more non-covalent interactions compared to the bromine and iodine atoms. Complexes 1 - 3 provide a unique opportunity to demonstrate that the powder X-ray diffraction (PXRD) pattern is better than IR and emission spectra to differentiate isomorphous mercury(II) halide CPs.
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- 2021
29. Substituent effects of polycarboxylate ligands on the construction of Cd(II) coordination polymers incorporating bis-pyridyl-bis-amide ligands
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Hsiu-Yi He, Pradhumna Mahat Chhetri, Xiang-Kai Yang, Chih-Hsun Hsu, Miao-Ning Chang, and Jhy-Der Chen
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chemistry.chemical_classification ,010405 organic chemistry ,Chemistry ,Coordination polymer ,Ligand ,Stereochemistry ,Substituent ,Polymer ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Inorganic Chemistry ,Crystallography ,chemistry.chemical_compound ,Amide ,Materials Chemistry ,Physical and Theoretical Chemistry ,Luminescence ,Single crystal ,Topology (chemistry) - Abstract
The synthesis, structures and properties of five new coordination polymers containing isomeric N,N′-di(pyridyl)suberoamide and polycarboxylate ligands, {[Cd(1,3-BDC)(L1)]·H2O}n [L1 = N,N′-di(3-pyridyl)suberoamide; 1,3-H2BDC = benzene-1,3-dicarboxylic Acid] 1; [Cd(5-OH-IPA)(L1)]n (5-OH-IPA = 5-hydroxyisophthalic Acid), 2; {[Cd3(1,3,5-BTC)2(L1)3(H2O)3]·8H2O}n (1,3,5-H3BTC = 1,3,5-benzenetricarboxylic Acid), 3; [Cd(5-Br-IPA)(L2)]n [L2 = N,N′-di(4-pyridyl)suberoamide; 5-Br-H2IPA = 5-bromoisophthalic Acid], 4; [Cd(5-tert-IPA)(L2)0.5]n (5-tert-H2IPA = 5-tert-butylisophthalic acid), 5, are reported, which have been characterized by single crystal X-ray diffraction. Complexes 1 and 2 show 2D double layers with the 3,5L2 topology and 3 reveals a 3D structure with the rare 3,4,4T90 topology. Complex 4 is a twofold interpenetrated 2D layer with a 2,6L1 topology and 5 shows a 3D coordination network with a rare 4,6T136 topology. In 5, the L2 ligand adopts a unique tetradentate bonding mode through two pyridyl nitrogen and two amide oxygen atoms. The structure-directing role roles of the substituent groups on the polycarboxylate ligands in determining the structural diversity are discussed. Their thermal and luminescent properties are also investigated.
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- 2017
30. Role of halogen atoms in the formation of one-dimensional Cu(I) coordination polymers based on 2-amino-5-halopyrimidine
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Yen-Hsun Chiang, Pradhumna Mahat Chhetri, Xiang-Kai Yang, Hui-Ling Hu, Jhy-Der Chen, and Yu-Chia Chang
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Aqueous solution ,Stereochemistry ,Coordination polymer ,Organic Chemistry ,Halide ,02 engineering and technology ,Crystal structure ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Analytical Chemistry ,Ion ,Inorganic Chemistry ,Crystallography ,chemistry.chemical_compound ,chemistry ,Zigzag ,Atom ,Halogen ,0210 nano-technology ,Spectroscopy - Abstract
The reactions of CuCl and CuBr with 2-amino-5-chloropyrimidine ( L-Cl ), 2-amino-5-bromopyrimidine ( L-Br ) and 2-amino-5-iodopyrimidine ( L-I ) in aqueous solutions of HCl and HBr afforded [CuCl 2 (H L-I ) · H 2 O] n , 1 , [CuBr 2 (H L-I ) · H 2 O] n , 2 , [CuCl 2 (H L-Br ) · H 2 O] n , 3 , [CuBr 2 (H L-Br ) · H 2 O] n , 4 , and [CuCl 2 (H L-Cl ) · H 2 O) n , 5 . Complexes 1 – 5 show 1D zigzag chains due to the zigzag arrangements of the bridging halide atoms. While the iodo atoms of the pyrimidyl rings in 1 and 2 are trans to the bridging halide anions and the Cu(I) ions are in a linear array, the chloro and bromo atoms of the pyrimidyl rings in 3 – 5 are cis to the bridging halide anions and the Cu(I) ions are in a zigzag fashion. The structural difference can most probably be ascribed to the identity of the halogen atoms. While the chloro and bromo atoms play the same role in the crystal structures, the iodo atom is distinct. X-ray crystallographic study and Hirshfeld surface analysis are invoked to investigate the structural differences.
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- 2017
31. Solvent-Mediated Reversible Structural Transformation of Mercury Iodide Coordination Polymers: Role of Halide Anions
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Jhy-Der Chen, Pradhumna Mahat Chhetri, and Xiang-Kai Yang
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chemistry.chemical_classification ,010405 organic chemistry ,Chemistry ,Inorganic chemistry ,Iodide ,Halide ,General Chemistry ,010402 general chemistry ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Solvent ,chemistry.chemical_compound ,Crystallography ,Adsorption ,General Materials Science ,Methanol ,Isostructural ,Acetonitrile ,Acetamide - Abstract
Solvothermal reactions of HgX2 with 2,2′-(1,2-phenylene)-bis(N-pyridin-3-yl)acetamide, L, in ethanol afforded [Hg(L)X2]n (X = Cl, 1; Br, 2; I, 3), which are isostructural one-dimensional (1D) zigzag chains, while layering reactions of a ethanoic solution of L with a methanoic solution and an acetonitrile solution of HgI2, respectively, gave 1D helical chains [Hg(L)I2·MeOH]n, 4, and [Hg(L)I2·MeCN]n, 5. In marked contrast to 1 and 2, the iodide-containing 3 is able to exhibit reversible structural transformation with 4 and 5 by adsorption and desorption of methanol and acetonitrile, suggesting the importance of N–H---X and Hg---X interactions in the evaluation of structural transformation. Moreover, complexes 4 and 5 exhibit reversible crystal to crystal transformation triggered by solvent exchange. Complexes 3–5 represent a unique example that the solvents show a significant effect on folding and unfolding of the HgI2 single-stranded helical coordination polymers.
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- 2017
32. Approximate Optimality Conditions for Composite Convex Optimization Problems
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Zai-Yun Peng, Xian-Jun Long, and Xiang-Kai Sun
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Convex analysis ,Mathematical optimization ,021103 operations research ,Optimization problem ,010102 general mathematics ,MathematicsofComputing_NUMERICALANALYSIS ,0211 other engineering and technologies ,Linear matrix inequality ,Proper convex function ,02 engineering and technology ,Subderivative ,Management Science and Operations Research ,01 natural sciences ,Convex optimization ,Convex combination ,0101 mathematics ,Conic optimization ,Mathematics - Abstract
The purpose of this paper is to study the approximate optimality condition for composite convex optimization problems with a cone-convex system in locally convex spaces, where all functions involved are not necessarily lower semi-continuous. By using the properties of the epigraph of conjugate functions, we introduce a new regularity condition and give its equivalent characterizations. Under this new regularity condition, we derive necessary and sufficient optimality conditions of \(\varepsilon \)-optimal solutions for the composite convex optimization problem. As applications of our results, we derive approximate optimality conditions to cone-convex optimization problems. Our results extend or cover many known results in the literature.
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- 2016
33. One-Dimensional Mercury Halide Coordination Polymers Based on A Semi-Rigid
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Pradhumna, Mahat Chhetri, Xiang-Kai, Yang, Chih-Tung, Yang, and Jhy-Der, Chen
- Abstract
Four one-dimensional (1D) mercury(II) halide coordination polymers have been synthesized by using a semi-rigid
- Published
- 2019
34. Existence of solutions and Hadamard well-posedness for generalized strong vector quasi-equilibrium problems
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Jing Zeng, Xiang-Kai Sun, Zai-Yun Peng, and Xian-Jun Long
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021103 operations research ,Algebra and Number Theory ,Hadamard transform ,0211 other engineering and technologies ,Applied mathematics ,010103 numerical & computational mathematics ,02 engineering and technology ,0101 mathematics ,01 natural sciences ,Analysis ,Well posedness ,Quasistatic process ,Mathematics - Published
- 2016
35. The Pre-Travel Error Study of Electrical Trigger Probe in On-Machine Measurement
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Xiang Kai Yao, Yong Lin Cai, Xiang Mo, Wei Qing Sun, and Ning Ning Cui
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Engineering ,Accuracy and precision ,business.product_category ,business.industry ,Mechanical Engineering ,Acoustics ,010401 analytical chemistry ,020206 networking & telecommunications ,02 engineering and technology ,01 natural sciences ,0104 chemical sciences ,Machine tool ,Optics ,Machining ,Mechanics of Materials ,0202 electrical engineering, electronic engineering, information engineering ,Ball (bearing) ,General Materials Science ,business ,Anisotropy ,Backlash - Abstract
On-machine measurement is a high-efficient measure method in NC machining, and there are pre-travel errors during measurement. What is more, these errors tend to present anisotropy, and affect the measurement accuracy. This paper aimed at measuring the anisotropy of probe’s pre-travel error. First, the standard ball is measured by changing the probe angle with the same machine tool moving direction, and the pre-travel errors with different probe angles under the same machine tool errors are obtained. Then, the machine tool backlash errors are measured and compensated, and the pre-travel errors with different probe angle are obtained. Finally, the mathematical model of pre-travel error is established. The method proposed in this paper can be used to determine probe’s pre-travel error with anisotropy.
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- 2016
36. Necessary optimality conditions for DC infinite programs with inequality constraints
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Xiang-Kai Sun, Jing Zeng, and Xiao-Le Guo
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Algebra and Number Theory ,Inequality ,media_common.quotation_subject ,010102 general mathematics ,0103 physical sciences ,0101 mathematics ,01 natural sciences ,Mathematical economics ,Analysis ,010305 fluids & plasmas ,media_common ,Mathematics - Published
- 2016
37. Structure-directing roles of phenylenediacetate ligands in the formation of N,N′-di(3-pyridyl)adipoamide-based coordination networks
- Author
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Pradhumna Mahat Chhetri, Jhy-Der Chen, Chin-Hsueh Chen, Xiang-Kai Yang, Yen-Fu Liu, and Han-Yun Chang
- Subjects
chemistry.chemical_classification ,010405 organic chemistry ,Metal ions in aqueous solution ,Iodide ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Inorganic Chemistry ,Electronegativity ,Crystallography ,chemistry.chemical_compound ,chemistry ,Bromide ,X-ray crystallography ,Bathochromic shift ,Materials Chemistry ,Molecule ,Physical and Theoretical Chemistry ,Single crystal - Abstract
A series of coordination networks constructed from divalent metal ions, N,N′-di(3-pyridyl)adipoamide (L) and phenylenediacetate ligands, including [Co(L)0.5(1,2-pda)(H2O)]n (1,2-H2pda = 1,2-phenylenediacetic acid), 1, [Co(L)(1,4-pda)]n (1,4-H2pda = 1,4-phenylenediacetic acid), 2, [Ni2(L)2(1,2-pda)2(H2O)2·4.5H2O]n, 3, [Ni(L)(1,4-pda)(H2O)0.5·2.5H2O]n, 4, [Zn(L)0.5(1,2-pda)]n, 5, [CdBr(L)(1,2-pda)0.5]n, 6, and [CdI(L)(1,2-pda)0.5]n, 7, have been synthesized by hydrothermal reactions and structurally characterized by single crystal X-ray diffraction. Complexes 1, 2 and 5 adopt the (42,63,8)(42,6)-3,4L83, (42,67,8)(42,6)-3,5L2 and (42,63,8)(42,6)-3,4L83 topologies, respectively, while 3 and 4 show the (48,67)-6T2 and (48,67)-sqc26 topologies, respectively, and both 6 and 7 display the (412,63)-pcu topology. The L ligands in 3 adopt three different conformations, while the pda2− ligands in 5 adopts the rare cis-conformation and those in the other complexes exhibit the trans-conformation. Moreover, the pda2− ligands in complexes 1, 2 and 5 display the μ3 bonding mode to afford the 2D layer structures, in contrast to those in the other complexes that show the μ4 and/or μ2 bonding modes to form the 3D frameworks. The conformations of the L ligands are subject to the changes of metal ions and pda2− ligands, resulting in various types of structure for 1–7. Temperature-dependent PXRD patterns of complexes 1, 3 and 4 indicate that their structural transformations upon removal of the water molecules are irreversible. The emission spectra of 6 and 7 reveal that the lower electronegativity of the iodide relative to the bromide has a significant effect on the bathochromic shift.
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- 2016
38. Dinitrogen-supported coordination polymers
- Author
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Xiang-Kai Yang, Kedar Bahadur Thapa, Jhy-Der Chen, Wayne Hsu, Kuan-Ting Chen, and Han-Yun Chang
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chemistry.chemical_classification ,Binodal ,010405 organic chemistry ,Stereochemistry ,General Chemistry ,Polymer ,010402 general chemistry ,Condensed Matter Physics ,Triethyl orthoformate ,01 natural sciences ,Medicinal chemistry ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Pyridine ,General Materials Science ,Methanol ,Topology (chemistry) - Abstract
The one-pot solvothermal reactions of 3- and 4-(aminomethyl)pyridine with triethyl orthoformate and Cu(O2CCH3)2 in methanol saturated with dinitrogen afforded the first examples of coordination polymers that are supported by dinitrogen, namely [Cu2.5(3-mpyf)(N2)1.5]n [3-Hmpyf = N,N′-bis(pyridine-3-ylmethyl)formamidine], 1, and {[Cu3(4-Hmpyf)(N2)3]·(CH3OH)}n [4-Hmpyf = N,N′-bis(pyridine-4-ylmethyl)formamidine], 2. The dinitrogen anions of 1 adopt the end-on-dinuclear (μ-η1:η1) bonding mode, resulting in a 4,4-connected binodal net with the new (53·73)2(54·82) topology, and those of 2 display both end-on-dinuclear and end-on-trinuclear (μ-η1:η1:η1) bonding modes, forming a 3,8-connected binodal net with the rare (53)4(58·64·78·84·94)2-3,8T16 topology.
- Published
- 2016
39. Community change of microorganisms in the Muztagata and Dunde glacier and climatic and environmental implications
- Author
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Shu-Rong Xiang, Lide Tian, Xiang-Kai Li, Yong Chen, Jing Si, and Guangjian Wu
- Subjects
geography ,geography.geographical_feature_category ,biology ,Microorganism ,Biogeography ,Glacier ,Snow ,biology.organism_classification ,Oceanography ,Ice core ,Rhodoferax ,Precipitation ,Glacial period ,human activities ,Geology - Abstract
Microorganisms are continuously blown onto the glacier snow, and thus the glacial depth profiles provide excellent geographic archives of the microbial communities. However, it is uncertain about how the microbial communities respond to the climatic and environmental changes over the glacier ice. In the present study, the live microbial density, stable isotopic ratios, 18O/16O in the precipitation, and mineral particle concentrations along the glacial depth profiles were collected from ice cores from the Muztagata glacier and the Dunde ice cap. Six bacterial 16S rRNA gene clone libraries were established from the Dunde ice core. The Muztagata ice core presented seasonal response patterns for both live and total cell density with high cell density occurring in the warming spring and summer. Both ice core data showed a frequent association of dust and microorganisms in the ice. Genera Polaromas sp., Pedobacter sp, Flavobacterium sp., Cryobacteriium sp., and Propionibacterium/Blastococcus sp. frequently appeared at the six tested ice layers, and constituted the dominant species endemic to the Dunde ice cap, whereas some genera such as Rhodoferax sp., Variovorax sp., Sphingobacterium sp., Cyanobacterium sp., Knoellia sp., and Luteolibacter sp. rarely presented in the ice. In conclusion, data present a discrete increase of microbial cell density in the warming seasons and biogeography of the microbial communities associated with the predominance of a few endemic groups in the local glacial regions. This reinforces our hypothesis of dust-borne and post-deposition being the main agents interactively controlling microbial load in the glacier ice.
- Published
- 2018
40. Some monotonicity properties and inequalities for the generalized digamma and polygamma functions
- Author
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Xiang Kai Dou, Li Yin, Zhi-Min Song, and Li-Guo Huang
- Subjects
Monotonicity ,Pure mathematics ,lcsh:Mathematics ,Research ,Concavity ,Applied Mathematics ,010102 general mathematics ,Mathematics::Classical Analysis and ODEs ,33B15 ,Monotonic function ,lcsh:QA1-939 ,01 natural sciences ,Generalized digamma and polygamma functions ,26A48 ,010101 applied mathematics ,Digamma function ,26A51 ,Discrete Mathematics and Combinatorics ,Inequalities ,0101 mathematics ,Analysis ,Mathematics - Abstract
Several monotonicity and concavity results related to the generalized digamma and polygamma functions are presented. This extends and generalizes the main results of Qi and Guo and others.
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- 2018
41. Design of Impedance Matching for Sound Signal Channel of PIND Testing Equipment
- Author
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Xin Qian, Qiang Wang, Xiang-kai Bai, Huimin Liang, and Guotao Wang
- Subjects
0209 industrial biotechnology ,Audio signal ,Computer science ,Smith chart ,Attenuation ,Impedance matching ,Testing equipment ,02 engineering and technology ,computer.software_genre ,Simulation software ,020901 industrial engineering & automation ,0202 electrical engineering, electronic engineering, information engineering ,Redundancy (engineering) ,Electronic engineering ,020201 artificial intelligence & image processing ,computer ,Electrical impedance - Abstract
Particle Impact Noise Detection (PIND) has been widely used in the detection of component redundancy due to its high efficiency and low cost. The traditional PIND device does not match the impedance of the sensor and the sound channel, so that the redundant signal will be attenuation and distortion in the transmission process, thus affecting its detection accuracy and sensitivity. Aiming at this problem, this paper presents a new scheme of impedance matching design, which uses the Smith chart method to match, and uses ADS simulation software to design impedance matching network. Finally, the matching experiment is used to verify the matching effect of impedance matching network.
- Published
- 2018
42. Mg(II) Coordination Polymers Based on Flexible Isomeric Tetracarboxylate Ligands: Syntheses, Structures, Structural Transformation and Luminescent Properties
- Author
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Jhy-Der Chen, Kedar Bahadur Thapa, and Xiang-Kai Yang
- Subjects
Polymers and Plastics ,Coordination polymer ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Hydrothermal circulation ,Article ,Ion ,lcsh:QD241-441 ,chemistry.chemical_compound ,lcsh:Organic chemistry ,Topology (chemistry) ,chemistry.chemical_classification ,Chemistry ,Ligand ,General Chemistry ,Polymer ,structural transformation ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Solvent ,Crystallography ,coordination polymer ,tetracarboxylate ,X-ray structure ,0210 nano-technology ,Luminescence - Abstract
By using a new flexible tetracarboxylic acid, bis(3,5-dicarboxyphenyl) adipoamide, H4L1, and its isomer, bis(2,5-dicarboxyphenyl)adipoamide, H4L2, three Mg(II) coordination polymers, {[Mg2(L1)(H2O)2]·2EtOH·3H2O}n, 1, [Mg2(L1)(H2O)8]n, 2, and {[Mg2(L2)(H2O)6]·H2O}n, 3, have been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Complexes 1 and 2 are the solvent ratio-dependent hydrothermally stable products. The tetracarboxylate ligand of complex 1 connects eight Mg(II) ions through nine oxygen atoms, resulting in a three-dimensional (3D) 5-connected uninodal net with a rare non-interpenetrating (44.66)-pcu-5-Pmna topology, whereas those of 2 and 3 link four Mg(II) ions through four oxygen atoms and six Mg(II) ions through six oxygen atoms, forming a 1D linear chain and a 3,6-connected 2-nodal 3D net having {4.62}2{42.610.83}-rtl topology, respectively. Complex 1 shows a series of structural transformations on heating to 200 °C and almost reversible structural transformation when the activated products were immersed in a mixture of ethanol and water or on hydrothermal. Likewise, complex 2 exhibits a reversible structural transformation on heating/hydrothermal, while 3 exhibits irreversible structural transformations. All three complexes exhibit blue light emissions, with that of complex 3 being much more intense.
- Published
- 2018
43. In-orbit operation of an atomic clock based on laser-cooled
- Author
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Liang, Liu, De-Sheng, Lü, Wei-Biao, Chen, Tang, Li, Qiu-Zhi, Qu, Bin, Wang, Lin, Li, Wei, Ren, Zuo-Ren, Dong, Jian-Bo, Zhao, Wen-Bing, Xia, Xin, Zhao, Jing-Wei, Ji, Mei-Feng, Ye, Yan-Guang, Sun, Yuan-Yuan, Yao, Dan, Song, Zhao-Gang, Liang, Shan-Jiang, Hu, Dun-He, Yu, Xia, Hou, Wei, Shi, Hua-Guo, Zang, Jing-Feng, Xiang, Xiang-Kai, Peng, and Yu-Zhu, Wang
- Subjects
Condensed Matter::Quantum Gases ,Astrophysics::Earth and Planetary Astrophysics ,Physics::Atomic Physics ,Article - Abstract
Atomic clocks based on laser-cooled atoms are widely used as primary frequency standards. Deploying such cold atom clocks (CACs) in space is foreseen to have many applications. Here we present tests of a CAC operating in space. In orbital microgravity, the atoms are cooled, trapped, launched, and finally detected after being interrogated by a microwave field using the Ramsey method. Perturbing influences from the orbital environment on the atoms such as varying magnetic fields and the passage of the spacecraft through Earth’s radiation belt are also controlled and mitigated. With appropriate parameters settings, closed-loop locking of the CAC is realized in orbit and an estimated short-term frequency stability close to 3.0 × 10−13τ−1/2 has been attained. The demonstration of the long-term operation of cold atom clock in orbit opens possibility on the applications of space-based cold atom sensors., Cold atom clocks are among the most precise measuring devices and play key roles in everyday life and scientific explorations. Here the authors demonstrate the first in-orbit atomic clock using cold Rb atoms operating in microgravity and opening possibilities of space surveys and tests of fundamental physics.
- Published
- 2018
44. Elastohydrodynamic lubrication characteristics of an O-ring hydraulic rod seal during transient operation
- Author
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Xu-dong Peng, Xiang-kai Meng, and Bing-ging Wang
- Subjects
Materials science ,law ,Lubrication ,Transient (oscillation) ,O-ring ,Composite material ,Seal (mechanical) ,law.invention - Published
- 2018
45. [Effect of overexpression of transcription factor Runx2 and Osterix on osteogenic differentiation of endothelial cells]
- Author
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Guang-Zheng, Yang, Wen-Jie, Zhang, Xun, Ding, Xiang-Kai, Zhang, Xin-Quan, Jiang, and Zhi-Yuan, Zhang
- Subjects
Osteogenesis ,Sp7 Transcription Factor ,Genetic Vectors ,Lentivirus ,Endothelial Cells ,Humans ,Cell Differentiation ,Core Binding Factor Alpha 1 Subunit ,Alkaline Phosphatase ,Transcription Factors - Abstract
To explore the effect of overexpression of Runx2 and Osterix (OSX) genes on osteogenic differentiation of human umbilical vein endothelial cells (HUVECs).Overexpressed Runx2 and OSX lentiviral vectors were transfected into HUVECs respectively. The osteogenic potential of transfected cells was identified by alkaline phosphatase (ALP) staining and ALP activity. Furthermore, real time-PCR, Western blot and immunofluorescence staining were performed to detect the expression of osteogenic genes and proteins in HUVECs. GraphPad Prism 6.01 software was used for statistical analysis.Overexpression of Runx2 gene was beneficial for osteogenic differentiation of HUVECs, while overexpression of osterix gene did not show osteogenic differential potential. Moreover, overexpression of Runx2 gene in HUVECs up-regulated the gene expression level of Runx2, OSX, ALP, bone sialoprotein (BSP), osteopontin (OPN), and osteocalcin (OCN), and up-regulated protein level of OPN and OCN.Overexpression of Runx2 could promote osteogenic differentiation of HUVECs.
- Published
- 2017
46. Metal and Ligand Effects on the Construction of Divalent Coordination Polymers Based on bis-Pyridyl-bis-amide and Polycarboxylate Ligands
- Author
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Pradhumna Mahat Chhetri, Xiang-Kai Yang, Miao-Ning Chang, and Jhy-Der Chen
- Subjects
Polymers and Plastics ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Article ,Divalent ,Isophthalic acid ,Metal ,Ligand isomerism ,lcsh:QD241-441 ,chemistry.chemical_compound ,lcsh:Organic chemistry ,Amide ,chemistry.chemical_classification ,Ligand ,Center (category theory) ,General Chemistry ,021001 nanoscience & nanotechnology ,polycarboxylate ,0104 chemical sciences ,Crystallography ,coordination polymer ,bis-pyridyl-bis-amide ,chemistry ,visual_art ,visual_art.visual_art_medium ,photodegradation ,0210 nano-technology ,Luminescence - Abstract
Ten coordination polymers constructed from divalent metal salts, polycarboxylic acids, and bis-pyridyl-bis-amide ligands with different donor atom positions and flexibility are reported. They were structurally characterized by single-crystal X-ray diffraction. The ten coordination polymers are as follows: (1) {[Ni(L1)(3,5-PDA)(H2O)3]·2H2O}n (L1 = N,N′-di(3-pyridyl)suberoamide, 3,5-H2PDA = 3,5-pyridinedicarboxylic acid); (2) {[Ni2(L1)2(1,3,5-HBTC)2(H2O)4]·H2O}n (1,3,5-H3BTC = 1,3,5-benzenetricarboxylic acid); (3) {[Ni(L2)(5-tert-IPA)(H2O)2]·2H2O}n (L2 = N,N′-di(3-pyridyl)adipoamide, 5-tert-H2IPA = 5-tert-butylisophthalic acid); (4) [Ni(L3)1.5(5-tert-IPA)]n (L3 = N,N′-di(4-pyridyl)adipoamide); (5) [Co(L1)(1,3,5-HBTC)(H2O)]n; (6) {[Co3(L1)3(1,3,5-BTC)2(H2O)2]·6H2O}n; (7) [Cu(L4)(AIPA)]n (L4 = N,N′-bis(3-pyridinyl)terephthalamide, H2AIPA = 5-acetamido isophthalic acid); (8) {[Cu(L2)0.5(AIPA)]·MeOH}n; (9) {[Zn(L4)(AIPA)]·2H2O}n; and (10) {[Zn(L2)(AIPA)]·2H2O}n. Complex 1 forms a 1D chain and 2 is a two-fold interpenetrated 2D layer with the sql topology, while 3 is a 2D layer with the hcp topology and 4 shows a self-catenated 3D framework with the rare (42·67·8)-hxg-d-5-C2/c topology. Different Co/1,3,5-H3BTC ratios were used to prepare 5 and 6, affording a 2D layer with the sql topology and a 2D layer with the (4·85)2(4)2(83)2(8) topology that can be further simplified to an hcp topology. While complex 7 is a 2D layer with the (42·67·8)(42·6)-3,5L2 topology and 8 is a 2-fold interpenetrated 3D framework with the pcu topology, complexes 9 and 10 are self-catenated 3D frameworks with the (424·64)-8T2 and the (44·610·8)-mab topologies, respectively. The effects of the identity of the metal center, the ligand isomerism, and the flexibility of the spacer ligands on the structural diversity of these divalent coordination polymers are discussed. The luminescent properties of 9 and 10 and their photocatalytic effects on the degradation of dyes are also investigated.
- Published
- 2017
47. Some characterizations of robust optimal solutions for uncertain convex optimization problems
- Author
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Xiao-Le Guo, Zai-Yun Peng, and Xiang-Kai Sun
- Subjects
Convex analysis ,Mathematical optimization ,021103 operations research ,Control and Optimization ,010102 general mathematics ,0211 other engineering and technologies ,Proper convex function ,Duality (optimization) ,02 engineering and technology ,Subderivative ,01 natural sciences ,Nonlinear programming ,Convex optimization ,Wolfe duality ,0101 mathematics ,Conic optimization ,Mathematics - Abstract
In this paper, we consider robust optimal solutions for a convex optimization problem in the face of data uncertainty both in the objective and constraints. By using the properties of the subdifferential sum formulae, we first introduce a robust-type subdifferential constraint qualification, and then obtain some completely characterizations of the robust optimal solution of this uncertain convex optimization problem. We also investigate Wolfe type robust duality between the uncertain convex optimization problem and its uncertain dual problem by proving duality between the deterministic robust counterpart of the primal model and the optimistic counterpart of its dual problem. Moreover, we show that our results encompass as special cases some optimization problems considered in the recent literature.
- Published
- 2015
48. A method of differential and sensitivity properties for weak vector variational inequalities
- Author
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Xiang-Kai Sun, Jing Zeng, Yi Chai, and Xiao-Le Guo
- Subjects
Algebra and Number Theory ,Variational inequality ,Applied mathematics ,Sensitivity (control systems) ,Analysis ,Differential (mathematics) ,Mathematics - Published
- 2015
49. Entanglement in Co(<scp>ii</scp>) coordination networks: polycatenation from single net to 2-fold and 3-fold interpenetrated nets
- Author
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Xiang-Kai Yang, Jhy-Der Chen, Hsiu-Yi He, Tsung-Tai Wu, and Wayne Hsu
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chemistry.chemical_compound ,Stereochemistry ,Chemistry ,Polycatenane ,General Materials Science ,General Chemistry ,Quantum entanglement ,Condensed Matter Physics ,Benzoic acid - Abstract
The synthesis, structures and properties of six coordination networks based on N,N′-di(4-pyridyl)suberoamide (L) and angular dicarboxylate ligands, {[Co(L)(MBA)]·2H2O}n (H2MBA = diphenylmethane-4,4′-dicarboxylic acid), 1, {[Co(L)0.5(MBA)]·CH3OH}n, 2, [Co(L)0.5(MBA)]n, 3, {[Co2(L)(OBA)2]·7CH3OH}n [H2OBA = 4,4′-oxybis(benzoic acid)], 4, {[Co(L)(hfipbb)]·2H2O}n [H2hfipbb = 4,4′-(hexafluoroisopropylidene)bis(benzoic acid)], 5, and {[Co(L)(SDA)]·H2O}n (H2SDA = 4,4′-sulfonyldibenzoic acid), 6, are reported. Complex 1 is a 1D → 2D polycatenane derived from the helical channels, whereas both complexes 2 and 3 show 2D layers with the (42·68·8·104)(4)2-2,6L1 topology, which are further entangled to form a 2-fold 2D → 2D interpenetration network and a 2D → 3D inclined polycatenation network, respectively, and complex 4 shows a 3-fold 3D → 3D interpenetration network with the (412·63)-pcu topology. The unusual topological features of 5 and 6 consist of 2- and 3-fold interpenetrated layers with the (44·62)-sql topology, which are further catenated to the two such adjacent sheets in parallel and uniform fashions to give 2D → 3D polycatenated networks. Complexes 1, 5 and 6 represent unique examples that the angular dicarboxylate ligands show significant effect on the degree of interpenetration of polycatenation coordination networks with interpenetrating modes. The CO2 capture is preferable to N2 and H2 in the gas sorption for the desolvated product of 4.
- Published
- 2015
50. Identification of rotational center in remote angular-velocity measurement with spatial filtering
- Author
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朱志雄 Zhu Zhi-xiong, 曾祥楷 Zeng Xiang-kai, 陈阳 Chen Yang, and 刘全顺 Liu Quan-shun
- Subjects
Physics ,Identification (information) ,Spatial filter ,Acoustics ,Center (algebra and category theory) ,Angular velocity ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials - Published
- 2015
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