Development of a NC System for Aero-engine Automatic Assembly Vehicle

Xian-jun Sheng,Tao Jiang,Jie Wang,Hang Gao,Rui Yang 한국생산제조학회 2014 한국생산제조시스템학회 학술발표대회 논문집 Vol.2014 No.9(2)

A comparison strategy for improving the precision of contour error estimation

Xian-Jun Sheng,Li-Fan Wang 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.8

Contour error estimation is one of the most important tasks in contour following control. The general way to estimate the contour error is by carrying out curve approximation at the current reference point. But it will suffer a loss of precision in large tracking lag condition. To improve the accuracy of estimation, iteration of the approximation process is usually inevitable. In this paper, a comparison strategy is proposed to ameliorate the accuracy of traditional contour error estimation. By searching the optimal reference point, then directly performing estimation near the neighbor of real contour error point, the estimation accuracy can be improved and the iteration process can be avoided. Principles and details of the proposed strategy are discussed by numerical simulations. The verification experiments are implemented by employing linear and circular based contour error estimation methods. The proposed strategy exhibits better universal estimation performance compared with several advanced algorithms and is easy to implement on external computer. The compensation results of ellipse path following task show the feasibility and efficiency of the proposed comparison strategy.

Flattened Calixarene-like Cyclic BODIPY Array: A New Photosynthetic Antenna Model

Ke, Xian-Sheng,Kim, Taeyeon,Lynch, Vincent M.,Kim, Dongho,Sessler, Jonathan L. American Chemical Society 2017 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.139 No.39

<P>A cyclic BODIPY array, characterized by a rigid flattened calixarene-like conformation, acts as a photosynthetic antenna mimic. The system in question, <B>triBODIPY</B>, is a better antenna than the corresponding BF<SUB>2</SUB>-free ligand. On the basis of absorption spectral studies and supporting calculations, it is concluded that exciton coupling between the BODIPY subunits occurs readily. <B>TriBODIPY</B> supports a complex with <B>Li</B><SUP><B>+</B></SUP><B>@C</B><SUB><B>60</B></SUB> that bring an antenna-like light absorber into close proximity to an electronic acceptor without the need for linking spacers. As inferred from X-ray diffraction analyses of complexes between <B>triBODIPY</B> and <B>C</B><SUB><B>60</B></SUB>, it is inferred that the fullerene complexes are stabilized via convex–concave donor–acceptor interactions. Steady state absorption/fluorescence, time-correlated single photon counting, and transient absorption measurements have allowed a complete characterization of the complexes in both the ground and excited states, including the host–guest recognition features, fluorescence quenching effects, and charge separation/recombination dynamics.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2017/jacsat.2017.139.issue-39/jacs.7b08611/production/images/medium/ja-2017-08611y_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja7b08611'>ACS Electronic Supporting Info</A></P>

Hetero Cu(III)–Pd(II) Complex of a Dibenzo[<i>g</i>,<i>p</i>]chrysene-Fused Bis-dicarbacorrole with Stable Organic Radical Character

Ke, Xian-Sheng,Hong, Yongseok,Tu, Peiyu,He, Qing,Lynch, Vincent M.,Kim, Dongho,Sessler, Jonathan L. American Chemical Society 2017 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.139 No.42

<P>Bis-dicarbacorrole (<B>bis-H</B><SUB><B>3</B></SUB>) with two adj-CCNN subunits was synthesized by incorporating a dibenzo[<I>g</I>,<I>p</I>]chrysene moiety into the macrocyclic structure. The two trianionic cores in <B>bis-H</B><SUB><B>3</B></SUB> can stabilize two Cu(III) ions (<B>bis-Cu</B>) or concurrently a Cu(III) cation and a Pd(II) ion in the form of a hetero bis-metal complex (<B>mix-Cu/Pd</B>). As prepared, <B>mix-Cu/Pd</B> displays organic π radical character, as confirmed by various techniques, including electron paramagnetic resonance spectroscopy, cyclic voltammetry, femtosecond transient absorption measurements, and DFT calculations. Radical formation is ascribed to one-electron transfer from the dicarbacorrole backbone to the Pd center allowing the d<SUP>8</SUP> Pd(II) center to be accommodated in a square planner coordination geometry. Nucleus-independent chemical shift and anisotropy of the induced current density calculations provide support for the conclusion that <B>bis-H</B><SUB><B>3</B></SUB> and <B>bis-Cu</B> both display antiaromatic character and contain two formally 16 π-electron dicarbacorrole subunits. On this basis, we suggest that <B>mix-Cu/Pd</B> is best considered as containing a fused 15 π-electron nonaromatic radical subunit and a 16 π-electron antiaromatic subunit. The spectroscopic observations are consistent with these assignments.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2017/jacsat.2017.139.issue-42/jacs.7b09167/production/images/medium/ja-2017-09167y_0009.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja7b09167'>ACS Electronic Supporting Info</A></P>

Metal-Stabilized Quinoidal Dibenzo[<i>g</i>, <i>p</i>]chrysene-Fused Bis-dicarbacorrole System

Ke, Xian-Sheng,Hong, Yongseok,Lynch, Vincent M.,Kim, Dongho,Sessler, Jonathan L. American Chemical Society 2018 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.140 No.24

<P>We report here a metal complexation-based strategy that permits access to a highly stable expanded porphyrin-type quinoidal polycyclic aromatic hydrocarbons (PAH). Specifically, double insertion of Pd(II) ions into a dibenzo[<I>g</I>,<I>p</I>]chrysene-fused bis-dicarbacorrole (<B>bis-H</B><SUB><B>3</B></SUB>) gives rise to a bis-metalated species (<B>bis-Pd</B>) that undergoes a facile benzenoid-quinonoid transformation. In contrast to what is true for the corresponding mono-Pd(II) complex, which has organic radical character, well resolved <SUP>1</SUP>H NMR and <SUP>19</SUP>F NMR spectra are seen for <B>bis-Pd</B>. This complex is also electron paramagnetic resonance (EPR) silent over a range of temperatures. On the basis of crystallographic analyses, Raman spectroscopic studies, harmonic oscillator model of aromaticity (HOMA), and nucleus-independent chemical shift (NICS) calculations, we suggest that the dibenzo[<I>g</I>, <I>p</I>]chrysene bridge in <B>bis-Pd</B> has quinoidal character and that the system as a whole is a closed shell species. As expected for a quinoidal system, <B>bis-Pd</B> is characterized by a lowest energy absorption band that is shifted into the NIR (λ<SUB>max</SUB> = ca. 1420 nm (ε > 1.5 × 10<SUP>5</SUP> M<SUP>-1</SUP> cm<SUP>-1</SUP>) for <B>bis-Pd</B> vs 780 nm (ε < 5.0 × 10<SUP>3</SUP> M<SUP>-1</SUP> cm<SUP>-1</SUP>) for <B>bis-H</B><SUB><B>3</B></SUB>). On the other hand, <B>bis-Pd</B> displays solvent dependent ground state and transient absorption spectral features. Such findings provide support for a zwitterionic resonance contribution to what is a predominantly a quinonoid-type ground state. The use of specific metalation to fine-tune the electronic features of polytopic ligands, as reported here, opens the door to what might be a potentially generalizable approach to the design of quinoidal PAH structures with long wavelength solvatochromic absorption features.</P> [FIG OMISSION]</BR>

Expanded Rosarin: A Versatile Fullerene (C₆₀) Receptor

Ke, Xian-Sheng,Kim, Taeyeon,Brewster, James T.,Lynch, Vincent M.,Kim, Dongho,Sessler, Jonathan L. American Chemical Society 2017 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.139 No.13

<P>An expanded rosarian (P3P6) with a bowl like conformation has been prepared and characterized in a one-pot procedure that involves condensing a bispyrrole pyridine precursor (P-1,P-2) with benzaldehyde, followed by oxidation. Single crystal X-ray diffraction analysis reveals a bowl-like conformation in the solid state with an upper rim diameter defined by the meso-phenyl substituents of ca. 13.5 angstrom and a depth of roughly 6.3 angstrom. P3P6 forms both 1:1 and 2:1 complexes with C-60 in the solid state. DFT reveals similar energies for the two binding modes. A 1:1 binding stoichiometry dominates in 1,2-dichlorobenzene-d(4) at the millimolar concentrations dictated by solubility consideration. The solution phase interactions between rosarian and C60 were studied using H-1 NMR, UV vis, and femtosecond transient absorption spectroscopies in 1,2-ichlorobenzene-d(4) or toluene. To our knowledge, this is the first report of an unfunctionalized porphyrinoid that forms a well-defined complex with C-60 in solution as well as in solid state.</P>

An Exploration of Underlying Consciousness of Chuan Di Xia′s Settlement Environment

Xu, Xian-sheng Korean Institute of Landscape Architecture 2001 Journal of the Korean institute of landscape archi Vol.1 No.-

Beijing Chuan Di Xia can be traced back to Ming and Qing Dynasties. It is located beside the old post way in the west of Beijing. At present, there are more than seventy units of traditional courtyard houses of Ming and Qing Dynasties and the antique features of the surroundings still survive. The dwelling suited to the historical and regional context and the profound cultural values accumulations etc., have precious historic and cultural values. Associated with the investigation of Chuan Di Xia, the paper explores the site selection, the layout, the spatial constructiveness and the underlying consciousness of Chinese traditional dwellings, unveils the common philosophic basis of traditional dwellings and offers new though for sustainable human settlements.

Sperm-mediated Gene Transfer in the Chinese Honeybee, Apis cerana cerana (Hymenoptera: Apidae)

Dong-Sheng Guo,Liang-Xian Sun,Zhi-Jiang Zeng,Xian-Bing Xie 한국응용곤충학회 2007 Journal of Asia-Pacific Entomology Vol.10 No.4

Transgenic Apis cerana cerana were produced by sperm-mediated gene transfer (SMGT). In the experiment, the foreign DNA was linearized and introduced with sperm during the instrumental insemination of virgin queen. The descendants of the experimental colonies were analyzed. In the green fluorescent-positive offspring, green fluorescence was observed for 1- to 2-day-old larvae, the predicted fragment was isolated by means of PCR amplification of genomic DNA and the expression of transferred genes was confirmed at transcriptional level by reverse transcription-polymerase chain reaction. These results showed that the exogenous gene could be integrated in a fraction of the germ line cells of the queen Apis cerana cerana and transmitted to offspring by SMGT.

Sperm-mediated Gene Transfer in the Chinese Honeybee, Apis cerana cerana (Hymenoptera: Apidae)

Guo, Dong-Sheng,Sun, Liang-Xian,Zeng, Zhi-Jiang,Xie, Xian-Bing Korean Society of Applied Entomology 2007 Journal of Asia-Pacific Entomology Vol.10 No.4

Transgenic Apis cerana cerana were produced by sperm-mediated gene transfer (SMGT). In the experiment, the foreign DNA was linearized and introduced with sperm during the instrumental insemination of virgin queen. The descendants of the experimental colonies were analyzed. In the green fluorescent-positive offspring, green fluorescence was observed for 1- to 2-day-old larvae, the predicted fragment was isolated by means of PCR amplification of genomic DNA and the expression of transferred genes was conferred at transcriptional level by reverse transcription-polymerase chain reaction. These results showed that the exogenous gene could be integrated in a traction of the germ line cells of the queen Apis cerana cerana and transmitted to offspring by SMGT.

Do Independent Director Characteristics Affect Firm Performance Under the COVID-19 Epidemic? Empirical Evidence from China

Xiaoqing ZHAO(Xiaoqing ZHAO),Qingbang MU(Qingbang MU),Brian Sheng-Xian TEO(Brian Sheng-Xian TEO ) 한국유통과학회 2023 The Journal of Asian Finance, Economics and Busine Vol.10 No.1

This paper investigates the effect of independent directorship on the firm performance of Chinese listed companies under the impact of the global COVID-19 epidemic. The study starts by assessing the relationship between independent director-related characteristics and firm performance, then mines independent director characteristics variables, collects variable data, proposes reasonable hypotheses, and constructs a data model. 1597 companies listed on Shanghai and Shenzhen stock index, China, from 2020 to 2021 has been selected as the research sample. An empirical study on the relationship between independent directors’ characteristics and firm performance was conducted using SPSS25. The results show that under the impact of the global COVID-19 epidemic, the proportion of independent directors on the board of directors, the age of independent directors, the remuneration of independent directors, and the overseas background of independent directors in Chinese listed companies have a negative relationship with the current firm performance, while the proportion of female independent directors and the part-time rate of independent directors do not have a positive effect on firm performance. The findings of this study strongly imply that independent directors’ characteristics play a significant role in corporate governance and firm performance in Chinese listed companies and that the external environment has an impact on how well independent directors can carry out their duties.