Connection Unit Research Articles

Supramolecular Nanopatterns of Molecular Spoked Wheels with Orthogonal Pillars: The Observation of a Fullerene Haze.

Molecular spoked wheels with intraannular functionalizable pillars are synthesized in a modular approach. The functionalities at their ends are variable, and a propargyl alcohol, a [6,6]‐phenyl‐C61‐butyrate, and a perylene monoimide are investigated. All compounds form two‐dimensional crystals on highly oriented pyrolytic graphite at the solid–liquid interface. As determined by submolecularly resolved scanning tunneling microscopy, the pillars adopt equilibrium distances of 6.0 nm. The fullerene has a residual mobility, limited by the length of the flexible connector unit. The experimental results are supported and rationalized by molecular dynamics simulations. These also show that, in contrast, the more rigidly attached perylene monoimide units remain oriented along the surface normal and maintain a smallest distance of 2 nm above the graphite substrate. The robust packing concept also holds for cocrystals with molecular hexagons that expand the pillar–pillar distances by 15 % and block unspecific intercalation.

Supramolecular Nanopatterns of Molecular Spoked Wheels with Orthogonal Pillars: The Observation of a Fullerene Haze

AbstractMolecular spoked wheels with intraannular functionalizable pillars are synthesized in a modular approach. The functionalities at their ends are variable, and a propargyl alcohol, a [6,6]‐phenyl‐C61‐butyrate, and a perylene monoimide are investigated. All compounds form two‐dimensional crystals on highly oriented pyrolytic graphite at the solid–liquid interface. As determined by submolecularly resolved scanning tunneling microscopy, the pillars adopt equilibrium distances of 6.0 nm. The fullerene has a residual mobility, limited by the length of the flexible connector unit. The experimental results are supported and rationalized by molecular dynamics simulations. These also show that, in contrast, the more rigidly attached perylene monoimide units remain oriented along the surface normal and maintain a smallest distance of 2 nm above the graphite substrate. The robust packing concept also holds for cocrystals with molecular hexagons that expand the pillar–pillar distances by 15 % and block unspecific intercalation.

Supporting semantic PLM by using a lightweight engineering metadata mapping engine

In order to handle a high variety of interdisciplinary processes and complex smart products, integration platforms are a useful approach to view and access data all along the product lifecycle, which is stored in different data management solutions like Product Lifecycle Management (PLM), Enterprise Resource Planning (ERP) and authoring systems. Here, the Metadata Repository for Semantic Product Lifecycle Management (SP²IDER) could serve as a supporting integration platform. An additional information layer on top of data source systems like PLM and ERP provides additional information, links data objects from different source systems, and provides access to these data. The SP²IDER platform consists of three basic parts: Connector units to fetch data from the source systems, a core unit with a Service Directory and a Mapping Engine, and a Metadata Store, where information about data objects is stored. This paper focuses on the view inside the Mapping Engine and the Metadata Store. The mapping engine has a three-way approach for the mapping of data objects and data types: The initial manual mapping at the data type level, second a rule-based, and third a machine-learning mapping at the data object level. This paper describes the manual mapping process, how the mapped data objects are stored inside the Metadata Store, and how this leads to a newly formed lightweight data model, that does not need heavyweight ontologies.

Dynamic response analysis of monorail steel-concrete composite beam-train interaction system considering slip effect

A new finite element model of steel-concrete composite beam which can simulate the slip phenomenon is proposed in this paper. The new model consists of concrete beam unit, shear connector unit and steel beam unit. Based on the improved model, a new steel-concrete composite track beam-train interaction system is derived for the dynamic analysis. Each vehicle of monorail train in the new steel-concrete composite track beam-train interaction system is idealized as a multi-body system with 18 degrees of freedom. The governing vibration equations of the new monorail steel-concrete composite track beam-train interaction system are derived based on Lagrange’s formulation. Validity of the model is verified by comparing the calculations with field-test data. The influence of the slip effect on the displacement amplitude of the track beam, vehicle acceleration and riding comfort is analyzed in detail. An interesting feature is that the graphic curves which reflect the dynamic responses of the steel-concrete composite beam-train interaction system under the influence of the slip can be divided into two regions (fluctuating area and smooth area), and there is an obvious critical value (0.8 × 106 N/m) between the two regions. When the connection stiffness reaches the critical value, the values of dynamic responses of the interaction system do not change anymore.

Enhanced Proton Loss from Neutral Free Radicals: Toward Carbon-Centered Superacids.

Radical centers close to protons are known to enhance their dissociation. Investigation of the generality of this radical enhanced deprotonation (RED-shift) phenomenon, and the kinds of structures in which it operates, are reported. The pKas for sulfinic, sulfonic, pentan-2,4-dione, and Meldrum's acid species, with adjacent radicals centered on C-, N-, and O atoms, were computed by a DFT method from free energies of deprotonation. All series showed significant RED-shifts that increased with the electronegativity of the radical center. The hugely negative pKa obtained for a Meldrum's acid with an alkoxyl radical substituent showed it to belong to the superacid class. The ethyne unit was found to be uniquely effective at enhancing acidity and conducting RED-shifts through chains up to and beyond 20 atoms. These connector units enable a radical center to alter the pKa of a spatially remote acidic group. RED-shifted species were characterized by conjugate radical anions displaying site exchange of spin with electronic charge.

Theoretical Investigation of the Newly Designed Benzimidazole Based Metal Mediated DNA Base Couples with DFT Method

DNA has the genetic information storage and transmission capacity according to the sequential order of the monomer and creates a central role in the chemical evolution by copying itself with the proliferation feature. Watson-Crick base pairs define two base pairs with hydrogen bonds. If metal coordination bonds replace hydrogen bonds more stable alternative metallo-DNA sequence can be established. If the replication feature can be obtained for the metallo-DNA, this will greatly benefit the creation of DNA computer keys. In this study, a new type of benzimidazole based metallo-DNA sensors consisting of a connector unit that unsaturated azinil bridge linked to Watson-Crick base pairs with Ni2+, Hg2+, Zn2+, Ag+, Pt2+, Pd2+ metal cations and a benzimidazole has been designed. Absorption and emission spectrum of the newly designed aqua medium based fluorophore and their metallo-DNA sensors with selected cations have been theoretically investigated by using DFT method. The logic gates of selected possible sensors which response in the visible region have also been examined in detail in acidic and water phase. As a result of calculated absorption-emission spectrum data show that T-Hg-A-Bnz, A-Ni-T-Bnz, C-Pt-G-Bnz, C-Ni-C-Bnz complexes produce OR gate. T-Zn-T-Bnz and G-Pt-C-Bnz results demonstrated XOR and AND logic gate, respectively.

Redox responsive liposomal nanohybrid cerasomes for intracellular drug delivery

Cerasome is a freshly developped bilayer vehicle that resemble traditional liposome but has higher mophorlogical stability. In this study, a novel redox-responsive cerasome (RRC) was developed for tumor-targeting drug delivery. The cerasome-forming lipid (CFL) that comprise a cleavable disulfide bond as connector unit of the triethoxysilyl head and the hydrophobic alkyl double chain was synthesized and subsequently used to prepare cerasome through ethanol injection method. RRC that has liposome-resembling lipid bilayer structure was proved being outstanding at drug loading capacity as well as morphological stability as compared to conventional liposomes. In addition, in vitro drug release tests of DOX/RRCs showed a redox-responsive drug release profile: accelerated DOX releasing compared to reduction-insensitive cerasomes (RICs) in the presence of 10mM of GSH. Under the same condition, the reduction sensibility of RRC was further proved by increased hydrodynamic diameter and destroying of integrity from DLS and SEM results. RRC showed non-toxic to human embryonic kidney 293 cells, indicating that this material has good biocompatibility. On the other hand, DOX/RRCs showed a resemble IC50 (half inhibitory concentration) value to that of free DOX to human hepatoma SMMC-7721 cells and breast cancer MCF-7 cells. IC50 values at 48h were found to decrease in the following order: DOX/RIC>DOX/RRC>DOX. Taken together, the RRC developped in this study is of great potential to be utilized as a promising platform for intracellular anticancer drug delivery.

Alignment tolerant expanded beam connector based on a gapless fiber-lens interface.

An expanded beam connector (EBC) has been proposed and realized, where a single-mode fiber is seamlessly integrated with a ball lens exhibiting a near-zero back focal length (BFL) so that the incoming small mode exiting the fiber translates into an enlarged collimated beam via the lens. The structural tolerance for the fiber-optic connector is primarily relaxed by relieving the restrictions imposed on the meticulous control of the gap between the lens and the fiber. The EBC has been designed through rigorous ray-optic simulations and then constructed based on a ball lens in LASF35 (n=∼1.98 at λ=1.3 μm), exhibiting an ultrashort BFL of ∼13 μm. It was practically confirmed that an input mode of a ∼10 μm spot relating to the single-mode fiber could be efficiently converted into a highly collimated beam of a ∼350 μm spot that emanates from the ball lens, leading to a 35-fold beam expansion. The alignment tolerance for the fiber as well as the connector unit was scrutinized with respect to the angular tilt and transverse displacement. The measured insertion loss for the EBC, allowing for no separation between the fiber and ball lens, was slightly over 0.8 dB.

Structural properties of metal‐organic frameworks within the density‐functional based tight‐binding method

AbstractDensity‐functional based tight‐binding (DFTB) is a powerful method to describe large molecules and materials. Metal‐organic frameworks (MOFs), materials with interesting catalytic properties and with very large surface areas, have been developed and have become commercially available. Unit cells of MOFs typically include hundreds of atoms, which make the application of standard density‐functional methods computationally very expensive, sometimes even unfeasible. The aim of this paper is to prepare and to validate the self‐consistent charge‐DFTB (SCC‐DFTB) method for MOFs containing Cu, Zn, and Al metal centers. The method has been validated against full hybrid density‐functional calculations for model clusters, against gradient corrected density‐functional calculations for supercells, and against experiment. Moreover, the modular concept of MOF chemistry has been discussed on the basis of their electronic properties. We concentrate on MOFs comprising three common connector units: copper paddlewheels (HKUST‐1), zinc oxide Zn4O tetrahedron (MOF‐5, MOF‐177, DUT‐6 (MOF‐205)), and aluminum oxide AlO4(OH)2 octahedron (MIL‐53). We show that SCC‐DFTB predicts structural parameters with a very good accuracy (with less than 5% deviation, even for adsorbed CO and H2O on HKUST‐1), while adsorption energies differ by 12 kJ mol−1 or less for CO and water compared to DFT benchmark calculations.

GFRP 교량 바닥판의 정적거동에 관한 연구

본 연구에서 교량바닥판용으로 조립식(Modular) 유리섬유 보강(GFRP) 바닥판의 개념을 제안하였다. 본 조립식 GFRP 바닥판시스템은 GFRP 주 단위모률(unite module)과 연결 단위모듈로 구성되어 있다. 본 GFRP 바닥판의 구조성능을 평가하기 위해 정적하중실험을 실시하였다. 그리고 구조성능 결과에 대해서 범용 유한요소 프로그램인 LUSAS을 이용한 수치해석 결과와 비교 분석하였다. 본 연구에서 제안한 조립식 GFRP 바닥판은 교량적용에 매우 유용할 수 있음을 확인할 수 있었다. 제안된 GFRP 바닥판의 파괴모드가 개발된 다른 상용화된 GFRP 바닥판의 파괴모드와 매우 유사한 파괴모들 나타내었다. A concept of Modular GFRP(Glass Fiber Reinforced Polymer) deck panel was proposed for bridge decks. The modular GFRP bridge deck system is comprised of main unit module and connector unit module with GFRP flanges and web. Its structural performance under static loading was evaluated and compared with the LUSAS finite element predictions. It was found that the presented GFRP modular panel was very efficient for use in bridges. The failure mode of the proposed GFRP deck was similar when compared with that of commercial other GFRP decks developed.

Study on Enhancing the Strength and Life of Mining Flat Type Chain Connector Units Based on CAE

ANSYS finite element software was utilized to simulate contact non-linear finite element analysis of chain connector for enhancing the structure strength and working life and productivity and manufacture craftwork of the existed ladder-type chain connector. Static and dynamic experiments were carried on several samples to test the broken positions of the chain connectors. The simulation results show that the main part of stress concentration is in teeth roots; experimental results also show that the teeth roots are the fragile parts in the chain connector. So experimental results conform to the results of simulation, it is reasonable for the simulation of contact non-linear finite element analysis of chain connector by ANSYS software. Then a structure of cambered surface tooth is promoted to enhance the strength and life of teeth parts, and petal-type clamps structure is adopted, that can carry out volume-producing to improve the productivity and processing precision.

Study on Manufacture Technology for Enhancing the Life of Mining Flat Type Chain Connector Units

To enhance the structure strength and working life of the existing ladder-type chain connector, and chain connector productivity and manufacture craftwork. The ANSYS finite element software is utilized to simulate contact non-linear finite element analysis of ladder type chain connector. And the static and dynamic experiments are carried on several samples. Finite element simulation results show that the main part of stress concentration is in teeth roots; experiments results show that the teeth roots are the fragile parts in the chain connector, the results of finite element analysis is conformed to the results of the experiments, thus that the ANSYS finite element software is utilized to simulate contact non-linear finite element analysis of chain connector is reasonable. Because of the shortcoming of straight tooth chain connector, then promoted a chain connector of cambered surface tooth structure. Through the analysis, it shows that cambered surface can augment the contact areas in teeth, and prevent partial loading in teeth meshing. When chain connector manufactured, clamping tongs are quite complex, but the petal-type clamps structures are adopted, that can carry out volume-producing, thereby, and the productivity and processing precision are improved.

Connector model for describing many-body interactions at surfaces

First-principles calculations based on density-functional theory indicate that high-order many-body interactions are significant in Al clusters on Al(110) and Al(100). The large number of many-body interactions renders a full-lattice-gas approach ineffective for such systems. To simplify the description of adsorbate interactions, we utilize two different schemes. First, we find effective parameters for Al adatom interactions using the leave-one-out cross-validation method. Second, we propose the connector model, which is based on additive single-atom connector units. The central idea of the connector model is to combine groups of many-body interactions into important structural units (e.g., step edges) that have a single interaction energy. We find that the connector model is more accurate and efficient in representing high-order many-body interactions than the traditional lattice-gas approach and it may be suitable for describing a variety of surface phenomena such as thin-film and crystal growth, adsorption, phase transitions, and catalysis at surfaces.

Exploring the connection unit in the HDAC inhibitor pharmacophore model: Novel uracil-based hydroxamates

Starting from the pharmacophore model for HDAC inhibitor design, a novel series of hydroxamates bearing a uracil moiety as connecting unit (CU) has been prepared and tested. Almost all compounds exhibited HDAC inhibiting activity at low nanomolar concentrations, the N-hydroxy-6-(3,4-dihydro-4-oxo-6-benzyl- and -6-phenyl-2-pyrimidinylthio)hexanamides 1d and 1l being more potent than SAHA in enzymatic assays. Such compounds also caused hyperacetylation in NIH3T3 cell core histones and were endowed with interesting antiproliferative and cytodifferentiating effects in human leukemia (HL-60) cells.

Experimental Study of a Bonded Plastic Fiber Reinforced Polymer Connector Assembly

In this paper the physical behaviors of a connection assembly comprising a molded glass reinforced plastic [plastic fiber reinforced polymer (PFRP)] connector unit currently commercially manufactured from sheet molding compound and two pultruded PFRP box section beams/columns are examined. A detailed review highlights the apparent lack of research in this area. A limited number of studies have indicated the potential benefits of this joining technology in comparison to mimicking steel-type connections in which ductility is exploited. Reflecting the internal asymmetries of the connector unit, rotationally similar tests have been undertaken in which the connection assembly has been subjected to loading and boundary conditions inducing predominantly shear and bending states, respectively. Load-displacement characteristics, strain measurements, and failure modes are reported. In the context of the basic geometric design of the connector unit and low strength parent material, the connection assembly is shown to perform well, mobilizing up to 26% of the ultimate bending strength of the pultruded box section and demonstrating the potential of the joining technology.

Fabrication and packaging of integrated chemo-optical sensors

This paper describes the design and fabrication of a sensitive integrated chemo-optical sensor supplied with on-chip fiber-to-waveguide connectors. The sensor is designed for TE-polarized light with wavelength of 633 nm. The fiber-to-chip connectors are based on easily fabricated silicon V-grooves combined with a smooth sawcut. The sawcut is defining the channel waveguide endface. The sensor is based on a phase modulated Mach-Zehnder interferometer, using the electro-optic effect of the waveguiding material zinc oxide (ZnO). The fiber-to-chip connector units have a typical coupling efficiency of 0.1–1%. The electro-optical voltage × length product V π is 15 ± 4 V cm at frequencies above 100 Hz. Preliminary experiments on the general (passive) sensor response showing its expected high sensitivity are discussed.

Effects of end distance and thickness on the tensile resistance of 102 mm shear plates

In this paper, an experimental study of the behavior of 102 mm shear plates subjected to tensile load is presented. The design requirements for shear plate connectors specified in the last three editions of the Canadian wood design standards (1980, 1984, and 1989) are also reviewed and compared with the experimental results. In the experimental study, 83 specimens were tested with shear plate end distances of 80, 145, 210, and 275 mm. Specimens were either 64 or 89 mm thick. Results for all tests were analyzed and 5th percentile resistance values were obtained for each end distance value, assuming a two-parameter Weibull distribution. Results show that connections using 102 mm shear plate connectors behave in a brittle manner when loaded in tension. It is also shown that the member thickness affects the tensile resistance of shear plates in thin members with small connector end distances and that it appears to impose a limit on the resistance for thin members with large connector end distances. Finally, it is shown that the 75% minimum limit on a member net area adjacent to a connector unit (clause 4.3.7.2 of O86.1-M89) is conservative for members with small connector end distances. Key words: wood, shear plate, end distance, resistance, thickness.

Estimation of interaction energies by the critical molecular weight method: 1. Blends with polycarbonates

AbstractThe interaction energies between PS, Pα‐MS, and PMMA with several bisphenol‐A‐based polycarbonates were quantitatively determined from oligomer/oligomer, oligomer/homopolymer, and homopolymer/copolymer blends. Interaction energies were calculated from the Flory‐Huggins theory and the Sanchez‐Lacombe equation of state theory using experimental cloud points or miscibility boundaries. Alkyl addition to the phenyl rings of polycarbonate is favorable for miscibility with polystyrene whereas halogenation of the bisphenol connector unit is favorable for miscibility with poly(methyl methacrylate). Interaction energies are quantitatively ranked and described qualitatively in terms of changes in the electronic charge distribution of the polymer repeat units as calculated by SYBYL software. © 1994 John Wiley & Sons, Inc.

Estimation of interaction energies by the critical molecular weight method: 2. Blends with polysulfones

AbstractThe interaction energies between PS, Pα‐MS, and PMMA, as well as acrylonitrile and maleic anhydride units, with a series of polysulfones were quantitatively determined from oligomer/oligomer, oligomer/homopolymer, and homopolymer/copolymer blends. Interaction energies were calculated from the Flory‐Huggins theory and the Sanchez‐Lacombe equation of state theory using experimental cloud points or miscibility boundaries. Alkyl addition to the phenyl rings of polysulfone is favorable for miscibility with polystyrene whereas halogenation of the bisphenol connector unit favors miscibility with poly(methyl methacrylate). Interaction energies are quantitatively ranked and described qualitatively in terms of changes in the electronic charge distribution of the polymer repeat units as calculated by SYBYL software. © 1994 John Wiley & Sons, Inc.

Steroid cyclophanes as artificial receptors embedded in synthetic bilayer membranes: Aggregation behavior and molecular recognition

AbstractTwo steroid cyclophanes, having individually L‐lysine and L‐aspartate residues as connector units interposed between a 1,6,20,25‐tetraaza[6.1.6.1]paracylophane skeleton and four cholate moieties, were designed and synthesized. The cationic steroid cyclophane, having L‐lysine residues, binds anionic and non‐ionic guests very efficiently, while it has no capacity to bind a guest with a positive charge in aqueous solution. On the other hand, the anionic steroid cyclophane, bearing L‐aspartate residues, shows good binding affinity toward hydrophobic guests in aqueous solution regardless of their charged states. Aggregate morphology of the cationic and anionic peptide lipids, involving an L‐alanine residue interposed between a charged head moiety and a hydrophobic double‐chain segment, in the sonicated vesicular state was not perturbed significantly upon formation of hybrid assemblies with the steroid cyclophanes in 2.5 mol%. Even though the anionic bilayer vesicle interacts only weakly with anionic guests, the corresponding hybrid assembly formed with the cationic steroid cyclophane is capable of marked molecular recognition of anionic guests, along with shape‐sensitive discrimination, through electrostatic and hydrophobic interactions in aqueous solution. In a similar manner, the cationic bilayer membrane alone is incapable of binding a cationic guest. However, the guest‐binding ability is not much enhanced in the presence of the anionic steroid cyclophane. Consequently, the cationic steroid cyclophane can act as an efficient cell‐surface receptor model for anionic guests while the anionic steroid cyclophane is not a good receptor model when both are embedded in bilayer membranes.