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The copolymerization of two or more monomers produces polymeric materials with unique properties that cannot be achieved with homopolymers. However, precise control over the polymer sequence remains challenging because the sequence is determined by the inherent reactivity of comonomers. Therefore, only limited methods using modified monomers or supramolecular interactions are reported. In this study, the sequence control of acrylate‐styrene copolymerization using multinuclear zinc complexes is reported. The copolymerization of the zinc acrylate complex with a polymeric sheet‐like structure and styrene in benzene affords a copolymer with a higher content of acrylate triad than calculated for the statistical random model, whereas tetranuclear zinc acrylate (TZA) affords a copolymer with fewer adjacent acrylate sequences. The copolymer with a higher content of acrylate triad exhibits a lower glass transition temperature because of the higher mobility of the longer polystyrene segments. These results highlight the promise of multinuclear zinc acrylate complexes as monomers for sequence‐controlled copolymerization. [ABSTRACT FROM AUTHOR]

Various types of numerical control (NC) machine tools can be standardly operated and controlled based on NC data that can be easily generated using widespread CAD/CAM systems. On the other hand, the operation environments of industrial robots still depend on conventional teaching and playback systems provided by the makers, so it seems that they have not been standardized and unified like NC machine tools yet. Additionally, robotic functional extensions, e.g., the easy implementation of a machine learning model, such as a convolutional neural network (CNN), a visual feedback controller, cooperative control for multiple robots, and so on, has not been sufficiently realized yet. In this paper, a hyper cutter location source (HCLS)-data-based robotic interface is proposed to cope with the issues. Due to the HCLS-data-based robot interface, the robotic control sequence can be visually and unifiedly described as NC codes. In addition, a VGG19-based CNN model for defect detection, whose classification accuracy is over 99% and average time for forward calculation is 70 ms, can be systematically incorporated into a robotic control application that handles multiple robots. The effectiveness and validity of the proposed system are demonstrated through a cooperative pick and place task using three small-sized industrial robot MG400s and a peg-in-hole task while checking undesirable defects in workpieces with a CNN model without using any programmable logic controller (PLC). The specifications of the PC used for the experiments are CPU: Intel(R) Core(TM) i9-10850K CPU 3.60 GHz, GPU: NVIDIA GeForce RTX 3090, Main memory: 64 GB. [ABSTRACT FROM AUTHOR]

Various types of numerical control (NC) machine tools can be standardly operated and controlled based on NC data that can be easily generated using widespread CAD/CAM systems. On the other hand, the operation environments of industrial robots still depend on conventional teaching and playback systems provided by the makers, so it seems that they have not been standardized and unified like NC machine tools yet. Additionally, robotic functional extensions, e.g., the easy implementation of a machine learning model, such as a convolutional neural network (CNN), a visual feedback controller, cooperative control for multiple robots, and so on, has not been sufficiently realized yet. In this paper, a hyper cutter location source (HCLS)-data-based robotic interface is proposed to cope with the issues. Due to the HCLS-data-based robot interface, the robotic control sequence can be visually and unifiedly described as NC codes. In addition, a VGG19-based CNN model for defect detection, whose classification accuracy is over 99% and average time for forward calculation is 70 ms, can be systematically incorporated into a robotic control application that handles multiple robots. The effectiveness and validity of the proposed system are demonstrated through a cooperative pick and place task using three small-sized industrial robot MG400s and a peg-in-hole task while checking undesirable defects in workpieces with a CNN model without using any programmable logic controller (PLC). The specifications of the PC used for the experiments are CPU: Intel(R) Core(TM) i9-10850K CPU 3.60 GHz, GPU: NVIDIA GeForce RTX 3090, Main memory: 64 GB.

In designing and manufacturing processes using CAD/CAM systems, cutter location source (CLS) data are generally used for intermediate data to finally generate numerical control (NC) data for various types of NC machine tools. CLS data mainly include statements as 'GOTO' to designate the position and orientation of a cutting tool. However, unfortunately, industrial robots and mechatronics systems have not been supported by such standardized CLS data. Also, it has not been realized for CLS data to be able to optionally have special statements for such as handling a customized end-effector and a camera system, executing a visual feedback control or cooperative control, and implementing AI systems like convolutional neural networks (CNNs). This paper aims to propose hyper-CLS data named HCLS data that can support the above functions. The effectiveness of HCLS data is experimentally evaluated by implementing a sequence work process using two small-sized robots with four-DOFs. The cost required for introducing multiple industrial robots is a serious issue for small and medium-sized manufacturers. Recently, there has been a growing need for small-sized industrial robots, which are comparatively easy to be introduced at low cost, in order to automate work processes that have previously relied on human hands, such as parts fitting tasks with a small clearance and cooperative task taking the timing. The proposed cooperative system based on two small-sized four-DOFs articulated robots enables a sequence control for picking and placing without using any programmable logic controller (PLC). The effectiveness and the validity of the proposed robot system are demonstrated through a pick and place experiment. [ABSTRACT FROM AUTHOR]

The photo copolymerization of N-ethylmaleimide (NEM) and methyl methacrylate (MMA) in 1,1,1,3,3,3- hexafluoro-2-propanol (HFP) and dichloromethane (DCM) was reported. The polymerization was carried out by Reversible Addition-Fragmentation Chain Transfer (RAFT) polymerization method using 2-(2-cyanopropyl) dithiobenzoate (CPDB) as the initiation-regulation dual functional agent. The copolymerization behavior of this monomer pair was investigated in detail at different reaction conditions. The structures of the copolymers were characterized by 1H-NMR and MALDI-TOF-MS. Results revealed that fluoroalcohols were quite effective in affording the copolymers with controlled molecular weights and adjustable MMA contents compared with the normal solvent DCM, due to the hydrogen-bonding interaction. When the molar ratio between HFP and monomer was 1∶1, the reaction rate of NEM was similar to that of MMA, and NEM and MMA were written alternately to the polymer chain to form an alternate copolymer with a well-defined sequence structure. [ABSTRACT FROM AUTHOR]

The statistical terpolymerization of epoxides, CO2 and cyclic anhydrides remains challenging, mainly because epoxide/CO2 and epoxide/anhydride copolymerizations typically proceed at considerably different rates. Herein, we report the syntheses of novel chiral terpolymers with unprecedented statistical distributions of carbonate and ester units (up to 50 % junction units) via the one‐pot reaction of cyclohexene oxide, phthalic anhydride, and CO2 under mild conditions using enantiopure bimetallic aluminum‐complex‐based catalyst systems. Notably, all resulting terpolymers exhibited excellent enantioselectivities (≥96 % ee) that were independent of the carbonate–ester distribution. The statistical compositions of the carbonate and ester units in the resulting terpolymers were determined via 1H and 13C NMR spectroscopies. Furthermore, thermal properties were tuned by altering the ester content of the chiral terpolymer without influencing the enantioselective ring‐opening step involving the meso‐epoxide. This asymmetric terpolymerization methodology is also compatible with a variety of meso‐epoxides to afford the corresponding terpolymers with 17 %–25 % junction units and excellent enantioselectivities (94 %–99 % ee). The present study is expected to provide new guidelines for preparing a broad range of biodegradable polymers with excellent enantioselectivities and adjustable properties. [ABSTRACT FROM AUTHOR]

Rational design of monomer sequence for desired properties is challenging. This study investigates the effect of monomer distribution of double hydrophilic copolymers (DHCs) with electron‐rich units on cluster triggered emission (CTE) capacity. By means of combining latent monomer strategy, reversible addition fragmentation chain transfer (RAFT) polymerization and selective hydrolysis technology, the random, pseudo di‐block and the gradient DHCs consisting of pH‐responsive polyacrylic acid (PAA) segments and thermo‐responsive poly(N‐isopropylacrylamide) (PNIPAM) segments were successfully synthesized in a controlled manner. Moreover, the gradient DHCs showed a tremendously increased luminescent intensity due to the distinct hydrogen‐bonding interaction compared to random and pseudo di‐block DHCs. To the best of our knowledge, this is the first reported the direct correlation between luminescent intensity and sequence structure of non‐conjugated polymer. Meanwhile, thermo and pH dual‐responsive clusteroluminescence could be easily performed. This work demonstrates a novel and facile method to tailor the hydrogen‐bonding for the stimuli‐responsive light‐emitting polymers. [ABSTRACT FROM AUTHOR]

As a post nanotechnology concept, nanoarchitectonics integrates nanotechnology with the other research fields to create new functional materials from nanounits, where polymer chemistry plays indispensable roles. In this perspective article, we showcase and discuss about recent and past hot examples on polymer synthesis with sequence and/or structure regulations, including one dimensional sequential polymer of man‐made structures and bio‐related structures, multidimensional polymers through supramolecular templating polymerization and polymerization based on crystals and liquid crystals, and covalent organic framework. [ABSTRACT FROM AUTHOR]

Rapid access to sequence‐controlled multi‐block copolymers (multi‐BCPs) remains as a challenging task in the polymer synthesis. Here we employ a Lewis pair (LP) composed of organophosphorus superbase and bulky organoaluminum to effectively copolymerize the mixture of methacrylate, cyclic acrylate, and two acrylates, into well‐defined di‐, tri‐, tetra‐ and even a hepta‐BCP in one‐pot one‐step manner. The combined livingness, dual‐initiation and CSC feature of Lewis pair polymerization enable us to achieve not only a trihexaconta‐BCP with the highest record in 8 steps by using four‐component monomer mixture as building blocks, but also the arbitrarily‐regulated monomer sequence in multi‐BCP, simply by changing the composition and adding order of the monomer mixtures, thus demonstrating the powerful capability of our strategy in improving the efficiency and enriching the composition of multi‐BCP synthesis. [ABSTRACT FROM AUTHOR]

Olefin metathesis polymerization has commanded great attention as a versatile method for preparing macromolecular materials with advanced architectures and functions in academia and industry. This Account summarizes our endeavors directed towards the preparation of various functional polymers by using olefin metathesis polymerization strategies in particular acyclic diene metathesis (ADMET) polymerization and ring-opening metathesis polymerization (ROMP), during the last ten years. In addition, the merits and limitations of ADMET polymerization and ROMP techniques are also demonstrated and compared. Notably, this Account highlights our recently developed sequence-controlled ROMP strategy for production of precision polymers in a regio-/stereoselective manner, the rollercoaster journey for the evolution of a macrobicyclic olefin system containing a sacrificial silyloxide bridge is described in detail. 1 Introduction 2 Olefin Metathesis Step-Growth Polymerization Approaches 3 Olefin Metathesis Chain-Growth Polymerization Approaches 4 ROMP of Cleavable Bridged Macrobicyclic Olefins 5 Conclusion [ABSTRACT FROM AUTHOR]

Sequenced-defined oligomer has been emerged as one of the hot topics in polymer chemistry due to its capability of precisely controlling both chain length and monomer sequence. Recent efforts have focused on development of synthetic methodologies using state-of-the-art chemistry tools. However, investigating the impact of minor changes in monomer sequence on physical properties of these materials is still underdeveloped. Herein, four sequenced pentamers are synthesized by a reversible addition-fragmentation chain transfer (RAFT) single unit monomer insertion technique, in which a base pentamer possesses a relatively rigid backbone comprising of five cyclic monomer units. One of the cyclic units in this base pentamer is replaced by an acyclic monomer at different locations (the 1st, 3rd and 5th unit) to produce three modified pentamers, which leads to a significant decrease of glass transition temperature (Tg) compared to the base pentamer. Meanwhile, the modified pentamers with identical primary structures but distinct monomer sequences also present different Tg values depending on the position of the acyclic monomer unit. The middle (3rd) position of the acyclic unit causes profound decrease of Tg due to its increased molecular flexibility. These synthetic pentamers have been demonstrated to be excellent oligomeric plasticizers to modulate thermal transitions of bulk polymer materials. [ABSTRACT FROM AUTHOR]

Based on the success of the demonstration experiment of MW-class Ocean Thermal Energy Conversion (OTEC) in East Sea, Korea, OTEC technology is expected to spread in the future. In order for this to happen, technology improvement factors, such as minimizing human error and reducing operating costs through automatic start and stop for stable operation, are to be applied. In this paper, the operation performance of a 20 kW-class pilot model for the automated start and stop of the recently demonstrated MW-class OTEC served as the basis for the scenario. The scenario derived from the operation experiment of the 20 kW-class pilot plant established the starting conditions of the surface water and deep water seawater inflow conditions with maximum flow conditions of 1,864 kg/s and 1,507 kg/s, respectively, at the initial start-up of the MW-class OTEC. The refrigerant circulation pump produces 86.4 kW initial power at 700 RPM (Max 1,150) when the turbine bypass valve is closed by 50%. The maximum flow condition of 104.0 kg/s through the sequential increase in refrigerant flow and decrease in the opening of the turbine bypass valve generated an output of 886.9 kW. In the stop condition, the RPM of the refrigerant pump is reduced to 800, and the bypass valve is fully closed. Moreover, the power generation output is reduced to 154.3 kW. In accordance with the normal stop condition of 200 kW or less, the bypass valve, which is fully opened, and the valve at the turbine inlet, which is completely opened and closed, block the inflow into the turbine. On the other hand, the opening degree of the bypass valve, which is fully opened, reduces the turbine output to 0 kW in the emergency stop condition. Then, the turbine inlet valve, which is completely opened and closed, blocks the working fluid inflow. As the bypass valve opens abruptly, the flow rate of the working fluid increases up to 328.0 kg/s due to the decrease in turbine resistance. In doing so, the flow rate decreases, and the working fluid amount in the liquid separator decreases. The construction of an automated system for the empirical model in the future will use the OTEC start and stop simulation results derived through this study. [ABSTRACT FROM AUTHOR]

Ring‐opening metathesis polymerization (ROMP) has been regarded as a powerful tool for sequence‐controlled polymerization. However, the traditional entropy‐driven ROMP of macrocyclic olefins suffers from the lack of ring strain and poor regioselectivity, whereas the relay‐ring‐closing metathesis polymerization inevitably brings some unnecessary auxiliary structure into each monomeric unit. We developed a macrobicyclic olefin system bearing a sacrificial silyloxide bridge on the α,β′‐positions of the double bond as a new class of sequence‐defined monomer for regioselective ROMP. The monomeric sequence information is implanted in the macro‐ring, while the small ring, a 3‐substituted cyclooctene structure with substantial ring tension, can provide not only narrow polydispersity, but also high regio‐/stereospecificity. Besides, the silyloxide bridge can be sacrificially cleaved by desilylation and deoxygenation reactions to provide clean‐structured, non‐auxiliaried polymers. [ABSTRACT FROM AUTHOR]

Multimaterial heterostructures have led to characteristics surpassing the individual components. Nature controls the architecture and placement of multiple materials through biomineralization of nanoparticles (NPs); however, synthetic heterostructure formation remains limited and generally departs from the elegance of self-assembly. Here, a class of block polymer structure-directing agents (SDAs) are developed containing repeat units capable of persistent (covalent) NP interactions that enable the direct fabrication of nanoscale porous heterostructures, where a single material is localized at the pore surface as a continuous layer. This SDA binding motif (design rule 1) enables sequence-controlled heterostructures, where the composition profile and interfaces correspond to the synthetic addition order. This approach is generalized with 5 material sequences using an SDA with only persistent SDA-NP interactions ("P-NP 1 -NP 2 "; NP i = TiO 2 , Nb 2 O 5 , ZrO 2 ). Expanding these polymer SDA design guidelines, it is shown that the combination of both persistent and dynamic (noncovalent) SDA-NP interactions ("PD-NP 1 -NP 2 ") improves the production of uniform interconnected porosity (design rule 2). The resulting competitive binding between two segments of the SDA (P- vs D-) requires additional time for the first NP type (NP 1 ) to reach and covalently attach to the SDA (design rule 3). The combination of these three design rules enables the direct self-assembly of heterostructures that localize a single material at the pore surface while preserving continuous porosity.

The terpolymerization of a non‐polar olefin (such as ethylene) and two different polar functional olefins in a controlled fashion is of great interest and importance but has hardly been explored to date. We report for the first time the terpolymerization of ethylene (E) and two different methoxyaryl‐substituted propylenes (AR1P=hexylanisyl propylene; AR2P=methoxynaphthyl propylene or methoxypyrenyl propylene) by a half‐sandwich scandium catalyst. The terpolymerization took place in a sequence‐controlled fashion, affording unique multi‐block copolymers composed of two different ethylene‐alt‐methoxyarylpropylene sequences E‐alt‐AR1P (soft segments) and E‐alt‐AR2P (hard segments) and relatively short ethylene–ethylene (EE) blocks (crystalline segments). The terpolymers exhibited excellent elasticity and unprecedented self‐healing as a result of microphase separation of nanodomains of the crystalline EE segments and the hard amorphous E‐alt‐AR2P segments from a very flexible E‐alt‐AR1P matrix, demonstrating unique synergy of the three different components. [ABSTRACT FROM AUTHOR]

Monomer sequence influences the properties and applications of polymers. Consequently, massive efforts have been made to implement sequence control of polymers. In this work, we developed a computer-aided droplet-flow polymerization based on photo-controlled reversible-deactivation radical polymerization (photo-RDRP), enabling synthesis of gradient copolymers of tunable sequential arrangements, low dispersity and good structural fidelity from various monomers without following their intrinsic reactivities, which is a key limitation in sequence control. The obtained gradient copolymers exhibit unique thermal properties and stimulus responsiveness comparing with the random and block counterparts, and their glass transition behaviour could be regulated by the gradient tendency. We believe that the unprecedented gradient photo-RDRP based on flow synthesis opens a robust and versatile avenue to streamline the synthesis of well-defined gradient polymers, and is compatible with other polymerization mechanisms. [ABSTRACT FROM AUTHOR]

Humans can learn and produce skilled movement sequences from memory, yet the nature of sequence planning is not well understood. Previous computational and neurophysiological work suggests that movements in a sequence are planned as parallel graded activations and selected for output through competition. However, the relevance of this planning pattern to sequence production fluency and accuracy, as opposed to the temporal structure of sequences, is unclear. To resolve this question, we assessed the relative availability of constituent movements behaviorally during the preparation of motor sequences from memory. In three separate multisession experiments, healthy participants were trained to retrieve and produce four-element finger press sequences with particular timing according to an abstract sequence cue. We evaluated reaction time (RT) and error rate as markers of movement availability to constituent movement probes. Our results demonstrate that longer preparation time produces more pronounced differences in availability between adjacent sequence elements, whereas no effect was found for sequence speed or temporal grouping. Further, participants with larger position-dependent differences in movement availability tended to initiate correct sequences faster and with a higher temporal accuracy. Our results suggest that competitive preactivation is established gradually during sequence planning and predicts sequence skill, rather than the temporal structure of the motor sequence. NEW & NOTEWORTHY Sequence planning is an integral part of motor sequence control. Here, we demonstrate that the competitive state of sequential movements during sequence planning can be read out behaviorally through movement probes. We show that position-dependent differences in movement availability during planning reflect sequence preparedness and skill but not the timing of the planned sequence. Behavioral access to the preparatory state of movements may serve as a marker of sequence planning capacity. [ABSTRACT FROM AUTHOR]

A series of copolymers containing 50 mol % acrylic acid (AA) and 50 mol % butyl acrylate (BA) but with differing composition profiles ranging from an AA‐BA diblock copolymer to a linear gradient poly(AA‐grad‐BA) copolymer were synthesized and their pH‐responsive self‐assembly behavior was investigated. While assemblies of the AA‐BA diblock copolymer were kinetically frozen, the gradient‐like compositions underwent reversible changes in size and morphology in response to changes in pH. In particular, a diblock copolymer consisting of two random copolymer segments of equal length (16 mol % and 84 mol % AA content, respectively) formed spherical micelles at pH >5, a mix of spherical and wormlike micelles at pH 5 and vesicles at pH 4. These assemblies were characterized by dynamic light scattering, cryo‐transmission electron microscopy and small angle neutron scattering. [ABSTRACT FROM AUTHOR]

Radiofrequency (RF) pulse transmitter is an important part of a nuclear magnetic resonance (NMR) spectrometer. In this paper, a simple NMR RF pulse transmitter was designed based on field programmable gate array (FPGA) and direct digital synthesis (DDS) chip AD9910. Digital modulation of various parameters was achieved. The control accuracy of frequency, phase and amplitude reached 32 bits, 16 bits and 14 bits, respectively. The time accuracy of pulse modulation was 0.01 μs, capable of generating soft/hard pulses with duration longer than 0.1 μs and frequency less than 400 MHz. A "pulse + delay" model was established, and a generic list-type sequence controller was presented, as such the requirements for higher-level control units were reduced. The enveloping waveform of soft pulses was optimized using Hanning window, instead of rectangular window. Simulation and experimental results demonstrated that the use of Hanning window could effectively reduce frequency sidebands of the soft pulses.

This paper investigates the attitude maneuver problem of a spacecraft containing internal movable masses with zero angular momentum. The spacecraft dynamics in one dimension is first studied using the proposed moving mass control system with predefined mass motion. Next, a small-angle attitude maneuver method based on the sliding mode control technique is designed to accomplish the reorientation when the required maneuver angle is within the control capability of single-direction movable mass motion. Furthermore, a novel mass-shifting procedure is proposed for achieving full-domain attitude reorientation. The procedure includes a rest-to-rest maneuver method together with the trajectory optimization. Which, the rest-to-rest maneuver takes advantage of the attitude difference caused by sequential mass motion and the trajectory optimization is carried out based on time sub-optimal motion planning methods. The procedure is next combined with the small-angle maneuver method to achieve a high precision reorientation. Finally, numerical simulation results show that high precision full-domain attitude reorientation can be realized using the proposed control system with three internal movable masses. • Feasibility of full-domain attitude reorientation using internal movable masses is investigated for the first time. • A novel control procedure using internal movable masses to achieve full-domain attitude reorientation is proposed. • A high precision reorientation method in a combination of sequence rotation with small angle maneuver is presented. [ABSTRACT FROM AUTHOR]

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An immortal N‐(diphenylphosphanyl)‐1,3‐diisopropyl‐4,5‐dimethyl‐1,3‐dihydro‐2H‐imidazol‐2‐imine/diisobutyl (2,6‐di‐tert‐butyl‐4‐methylphenoxy) aluminum (P(NIiPr)Ph2/(BHT)AliBu2)‐based frustrated Lewis pair (FLP) polymerization strategy is presented for rapid and scalable synthesis of the sequence‐controlled multiblock copolymers at room temperature. Without addition of extra initiator or catalyst and complex synthetic procedure, this method enabled a tripentacontablock copolymer (n=53, k=4, dpn=50) to be achieved with the highest reported block number (n=53) and molecular weight (Mn=310 kg mol−1) within 30 min. More importantly, this FLP polymerization strategy provided access to the multiblock copolymers with tailored properties by precisely adjusting the monomer sequence and block numbers. [ABSTRACT FROM AUTHOR]

Poly(hydroxy acid)s are a family of biocompatible and (bio)degradable polyesters with various outcomes in different domains of application. To date, poly(hydroxy acid)s are best prepared by ring‐opening polymerization (ROP) of the corresponding cyclic esters. Using racemic chiral monomers featuring side‐chain groups enables to access, providing a stereoselective catalyst/initiator system is implemented, stereoregular functional polymers, thereby improving their physico–chemical properties, and ultimately, widening their range of uses. Here, we highlight a few important advances in metal‐mediated stereoselective ROP of cyclic esters towards the synthesis of (functional) stereoregular poly(hydroxy acid)s that have recently been disclosed, emphasizing on (functional) β‐ and γ‐lactones, diolide and O‐carboxyanhydride (OCA) monomers and yttrium‐based catalysis. Fine‐tuning of the substituents flanked on the catalyst ligand enables reaching poly(hydroxy acid)s with syndiotactic and also isotactic microstructures. The stereocontrol mechanisms at work and their probable origin, relying on steric but also electronic factors imparted in particular by the ligand substituents, are discussed. Taking advantage of such stereoselective ROPs, original copoly(hydroxy acid)s with gradient or alternated patterns then become accessible from the use of mixtures of chemically different, oppositely configured enantiopure monomers. [ABSTRACT FROM AUTHOR]

An advanced light‐induced avenue to monodisperse sequence‐defined linear macromolecules via a unique photochemical protocol is presented that does not require any protection‐group chemistry. Starting from a symmetrical core unit, precision macromolecules with molecular weights up to 6257.10 g mol−1 are obtained via a two‐monomer system: a monomer unit carrying a pyrene functionalized visible light responsive tetrazole and a photo‐caged UV responsive diene, enabling an iterative approach for chain growth; and a monomer unit equipped with a carboxylic acid and a fumarate. Both light‐induced chain growth reactions are carried out in a λ‐orthogonal fashion, exciting the respective photosensitive group selectively and thus avoiding protecting chemistry. Characterization of each sequence‐defined chain (size‐exclusion chromatography (SEC), high‐resolution electrospray ionization mass spectrometry (ESI‐MS), and NMR spectroscopy), confirms the precision nature of the macromolecules. [ABSTRACT FROM AUTHOR]

In this paper, a systematic synchronization procedure is proposed for a doubly fed induction generator (DFIG) during unbalanced grid voltage conditions. The initial induced voltage at the open stator terminal is required to synchronize with the grid voltage in magnitude, frequency and phase. An open stator negative sequence rotor current controller is implemented with the conventional DFIG vector controller, which allows the induced stator voltage to become as unbalanced as the grid voltage, hence enabling a smooth connection. A brief comparison is provided for practical issues such as controller structure variation between DFIG open stator and normal operating conditions, and initial encoder rotor angle measurement offset. The procedure is validated experimentally on a 2.2 kW laboratory-scaled DFIG test bench.

ABSTRACT: The present work provides an ideal model for intra‐chain energy transfer study in conjugated polymer through shielding the polymer backbone by using bulky polyhedral oligomeric silsesquioxanes (POSS). POSS provides a circumference shielding of the polymer backbone to prevent closed packing of the polymer chains, allowing the intra‐chain energy transfer dominating in large concentration range. Bi‐functional POSS (B‐POSS) is specially designed to separate donor (fluorene) and acceptor (benzothiadiazole) within the polymer chain. The dynamics of energy transfer in poly(fluorene‐POSS‐alt‐POSS‐benzothiodiazole) (PTBtTbOFl3) is studied by steady state as well as time resolved fluorescence spectroscopy at different donor/acceptor ratios. Results reveal that POSS can effectively shield inter‐chains energy transfer of the polymers, suggesting it is an effective model for energy transfer study with less inter‐chains effects. PTBtTbOFl3 works as a chemosensors is also reported in the detection of explosive derivatives. These results provide insights for optimizing nanostructured materials for use in optoelectronic devices. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 1225–1233 [ABSTRACT FROM AUTHOR]

Abstract: Precision synthesis of optically active poly(lactic‐alt‐caprolactic acid) is realized using cross‐metathesis polymerization (CMP) and hydrogenation. Enantiopure monomers ML and MD are generated through two consecutive esterification reactions. CMP of these two monomers in different feed ratios, followed by hydrogenation, afford saturated polymers HPL, HPD, and HPDL comprising L‐lactic and/or D‐lactic acid and ε‐caprolactone‐derived motifs with alternating sequences. CMP kinetic analysis by nuclear magnetic resonance (NMR) is performed by employing a racemic monomer Mrac. Enantiomeric polyesters HPL and HPD display opposite rotation values and mirror‐imaged cotton effects in circular dichroism (CD) spectra, whereas HPDL derived from equimolar ML and MD shows inactive optical rotation and no CD response. Stereocomplex HPD+HPL is obtained by equimolar mixing of HPL and HPD, since this specimen is the only one to exhibit a sharp melting peak on differential scanning calorimetry (DSC) curve at 45.7 °C. Hence, an amorphous, enantiomerically pure polyester becomes crystalline via stereocomplexation with its complementary enantiomer. [ABSTRACT FROM AUTHOR]

Abstract: Synthetic polymers have shown promise in combating multidrug‐resistant bacteria. However, the biological effects of sequence control in synthetic antimicrobial polymers are currently not well understood. As such, we investigate the antimicrobial effects of monomer distribution within linear high‐order quasi‐block copolymers consisting of aminoethyl, phenylethyl, and hydroxyethyl acrylamides made in a one‐pot synthesis approach via photoinduced electron transfer–reversible addition–fragmentation chain transfer polymerisation (PET‐RAFT). Through different combinations of monomer/polymer block order, antimicrobial and haemolytic activities are tuneable in a manner comparable to antimicrobial peptides. [ABSTRACT FROM AUTHOR]

Abstract: We introduce the convergent synthesis of linear monodisperse sequence‐defined oligomers through a unique approach, combining the Passerini three‐component reaction (P‐3CR) and a Diels–Alder (DA) reaction based on photocaged dienes. A set of oligomers is prepared resting on a Passerini linker unit carrying an isocyano group for chain extension by P‐3CR and a maleimide moiety for photoenol conjugation enabling a modular approach for chain growth. Monodisperse oligomers are accessible in a stepwise fashion by switching between both reaction types. Employing sebacic acid as a core unit allows the synthesis of a library of symmetric sequence‐defined oligomers. The oligomers consist of alternating P‐3CR and photoblocks with molecular weights up to 3532.16 g mol−1, demonstrating the successful switching from P‐3CR to photoenol conjugation. In‐depth characterization was carried out including size‐exclusion chromatography (SEC), high‐resolution electrospray ionization mass spectrometry (ESI‐MS) and NMR spectroscopy, evidencing the monodisperse nature of the precision oligomers. [ABSTRACT FROM AUTHOR]

In this paper, four types of deposition control processes such as temperature, pressure, input/output(I/O), and gas were replaced by the Internet of Things(IoT) to analyze the data load and sequence procedure before and after the application of it. Through this analysis, we designed the load balancing in the sensing area of the deposition process by creating the sequence diagram of the deposition process. In order to do this, we were modeling of the sensor I/O according to the arrival process and derived the result of measuring the load of CPU and memory. As a result, it was confirmed that the reliability on the deposition processes were improved through performing some functions of the equipment controllers by the IoT. As confirmed through this paper, by applying the IoT to the deposition process, it is expected that the stability of the equipment will be improved by minimizing the load on the equipment controller even when the equipment is expanded. [ABSTRACT FROM AUTHOR]

The scope and accessibility of sequence-controlled multiblock copolymers is demonstrated by direct 'in situ' polymerization of hydrophobic, hydrophilic and fluorinated monomers. Key to the success of this strategy is the ability to synthesize ABCDE, EDCBA and EDCBABCDE sequences with high monomer conversions (>98 %) through iterative monomer additions, yielding excellent block purity and low overall molar mass dispersities (Ð<1.16). Small-angle X-ray scattering showed that certain sequences can form well-ordered mesostructures. This synthetic approach constitutes a simple and versatile platform for expanding the availability of tailored polymeric materials from readily available monomers. [ABSTRACT FROM AUTHOR]

The straightforward convergent synthesis of sequence-defined and multifunctionalized macromolecules is described herein. The first combination of two efficient approaches for the synthesis of sequence-defined macromolecules is reported: thiolactone chemistry and the Passerini three-component reaction (P-3CR). The thiolactone moiety was used as protecting group for the thiol, allowing the synthesis of a library of sequence-defined α,ω-functionalized building blocks. These building blocks were subsequently efficiently coupled to oligomers with carboxylic acid functionalities in a P-3CR. Thus, larger oligomers with molecular weights of up to 4629.73 g mol−1 were obtained in gram quantities in a convergent approach along with the introduction of independently selectable side chains (up to 15), thus clearly demonstrating the high versatility and the efficiency of the reported approach. [ABSTRACT FROM AUTHOR]

Uniform synthetic polymers with precisely defined molar mass and monomer sequence (primary structure) have many potential high-value applications. However, a robust and versatile synthetic strategy for these materials remains one of the great challenges in polymer synthesis. Herein we describe proof-of-principle experiments for a modular strategy to produce discrete oligomers by a visible-light-mediated radical chain process. We utilize the high selectivity provided by photo-induced electron/energy transfer (PET) activation to develop efficient single unit monomer insertion (SUMI) into reversible addition-fragmentation chain-transfer (RAFT) agents. A variety of discrete oligomers (single unit species, dimers, and, for the first time, trimers) have been synthesized by sequential SUMI in very high yield under mild reaction conditions. The trimers were used as building blocks for the construction of uniform hexamers and graft copolymers with precisely defined branches. [ABSTRACT FROM AUTHOR]

For the copolymerization of non-conjugated olefins and maleimides, it is known that under certain conditions periodic ABA monomer sequences are formed. In this work, such a copolymerization is used to create polymers which have defined (periodic) monomer sequences and can be functionalized after polymerization. The copolymerization of pentafluorophenol (PFP) active esters of 4-pentenoic acid and perillic acid with N-phenyl maleimide (PhMI) was studied in 1,2-dichloroethane (DCE) and 1,1,1,3,3,3-hexafluoro-2-phenyl-2-propanol (HFPP). In DCE and for the copolymerization of the PFP ester of 4-pentenoic acid and PhMI in HFPP, polymers were formed where the active esters were separated by at least one PhMI unit. The average number of separating PhMI units can be controlled by varying the feed ratio of the monomers. For the copolymerization of the PFP ester of perillic acid in HFPP, a preference for the formation of periodic copolymers was observed, where active esters were preferably separated from each other by a maximum of two PhMI moieties. Therefore, the copolymerization of said active ester containing monomers with PhMI provides a platform to create polymers in which reactive moieties are distributed along the polymer chain in different fashions. The active esters in the non-conjugated vinyl monomers could be used in a post-polymerization functionalization step to create functionalized polymers with defined monomer sequences in a modular way. [ABSTRACT FROM AUTHOR]

ABSTRACT We report the thermal, optical, and mechanical properties of random copolymers produced by radical copolymerizations of diisopropyl fumarate (DiPF) with 1-adamantyl acrylate (AdA) and bornyl acrylate (BoA). The effects of a methylene spacer included in the main chain and bulky ester alkyl groups in the side chain on the copolymer properties are discussed. The produced copolymers are characterized by NMR and UV-vis spectroscopies, size exclusion chromatography, thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis (DMA). The copolymerization rate and the molecular weight of the copolymers increase with an increase in the acrylate content in feed during the copolymerization ( Mw = 25-110 × 103). The onset temperature of decomposition ( Td5) and the glass transition temperature ( Tg) of the copolymers also increase according to the content of the acrylate units ( Td5 = 296-329 °C and 281-322 °C, Tg = 80-133 °C and 91-106 °C for the copolymers of DiPF with AdA and BoA, respectively). Transparent and flexible copolymer films are obtained by a casting method and their optical properties such as transparency and refractive indices are investigated ( nD = 1.478-1.479). The viscoelastic data of the copolymers are collected by DMA measurements under temperature control. The storage modulus decreases at a temperature region over the Tg value of the copolymers, depending on the structure and amount of the acrylate units. The sequence structure of the copolymers is analyzed based on monomer reactivity ratios and composition in order to discuss the copolymer properties related to chain rigidity and sequence length distribution. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 288-296 [ABSTRACT FROM AUTHOR]