高精度时栅转台控制系统设计（英文）

为了提高时栅转台控制系统的位置检测精度,提出了一种以卡尔曼滤波和PI控制融合的控制方法,并在此基础上设计了高精度伺服控制系统。该方法利用卡尔曼滤波预测实现PI控制器的参数预测自适应整定,控制系统以则采用以电流环作为内环、位置环为外环的双闭环控制结构和时栅传感器为转台位移反馈部件,同时,以ARM(LPC2124)为控制核心,结合电源电路、SP3232串口通信等硬件电路实现卡尔曼滤波和PI控制相融合的控制方法。经实验测试,设计的时栅转台伺服系统具有运动稳定可靠性,位置检测精度在-0. 8″～1. 2″范围内,满足高精度时栅转台控制系统的精度要求。

流体多参数超声波测量仪设计

针对目前流体测量仪测量参数单一的问题,提出了一种用超声波技术测量流体多参数的方法。当传播距离不变时,利用超声波在流体中的传播速度间接得到流体的体积流量、密度、质量流量。由于流体流量、密度等参数均受温度影响,故设计过程中以温度作为参考信号,为所求参数就行实时补偿。同时,测量仪以FPGA为控制核心,实现高速信号采集与处理,以软件插补算法实现超声波传播时间的精密计算,使测量结果更加稳定可靠。

Key progresses of MOE key laboratory of macromolecular synthesis and functionalization in 2021

In 2021,The MOE Key Laboratory of Macromolecular Synthesis and Functionalization in Zhejiang University had achieved several important results.First,a series of versatile organoboron catalysts were synthesized for ring-opening(co)polymerizations.Second,a catalyst-free polycondensation mechanism was proposed for the production of polyesters with high molecular weights.Third,a co-assembly method that can fabricate films and coatings with controllable structures and properties on various substrates was demonstrated,providing a platform for the construction of novel surface coatings.Forth,facile methods for producing high-productivity poly(propylene carbonate)and semicrystalline polyester have been discovered.And linear non-conjugated polyesters exhibiting yellow-green clusteroluminescence were developed for the first time.Fifth,a supramolecular prodrug nano-assembly strategy has been developed for reactive nitrogen species potentiated chemotherapy.Sixth,a series of tough and stiff supramolecular hydrogels with shape memory properties have been used for information encryption.Seventh,reversible fusion and fission of wet-spun graphene oxide fibers has been successfully achieved.Eighth,three non-conjugated polypeptides were synthesized and the mechanism of clusteroluminescence was studied.Ninth,a series of conducting covalent organic frameworks with high electrical conductivity and carrier mobility have been used as high-performance chemiresistor,electrocatalyst,and organic field-effect transistor.Tenth,the exploration of non-fused electron acceptors,and their photostable mechanism are exemplified for developing high-performance,low-cost and eco-friendly polymer solar cells.Finally,gel-grown long-range ordering bulk-heterojunctions has achieved improved X-ray detector performance.

Clusteroluminescence:A gauge of molecular interaction

Clusteroluminescence(CL)materials,as an emerging class of luminescent materials with unique photophysical properties,have received increasing attention owing to their great theoretical significance and potential for biological applications.Although much progress has been made in the design,synthesis and application of CL materials,there is still a big challenge in the emission mechanism.So far,throughspace interaction has been proposed as the preliminary mechanism of the corresponding clusterizationtriggered emission(CTE)effect,but a systematic theory is still needed.This review summarizes the current mechanistic understanding of CL materials including organic/inorganic small molecules,and polymers with/without isolated aromatic structures.In addition,some strategies to achieve high quantum yield,adjustable emission color,and persistent room temperature phosphorescence in CL materials are also summarized.At last,a perspective of the mechanism and application of CL materials are demonstrated,which inspire the researchers working on the development of new kinds of functional materials.

Synergistic regulation of temperature resistance and thermal insulation performance of zirconia-based ceramic fibers

ZrO_(2) fiber is a promising high-temperature resistant and heat-insulating fiber material.However,the decrease in mechanical properties caused by grain growth at high temperatures seriously affects its application.How to achieve the synergy of its temperature resistance and the thermal insulation performance is still the focus of the current industry.In this work,we started with doping inequivalent elements and studied the phase composition,temperature resistance,and thermal insulation properties of Y_(2)O_(3)-ZrO_(2) ceramic fibers by adjusting the Y/Zr molar ratio.The results showed that Y_(2)O_(3) could enter the crystal lattice of ZrO_(2) and form a solid solution.With the increase in Y_(2)O_(3) content,the structure of fibers changed from a tetragonal phase to a cubic phase,and the configurational entropy of the system increased.The larger configuration entropy in the sample could produce a robust steric hindrance effect,inhibiting grain growth.After heat treatment at 1300℃,the grain size of Y_(2)Zr_(2)O_(7)(Y5Z5)fibers was only 61.8%that of Y_(0.1)Zr_(0.9)O_(1.95)(Y1Z9)fibers.The smaller grain size made the Y5Z5 fibers still have excellent flexibility and deformation recovery performance after heat treatment at 1300℃and could still return to the original state after 85%compression or folded in half.In addition,due to the larger configurational entropy,the mean free path of phonon scattering was shortened,thereby improving the thermal insulation performance of the fiber.In short,this work achieves the synergistic effect of temperature resistance and thermal insulation properties of zirconia-based fiber materials only through simple inequivalent element doping.

Organocatalytic polymerization

Organocatalysis, defined as the use of small organic molecules for catalyzing chemical transformations, can be traced back more than a century and has become a thriving area over the past 20 years.

Recent Progress on COS-derived Polymers

The synthesis of sulfur-containing polymer, a very promising functional material, has made a great progress in the past several years. This review is focused on the very recent advances in poly(monothiocarbonate)s derived from carbonyl sulfide(COS) and epoxides including biomass-derived epoxides. Of significance, metal-free catalyst systems, including triethyl borane/Lewis base pair and thiourea/Lewis base pair are developed for the alternating copolymerization of COS with epoxides. Thereof, the thiourea/Lewis base pair is highly active to the copolymerization of COS with epoxide in a living manner. Moreover, a series of crystalline poly(monothiocarbonate)s are presented, including the copolymers derived from COS with oxetane, ethylene oxide, enantiopure epichlorohydrin, and achiral mesoepoxides via enantioselective copolymerization. Based on these COS/epoxide copolymerization process, a variety of COS-based block copolymers with well-defined structure are presented.

Highly Regioselective Sequential 1,1-Dihydrosilylation of Terminal Aliphatic Alkynes with Primary Silanes

Summary of main observation and conclusion A regioselective double 1,1-hydrosilylation of terminal aliphatic alkynes with primary silanes catalyzed by one cobalt catalyst has been developed. gem-Bis(dihydrosilyl)alkanes containing four silicon-hydrogen bonds are efficiently constructed in an atom-economical man ner. Tolerated substrates include simplest alkyne-ethyne, a complicated drug derivative and various functi on alized terminal aliphatic alkynes. Asymmetric approach using two catalysts is achieved with excelle nt enan tioselectivities to access corresp on ding chiral products. The tra nsformations of Si—H bonds into Si—C, Si—O, and Si —F bonds and the synthesis of enantioriched a-hydroxysilane show synthetic utility.

Anionic Copolymerization of Carbonyl Sulfide with Epoxides via Alkali Metal Alkoxides

Carbonyl sulfide （COS）, an analogue of carbon dioxide （CO2）, can be converted to CO2 via the carbonic anhydride enzymes widely existing in nature. COS is an ideal monomer for making poly（monothiocarbonate）s, which are difficult to synthesize by traditional methods. Herein, for the first time, we describe an anionic copolymerization of COS with epoxides using alkali metal alkoxides as the catalysts （initiators）, affording poly（monothiocarbonate）s with 100% alternating degree, 〉99% tail-to-head （T-H） content, high number-average molecular weights （Mns, up to 90.3 kg/mol） with narrow molecular weight distributions （D=Mw/Mn, 1.05-1.31 for COS/propylene oxide copolymers） under solvent-free and mild conditions. Oxygen-sulfur exchange reaction （O/S ER）, which can result in the production of contaminated dithiocarbonate and carbonate units in the main chain, was nearly completely depressed at 0 ℃. In addition, in contrast to previously reported salen chromium （iron） complexes that required multiple synthetic steps, this work provides simple, low-cost, and effective catalysts for making colorless sulfur-containing polymers.

Manipulation of clusteroluminescence in carbonyl-based aliphatic polymers

Clusteroluminogens(CLgens),nonconjugated structures with visible luminescence at the clustering state,have recently received remarkable attention due to their great theoretical significance and practical values.In carbonyl-based aliphatic polymers,(n,π*)transition of carbonyl groups and the through-space interactions have been demonstrated to play an important role in their clusteroluminescence(CL)properties,but it is still a big challenge to manipulate their CL at the molecular level.In this work,six nonconjugated carbonyl-based polymers with different heteroatoms and steric hindrances were synthesized,and their photophysical properties were systematically studied.These polymers all showed CL but with different emission efficiency and wavelength.Experimental and theoretical studies indicated that the CL properties could be manipulated by changing the electronic structures of carbonyl groups and the rigidity of polymer chains.This work not only gains further insights into the CL mechanism but also provides reliable strategies to design and manipulate non-conjugated luminescent materials.

Poly(thioether)-b-polysiloxane-b-poly(thioether)triblock copolymer towards homogeneous dielectric elastomer with high dielectric performance

Dielectric elastomers(DEs)have drawn much attention owing to their application prospects in artificial muscles and soft robotics,it is still a big challenge to prepare DEs with high electromechanical performances.This work reports a highly stretchable poly(thioether)-b-polysiloxane-b-poly(thioether)triblock copolymer based homogenous DEs with high electromechanical properties.The triblock copolymer(PSiPGE)was synthesized through the ring-opening polymerization(ROP)of phenyl glycidyl ether(PGE)and carbonyl sulfide(COS)catalyzed by silicon alkoxides.The dipoles(benzene rings)on the side groups of PSiPGE improved the dipole polarizations and the phase separation structure of this triblock copolymer enhanced the interfacial polarizations between poly(thioether)and polysiloxane,and thus improving the dielectric constant(ε',up to 5.8).In addition,the PSiPGE exhibited low elastic modulus(Y,0.04 MPa),and thus possessed high electromechanical sensitivity(β,~145 MPa^(-1)) which is much higher than that of most homogenous DEs.This work provides a new strategy to construct homogenous DEs with excellent electromechanical performances,leading to a greater application aspect in the actuated devices.

Dual cooperative organocatalysts for one-pot synthesis of polyester-polythiocarbonate block copolymers from multiple monomers

The sequential arrangement of multiple monomer units in a polymer chain remains a major challenge in synthetic chemistry.Here we describe a versatile route to the novel polyester-polythiocarbonate block copolymer from commercially available lactones, epoxides, and carbonyl sulfide(COS). A bicomponent organocatalyst combining triazabicyclodecene(TBD) with triethyl borane(TEB) generates two types of tunable active sites, i.e., TBD-capped alcohol via hydrogen bond and TEB-capped alcohol via O→B coordination bond, which can successively catalyze ring-opening polymerization of lactones and ring-opening copolymerization of COS and epoxides from mixed monomers in one pot. Because of the reversible activated propagating anions and fast activity exchange between the active and dormant species, all of the polymer chains are enchained with both polyester and polythiocarbonate blocks. Kinetic determination quantitatively confirms the proposed mechanism. This method enables diverse lactones and epoxides to form sulfur-containing block copolymers with readily tunable structures.

HCAⅡ-inspired Catalysts for Making Carbon Dioxide-based Copolymers:The Role of Metal-hydroxide Bond

The general characteristics of the active center of the catalysts（including zinc-cobalt（III） double metal cyanide complex [Zn-Co（Ⅲ） DMCC]） for the copolymerization reaction of carbon dioxide（CO2） with epoxide are summarized. By comparing the active center, catalytic performance of the Zn-Co（Ⅲ） DMCC（and other catalysts） with HCAII enzyme in the organism for activating CO2（COS and CS2）, we proposed that the metal-hydroxide bond（M-OH）, which is the real catalytic center of human carbonic anhydride Ⅱ（HCAⅡ）, is also the catalytic（initiating） center for the copolymerization. It accelerates the copolymerization and forms a closed catalytic cycle through the chain transfer reaction to water（and thus strictly meets the definition of the catalyst）. In addition, the metal-hydroxide bond catalysis could well explain the oxygen/sulfur exchange reaction（O/S ER） in metal（Zn, Cr）-catalyzed copolymerization of COS（and CS2） with epoxides. Therefore, it is very promising to learn from HCAⅡ enzyme to develop biomimetic catalyst for highly active CO2/epoxide copolymerization in a well-controlled manner under mild conditions.