Distributed Collaborative Response Surface Method for Mechanical Dynamic Assembly Reliability Design

Because of the randomness of many impact factors influencing the dynamic assembly relationship of complex machinery, the reliability analysis of dynamic assembly relationship needs to be accomplished considering the randomness from a probabilistic perspective. To improve the accuracy and efficiency of dynamic assembly relationship reliability analysis, the mechanical dynamic assembly reliability（MDAR） theory and a distributed collaborative response surface method（DCRSM） are proposed. The mathematic model of DCRSM is established based on the quadratic response surface function, and verified by the assembly relationship reliability analysis of aeroengine high pressure turbine（HPT） blade-tip radial running clearance（BTRRC）. Through the comparison of the DCRSM, traditional response surface method（RSM） and Monte Carlo Method（MCM）, the results show that the DCRSM is not able to accomplish the computational task which is impossible for the other methods when the number of simulation is more than 100 000 times, but also the computational precision for the DCRSM is basically consistent with the MCM and improved by 0.40-4.63% to the RSM, furthermore, the computational efficiency of DCRSM is up to about 188 times of the MCM and 55 times of the RSM under 10000 times simulations. The DCRSM is demonstrated to be a feasible and effective approach for markedly improving the computational efficiency and accuracy of MDAR analysis. Thus, the proposed research provides the promising theory and method for the MDAR design and optimization, and opens a novel research direction of probabilistic analysis for developing the high-performance and high-reliability of aeroengine.

Distributed collaborative extremum response surface method for mechanical dynamic assembly reliability analysis

To make the dynamic assembly reliability analysis more effective for complex machinery of multi-object multi-discipline(MOMD),distributed collaborative extremum response surface method(DCERSM)was proposed based on extremum response surface method(ERSM).Firstly,the basic theories of the ERSM and DCERSM were investigated,and the strengths of DCERSM were proved theoretically.Secondly,the mathematical model of the DCERSM was established based upon extremum response surface function(ERSF).Finally,this model was applied to the reliability analysis of blade-tip radial running clearance(BTRRC)of an aeroengine high pressure turbine(HPT)to verify its advantages.The results show that the DCERSM can not only reshape the possibility of the reliability analysis for the complex turbo machinery,but also greatly improve the computational speed,save the computational time and improve the computational efficiency while keeping the accuracy.Thus,the DCERSM is verified to be feasible and effective in the dynamic assembly reliability(DAR)analysis of complex machinery.Moreover,this method offers an useful insight for designing and optimizing the dynamic reliability of complex machinery.

Analysis and Inverse Substructuring Computation on Dynamic Quality of Mechanical Assembly

Mechanical assembly has its own dynamic quality directly affecting the dynamic quality of whole product and should be considered in quality inspection and estimation of mechanical assembly. Based on functional relations between dynamic characteristics involved in mechanical assembly, the effects of assembling process on dynamic characteristics of substructural components of an assembly system are investigated by substructuring analysis. Assembly-coupling dynamic stiffness is clarified as the dominant factor of the effects and can be used as a quantitative measure of assembly dynamic quality. Two computational schemes using frequency response functions（FRFs） to determine the stiffness are provided and discussed by inverse substructuring analysis, including their applicable conditions and implementation procedure in application. Eigenvalue analysis on matrix-ratios of FRFs before and after assembling is employed and well validates the analytical outcomes and the schemes via both a lumped-parameter model and its analogic experimental counterpart. Applying the two schemes to inspect the dynamic quality provides the message of dynamic performance of the assembly system, and therefore improves conventional quality inspection and estimation of mechanical assembly in completeness.

Dynamic Assemblies and Photophysical Changes of Zinc Porphyrin Dimer Regulated by N-Containing Ligands

Zinc porphyrin dimer （1） has been designed and synthesized as a novel host of N-containing ligands. The assembly behavior and photophysical changes of its host-guest complexes were evaluated by IH NMR, fluorescence, and UV-visible titrations, and the processes reveal that the host-guest assembly first creates a stable sandwich complex, then an axial coordination equilibrium appears between the sandwich complex and free ligand. The changes of absorption spectra of the assembly processes rely on the stabilities of the complexes, and fluorescence quenching depends on the axial coordination equilibrium, which indicates that the axial ligation/de-ligation dynamics is indeed a pathway from the excited state to the ground state for metalloporphyrin complexes.

Impaired dynamic interaction of axonal endoplasmic reticulum and ribosomes contributes to defective stimulus-response in spinal muscular atrophy

Background:Axonal degeneration and defects in neuromuscular neurotransmission represent a pathological hall-mark in spinal muscular atrophy(SMA)and other forms of motoneuron disease.These pathological changes do not only base on altered axonal and presynaptic architecture,but also on alterations in dynamic movements of organelles and subcellular structures that are not necessarily reflected by static histopathological changes.The dynamic inter-play between the axonal endoplasmic reticulum(ER)and ribosomes is essential for stimulus-induced local translation in motor axons and presynaptic terminals.However,it remains enigmatic whether the ER and ribosome crosstalk is impaired in the presynaptic compartment of motoneurons with Smn(survival of motor neuron)deficiency that could contribute to axonopathy and presynaptic dysfunction in SMA.Methods:Using super-resolution microscopy,proximity ligation assay(PLA)and live imaging of cultured motoneu-rons from a mouse model of SMA,we investigated the dynamics of the axonal ER and ribosome distribution and activation.Results:We observed that the dynamic remodeling of ER was impaired in axon terminals of Smn-deficient motoneu-rons.In addition,in axon terminals of Smn-deficient motoneurons,ribosomes failed to respond to the brain-derived neurotrophic factor stimulation,and did not undergo rapid association with the axonal ER in response to extracellular stimuli.Conclusions:These findings implicate impaired dynamic interplay between the ribosomes and ER in axon terminals of motoneurons as a contributor to the pathophysiology of SMA and possibly also other motoneuron diseases.

Protonic recognition and assembly for the creation of porous Bronsted acid catalysts with enhanced catalytic efficiency

Due to the high local concentration of substrates in confined space, porous solid Bronsted acids have been extensively explored for efficient acid-catalyzed reaction. However, the porous structures with strong Bronsted acids lack long-term stability due to chemical hydrolysis. Moreover, the products inhibition effect in confined rigid cavities severely obstructs subsequent catalysis. Here, tubular Bronsted acid catalyst with unique recognition of protons was presented by self-assembly of p H-responsive aromatic amphiphiles. The responsive assembly could mechanically transfer hydrogen ions from low-concentration acidic solution into tubular defined pores, thereby producing effective catalytic activity for Mannich reactions in mildly acidic solution. Notably, the tubular catalyst unfolded into flat sheets upon addition of triethylamine for efficient release of products, which could be recovered by subsequent acidification and the catalytic activity still remained. Therefore, the porous Bronsted acid with reversible assembly provides a new strategy for mass synthesis through increasing conversion times.

内源性双miRNA触发响应的DNA纳米结构动态自组装用于原位递送siRNA

通过多重miRNA触发的原位siRNA递送治疗策略可以有效提高对癌细胞的精确治疗.基于DNA纳米结构的可编程性、特异性分子识别、易于功能化修饰和良好生物相容性的特点,我们设计了一个3D DNA纳米治疗平台,用于实现双miRNA触发响应的siRNA原位递送.这种3D DNA纳米结构(TY1Y2)是由DNA四面体支架、两组Y型DNA(Y1和Y2)和EpCAM核酸适体通过自组装构建而成的.TY1Y2被特异性内化至靶标癌细胞后,能够被两个内源性miRNA(miR-21和miR-122)触发,从而产生强的荧光共振能量转移信号,用于双miRNAs成像.同时,治疗性的siRNA(siSurvivin和siBcl2)也可以通过链置换反应从TY1Y2中产生并进行原位释放,实现癌细胞的协同基因治疗.这种3D DNA纳米结构将内源性生物标记物的特异性成像和治疗性基因的原位递送整合为一个多功能纳米平台,在癌症诊断和治疗方面显示出广阔的应用前景.

Rotor orientation direction controls geometric curvature and chirality for assemblies of motor amphiphiles in water

Control over geometric curvature and chirality of assemblies in pure aqueous media is key to the design of responsive materials and molecular machines.Here we show how aggregate geometric curvature and chirality of motor amphiphiles could be switched from bicontinuous calabashes to nanoribbons or from vesicles to nanoribbons by modulating rotor orientation direction with dual light/heat stimuli to influence spontaneous curvature in assemblies.The photoisomerization and thermal helix inversion processes of molecular motors have been studied at the molecular level,and the transformation of supramolecular assemblies has been investigated at the microscopic level.The morphological evolution of the calabash-shaped assembly can be kinetically captured,suggesting that the bicontinuous calabash-shaped structures are different from the bowl-shaped aggregates based on solvent-driven assembly upon the addition of non-solvent or solvent.The investigation of dual optical/thermal control of rotor orientation can provide a new strategy for tuning the geometric curvature and chirality of nanoassemblies at the nanoscale,arriving ultimately the clusteroluminescence through-space electronic communication at responsive supramolecular nanosystems.

Host–Guest Interaction Driven Peptide Assembly into Photoresponsive Two-Dimensional Nanosheets with Switchable Antibacterial Activity

Selectively controlling the bioactivity of antimicrobial peptides is not only a fascinating scientific challenge but also a necessity in localized antibacterial therapy.Here,a smart antimicrobial system has been fabricated via host–guest driven dynamic selfassembly between a branched cyclodextrin and cationic linear peptides appended with azobenzene side chains.The self-assembly structure of the host–guest system could be controlled reversibly through the photoresponsive isomerization of azobenzene moieties.

Synthesis of Finite Molecular Nanotubes by Connecting Axially Functionalized Macrocycles

Monodispersed molecular nanotubes,particularly those with uniform lengths,are challenging targets for chemical synthesis.Here,we report the general design and efficient synthesis of finite molecular nanotubes,utilizing a dynamic assembly strategy to precisely stack axially functionalized macrocycles by chemical connections.Discrete tubular molecules,ranging from 7.8 to 19.8 kDa with covalent or coordinative connections,have been prepared from modular macrocyclic building blocks through highly convergent routes.The discrete molecular nature and structural anisotropy of these synthetic tubes warrant postsynthesis modifications and solution processing methods,as demonstrated by the controllable orientations when deposited onto different prefabricated surfaces.