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In tumor therapy, nanodrug delivery systems have gained momentum in the last decade. However, its efficacy remains insufficient for clinical applications. The physical properties of nanoparticles, including size, shape, and surface characteristics, can strongly affect the delivery efficacy. Ironically, research on shape function is relatively scarce, although the nanoparticle shape greatly impacts their performance; for example, nanorods with a high aspect ratio (AR) achieve greater accumulation, but their penetration is relatively weak. Hence, rather than selecting a suitable AR to balance them, the strategy of a transformable AR (i.e., transformation) is ideal in this case. Nanoparticle transformation can be achieved by either internal stimuli (such as pH and enzymes) or external stimuli (such as light) spatially and temporally with precision, thereby dramatically enhancing the efficiency of drug delivery. Thus, nanoparticle transformation is becoming a promising prospect for improving cancer treatment. In this review, first, the effect of shape on drug delivery is summarized, then, the recently transformable drug delivery systems are reviewed, and finally, the future direction of shape-transformable nanoparticles in tumor therapy is discussed. [ABSTRACT FROM AUTHOR]

The shape diversity and controlled reconfigurability of closed surfaces and filamentous structures, universally found in cellular colonies and living tissues, are challenging to reproduce. Here, we demonstrate a method for the self-shaping of liquid crystal (LC) droplets into anisotropic and three-dimensional superstructures, such as LC fibers, LC helices, and differently shaped LC vesicles. The method is based on two surfactants: one dissolved in the LC dispersed phase and the other in the aqueous continuous phase. We use thermal stimuli to tune the bulk LC elasticity and interfacial energy, thereby transforming an emulsion of polydispersed, spherical nematic droplets into numerous, uniform-diameter fibers with multiple branches and vice versa. Furthermore, when the nematic LC is cooled to the smectic-A LC phase, we produce monodispersed microdroplets with a tunable diameter dictated by the cooling rate. Utilizing this temperature-controlled self-shaping of LCs, we demonstrate life-like smectic LC vesicle structures analogous to the biomembranes in living systems. Our experimental findings are supported by a theoretical model of equilibrium interface shapes. The shape transformation is induced by negative interfacial energy, which promotes a spontaneous increase of the interfacial area at a fixed LC volume. The method was successfully applied to many different LC materials and phases, demonstrating a universal mechanism for shape transformation in complex fluids. [ABSTRACT FROM AUTHOR]

Eutectic gallium indium (EGaIn) spherical liquid metal nanoparticles (NPs) can transform to gallium oxide hydroxide (GaOOH) microrods in water. Nevertheless, the mechanism of this process still remains unrevealed. In this work, the whole shape transformation process of EGaIn NPs is investigated via monitoring the change of NPs' composition and morphology. Gallium (Ga) element in EGaIn NPs can be oxidized to form gallium oxide, which further reacts with water to generate micrometer‐sized GaOOH crystals. This chemical variation occurs gently at room temperature and is accelerated by heating. With continuous consumption of Ga element, indium condenses to form individual NPs. The dynamic temperature‐dependent dissolution and precipitation of GaOOH microrods in water are further demonstrated. Deep understanding of the mechanism of EGaIn NPs' shape transformation would provide more approaches to control the surface and bulk properties of NPs for potential applications in various fields including soft robotics, wearable devices, and nanomedicine. [ABSTRACT FROM AUTHOR]

Soft materials play a crucial role in small-scale robotic applications by closely mimicking the complex motion and morphing behavior of organisms. However, conventional fabrication methods face challenges in creating highly integrated small-scale soft devices. In this study, microfluidics is leveraged to precisely control reaction-diffusion (RD) processes to generate multifunctional and compartmentalized calcium-cross-linkable alginate-based microfibers. Under RD conditions, sophisticated alginate-based fibers are produced for magnetic soft continuum robotics applications with customizable features, such as geometry (compact or hollow), degree of cross-linking, and the precise localization of magnetic nanoparticles (inside the core, surrounding the fiber, or on one side). This fine control allows for tuning the stiffness and magnetic responsiveness of the microfibers. Additionally, chemically cleavable regions within the fibers enable disassembly into smaller robotic units or roll-up structures under a rotating magnetic field. These findings demonstrate the versatility of microfluidics in processing highly integrated small-scale devices., (© 2024 The Author(s). Advanced Materials published by Wiley‐VCH GmbH.)

Bilayer hydrogels, endowed with multiresponsive and switchable color-changing properties, have garnered significant attention for bioinspired artificial intelligent materials. However, the design and fabrication of such hydrogels that can fully mimic the adaptation of the live organism, i.e ., simultaneous changes in shape, fluorescent, and/or visible color, still remain significant challenges. Herein, a multiresponsive (e.g., temperature, salt, and pH) and multiadaptive (shape, fluorescent color, and visible color changes) hydrogel was fabricated by employing monomers featuring pH-responsive fluorescence 4-(2-(4-(dimethylamino) phenyl)-1-isocyanovinyl) phenol (DP) and switchable color-changing 4-(2-sulfethyl) -1-(4-vinylbenzyl) pyridinium betaine (VPES). The bilayer hydrogel comprises a temperature- and pH-responsive gel layer, poly( N -isopropylacrylamide- co -2-(dimethylamino) ethyl methacrylate), along with a pH-, temperature-, and salt-responsive gel layer, poly(acrylamide- co -2-(dimethylamino)ethyl methacrylate- co -VPES)@DP. Due to the opposite swelling/shrinking behavior between the two layers, the prepared hydrogel exhibits shape changes in response to thermal, salt, and pH stimuli, along with switchable fluorescent color and visible color change that originate from DP and polyVPES, respectively. Apart from multiresponsive behavior, this hydrogel also shows an excellent antifatigue property and high sensitivity, which makes it hold significant potential in many applications. We anticipate that this strategy to realize multiresponsive capability in this work can also inspire the design of the biomimetic smart materials.

Plant tissues are constructed as composite material systems of stiff cellulose microfibers reinforcing a soft matrix. Thus, they comprise smart and multifunctional structures that can change shape in response to external stimuli due to asymmetrical fiber alignment and possess robust mechanical properties. Herein, we demonstrate the biomimetics of the plant material system using silk fiber-reinforced alginate hydrogel matrix biocomposites. We fabricate single and bilamellar biocomposites with different fiber orientations. The mechanical behavior of the biocomposites is nonlinear, with large deformations, as in plant tissues. In general, the bilamellar system shows increased modulus, strain UTS, and toughness compared to the single-lamellar system for most of the tested orientations. Overall, the biocomposites present a wide range of elastic modulus values (3.0 ± 0.6-104.7 ± 11.3 MPa) and UTS values (0.23 ± 0.04-12.5 ± 2.0 MPa). The bilamellar biocomposites demonstrated shape-transforming abilities with diverse morphing modes, emulating different plant tissues and creating complex shape-morphing structures. These multifunctional biocomposites possess tunable and robust mechanical properties, controllable shape-morphing deformations, and the ability to self-controlled encapsulation, grip, and release objects. By harnessing biomimetic principles, these soft, smart, and multifunctional materials hold potential applications spanning from soft robotics, medicine, and tissue engineering to sensing and drug delivery.

Soft materials possess magnificent properties which could be harnessed for different potential applications. Compared to other soft materials, hydrogels have some unique advantages which can be used in the shape deformation or shape transformation of structures. This paper aims to investigate the deformation mechanisms of hydrogel-based bi-material beam structures and study the non-uniform geometric effects on the shape transformation including programmable scroll and helical deformations. With a sloped thickness design, the structures could be transformed from an initial quasi-2D beam configuration into some other 2D self-scroll and 3D self-helical configurations. From the hydrogel material model, a modified deformation formula for bi-material beam structures based on the framework of the classical beam theory has been developed to predict the shape morphing behaviors. The relationship between the curvature and the mismatch strain is derived in its explicit form and the theoretical results are verified through several numerical simulations. Furthermore, experiments are carried out to demonstrate the design principles for reconfigurable bi-material beam structures and the experiments show that the structures tend to deform similarly to that predicted by the analytical models. The presented work could provide guidance for future applications of responsive hydrogel-based bi-material beam structures such as in soft actuators and soft robots. [ABSTRACT FROM AUTHOR]

• We have fabricated mixed halide perovskite films by anion exchange reaction (AER). • AER provides better control over size, shape and morphology with tunable band gap. • A shape transformation from nanocube-hollow tetraoids-nanocubes/plate was observed. • The underlying mechanism of shape transformation was discussed. • The best performing device shows a PCE of 12.79% in forward sweep. In this article, we report the tailoring of nanostructured mixed halide perovskite MAPb(I 1-x Br x) 3 films with tunable band gap fabricated by anion exchange reaction. In this process, we used PbBr 2 and methyl ammonium iodide (MAI) in order to fabricate mixed halide perovskite films. We have observed an uncommon shape transformation from nanocube-hollow tetraoids-nanocubes/plate. The underlying mechanism of shape transformation was discussed based on experimental results. The driving force for such shape transformation is combined effect of anion exchange reaction between I− and Br− at the solid/liquid interface of PbBr 2 and MAI, and mechanical driving force exerted by the spin coating process. The shape transformation is highly reproducible, verified by two step process, dipping as well as spinning process. The best performing device using the nanostructured perovskite films in a device architecture FTO/TiO 2 /MAPb(I 1-x Br x) 3 /Spiri-OMeTAD/Au shows a current density (J sc,) of 23.58 mA/cm2, open circuit voltage (V oc) of 0.891 V and fill factor (FF) of 0.608, with a power conversion efficiency (η) of 12.79% in forward sweep. In reverse sweep, the device shows the J sc (mA/cm2) , V oc (V) , FF, and η (%) are 23.852, 0.891, 0.716 and 15.237, respectively. [ABSTRACT FROM AUTHOR]

This paper describes an algorithm for generating a guaranteed intersection-free interpolation sequence between any pair of compatible polygons. Our algorithm builds on prior results from linkage unfolding, and if desired it can ensure that every edge length changes monotonically over the course of the interpolation sequence. The computational machinery that ensures against self-intersection is independent from a distance metric that determines the overall character of the interpolation sequence. This decoupled approach provides a powerful control mechanism for determining how the interpolation should appear, while still assuring against intersection and guaranteeing termination of the algorithm. Our algorithm also allows additional control by accommodating a set of algebraic constraints that can be weakly enforced throughout the interpolation sequence.

Soft robots with magnetic responsiveness exhibit diverse motion modes and programmable shape transformations. While the fixed magnetization configuration facilitates coupling control of robot posture and motion, it limits individual posture control to some extent. This poses a challenge in independently controlling the robot's transformation and motion, restricting its versatile applications. This research introduces a multifunctional helical robot responsive to both light and magnetism, segregating posture control from movements. Light fields assist in robot shaping, achieving a 78% maximum diameter shift. Magnetic fields guide helical robots in multimodal motions, encompassing rotation, flipping, rolling, and spinning-induced propulsion. By controlling multimodal locomotion and shape transformation on demand, helical robots gain enhanced flexibility. This innovation allows them to tightly grip and wirelessly transport designated payloads, showcasing potential applications in drug delivery, soft grippers, and chemical reaction platforms. The unique combination of structural design and control methods holds promise for intelligent robots in the future.

As one of the most important cellular compartments, the nucleus contains genetic materials and separates them from the cytoplasm with the nuclear envelope (NE), a thin membrane that is susceptible to deformations caused by intracellular forces. Interestingly, accumulating evidence has also indicated that the morphology change of NE is tightly related to nuclear mechanotransduction and the pathogenesis of diseases such as cancer and Hutchinson–Gilford Progeria Syndrome. Theoretically, with the help of well-designed experiments, significant progress has been made in understanding the physical mechanisms behind nuclear shape transformation in different cellular processes as well as its biological implications. Here, we review different continuum-level (i.e., energy minimization, boundary integral and finite element-based) approaches that have been developed to predict the morphology and shape change of the cell nucleus. Essential gradients, relative advantages and limitations of each model will be discussed in detail, with the hope of sparking a greater research interest in this important topic in the future.

Traditionally, shape transformation using implicit functions is performed in two distinct steps: 1) creating two implicit functions, and 2) interpolating between these two functions. We present a new shape transformation method that combines these two tasks into a single step. We create a transformation between two N-dimensional objects by casting this as a scattered data interpolation problem in N +1 dimensions. For the case of 2D shapes, we place all of our data constraints within two planes, one for each shape. These planes are placed parallel to one another in 3D. Zero-valued constraints specify the locations of shape boundaries and positivevalued constraints are placed along the normal direction in towards the center of the shape. We then invoke a variational interpolation technique (the 3D generalization of thin-plate interpolation), and this yields a single implicit function in 3D. Intermediate shapes are simply the zero-valued contours of 2D slices through this 3D function. Shape transformation between 3D shapes can be performed similarly by solving a 4D interpolation problem. To our knowledge, ours is the first shape transformation method to unify the tasks of implicit function creation and interpolation. The transformations produced by this method appear smooth and natural, even between objects of differing topologies. If desired, one or more additional shapes may be introduced that influence the intermediate shapes in a sequence. Our method can also reconstruct surfaces from multiple slices that are not restricted to being parallel to one another. Copyright ACM 1999.

In this study, a confocal optical system formed by a combination of two axicon lenses, a parabolic annular mirror and a concave mirror was used to obtain an adjustable microstructured beam. The two axicons were used to create a collimated hollow annular beam whose diameter varies with the distance between the two components, and the duty cycle ε of the hollow beam changes accordingly. At the same time, the annular factor δ also changes correspondingly after the hollow beam was concentrated. According to the scalar diffraction integral theory, the change of focusing characteristics of different annular factor δ after a parabolic annular mirror was studied. The concentrated beam was reflected by a concave mirror to form a confocal optical system. According to the numerical simulation, the size of the focused spot varies from 2.8 to 4. 3 μ m in the range of the annular factor δ from 1.19 to 1.09. Detailed characteristics of the microstructure beam shape changes were analyzed. These results have important implications for particle manipulation and other applications. • Confocal beam trap is characterized by simplicity, stability, and versatility. • The parabolic annular and the concave mirror combine to form a confocal beam trap. • The Hollow-Bottle microstructure beam for different experiments was obtained. [ABSTRACT FROM AUTHOR]

Fluorescent polymersomes with both aggregation‐induced emission (AIE) and CO2‐responsive properties were developed from amphiphilic block copolymer PEG‐b‐P(DEAEMA‐co‐TPEMA) in which the hydrophobic block was a copolymer made of tetraphenylethene functionalized methacrylate (TPEMA) and 2‐(diethylamino)ethyl methacrylate (DEAEMA) with unspecified sequence arrangement. Four block copolymers with different DEAEMA/TPEMA and hydrophilic/hydrophobic ratios were synthesized, and bright AIE polymersomes were prepared by nanoprecipitation in THF/water and dioxane/water systems. Polymersomes of PEG45‐b‐P(DEAEMA36‐co‐TPEMA6) were chosen to study the CO2‐responsive property. Upon CO2 bubbling vesicles transformed to small spherical micelles, and upon Ar bubbling micelles returned to vesicles with the presence of a few intermediate morphologies. These polymersomes might have promising applications as sensors, nanoreactors, or controlled release systems. [ABSTRACT FROM AUTHOR]

Shape transformation, a key mechanism for organismal survival and adaptation, has gained importance in developing synthetic shape-shifting systems with diverse applications ranging from robotics to bioengineering. However, designing and controlling microscale shape-shifting materials remains a fundamental challenge in various actuation modalities. As materials and structures are scaled down to the microscale, they often exhibit size-dependent characteristics, and the underlying physical mechanisms can be significantly affected or rendered ineffective. Additionally, surface forces such as van der Waals forces and electrostatic forces become dominant at the microscale, resulting in stiction and adhesion between small structures, making them fracture and more difficult to deform. Furthermore, despite various actuation approaches, acoustics have received limited attention despite their potential advantages. Here, we introduce "SonoTransformer," the acoustically activated micromachine that delivers shape transformability using preprogrammed soft hinges with different stiffnesses. When exposed to an acoustic field, these hinges concentrate sound energy through intensified oscillation and provide the necessary force and torque for the transformation of the entire micromachine within milliseconds. We have created machine designs to predetermine the folding state, enabling precise programming and customization of the acoustic transformation. Additionally, we have shown selective shape transformable microrobots by adjusting acoustic power, realizing high degrees of control and functional versatility. Our findings open new research avenues in acoustics, physics, and soft matter, offering new design paradigms and development opportunities in robotics, metamaterials, adaptive optics, flexible electronics, and microtechnology., Competing Interests: Competing interests statement:The authors declare no competing interest.

Post‐synthetic shape‐transformation processes provide access to colloidal nanocrystal morphologies that are unattainable by direct synthetic routes. Herein, we report our finding about the ligand‐induced fragmentation of CsPbBr3 perovskite nanowires (NWs) into low aspect‐ratio CsPbX3 (X=Cl, Br and I) nanorods (NRs) during halide ion exchange reaction with PbX2–ligand solution. The shape transformation of NWs‐to‐NRs resulted in an increase of photoluminescence efficiency owing to a decrease of nonradiative decay rates. Importantly, we found that the perovskite NRs exhibit single photon emission as revealed by photon antibunching measurements, while it is not detected in parent NWs. This work not only reports on the quantum light emission of low aspect ratio perovskite NRs, but also expands our current understanding of shape‐dependent optical properties of perovskite nanocrystals. Quantum emitter: CsPbBr3 perovskite nanowires (NWs) break into low aspect‐ratio CsPbX3 (X=Cl, Br and I) nanorods (NRs) of different halide compositions by reaction with PbX2–ligand solution. These perovskite NRs can serve as quantum light sources at room temperature, while the corresponding NWs did not show photon antibunching characteristics. [ABSTRACT FROM AUTHOR]

Abstract Geometric deviations arising from multiple variation sources in Additive Manufacturing (AM) process chain have been a major issue regarding product quality. Therefore, effective modeling of the geometric deviations is becoming critical for AM. In this paper, in-plane geometric deviations are investigated based on the assumption that typical deviation sources in AM can be mapped to different transformations (scaling, rotation, translation) on the nominal shape. By defining transformation parameters, analytical deviation models of regular shapes can be derived in the deviation space, and calibrated based on measurement data. A case study is presented to show the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]

Accurate control of the shape transformation of polymersome is an important and interesting challenge that spans across disciplines such as nanomedicine and nanomachine. Here, we report a fast and facile methodology of shape manipulation of polymersome via out-of-equilibrium polymer self-assembly and shape change by chemical addition of additives. Due to its increased permeability, hydrophilicity, and fusogenic properties, poly(ethylene oxide) was selected as the additive for bringing the system out of equilibrium via fast addition into the polymersome organic solution. A new shape, stomatocyte-in-stomatocyte (sto-in-sto), is obtained for the first time. Moreover, fast shape transformation within less than 1 min to other relevant shapes such as stomatocyte and large compound vesicles was also obtained and accurately controlled in a uniform dispersion. This methodology is demonstrated as a general strategy with which to push the assembly further out of equilibrium to generate unusual nanostructures in a controllable and fast manner. [ABSTRACT FROM AUTHOR]

Engineering structures have increasingly begun to utilize mechanical instability in areas such as energy absorption, shape reconfiguration, and vibration attenuation. Most multi-stable mechanisms use 1D architectures such as pre-curved beams or inclined trusses to achieve multiple strain energy minima. These structures pose several limitations, (1) they generally require external support for functionality, (2) they often balance the competing demands of large stiffness and large amplitude in shape change, and (3) they are inherently less energetically dense compared to shell-based structures as there is negligible stretching in the material. In this work, we introduce a novel class of 4D printed bistable shell structures that morph from flat surfaces. We investigate both the formation of the structural geometry, and the mechanics of the shells once morphed. Following the precepts of 4D printing, the structural geometry is achieved in two stages. First 3D printing is used to fabricate flat polygon unit cells which are then morphed into symmetrical bistable shells. Utilizing Fused Filament Fabrication, a viscoelastic material is pre-strained as it is deposited on the print bed. By tuning the printing parameters, a predictable 2D to 3D shape morphing is triggered with heat, resulting in a height increase of up to 22.9 times the original size. Some resulting unit cells exhibit an elastic bistable response with a high peak force from a point indentation. Shape morphing and structural bistability is predicted using Finite-Element Analysis with prescribed pre-strain aligned with the fiber extrusion direction. The resulting geometries are analyzed for their mechanical behavior. Buckling simulations show good agreement with experimental results. To demonstrate an energy-dissipating metamaterial, we fabricate a planar meta-surface tiled using triangular unit cells to create an auxetic pattern. This sheet morphs to conform to a doubly curved surface globally, with each unit-cell transforming to a bistable shell locally. With this approach, we create a new generation of 4D printed bistable structures that can be applied to a variety of engineering applications. [Display omitted] • Autonomous deployment of 3D printed planar surfaces to 3D shell structures. • The geometry of the morphed shells are tuned by the print path, print speed, and the nozzle temperature. • The morphed shells exhibit tunable modes of stability under mechanical loading. • The deployability and the structural stiffness of the 4D printed morphing shells constitute a novel category of load bearing structures. [ABSTRACT FROM AUTHOR]

Conventional manufacturing techniques—moulding, machining and casting—exist to produce three-dimensional (3D) shapes. However, these industrial processes are typically geared for mass production and are not directly applicable to residential settings, where inexpensive and versatile tools are desirable. Moreover, those techniques are, in general, not adequate to process soft elastic materials. Here, we introduce a new concept of forming 3D closed hollow shapes from two-dimensional (2D) elastic ribbons by controlled buckling. We numerically and experimentally characterize how the profile and thickness of the ribbon determine its buckled shape. We find a 2D master profile with which various elliptical 3D shapes can be formed. More complex natural and artificial hollow shapes, such as strawberry, hourglass and wheel, can also be achieved via strategic design and pattern engraving on the ribbons. The nonlinear response of the post-buckling regime is rationalized through finite-element analysis, which shows good quantitative agreement with experiments. This robust fabrication should complement conventional techniques and provide a rich arena for future studies on the mechanics and new applications of elastic hollow structures.

The article concerns a parametric description of unconventional building forms roofed with folded sheeting transformed elastically into shells. The description supports the designer in the search for attractive forms and a rational use of materials. The adoption of strictly defined sets of initial parameters determines the diversification of the designed architectural free-forms. An impact of selected proportions between these parameters on these forms is illustrated by an example of a single structure. Folded elevations and a segmented shell roof make each such structure internally coherent and externally sensitive. The mutual position and proportions of the shape of all elements, such as the roof, eaves, and façades, along with regular patterns in the same structure, determine this consistency of its form and sensitivity to harmonious incorporation into the natural or built environments. The study is a new insight into shaping free-forms of buildings in which the modern and ecological materials determine the important shape and mechanical limitations of these forms. With a skillful approach, the materials allow their extensive use in buildings. However, various interdisciplinary problems related to architectural shaping of free-forms and static and strength work thin-walled shell sheeting roofs must be solved. For effective design it is necessary to use relevant software applications, where spatial reasoning is crucial for ordering the three-dimensional space by means of simplified engineering models.

The article presents author’s propositions for shaping free forms of buildings sensitive to harmonious incorporation into built or natural environments. Complex folded structures of buildings roofed with regular shell structures are regarded as the most useful in creative shaping the free forms that can easily adapt to various expected environmental conditions. Three more and more sophisticated methods are proposed for creating variously conditioned free form structures. The first method allows the possibility of combining many single free forms into one structure and leaves the designer full freedom in shaping regular or irregular structures. The second, more sophisticated method introduces additional rules supporting the designer’s spatial reasoning and intuition in imposing regularity of the shapes of the building structure and its roof shell structure. The third, most sophisticated method introduces additional conditions allowing the optimization of the regular shapes and arrangement of complete shell roof segments on the basis of an arbitrary reference surface and a finite number of straight lines normal to the surface. This original, interdisciplinary study offers new insight into, and knowledge of, unconventional methods for the creative shaping of innovative free forms, where great possibility and significant restrictions result from geometrical and mechanical properties of the materials used. Solving a number of issues in the field of civil engineering, descriptive geometry and architecture is crucial in the process of creating these structures.

Recurrent neural network (RNN) and Long Short-term Memory (LSTM) networks are the common go-to architecture for exploiting sequential information where the output is dependent on a sequence of inputs. However, in most considered problems, the dependencies typically lie in the latent domain which may not be suitable for applications involving the prediction of a step-wise transformation sequence that is dependent on the previous states only in the visible domain with a known terminal state. We propose a hybrid architecture of convolution neural networks (CNN) and stacked autoencoders (SAE) to learn a sequence of causal actions that nonlinearly transform an input visual pattern or distribution into a target visual pattern or distribution with the same support and demonstrated its practicality in a real-world engineering problem involving the physics of fluids. We solved a high-dimensional one-to-many inverse mapping problem concerning microfluidic flow sculpting, where the use of deep learning methods as an inverse map is very seldom explored. This work serves as a fruitful use-case to applied scientists and engineers in how deep learning can be beneficial as a solution for high-dimensional physical problems, and potentially opening doors to impactful advance in fields such as material sciences and medical biology where multistep topological transformations is a key element. [ABSTRACT FROM AUTHOR]

Sparse representation based face recognition (SRC) has been paid much attention in recent years. Representative algorithms are deformable sparse-representation based classification (DSRC) and shape-constrained texture matching, which focus on misalignment and shape change respectively. Although these algorithms obtain improved accuracy and robustness, their efficiency is not satisfied particularly when applied in a large-scale system. The main difficulty is the expensive calculation in aligning gallery images and the probe image. To solve these problems, this paper proposes a fast alignment strategy for sparse representation based algorithms. The key idea is to pre-compute the most expensive operation, Hessian matrix, which was needed to be calculated in each iteration. Subsequently, with help of the proposed fast alignment strategy, two algorithms, deformable SRC and shape-constrained texture matching, are extended to their fast versions, i.e., fast deformable SRC and fast shape-constrained texture matching. Experimental evaluations have been conducted on the public datasets such as Multi-PIE, FERET, and Cohn-Kanade. We demonstrate that the proposed alignment strategy greatly improves the efficiency of original algorithms without losing accuracy and robustness. [ABSTRACT FROM AUTHOR]

Tailoring the driving force of shape revolution for Au nanoparticles is proposed, and faceted single crystalline Au nanoparticles are prepared by a magnetron sputtering and post thermal annealing route. Theoretical investigation demonstrates that the grain boundary migration is driven by thermal stress at the annealing temperature lower than 600 °C, and in the higher temperature range till up to 900 °C, the shape transformation is driven by minimizing the formation energy. The experimental results successfully replicate the shape revolution of Au films to faceted single crystalline Au nanoparticles, demonstrating that in the first annealing temperature range from 400 to 600 °C, the nanoparticles change more easily from polycrystal grains into single-crystal grains as the annealing temperature increases. While, for the higher temperature range from 700 to 900 °C, the nanoparticles tend to form nanoprisms with regular hexagonal shape when the annealing temperature increasing. [ABSTRACT FROM AUTHOR]

Self-assembly schemes provide a simple and tunable approach to creating a myriad of well-defined nanostructures from design of macromolecules in bulk, thin film and solution environments. Here we demonstrated a facile method to construction of tetraphenylethylene nanoparticles (TPE NPs) by decomposition-assembly from pH-responsive and AIE-characteristic vesicles, which were self-assembled by an amphiphilic PEG 750 -POSS-(TPE) 7 polymer in aqueous solutions. The introduction of Schiff base bonds furnished the fluorescent polymersomes with unique pH responsiveness that is stable under physiological conditions but quickly degradable in acidic environments. Interestingly, the luminous vesicles were transformed into spherical TPE NPs in a solution of lower pH on account of the synergetic combination of cleavage rate of the Schiff base bonds and guidance effect of the entangled tadpole-shaped polymeric chains. The AIE feature of TPE molecule was completely retained in the TPE NPs. Compared to the pH-responsive PEG 750 -POSS-(TPE) 7 vesicles, these AIE-active TPE NPs possessed stable morphology and adjustable size by manipulation of the incubation time. These TPE NPs can be quickly internalized into the tumors through endocytosis pathway and retain strong blue luminescence inside the living cells for a long period, presenting the good photostability and biological imaging property. Cytotoxicity assay revealed that TPE NPs were biocompatible and thus can be utilized for long-term live cell imaging and biomedical applications. [ABSTRACT FROM AUTHOR]

The article concerns the unconventional architectural forms of buildings roofed with transformed shells made up of thin-walled steel fold sheets, and a parametric description of how they are shaped. Complicated deformations of flanges and webs, as well as the complex static⁻strength work of the folds in a shell roof, demand the creation of simplified models regarding the parameterization of such shells and their integration with the general forms of the buildings. To obtain favorable results, it was necessary to write computer applications because of both the complicated problems related to the significant limitations of the transformations, as well as the great possibilities of shaping shell roofs by means of directrices of almost free shape and mutual position. The developed procedures enable the prediction of shapes and states of all the folds in the designed shell. They take account of two basic conditions related to these restrictions, which guarantee that the folds encounter little resistance when matching their transformed forms to the roof directrices, and that their initial effort was as low as possible. The developed procedures required solving a number of issues in the fields of architecture, civil engineering, and structures, and are illustrated with an example of shaping one unconventional architectural form. The interdisciplinary study explains a new insight into shaping such forms.

The manipulation of nano-objects through heating is an effective strategy for inducing structural modifications and therefore changing the optoelectronic properties of semiconducting materials. Despite its potential, the underlying mechanism of the structural transformations remains elusive, largely due to the challenges associated with their in situ observations. To address these issues, we synthesize temperature-sensitive CsPbBr 3 perovskite nanoplatelets and investigate their structural evolution at the nanoscale using in situ heating transmission electron microscopy. We observe the morphological changes that start from the self-assembly of the nanoplatelets into ribbons on a substrate. We identify several paths of merging nanoplates within ribbons that ultimately lead to the formation of nanosheets dispersed randomly on the substrate. These observations are supported by molecular dynamics simulations. We correlate the various paths for merging to the random orientation of the initial ribbons along with the ligand mobility (especially from the edges of the nanoplatelets). This leads to the preferential growth of individual nanosheets and the merging of neighboring ones. These processes enable the creation of structures with tunable emission, ranging from blue to green, all from a single material. Our real-time observations of the transformation of perovskite 2D nanocrystals reveal a route to achieve large-area nanosheets by controlling the initial orientation of the self-assembled objects with potential for large-scale applications.

Additive Manufacturing (AM) technologies have gained extensive applications due to their capability to manufacture parts with complex shape, architected materials and multiple structure. However, the dimensional and geometrical accuracy of the resulting product remain a bottleneck for AM regarding quality assurance and control. Design for Additive Manufacturing (DfAM) aims at using different methodologies to help designer take into account the technological or geometrical specificities of AM, to maximize product performance during the design stage. As a main concern in DfAM, the consistency between the digital product and the final outcome should be effectively assessed. Therefore, the geometric deviations between designed model and real product should be modeled, in order to derive correction and compensation plans to increase geometrical accuracy, or to predict product performance more precisely. In this paper, a new deviation modeling method based on the STL file is proposed. A new shape transformation method is developed based on contour point displacement. In each slice, systematic deviations are represented by polar and radial functions and random deviations are modeled by translating the contour points with a given distance derived from the random field theory. The proposed method makes a good prediction of both repeatable and unexpected deviations of product shape, thus providing the designer with meaningful information for design improvement. [ABSTRACT FROM AUTHOR]