Highly Thermoconductive,Strong Graphene‑Based Composite Films by Eliminating Nanosheets Wrinkles

Graphene-based thermally conductive composites have been proposed as effective thermal management materials for cooling high-power electronic devices.However,when flexible graphene nanosheets are assembled into macroscopic thermally conductive composites,capillary forces induce shrinkage of graphene nanosheets to form wrinkles during solution-based spontaneous drying,which greatly reduces the thermal conductivity of the composites.Herein,graphene nanosheets/aramid nanofiber(GNS/ANF)composite films with high thermal conductivity were prepared by in-plane stretching of GNS/ANF composite hydrogel networks with hydrogen bonds andπ-πinteractions.The in-plane mechanical stretching eliminates graphene nanosheets wrinkles by suppressing inward shrinkage due to capillary forces during drying and achieves a high in-plane orientation of graphene nanosheets,thereby creating a fast in-plane heat transfer channel.The composite films(GNS/ANF-60 wt%)with eliminated graphene nanosheets wrinkles showed a significant increase in thermal conductivity(146 W m^(−1)K^(−1))and tensile strength(207 MPa).The combination of these excellent properties enables the GNS/ANF composite films to be effectively used for cooling flexible LED chips and smartphones,showing promising applications in the thermal management of high-power electronic devices.

Stretchable,Transparent,and Ultra-Broadband Terahertz Shielding Thin Films Based on Wrinkled MXene Architectures

With the increasing demand for terahertz(THz)technology in security inspection,medical imaging,and flexible electronics,there is a significant need for stretchable and transparent THz electromagnetic interference(EMI)shielding materials.Existing EMI shielding materials,like opaque metals and carbon-based films,face challenges in achieving both high transparency and high shielding efficiency(SE).Here,a wrinkled structure strategy was proposed to construct ultra-thin,stretchable,and transparent terahertz shielding MXene films,which possesses both isotropous wrinkles(height about 50 nm)and periodic wrinkles(height about 500 nm).Compared to flat film,the wrinkled MXene film(8 nm)demonstrates a remarkable 36.5%increase in SE within the THz band.The wrinkled MXene film exhibits an EMI SE of 21.1 dB at the thickness of 100 nm,and an average EMI SE/t of 700 dBμm^(−1)over the 0.1-10 THz.Theoretical calculations suggest that the wrinkled structure enhances the film’s conductivity and surface plasmon resonances,resulting in an improved THz wave absorption.Additionally,the wrinkled structure enhances the MXene films’stretchability and stability.After bending and stretching(at 30%strain)cycles,the average THz transmittance of the wrinkled film is only 0.5%and 2.4%,respectively.The outstanding performances of the wrinkled MXene film make it a promising THz electromagnetic shielding materials for future smart windows and wearable electronics.

Trunk‑Inspired SWCNT‑Based Wrinkled Films for Highly‑Stretchable Electromagnetic Interference Shielding and Wearable Thermotherapy

Nowadays,the increasing electromagnetic waves generated by wearable devices are becoming an emerging issue for human health,so stretchable electromagnetic interference(EMI)shielding materials are highly demanded.Elephant trunks are capable of grabbing fragile vegetation and tearing trees thanks not only to their muscles but also to their folded skins.Inspired by the wrinkled skin of the elephant trunks,herein,we propose a winkled conductive film based on single-walled carbon nanotubes(SWCNTs)for multifunctional EMI applications.The conductive film has a sandwich structure,which was prepared by coating SWCNTs on both sides of the stretched elastic latex cylindrical substrate.The shrinking-induced winkled conductive network could withstand up to 200%tensile strain.Typically,when the stretching direction is parallel to the polarization direction of the electric field,the total EMI shielding effectiveness could surprisingly increase from 38.4 to 52.7 dB at 200%tensile strain.It is mainly contributed by the increased connection of the SWCNTs.In addition,the film also has good Joule heating performance at several voltages,capable of releasing pains in injured joints.This unique property makes it possible for strain-adjustable multifunctional EMI shielding and wearable thermotherapy applications.

The Application of Digital Optical 3D Image Analyzer Evaskin in The Evaluation of Wrinkles

To verify the effectiveness of digital optical 3D image analyzer EvaSKIN in the objective and quantitative evaluation of wrinkles.A total of 115 subjects were recruited,the facial images of the subjects were collected by digital optical 3D image analyzer and manual camera,the changes of crow’s feet with age were analyzed.Pictures obtained by manual photography can be directly used for observation and preliminary grading of wrinkles.However,the requirements for evaluators are high,and the results are prone to errors,which will affect the accuracy of the evaluation.Therefore,skilled raters are needed.Compared with the manual photography method,the digital optical 3D image analyzer EvaSKIN can realize three-dimensional extraction of wrinkles,and obtain the change trend of crow’s feet with age.20~30 years old,wrinkles begin to appear slowly;wrinkles will increase rapidly at the age of 30~50;The length of 50~60 year old wrinkles is basically fixed,the wrinkles develop longitudewise,gradually widen and deepen,and the area,depth and volume increase is obvious,and the skin aging condition is intensified.the digital optical 3D image analyzer EvaSKIN realizes the 3D extraction of wrinkles,quantifies the circumference,area,average depth,maximum depth and volume of wrinkles,realizes the objective and quantitative evaluation of wrinkle state,is more accurate in the measurement of wrinkles,and provides a new instrument and method for the evaluation of wrinkles.it is a perfect and supplement to the traditional evaluation methods,and to a certain extent,it helps the research and development and evaluation institutions of cosmetics to obtain more abundant and three-dimensional data support.

Formation and modification of wrinkle ridges in the central Tharsis region of Mars as constrained by detailed geomorphological mapping and landsystem analysis

Wrinkle ridges are common landforms documented on all rocky planets and the Moon in the inner solar system.Despite the long research history,their formation mechanisms remain debated.A key unresolved issue is whether the wrinkle-ridge formation is related to igneous processes.This is because wrinkle ridges are mostly associated in space and possibly in time with the occurrence of flood-basalt volcanism in all cases in the inner solar system.To address this issue,we conducted geomorphological mapping,a topographic-data analysis,and a detailed landform and landsystem analysis of satellite images at a resolution of 25 cm/pixel to 6 m/pixel in the central Tharsis region of Mars.The main results of this work are in the form of(1)a regional geomorphological map at a resolution of 6 m/pixel and(2)a local geomorphological map at a resolution of 50 cm/pixel.Our work suggests the following older-to-younger sequence of geological events in the study area:(1)formation of a northeast-trending mountain range(i.e.,the Thaumasia plateau)along the eastern margin of the Tharsis rise that was created by the Himalayan-style crustal-scale thrusting;(2)coeval volcanic-plateau construction west of the thrusting-induced rising mountain range;(3)eastward-flowing lavas that were sourced from a volcanic plateau to the west terminated at the rising Thaumasia plateau to the east;(4)wrinkle-ridge development by decollement folding of recently emplaced warm,ductile volcanic-lava piles;(5)emplacement of a regionally extensive ice sheet over the central Tharsis region that produced extensive boulder-bearing materials,striated surfaces,and boulder-bearing dendritic-ridge networks possibly representing subglacial eskers;and(6)local deposition of highly concentrated glacial flours resulted in the formation of mantled terrain on plains between wrinkle ridges.Our work supports the early suggestion that the Tharsis wrinkle ridges were created by horizontal shortening induced by crustal-scale tectonic processes.In detail,however,the occurrence of flow-front-like fold margins associated with many mapped wrinkle ridges suggests the involvement of ductile-flow deformation during ridge formation.We attribute the flow-like fold fronts to ductile deformation of thermally weakened lava piles that were emplaced during or immediately before the folding event.Our compression-induced wrinkle-ridge model also differs from the early hypotheses in that the thin-skinned folding is associated with basement subduction,which explains the lack of coeval and parallel folding and extensional faulting associated with wrinkle ridge formation in the study area.Post-folding glacial modification means that the present wrinkle-ridge morphologies may differ significantly from the original fold shapes,which prevents the utility of using topographic profiles across wrinkle ridges for inverting the underlying thrust geometries.

The Neglected Importance of Sleep on the Formation and Aggravation of Facial Wrinkles and Their Prevention

The duration of sleep and the position of the face while resting on a pillow have a negative impact on the facial skin appearance and may lead to the formation of sleep wrinkles. Sleep lines occur when there is repetitive, long-term tension on the facial skin, which pushes or pulls the skin in a direction that is perpendicular to the direction of the muscles of the face. These lines tend to be more vertically oriented than expression lines and can be found on the forehead, around the eyebrows, the eyes, the cheeks, the chin, and the nasolabial folds. Our studies revealed that the average reduction of wrinkles in total investigated area of the face (expressed as the density of wrinkle per surface skin) was approximately 12% after 28 days of sleep on a specially-designed pillow. The specially designed anti-wrinkle pillows eliminate the pressure on the cheeks, the eyes and the mouth during sleep. Many such pillows have been designed to reduce the aging process and to encourage users to sleep in specific positions. Evidence supporting the claim that a special pillow prevents wrinkles was presented. Nevertheless, prolonged human studies are required to further elucidate the role of sleeping on appearance of facial wrinkles.

Objective Fitting Evaluation Model for Dressing Fit Based on Wrinkle Index of Dressing Image

An effective model(image to wrinkle, ITW) for garment fitting evaluation is presented. The proposed model is to improve the accuracy of garment fitting evaluation based on dressing image. The ITW model is an objective evaluation model of fitting based on the wrinkle index of dressing image. The ITW model consists of two main steps, the gray curve-fitting(GCF) threshold segmentation algorithm and Canny edge detection algorithm. In the ITW model, three types of wrinkle trends are defined. And the network dressing image is evaluated and simulated by three quantitative indexes: wrinkle number, wrinkle regularity and wrinkle unevenness. Finally, the fitness of three kinds of dress effects(tight, fit and loose) is quantified by objective fitting evaluation model.

Sleeping on an Anti-Wrinkle Pillow Reduces Facial Wrinkles: Results from an Anatomical Study

Background: A special pillow was designed to redistribute mechanical stress during sleeping in order to slow down the formation of facial skin wrinkles. Objective: To investigate whether sleeping on a specially designed pillow reduces facial skin wrinkles. Participants and Methods: A 28-day pilot study was carried out in which fifteen healthy female volunteers aged 23 - 55 years (mean age 35. 6 ± 8.5) slept on an antiwrinkle pillow. Evaluation of facial wrinkles was conducted before commencing the study (T0), following at 14 days (T14), and at 28 days (T28) when the study ended. Wrinkle density was assessed by computerized analysis of 2D images of participants’ faces. Results: A statistically significant decrease in wrinkle density was detected while smiling around both eyes, around the right eye in a relaxed facial expression, on average in all observed facial areas, around the left periorbital area in participants who predominantly slept on their left side of the body, but not on the frontal area. Limitations: A 3D camera could be used to better visualize and analyze wrinkle density. Conclusions: Sleeping on the specially designed pillow reduces facial wrinkles.

Prediction and Control of Wrinkle and Fracture for Stamping Regular Polygonal Box

Based on the deformation characteristic of regular polygonal box stamped parts and the superfluous triangle material wrinkle model,the criterion of regular polygonal box stamped parts without wrinkle was deduced and used to predict and control the wrinkle limit.According to the fracture model,the criterion of regular polygonal box stamped parts without fracture was deduced and used to predict and control the fracture limit.Combining the criterion for stamping without wrinkle with that without fracture,the stamping criterion of regular polygonal box stamped parts was obtained to predict and control the stamping limit.Taken the stainless steel0Cr18Ni9(SUS304)sheet and the square box stamped part as examples,the limit diagram was given to predict and control the wrinkle,fracture and stamping limits.It is suitable for the deep drawing without flange,the deep drawing and stretching combined forming with flange and the rigid punch stretching of plane blank.The limit deep-drawing coefficient and the minimum deep-drawing coefficient can be determined,and the appropriate BHF(blank holder force)and the deep-drawing force can be chosen.These provide a reference for the technology planning,the die and mold design and the equipment determination,and a new criterion evaluating sheet stamping formability,which predicts and controls the stamping process,can be applied to the deep drawing under constant or variable BHF conditions.

Anisotropic,Wrinkled,and Crack-Bridging Structure for Ultrasensitive,Highly Selective Multidirectional Strain Sensors

Flexible multidirectional strain sensors are crucial to accurately determining the complex strain states involved in emerging sensing applications.Although considerable efforts have been made to construct anisotropic structures for improved selective sensing capabilities,existing anisotropic sensors suffer from a trade-off between high sensitivity and high stretchability with acceptable linearity.Here,an ultrasensitive,highly selective multidirectional sensor is developed by rational design of functionally different anisotropic layers.The bilayer sensor consists of an aligned carbon nanotube(CNT)array assembled on top of a periodically wrinkled and cracked CNT-graphene oxide film.The transversely aligned CNT layer bridge the underlying longitudinal microcracks to effectively discourage their propagation even when highly stretched,leading to superior sensitivity with a gauge factor of 287.6 across a broad linear working range of up to 100%strain.The wrinkles generated through a pre-straining/releasing routine in the direction transverse to CNT alignment is responsible for exceptional selectivity of 6.3,to the benefit of accurate detection of loading directions by the multidirectional sensor.This work proposes a unique approach to leveraging the inherent merits of two cross-influential anisotropic structures to resolve the trade-off among sensitivity,selectivity,and stretchability,demonstrating promising applications in full-range,multi-axis human motion detection for wearable electronics and smart robotics.

Numerical simulation of wrinkle phenomenon during multi-point forming process of shallow rectangle cup

In this paper, the principle of multi-point forming (MPF) technique is presented. One of the most serious defects, wrinkling, during the multi-point forming process of a shallow rectangle cup is discussed by means of numerical simulation on the shallow rectangle cup forming process. The effects of thickness, material of sheet metal and the pressure of the blank holder are investigated. Based on the simulation results, the reasons and control methods of wrinkling are pointed out. Moreover, the experiment on the multi-point die forming of the shallow rectangle cup by the MPF machine is done to validate the efficiency of the numerical simulation, and the result proves that the application of an elastic cushion in the forming can restrain wrinkling efficiently.

Classification of facial wrinkles among Chinese women

It is generally recognized that Caucasians and Asians have different skin aging features. The aim of this study was to develop a facial wrinkle grading scale for Chinese women. Standard photographs were taken of 242 Chinese women. Six sets of 0 to 9 wrinkle scales with reference photographs and descriptions were selected, including grading scales for resting and hyperkinetic crow＇s feet, frontalis lines, glabellar frown lines, and nasolabial folds. To identify the scale by objective quantitative measurement, skin surface measurements from the Visioscan~ VC98 were used. To test the reliability and validity of our wrinkle scale, a multi-rater consensus method was used. A double-blind, randomized, vehicle-controlled 12-week study was conducted to use this clinical photo-score to evaluate the efficacy and safety of Centella triterpenes cream~ in treating crow＇s feet. A newly developed 10-point photographic and descriptive scale emerged from this study. The final atlas of these photographs contained a total of 6 sets with 10 pictures each. From 0 to 9, surface evaluation of smoothness （SEsm） parametric measurements decreased progressively, indicating that the scale increased inversely. Weighted kappa coefficients for intra-assessor were between 0.75-0.87. The overall Kendall＇s coefficient is 0.86 on the first rating and 0.87 on the second rating. Thirty- six volunteers were recruited and 35 subjects completed a 12-week trial. Clinical photo-score by investigator showed a significant difference （P 〈 0.05） between the treatment side and control side after 4 weeks. Use of these scales in clinical settings to evaluate facial wrinkles in Asians individuals is recommended.

WRINKLE LIMIT BLANK HOLDER FORCE MODELS IN SQUARE-BOX DEEP DRAWING WITH VARIABLE SEGMENT BLANK-HOLDERS

Constituting the reasonable control models of the wrinkle limit blank holder forces is the sticking point of the processes of the deep drawing with variable blank-holder forces, especially in the square-box forming. To begin with, a mode of segmenting flange of the square-box into eight zones is put forward according to the fact that the uniformity of flange deforming can be improved by control-ling segment blank-holders. Considering the integral influence of shear stress, a new concept, strain relaxation factor is defined. Hereby, the law of distribution of stress and stain in the deforming flange of square-box is achieved. Then based on these mechanical analysis models and the energy principle, the wrinkling flexivity functions of the straight flange and the circle flange are given, and the corresponding formulae of wrinkling limit blank-holder force in these two situations are also educed. In these processes, ply-anisotropy, strain hardening, thickness and friction are considered. In the end, a calculating example is designed to validate the rationality of the formulae of wrinkling limit blank-holder force, at the same time, the influences of the ply-anisotropy exponent and the strain hardening exponent on the wrinkle limit blank holder forces are also analyzed.

Prediction and Control of both Wrinkle Limit and Fracture Limiton Cylindrical Cup Deep-drawing(Ⅱ)

The prediction and control criterion of both the wrinkle limit and fracture limit on the cylindrical cup deep-drawing are given, and the prediction and control diagram of both the wrinkle limit and fracture limit are also given. The results show that it is suitable for no-flange cylindrical cup deep-drawing, narrow-flange cylindrical cup deep-drawing, wide-flange cylindrical cup deep-drawing/expanding compound forming and rigid punch expanding forming.

Prediction and Control of Both Wrinkle Limit and Fracture Limit on Cylindrical Cup Deep-Drawing

hased on both the wrinkle model and fracturc model, the wrinkle critical tangent pressure and the fractureon critical radial tensile stress are calculated respectively. The maximum tangent pressure formula in the flange deformation zone and the maximum radial tensile stress formula in the cylinder-wall pass force zone are given, and both theno-wrinkle limitl criterion and no-fracture limit criterion are put froward. The prediction and control criterion anddiagram of both the wrinkle limit and fracture limit on cylindrical cup deep-drawing, the most suitable formingzone and the limit deep-drawing coefficient are obtained. Comparing with present experience formulae and actualproduct's production, this prediction and control are quite accurate.

Numerical analysis and experimental studies of membrane wrinkles

Wrinkling patterns and the rules of wrinkling formation and expansion were analyzed in this paper. Direct disturbing method,a numerical method for membrane wrinkling analysis,was established based on finite element programme. The experimental results using photogrammetric procedure were compared with numerical analysis results. It is shown that the reasonable wrinkling deformation can be obtained by rational mesh density and timely removes the initial flaw during analysis. Wrinkles firstly appear on the left and right sides then extend to the membrane center,and the wrinkling amplitude increases with shear displacement. Results from both of the experiments and numerical analysis have a good agreement,which verifies the rationality of the numerical analysis method.

Deformation of wrinkled membrane inflatable structures under concentrated loads

The axisymmetric deformation of a paraboloidal membrane inflatable structure subjected to a concentrated load at its apex and a uniform internal pressure was analyzed. The wrinkle angle was obtained according to the membrane theory when wrinkles appeared and determined the wrinkle region. The wrinkled deformation was obtained based on the relaxed energy function. The effects of inflation pressure and concentrated loads on the wrinkle angle were analyzed and the deformation was obtained at the apex of structure. According to the numerical analysis, the shape of deformed meridians with wrinkles was obtained.

Wrinkle-crease interaction behavior simulation of a rectangular membrane under shearing

Wrinkling analysis of a rectangular membrane with a single crease under shearing is performed to understand the wrinkle-crease interaction behaviors. The crease is considered by introducing the residual stresses from creasing and the effective modulus into the baseline configuration with assumed circular cross-sectional crease geometry. The wrinkling analysis of the creased membrane is then performed by using the direct perturb-force （DP） simulation technique which is based on our modified displacement components （MDC） method. Results reveal that the crease may influence the stress transfer path in the membrane and further change the wrinkling direction. The crease appears to improve the bending stiffness of the membrane which has an effective resistance on the wrinkling evolution. The effects of the crease orientation on wrinkle-crease interaction are studied toward the end of this paper. The results show that the wrinkling amplitude, wavelength, and direction increase as the crease orientation increases, and the wrinkling number decreases with the increasing crease orientation. These results will be of great benefit to the analysis and the control of the wrinkles in the membrane structures.

Porcine Placenta Extract Reduced Wrinkle Formation by Potentiating Epidermal Hydration

Background: Placenta extract is used as an alternative medicine especially in Asian countries as it is a rich reservoir of diverse bioactive molecules. The effects of placenta extract on skin conditions have been previously reported, however, the mechanism underlying for reduced wrinkle formation remains unclear. Objective: The primary objective of this study was to determine whether the continuous application of porcine placenta extract (PPE) alleviates wrinkle formation in humans and explore the underlying mechanism. Methods: Wrinkle formation, skin hydration, and skin elasticity were measured in 15 volunteers at weeks 0 and 6 after continuous application of a gel containing PPE. The production of type I collagen and hyaluronic acid from fibroblasts and keratinocytes, respectively, were measured using ELISA. Expression levels of ceramide synthase 3 (CERS3), filaggrin (FLG), transglutaminase 1 (TGM1), and kallikrein-7 (KLK7) were evaluated by quantitative real-time PCR. Results: The wrinkle index was significantly reduced to 72.1% after a 6-week of applying the PPE gel, along with a significant increase in skin hydration to 126.5%. Type I collagen production from fibroblasts was enhanced slightly but significantly following treatment with PPE. PPE accelerated the expression of CERS3 (1.85-fold), FLG (1.35-fold), TGM1 (1.76-fold), and KLK7 (1.62-fold). Conclusion: Treatment with PPE alleviates wrinkle formation and simultaneously enhances skin hydration, which is induced via the accelerated expression of moisturizing-related proteins. These findings suggest that PPE is effective for combating dryness-induced wrinkle formation.

Wrinkle Resistant Finishing of Cotton Fabrics with the Complex System of PBTCA/CA

In this paper,the wrinkle resistant finishing of cotton fabric with the complex system of PBTCA and CA was mainly discussed.The influence of finishing conditions such as the amount of finishing agent and catalyst,curing temperature and curing time were studied.Wrinkle recovery angle(WRA),breaking strength(BS) and whiteness(Wh) of finished fabric were measured.The experimental data indicated that the best finishing conditions were PBTCA 120g/L,CA 50g/L,sodium hypophosphite 50g/L,triethanolamine 20g/L,cured 170℃ for 120s.