It is highly desirable to develop fiber materials with high strength and toughness while increasing fiber strength always results in a decrease in toughness.Spider silk is a natural fiber material with an excellent co...It is highly desirable to develop fiber materials with high strength and toughness while increasing fiber strength always results in a decrease in toughness.Spider silk is a natural fiber material with an excellent combination of high strength and toughness,which is produced from the spinning dope solution by gelation and drawing spinning process.This encourages people to prepare artificial fibers by mimicking the material,structure,and spinning of natural spider silk.In this review,we first summarized the preparation of artificial spider silk prepared via such a gelation process from different types of materials,including nonrecombinant proteins,recombinant proteins,polypeptides,synthetic polymers,and polymer nanocomposites.In addition,different spinning approaches for spinning artificial spider silk are also summarized.In the third section,some novel application scenarios of the artificial spider silk were summarized,such as artificial muscles,sensing,and smart fibers.展开更多
主题语境:人与自然篇幅:379词关键词:structural color1 Scientists at the University of Central Florida(UCF)have created a new kind of paint thats super light and super tough.The colors in the new paint arent at all like ...主题语境:人与自然篇幅:379词关键词:structural color1 Scientists at the University of Central Florida(UCF)have created a new kind of paint thats super light and super tough.The colors in the new paint arent at all like those in most paints.Instead,theyre more like the colors on a butterflys wings.展开更多
On March 12,the official account of the International Business Daily of the Ministry of Commerce published an article titled“Foreign trade enterprises:full of confidence,clear direction,strong motivation”.The conten...On March 12,the official account of the International Business Daily of the Ministry of Commerce published an article titled“Foreign trade enterprises:full of confidence,clear direction,strong motivation”.The content is as follows:This year,China is still facing a tough foreign trade situation.On the one hand,many international organizations predict that global economic growth in 2024 will still be lower than the historical average and the pressure on external demand will increase;on the other hand,trade protectionism and unilateralism are on the rise,geopolitical conflicts,the global“super election year”and other spillover factors have created many uncertainties.展开更多
For legged robots,collecting tactile information is essential for stable posture and efficient gait.However,mounting sensors on small robots weighing less than 1 kg remain challenges in terms of the sensor’s durabili...For legged robots,collecting tactile information is essential for stable posture and efficient gait.However,mounting sensors on small robots weighing less than 1 kg remain challenges in terms of the sensor’s durability,flexibility,sensitivity,and size.Crackbased sensors featuring ultra-sensitivity,small-size,and flexibility could be a promising candidate,but performance degradation due to crack growing by repeated use is a stumbling block.This paper presents an ultra-stable and tough bio-inspired crack-based sensor by controlling the crack depth using silver nanowire(Ag NW)mesh as a crack stop layer.The Ag NW mesh inspired by skin collagen structure effectively mitigated crack propagation.The sensor was very thin,lightweight,sensitive,and ultra-durable that maintains its sensitivity during 200,000 cycles of 0.5%strain.We demonstrate sensor’s feasibility by implementing the tactile sensation to bio-inspired robots,and propose statistical and deep learning-based analysis methods which successfully distinguished terrain type.展开更多
3.90 mm 65Si2CrV汽车尾门弹簧钢丝生产过程中出现表面龟裂。对表面龟裂产生的主要原因进行分析,6.50 mm钢丝剥皮过程中表面产生厚度约3~4μm白亮层,在韧化转变不充分时遗传下来,后续拉拔时在钢丝表面重新生成白亮层,形成微裂纹,随着拉...3.90 mm 65Si2CrV汽车尾门弹簧钢丝生产过程中出现表面龟裂。对表面龟裂产生的主要原因进行分析,6.50 mm钢丝剥皮过程中表面产生厚度约3~4μm白亮层,在韧化转变不充分时遗传下来,后续拉拔时在钢丝表面重新生成白亮层,形成微裂纹,随着拉拔道次增加,表面白亮层厚度和裂纹深度不断增大,形成裂纹。通过调整剥皮钢丝的韧化工艺,在原韧化温度基础上提高50℃处理后,钢丝表面龟裂未再发生。展开更多
In a captivating video that has swept across Chinese social media in recent weeks,a middle-aged dancermoveswithmasculine energy,his bold and graceful gestures expressing the untamed spirit of the Mongolian grasslands....In a captivating video that has swept across Chinese social media in recent weeks,a middle-aged dancermoveswithmasculine energy,his bold and graceful gestures expressing the untamed spirit of the Mongolian grasslands.This leading performer is Jiang Tiehong,the 56-year-old dean of the College of Dance at Minzu University of China based in Beijing.Jiang is the fifth-generation lead of this iconic dance piece Keep Galloping.Many netizens commented that he epitomizes the idea of the"tough man with a gentle heart."展开更多
如何在逆境中坚持不懈,将失败转化为通往成功的阶梯?让我们一起到文章中寻找答案!Life is like a big picture, and every part of it stands for a choice, a hard time,or a win. Making your own way isn't just about getting w...如何在逆境中坚持不懈,将失败转化为通往成功的阶梯?让我们一起到文章中寻找答案!Life is like a big picture, and every part of it stands for a choice, a hard time,or a win. Making your own way isn't just about getting where you want to go;it's about keeping on trying, even when things get tough.展开更多
As a renewable,biocompatible,biodegradable soft material,chitin hydrogels have better advantages in stability,antibacterial activity,antifouling,cost,immunogenicity,and so on than most polymer hydrogels.However,compar...As a renewable,biocompatible,biodegradable soft material,chitin hydrogels have better advantages in stability,antibacterial activity,antifouling,cost,immunogenicity,and so on than most polymer hydrogels.However,compared with other widely used polymer hydrogels with high strength and toughness,the practical applications of chitin-based hydrogels have been limited by their weak mechanical properties,such as cartilage repair and meniscus replacement.Here,we present the design and fabrication of chitin hydrogels with excellent mechanical strength and toughness by a dehydration and rehydration strategy.By sequential dehydration and rehydration processes,the crystalline domains in the chitin hydrogels can be properly controlled.With optimized crystallinity,the elastic modulus of the chitin hydrogels exceeds all previously reported values,and the fracture toughness is even comparable to some synthetic polymer hydrogels,while maintaining a high-water-content of about 80 wt.%.At the same water content,the mechanical properties of the chitin hydrogels are positively correlated with the hydrogel crystallinity,which proves that the change of mechanical properties of hydrogels is not simply dependent on weight concentration.The hydrogels can be further strengthened by incorporating other biopolymers that are intrinsically weak,which makes the hydrogels promising for applications in fields such as cartilage repair and meniscus replacement.Moreover,the hydrogels enable loading and release of water-soluble and poorly water-soluble drugs.This highly extendable strengthening and toughening strategy of chitin and chitin-based biopolymer hydrogels paves the way for their widely applications.展开更多
Semi-interpenetrating(semi-IPN)hydrogels formed by the continuous interpenetration of cross-linked polymer network and linear non-crosslinked polymer with multifunctionality are widely used in biomedical and other fie...Semi-interpenetrating(semi-IPN)hydrogels formed by the continuous interpenetration of cross-linked polymer network and linear non-crosslinked polymer with multifunctionality are widely used in biomedical and other fields.However,the negative impact of linear polymer on the homogeneity of the cross-linked network often leads to a decrease in the mechanical properties of semi-IPN hydrogels and severely limits their applications.Herein,a bioinspired hydrogen-bonding induced phase separation strategy is presented to construct the tough semi-IPN polyvinylpyrrolidone/polyacrylamide hydrogels(named PVP/PAM hydrogels),including the linear polymer polyvinylpyrrolidone(PVP)and cross-linked polyacrylamide(PAM)network.The resultant PVPx/PAM hydrogels exhibit unique phase separation induced by the hydrogen bonding between PVP and PAM and affected by the amount of substance of PVP.Meanwhile,the phase separation of PVPx/PAM hydrogels results in excellent mechanical properties with a strain of 2590%,tensile strength of 0.28 MPa and toughness of 2.17 MJ/m^(3).More importantly,the hydrogen bonding between PVP and PAM firstly disrupts to dissipate energy under external forces,so the PVPx/PAM hydrogels exhibit good self-recovery properties and outperform chemically cross-linked PAM hydrogels in impact resistance and damping applications.It is believed that the PVPx/PAM hydrogels with hydrogen-bonding induced phase separation possess more potential application prospects.展开更多
Organic rich dark shale of Q Formation can be found in many areas(e.g.,in the North of S Basin).The shale target stratum is easy to hydrate and often undergoes spallation.Therefore,centering the casing in the horizont...Organic rich dark shale of Q Formation can be found in many areas(e.g.,in the North of S Basin).The shale target stratum is easy to hydrate and often undergoes spallation.Therefore,centering the casing in the horizontal section of the irregular borehole is relatively difficult.Similarly,achieving a good cementflushing efficiency under complex borehole conditions is a complex task.Through technologies such as centralizer,efficient preflushing,multi-stageflushing and ductile cement slurry,better performances can be achieved.In this study,it is shown that the cementing rate in the DY2H horizontal section is 97.8%,which is more than 34%higher than that of adjacent wells.This cementing matching technology for sidetracking horizontal wells can be used to improve the cementing quality of continental shale and provides a reference for future applications in thisfield.展开更多
Corneal transplantation is an effective clinical treatment for corneal diseases,which,however,is limited by donor corneas.It is of great clinical value to develop bioadhesive corneal patches with functions of“Transpa...Corneal transplantation is an effective clinical treatment for corneal diseases,which,however,is limited by donor corneas.It is of great clinical value to develop bioadhesive corneal patches with functions of“Transparency”and“Epithelium&Stroma generation”,as well as“Suturelessness”and“Toughness”.To simultaneously meet the“T.E.S.T.”requirements,a light-curable hydrogel is designed based on methacryloylated gelatin(GelMA),Pluronic F127 diacrylate(F127DA)&Aldehyded Pluronic F127(AF127)co-assembled bi-functional micelles and collagen type I(COL I),combined with clinically applied corneal cross-linking(CXL)technology for repairing damaged cornea.The patch formed after 5 min of ultraviolet irradiation possesses transparent,highly tough,and strongly bio-adhesive performance.Multiple cross-linking makes the patch withstand deformation near 600%and exhibit a burst pressure larger than 400 mmHg,significantly higher than normal intraocular pressure(10-21 mmHg).Besides,the slower degradation than GelMA-F127DA&AF127 hydrogel without COL I makes hydrogel patch stable on stromal beds in vivo,supporting the regrowth of corneal epithelium and stroma.The hydrogel patch can replace deep corneal stromal defects and well bio-integrate into the corneal tissue in rabbit models within 4 weeks,showing great potential in surgeries for keratoconus and other corneal diseases by combining with CXL.展开更多
The arch wire(AW)plays an important role in providing continuous force,aligning the teeth,and excellent dental arch stability for orthodontic treatment.However,the high friction performance of the AW surface can incre...The arch wire(AW)plays an important role in providing continuous force,aligning the teeth,and excellent dental arch stability for orthodontic treatment.However,the high friction performance of the AW surface can increase bacterial adhesion and colonization,leading to oral hygiene problems.Herein,a simple method is developed to modify the surface of the orthodontic wire with a poly(vinyl alcohol)(PVA)hydrogel coating,which can improve the lubricity and antibacterial adhesion of the AW and prevent the oral hygiene problems caused by itself.The PVA hydrogel coating can toughly adhere to the surface of the AW and remarkably reduce the friction performance of the AW,and then its friction coefficient in water can reach 0.005.Under the action of brushing and bending,the PVA hydrogel coating possesses superior ultralubrication and hardly affects the mechanical properties of the stainless-steel substrate.Moreover,the PVA hydrogel coating can significantly inhibit bacterial adhesion on the surface of the AW,thereby reducing bacterial colonization and maintaining oral hygiene while correcting the shape of the mouth and jaw.Therefore,the PVA hydrogel coating exhibits tough adhesion and good antibacterial adhesion while maintaining the mechanical properties of the AW,and it is a promising antifouling coating for improving the performance of the AW.展开更多
基金This study was supported by the National Key Research and Development Program of China(Nos.2019YFE0119600,2022YFB3807103)the National Natural Science Foundation of China(Nos.52090034,52225306,51973093,and 51773094)+4 种基金Frontiers Science Center for New Organic Matter,Nankai University(No.63181206)the National Special Support Plan for High-Level Talents People(No.C041800902)the Science Foundation for Distinguished Young Scholars of Tianjin(No.18JCJQJC46600)the Fundamental Research Funds for the Central Universities(No.63171219)the Operation Huiyan(No.62502510601).
文摘It is highly desirable to develop fiber materials with high strength and toughness while increasing fiber strength always results in a decrease in toughness.Spider silk is a natural fiber material with an excellent combination of high strength and toughness,which is produced from the spinning dope solution by gelation and drawing spinning process.This encourages people to prepare artificial fibers by mimicking the material,structure,and spinning of natural spider silk.In this review,we first summarized the preparation of artificial spider silk prepared via such a gelation process from different types of materials,including nonrecombinant proteins,recombinant proteins,polypeptides,synthetic polymers,and polymer nanocomposites.In addition,different spinning approaches for spinning artificial spider silk are also summarized.In the third section,some novel application scenarios of the artificial spider silk were summarized,such as artificial muscles,sensing,and smart fibers.
文摘主题语境:人与自然篇幅:379词关键词:structural color1 Scientists at the University of Central Florida(UCF)have created a new kind of paint thats super light and super tough.The colors in the new paint arent at all like those in most paints.Instead,theyre more like the colors on a butterflys wings.
文摘On March 12,the official account of the International Business Daily of the Ministry of Commerce published an article titled“Foreign trade enterprises:full of confidence,clear direction,strong motivation”.The content is as follows:This year,China is still facing a tough foreign trade situation.On the one hand,many international organizations predict that global economic growth in 2024 will still be lower than the historical average and the pressure on external demand will increase;on the other hand,trade protectionism and unilateralism are on the rise,geopolitical conflicts,the global“super election year”and other spillover factors have created many uncertainties.
基金the Defense Acquisition Program Administration’s Critical Technology R&D program(No.UC190002D).
文摘For legged robots,collecting tactile information is essential for stable posture and efficient gait.However,mounting sensors on small robots weighing less than 1 kg remain challenges in terms of the sensor’s durability,flexibility,sensitivity,and size.Crackbased sensors featuring ultra-sensitivity,small-size,and flexibility could be a promising candidate,but performance degradation due to crack growing by repeated use is a stumbling block.This paper presents an ultra-stable and tough bio-inspired crack-based sensor by controlling the crack depth using silver nanowire(Ag NW)mesh as a crack stop layer.The Ag NW mesh inspired by skin collagen structure effectively mitigated crack propagation.The sensor was very thin,lightweight,sensitive,and ultra-durable that maintains its sensitivity during 200,000 cycles of 0.5%strain.We demonstrate sensor’s feasibility by implementing the tactile sensation to bio-inspired robots,and propose statistical and deep learning-based analysis methods which successfully distinguished terrain type.
文摘3.90 mm 65Si2CrV汽车尾门弹簧钢丝生产过程中出现表面龟裂。对表面龟裂产生的主要原因进行分析,6.50 mm钢丝剥皮过程中表面产生厚度约3~4μm白亮层,在韧化转变不充分时遗传下来,后续拉拔时在钢丝表面重新生成白亮层,形成微裂纹,随着拉拔道次增加,表面白亮层厚度和裂纹深度不断增大,形成裂纹。通过调整剥皮钢丝的韧化工艺,在原韧化温度基础上提高50℃处理后,钢丝表面龟裂未再发生。
文摘In a captivating video that has swept across Chinese social media in recent weeks,a middle-aged dancermoveswithmasculine energy,his bold and graceful gestures expressing the untamed spirit of the Mongolian grasslands.This leading performer is Jiang Tiehong,the 56-year-old dean of the College of Dance at Minzu University of China based in Beijing.Jiang is the fifth-generation lead of this iconic dance piece Keep Galloping.Many netizens commented that he epitomizes the idea of the"tough man with a gentle heart."
基金supported by the National Natural Science Foundation of China(52125201 and 21975141)the National Key Basic Research and Development Program of China(2020YFA0210702)。
文摘如何在逆境中坚持不懈,将失败转化为通往成功的阶梯?让我们一起到文章中寻找答案!Life is like a big picture, and every part of it stands for a choice, a hard time,or a win. Making your own way isn't just about getting where you want to go;it's about keeping on trying, even when things get tough.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Nos.XDB0470303 and XDB0450402)the National Key Research and Development Program of China(Nos.2018YFE0202201 and 2021YFA0715700)+1 种基金the National Natural Science Foundation of China(No.22293044)the Major Basic Research Project of Anhui Province(No.2023z04020009).
文摘As a renewable,biocompatible,biodegradable soft material,chitin hydrogels have better advantages in stability,antibacterial activity,antifouling,cost,immunogenicity,and so on than most polymer hydrogels.However,compared with other widely used polymer hydrogels with high strength and toughness,the practical applications of chitin-based hydrogels have been limited by their weak mechanical properties,such as cartilage repair and meniscus replacement.Here,we present the design and fabrication of chitin hydrogels with excellent mechanical strength and toughness by a dehydration and rehydration strategy.By sequential dehydration and rehydration processes,the crystalline domains in the chitin hydrogels can be properly controlled.With optimized crystallinity,the elastic modulus of the chitin hydrogels exceeds all previously reported values,and the fracture toughness is even comparable to some synthetic polymer hydrogels,while maintaining a high-water-content of about 80 wt.%.At the same water content,the mechanical properties of the chitin hydrogels are positively correlated with the hydrogel crystallinity,which proves that the change of mechanical properties of hydrogels is not simply dependent on weight concentration.The hydrogels can be further strengthened by incorporating other biopolymers that are intrinsically weak,which makes the hydrogels promising for applications in fields such as cartilage repair and meniscus replacement.Moreover,the hydrogels enable loading and release of water-soluble and poorly water-soluble drugs.This highly extendable strengthening and toughening strategy of chitin and chitin-based biopolymer hydrogels paves the way for their widely applications.
基金This work was financially supported by the National Natural Science Foundation of China(No.52273210).
文摘Semi-interpenetrating(semi-IPN)hydrogels formed by the continuous interpenetration of cross-linked polymer network and linear non-crosslinked polymer with multifunctionality are widely used in biomedical and other fields.However,the negative impact of linear polymer on the homogeneity of the cross-linked network often leads to a decrease in the mechanical properties of semi-IPN hydrogels and severely limits their applications.Herein,a bioinspired hydrogen-bonding induced phase separation strategy is presented to construct the tough semi-IPN polyvinylpyrrolidone/polyacrylamide hydrogels(named PVP/PAM hydrogels),including the linear polymer polyvinylpyrrolidone(PVP)and cross-linked polyacrylamide(PAM)network.The resultant PVPx/PAM hydrogels exhibit unique phase separation induced by the hydrogen bonding between PVP and PAM and affected by the amount of substance of PVP.Meanwhile,the phase separation of PVPx/PAM hydrogels results in excellent mechanical properties with a strain of 2590%,tensile strength of 0.28 MPa and toughness of 2.17 MJ/m^(3).More importantly,the hydrogen bonding between PVP and PAM firstly disrupts to dissipate energy under external forces,so the PVPx/PAM hydrogels exhibit good self-recovery properties and outperform chemically cross-linked PAM hydrogels in impact resistance and damping applications.It is believed that the PVPx/PAM hydrogels with hydrogen-bonding induced phase separation possess more potential application prospects.
基金funded by the CNPC Science and Technology Department Project(2021ZZ10-03)。
文摘Organic rich dark shale of Q Formation can be found in many areas(e.g.,in the North of S Basin).The shale target stratum is easy to hydrate and often undergoes spallation.Therefore,centering the casing in the horizontal section of the irregular borehole is relatively difficult.Similarly,achieving a good cementflushing efficiency under complex borehole conditions is a complex task.Through technologies such as centralizer,efficient preflushing,multi-stageflushing and ductile cement slurry,better performances can be achieved.In this study,it is shown that the cementing rate in the DY2H horizontal section is 97.8%,which is more than 34%higher than that of adjacent wells.This cementing matching technology for sidetracking horizontal wells can be used to improve the cementing quality of continental shale and provides a reference for future applications in thisfield.
基金This work was supported by the Shanghai Rising-Star Program(Grants No.21QA1401500)Clinical Research Plan of SHDC(Grants No.SHDC2020CR1043B).
文摘Corneal transplantation is an effective clinical treatment for corneal diseases,which,however,is limited by donor corneas.It is of great clinical value to develop bioadhesive corneal patches with functions of“Transparency”and“Epithelium&Stroma generation”,as well as“Suturelessness”and“Toughness”.To simultaneously meet the“T.E.S.T.”requirements,a light-curable hydrogel is designed based on methacryloylated gelatin(GelMA),Pluronic F127 diacrylate(F127DA)&Aldehyded Pluronic F127(AF127)co-assembled bi-functional micelles and collagen type I(COL I),combined with clinically applied corneal cross-linking(CXL)technology for repairing damaged cornea.The patch formed after 5 min of ultraviolet irradiation possesses transparent,highly tough,and strongly bio-adhesive performance.Multiple cross-linking makes the patch withstand deformation near 600%and exhibit a burst pressure larger than 400 mmHg,significantly higher than normal intraocular pressure(10-21 mmHg).Besides,the slower degradation than GelMA-F127DA&AF127 hydrogel without COL I makes hydrogel patch stable on stromal beds in vivo,supporting the regrowth of corneal epithelium and stroma.The hydrogel patch can replace deep corneal stromal defects and well bio-integrate into the corneal tissue in rabbit models within 4 weeks,showing great potential in surgeries for keratoconus and other corneal diseases by combining with CXL.
基金Excellent Youth Fund Project of Henan Natural Science Foundation(Grant No.202300410166)the National Natural Science Foundation of China(Grant No.22202051)+2 种基金the Major Project of WIUCAS(Grant Nos.WIUCASQD2021004 and WIUCASQD2021035)the Project of Wenzhou Key Lab(Grant No.2021HZSY0069)the Science Foundation of Oujiang Laboratory(Grant No.OJQDSP2022018)。
文摘The arch wire(AW)plays an important role in providing continuous force,aligning the teeth,and excellent dental arch stability for orthodontic treatment.However,the high friction performance of the AW surface can increase bacterial adhesion and colonization,leading to oral hygiene problems.Herein,a simple method is developed to modify the surface of the orthodontic wire with a poly(vinyl alcohol)(PVA)hydrogel coating,which can improve the lubricity and antibacterial adhesion of the AW and prevent the oral hygiene problems caused by itself.The PVA hydrogel coating can toughly adhere to the surface of the AW and remarkably reduce the friction performance of the AW,and then its friction coefficient in water can reach 0.005.Under the action of brushing and bending,the PVA hydrogel coating possesses superior ultralubrication and hardly affects the mechanical properties of the stainless-steel substrate.Moreover,the PVA hydrogel coating can significantly inhibit bacterial adhesion on the surface of the AW,thereby reducing bacterial colonization and maintaining oral hygiene while correcting the shape of the mouth and jaw.Therefore,the PVA hydrogel coating exhibits tough adhesion and good antibacterial adhesion while maintaining the mechanical properties of the AW,and it is a promising antifouling coating for improving the performance of the AW.
