The PICOSEC Micromegas(MM)is a precise timing gaseous detector based on a Cherenkov radiator coupled with a semi-transparent photocathode and an MM amplifying structure.It features a two-stage amplification process th...The PICOSEC Micromegas(MM)is a precise timing gaseous detector based on a Cherenkov radiator coupled with a semi-transparent photocathode and an MM amplifying structure.It features a two-stage amplification process that leads to a significant deterioration of non-uniformity when scaling up to larger areas.Since the performance of gaseous detectors is highly dependent on the choice of working gas,optimizing the gas mixture offers a promising solution to improve the uniformity performance.This paper addresses these challenges through a combined approach of simulation based on Garfield++and experimental studies.The simulation investigates the properties of different mixing fractions of gas mixtures and their impact on detector performance,including gain uniformity and time resolution.To verify the simulation results,experimental tests were conducted using a multi-channel PICOSEC MM prototype with different gas mixtures.The experimental results are consistent with the findings of the simulation,indicating that a higher concentration of neon significantly improves the detector’s gain uniformity.Furthermore,the influence of gas mixtures on time resolution was explored as a critical performance indicator.The study presented in this paper offers valuable insights for improving uniformity in large-area PICOSEC MM detectors and optimizing overall performance.展开更多
When the protective and protected systems are detached,the former can be allowed to absorb the kinetic energy of the impacting projectile through large deformation without considering the back face signature of the la...When the protective and protected systems are detached,the former can be allowed to absorb the kinetic energy of the impacting projectile through large deformation without considering the back face signature of the latter.This paper presents a novel double-face knitted fabric(DFKF)designed for this very impacting scenario.Shooting tests equipped with high-speed camera were used to characterize the ballistic performance with the impact velocities ranging from 100 m/s to 450 m/s.The results showed that the ballistic limits(V_(bl))of DFKF are approximately triple and double that of its counterpart UD and plain fabrics,respectively.For mass-normalized metrics,the specific energy absorption(SEA)is 250%and 350%greater than the UD and plain fabrics at their corresponding V_(bl)s.The quasi-static tests showed that the DFKF displayed greater resilience,crease recovery properties,and flexibility,which also made it an especially better candidate than UD and plain weaves for the design of umbrella surface cloth.It was also found that DFKF is dependent on yarn count and the incorporation of spandex.A prototype anti-ballistic umbrella is manufactured using DFKF made of 200D multi-filament yarn.The ballistic performance is also sensitive to the impact site when the umbrella is subjected to impact.展开更多
Aramid fibers,due to their relatively high inter-yarn friction,high strength,high modulus,and other characteristics,have become a typical representative of flexible anti-ballistic materials in modern warfare.Current r...Aramid fibers,due to their relatively high inter-yarn friction,high strength,high modulus,and other characteristics,have become a typical representative of flexible anti-ballistic materials in modern warfare.Current research on the anti-penetration of aramid fabrics mostly focuses unilaterally on the structure and performance of aramid fabrics or the shape and size of projectiles,with fewer studies on the coupled effect of both on ballistic performance.This study analyzes how the coupling relationship(or size effect)between the projectile and fiber bundle dimensions affects the fabric ballistic performance from a mesoscopic scale perspective.Taking plain weave aramid fabric as the research object,considering different diameter projectiles,through a large number of ballistic impact tests and numerical simulations,parameters such as ballistic limit velocity,average energy absorption of fabric,and specific energy absorption ratio(average energy absorption of fabric divided by projectile cross-sectional area)are obtained for ballistic performance analysis.The influence law of projectile size on the ballistic performance of high-performance fabrics is as follows:The relative range of fitted ballistic limit velocity at different target positions gradually decreases and then stabilizes as the projectile diameter increases,indicating that the fabric structure effect gradually disappears at a projectile diameter of 12 mm;The average ballistic limit velocity at three impact positions,P1,P2,and P3,provides the corresponding ballistic limit velocity for 1000D aramid fabric,which increases with projectile diameter but the rate of increase slows down at an inflection point,which in this study occurs where the fabric structure effect nearly disappears at a projectile diameter of 12 mm;The energy absorption ratio increases and then decreases as the projectile diameter increases from 4 mm to 20 mm,reaching a peak at the diameter of 12 mm due to the gradual disappearance of the fabric structural effect.The projectile diameter of 12 mm corresponds to the coupling size of 11.159,which provides a size design reference for the macroscopic-based continuum models of aramid plain weave fabrics.展开更多
The ballistic perforation response of composite fabrics made by combining plain weaves with seaming technology is reported and compared with conventional unseamed plain fabrics.The effect of the seaming technique on t...The ballistic perforation response of composite fabrics made by combining plain weaves with seaming technology is reported and compared with conventional unseamed plain fabrics.The effect of the seaming technique on the ballistic resistance of aramid plain fabrics is investigated by varying the seaming process.The ballistic experiment uses 8 mm diameter spherical projectiles to impact different fabric sample targets with velocities of 230 m/s and 400 m/s.The ballistic performance of seamed and unseamed fabrics is characterized by the specific energy absorption(SEA)values of the fabrics.The results show that the seamed fabric has a better energy absorption capacity than the unseamed fabric,e.g.,the SEA of sample 5(seaming lines on every four yarns in a single-ply fabric system)is 135%of sample 1(plain weave without thread seaming).In the single-layer system,the effect of the seaming technique on the energy absorption of the fabric in significant when considering seaming density,seaming orientation,seaming distance,and seaming material on the plain fabric;In addition,it is found that in multi-layer systems,seamed panels(e.g.,sample 7)exhibit better ballistic performance than multi-layer fabrics(e.g.,sample 2),and the specific energy absorption of sample 7 is approximately 156%and 200%of sample 6 and sample 2,respectively.Meanwhile,the energy absorption of the fabric decreases with the increase of impact velocity,which is related to the energy absorption mechanism of the soft fabric system at high impact velocities.The yarn pull-out tests shows that the constraint provided by the seaming thread increases the friction between the fabric-forming yarns.However,when the constraint exceeds a certain level,it is detrimental to the energy absorption of the fabric,which may be due to the overconstraint of yarn mobility.展开更多
OBJECTIVE To investigate 3-O-(Z)-coumaroyloleanolic acid(3-COA),an active ingredient of oleanolic acid in the TAIWANG leaves of E.oldhamii Maxim,that has been shown to have antitumor activity against A549 lung cancer ...OBJECTIVE To investigate 3-O-(Z)-coumaroyloleanolic acid(3-COA),an active ingredient of oleanolic acid in the TAIWANG leaves of E.oldhamii Maxim,that has been shown to have antitumor activity against A549 lung cancer cells,overcomes Cks1b-induced chemoresistance in lung cancer by inhibiting Hsp90 and MEK pathways.METHODS Cisplatin(CDDP)and doxorubicin(DOX)sensitivity was assessed through proliferation,viability,and clonogenic potential induction in cells overexpressing Cks1b(Cks1b-OE).The mechanism for resistance and 3-COA sensitivity were elucidated by immunoblot analysis of Hsp90 and MEK,and confirmed by sh RNA knockdown.Inhibition of 3-COA or3-COA combined with CDDP(3-COA&CDDP)was assayed in early primary lung cancer(IPH),late primary lung cancer(RFH)cells,and tumor-burdened immunodeficiency mice in vivo.RESULTS The ectopic overexpression of Cks1b in human lung cancer cells induces chemoresistance of the cells to CDDP and DOX,but not3-COA,through mechanisms independent of its canonical Skp2-p27 pathway.Further dissection with application of shR NA and selective inhibitors reveals that Hsp90 and MEK1/2 are the critical components of the non-canonical pathways responsible for the Cks1b-induced chemoresistance.Interestingly,inhibition of either Hsp90 or MEK1/2rendered a similar magnitude of antitumor activity by resensitization of the chemoresistant Cks1b-OE cells to CDDP and DOX,suggesting that both Hsp90 and MEK1/2are essentialto Cks1b for induction of chemoresistance.IC50of 3-COA is 6.82μmol·L-1in H358 Cks1b and8.22μmol·L-1in H226 Cks1b,which were not significantly higher than those in H358 EV and H226 EV,respectively.Furthermore,3-COA mimicked PU-H71,a Hsp90-specific inhibitor,targeted Hsp90 and MEK to reduce the expression of their downstream,respectively.Importantly,compared with CDDP treatment,3-COA or 3-COA&CDDP signifi-cantly inhibited RFH cells in vitro.Moreover,3-COA or3-COA&CDDP significantly prolonged more survival for a H358 Cks1b-OE inducing tumor-burdened mice than PD98059(a MEK-specific inhibitor)in vivo.CONCLUSION Our data report for the first time that Cks1b employs Hsp90 and MEK1/2 pathways in lung cancer cells to develop chemoresistance and identify 3-COA as a potential antitumor drug for clinical treatment of chemoresistant lung cancer.展开更多
It has been reported that the ply gap influences the ballistic resistance of spaced multi-ply fabric systems,but its working mechanism was not well-understood. This paper reports the experimental and numerical approac...It has been reported that the ply gap influences the ballistic resistance of spaced multi-ply fabric systems,but its working mechanism was not well-understood. This paper reports the experimental and numerical approaches and results of an investigation on the mechanisms that enable the improved ballistic performance of spaced multi-ply systems. Penetration tests were performed over a range of impact velocities ranging from 200 m/s to 400 m/s. The results confirmed that the ply gap is beneficial to the energy absorption capability of the systems. This is because the front plies tend to absorb more energy when they are not immediately constrained by the rear plies. During a ballistic event, the gap relieves the reflection of the compressive pulse, prolonging the projectile engagement time with the front plies;on the other hand, the rear plies become increasingly less active in dissipating energy as the gap increases.When the gap is sufficiently widened to avoid any interference between the plies before the failure of the front ply, the responses of the whole system no longer vary. It was also found that the ballistic performance of the spaced systems is influenced by ply thickness, impact velocity, and the stacking order of the ply gap.展开更多
基金supported by the National Natural Science Foundation of China(12125505).
文摘The PICOSEC Micromegas(MM)is a precise timing gaseous detector based on a Cherenkov radiator coupled with a semi-transparent photocathode and an MM amplifying structure.It features a two-stage amplification process that leads to a significant deterioration of non-uniformity when scaling up to larger areas.Since the performance of gaseous detectors is highly dependent on the choice of working gas,optimizing the gas mixture offers a promising solution to improve the uniformity performance.This paper addresses these challenges through a combined approach of simulation based on Garfield++and experimental studies.The simulation investigates the properties of different mixing fractions of gas mixtures and their impact on detector performance,including gain uniformity and time resolution.To verify the simulation results,experimental tests were conducted using a multi-channel PICOSEC MM prototype with different gas mixtures.The experimental results are consistent with the findings of the simulation,indicating that a higher concentration of neon significantly improves the detector’s gain uniformity.Furthermore,the influence of gas mixtures on time resolution was explored as a critical performance indicator.The study presented in this paper offers valuable insights for improving uniformity in large-area PICOSEC MM detectors and optimizing overall performance.
基金support from the following for aspects of the research,authorship,and/or publication of this article:National Natural Science Foundation of China(Grant No.12302187)Innovation Program of Wuhan-Shuguang Project(Grant No.202201080102).
文摘When the protective and protected systems are detached,the former can be allowed to absorb the kinetic energy of the impacting projectile through large deformation without considering the back face signature of the latter.This paper presents a novel double-face knitted fabric(DFKF)designed for this very impacting scenario.Shooting tests equipped with high-speed camera were used to characterize the ballistic performance with the impact velocities ranging from 100 m/s to 450 m/s.The results showed that the ballistic limits(V_(bl))of DFKF are approximately triple and double that of its counterpart UD and plain fabrics,respectively.For mass-normalized metrics,the specific energy absorption(SEA)is 250%and 350%greater than the UD and plain fabrics at their corresponding V_(bl)s.The quasi-static tests showed that the DFKF displayed greater resilience,crease recovery properties,and flexibility,which also made it an especially better candidate than UD and plain weaves for the design of umbrella surface cloth.It was also found that DFKF is dependent on yarn count and the incorporation of spandex.A prototype anti-ballistic umbrella is manufactured using DFKF made of 200D multi-filament yarn.The ballistic performance is also sensitive to the impact site when the umbrella is subjected to impact.
基金National Natural Science Foundation of China(Grant Nos.12172179,11802141 and U2341244)National Natural Science Foundation for Young Scientists of China(Grant No.12202207)+3 种基金China Postdoctoral Science Foundation(Grant No.2022M711623)Natural Science Foundation of Jiangsu Province(Grant No.BK20220968)Open Funds for Key Laboratory of Impact and Safety Engineering(Ningbo University),Ministry of Education(Grant No.CJ202201)Open Funds for Shock and Vibration of Engineering Materials and Structures Key Laboratory of Sichuan Province(Grant No.22kfgk03)。
文摘Aramid fibers,due to their relatively high inter-yarn friction,high strength,high modulus,and other characteristics,have become a typical representative of flexible anti-ballistic materials in modern warfare.Current research on the anti-penetration of aramid fabrics mostly focuses unilaterally on the structure and performance of aramid fabrics or the shape and size of projectiles,with fewer studies on the coupled effect of both on ballistic performance.This study analyzes how the coupling relationship(or size effect)between the projectile and fiber bundle dimensions affects the fabric ballistic performance from a mesoscopic scale perspective.Taking plain weave aramid fabric as the research object,considering different diameter projectiles,through a large number of ballistic impact tests and numerical simulations,parameters such as ballistic limit velocity,average energy absorption of fabric,and specific energy absorption ratio(average energy absorption of fabric divided by projectile cross-sectional area)are obtained for ballistic performance analysis.The influence law of projectile size on the ballistic performance of high-performance fabrics is as follows:The relative range of fitted ballistic limit velocity at different target positions gradually decreases and then stabilizes as the projectile diameter increases,indicating that the fabric structure effect gradually disappears at a projectile diameter of 12 mm;The average ballistic limit velocity at three impact positions,P1,P2,and P3,provides the corresponding ballistic limit velocity for 1000D aramid fabric,which increases with projectile diameter but the rate of increase slows down at an inflection point,which in this study occurs where the fabric structure effect nearly disappears at a projectile diameter of 12 mm;The energy absorption ratio increases and then decreases as the projectile diameter increases from 4 mm to 20 mm,reaching a peak at the diameter of 12 mm due to the gradual disappearance of the fabric structural effect.The projectile diameter of 12 mm corresponds to the coupling size of 11.159,which provides a size design reference for the macroscopic-based continuum models of aramid plain weave fabrics.
基金supported by the National Natural Science Foundation of China(11902008)Hubei Province Science and Technology Project(2021BAA069)。
文摘The ballistic perforation response of composite fabrics made by combining plain weaves with seaming technology is reported and compared with conventional unseamed plain fabrics.The effect of the seaming technique on the ballistic resistance of aramid plain fabrics is investigated by varying the seaming process.The ballistic experiment uses 8 mm diameter spherical projectiles to impact different fabric sample targets with velocities of 230 m/s and 400 m/s.The ballistic performance of seamed and unseamed fabrics is characterized by the specific energy absorption(SEA)values of the fabrics.The results show that the seamed fabric has a better energy absorption capacity than the unseamed fabric,e.g.,the SEA of sample 5(seaming lines on every four yarns in a single-ply fabric system)is 135%of sample 1(plain weave without thread seaming).In the single-layer system,the effect of the seaming technique on the energy absorption of the fabric in significant when considering seaming density,seaming orientation,seaming distance,and seaming material on the plain fabric;In addition,it is found that in multi-layer systems,seamed panels(e.g.,sample 7)exhibit better ballistic performance than multi-layer fabrics(e.g.,sample 2),and the specific energy absorption of sample 7 is approximately 156%and 200%of sample 6 and sample 2,respectively.Meanwhile,the energy absorption of the fabric decreases with the increase of impact velocity,which is related to the energy absorption mechanism of the soft fabric system at high impact velocities.The yarn pull-out tests shows that the constraint provided by the seaming thread increases the friction between the fabric-forming yarns.However,when the constraint exceeds a certain level,it is detrimental to the energy absorption of the fabric,which may be due to the overconstraint of yarn mobility.
基金The project supported by National Natural Science Foundation of China(81402023)Natural Science Foundation of Guangdong Province(2014A030310022)+1 种基金Scientific Research Projects of Guangzhou(201510010212)College Students Cultivate Special Science and Technology Innovation Projects of Guangdong in 2016(pdjh2016b0408)
文摘OBJECTIVE To investigate 3-O-(Z)-coumaroyloleanolic acid(3-COA),an active ingredient of oleanolic acid in the TAIWANG leaves of E.oldhamii Maxim,that has been shown to have antitumor activity against A549 lung cancer cells,overcomes Cks1b-induced chemoresistance in lung cancer by inhibiting Hsp90 and MEK pathways.METHODS Cisplatin(CDDP)and doxorubicin(DOX)sensitivity was assessed through proliferation,viability,and clonogenic potential induction in cells overexpressing Cks1b(Cks1b-OE).The mechanism for resistance and 3-COA sensitivity were elucidated by immunoblot analysis of Hsp90 and MEK,and confirmed by sh RNA knockdown.Inhibition of 3-COA or3-COA combined with CDDP(3-COA&CDDP)was assayed in early primary lung cancer(IPH),late primary lung cancer(RFH)cells,and tumor-burdened immunodeficiency mice in vivo.RESULTS The ectopic overexpression of Cks1b in human lung cancer cells induces chemoresistance of the cells to CDDP and DOX,but not3-COA,through mechanisms independent of its canonical Skp2-p27 pathway.Further dissection with application of shR NA and selective inhibitors reveals that Hsp90 and MEK1/2 are the critical components of the non-canonical pathways responsible for the Cks1b-induced chemoresistance.Interestingly,inhibition of either Hsp90 or MEK1/2rendered a similar magnitude of antitumor activity by resensitization of the chemoresistant Cks1b-OE cells to CDDP and DOX,suggesting that both Hsp90 and MEK1/2are essentialto Cks1b for induction of chemoresistance.IC50of 3-COA is 6.82μmol·L-1in H358 Cks1b and8.22μmol·L-1in H226 Cks1b,which were not significantly higher than those in H358 EV and H226 EV,respectively.Furthermore,3-COA mimicked PU-H71,a Hsp90-specific inhibitor,targeted Hsp90 and MEK to reduce the expression of their downstream,respectively.Importantly,compared with CDDP treatment,3-COA or 3-COA&CDDP signifi-cantly inhibited RFH cells in vitro.Moreover,3-COA or3-COA&CDDP significantly prolonged more survival for a H358 Cks1b-OE inducing tumor-burdened mice than PD98059(a MEK-specific inhibitor)in vivo.CONCLUSION Our data report for the first time that Cks1b employs Hsp90 and MEK1/2 pathways in lung cancer cells to develop chemoresistance and identify 3-COA as a potential antitumor drug for clinical treatment of chemoresistant lung cancer.
基金supported by the National Natural Science Foundation of China (Grant Nos. 51708553, 12202498, 52371299,12302187)Natural Science Foundations of Jiangsu Province (Grant No. BK20210438)Knowledge Innovation Program of WuhanShuguang Project (Grant No. 202201080102)。
文摘It has been reported that the ply gap influences the ballistic resistance of spaced multi-ply fabric systems,but its working mechanism was not well-understood. This paper reports the experimental and numerical approaches and results of an investigation on the mechanisms that enable the improved ballistic performance of spaced multi-ply systems. Penetration tests were performed over a range of impact velocities ranging from 200 m/s to 400 m/s. The results confirmed that the ply gap is beneficial to the energy absorption capability of the systems. This is because the front plies tend to absorb more energy when they are not immediately constrained by the rear plies. During a ballistic event, the gap relieves the reflection of the compressive pulse, prolonging the projectile engagement time with the front plies;on the other hand, the rear plies become increasingly less active in dissipating energy as the gap increases.When the gap is sufficiently widened to avoid any interference between the plies before the failure of the front ply, the responses of the whole system no longer vary. It was also found that the ballistic performance of the spaced systems is influenced by ply thickness, impact velocity, and the stacking order of the ply gap.
