For eliminating the zero-order image in digital holography, a new method using the differential of the hologram intensity instead of the hologram itself for numerical reconstruction is proposed. This method is based o...For eliminating the zero-order image in digital holography, a new method using the differential of the hologram intensity instead of the hologram itself for numerical reconstruction is proposed. This method is based on digital image processing. By analyzing the spatial spectrum of the off-axis digital hologram, it theoretically proves that the zero-order image can be effectively eliminated by differential before reconstruction. Then, the detected hologram is processed in the program with differential and reconstruction. Both the theoretical analysis and digital reconstruction results show that it can effectively eliminate the large bright spot in the center of the reconstructed image caused by the zero-order image, improve the image quality significantly, and render a better contrast of the reconstructed image. This method is very simple and convenient due to no superfluous optical elements and requiring only one time record.展开更多
Shell structures have increasingly widespread applications in biomedical ultrasound fields such as contrast agents and drug delivery,which requires the precise prediction of the acoustic radiation force under various ...Shell structures have increasingly widespread applications in biomedical ultrasound fields such as contrast agents and drug delivery,which requires the precise prediction of the acoustic radiation force under various circumstances to improve the system efficiency.The acoustic radiation force exerted by a zero-order quasi-Bessel-Gauss beam on an elastic spherical shell near an impedance boundary is theoretically and numerically studied in this study.By means of the finite series method and the image theory,a zero-order quasi-Bessel-Gauss beam is expanded in terms of spherical harmonic functions,and the exact solution of the acoustic radiation force is derived based on the acoustic scattering theory.The acoustic radiation force function,which represents the radiation force per unit energy density and per unit cross-sectional surface,is especially investigated.Some simulated results for a polymethyl methacrylate shell and an aluminum shell are provided to illustrate the behavior of acoustic radiation force in this case.The simulated results show the oscillatory property and the negative radiation force caused by the impedance boundary.An appropriate relative thickness of the shell can generate sharp peaks for a polymethyl methacrylate shell.Strong radiation force can be obtained at small half-cone angles and the beam waist only affects the results at high frequencies.Considering that the quasi-Bessel-Gauss beam possesses both the energy focusing property and the non-diffracting advantage,this study is expected to be useful in the development of acoustic tweezers,contrast agent micro-shells,and drug delivery applications.展开更多
With derivative spectrophotometric method,the complexes of lanthanides with 2-(5-bromo-2-pyridylazo)-5-diethylaminophen- ol(5-Br-PADAP)in the presence of octylphenol poly(ethyleneg- lycol)ether(TX-100)were studied.It ...With derivative spectrophotometric method,the complexes of lanthanides with 2-(5-bromo-2-pyridylazo)-5-diethylaminophen- ol(5-Br-PADAP)in the presence of octylphenol poly(ethyleneg- lycol)ether(TX-100)were studied.It is found that the maximum absorption of fourth-order derivative spectra of the neodymium complex by 4f electron transitions is at 579(+)nm and 582(-)nm with molar derivative absorptivities of 5.2×10~3 1.mol^(-1).cm^(-1). The maximum absorption of the zero-order derivative spectra of the complexes for neodymium and praseodymium is at 580hm,the molar absorptivities are 1.47×10~5 l.mol^(-1).cm^(-1)for Nd and 1.26 ×10~5 l.mol^(-1).cm^(-1)for Pr.The component ratio of the complex is Nd:5-Br-PADAP=1:4.Beer's law is obeyed in the range of 0-3.75μg of Nd and Pr in 25ml of solution.The method has been used for the simultaneous determination of Nd and Pr in four synthetic samples and the results obtained are satisfactory.展开更多
In this research, we have improved a relaxation method for triangular meshes intended for finite element fluid simulations which contain discrete element particles. The triangle edges are treated as springs which rela...In this research, we have improved a relaxation method for triangular meshes intended for finite element fluid simulations which contain discrete element particles. The triangle edges are treated as springs which relax their lengths towards a “better” force equilibrium where the triangles are closer to equilateral shape. The actual kernel is an improved zero order integrator which is able to follow reconfigurations of the particles faster than earlier methods. The improved relaxation allows larger timesteps in the flow simulation and leads to more stable, faster mesh reconfigurations for fast moving particles in the flow. Additionally, this demonstrates how integrators of the same order zero can nevertheless have different convergence speeds towards展开更多
Supramolecular hydrogels demonstrate considerable potential in drug delivery owing to their distinctive features,including bio-adhesiveness,self-healing behaviors,biodegradability,and biocompatibility.Nevertheless,the...Supramolecular hydrogels demonstrate considerable potential in drug delivery owing to their distinctive features,including bio-adhesiveness,self-healing behaviors,biodegradability,and biocompatibility.Nevertheless,the fabrication of supramolecular hydrogels utilizing exclusively clinically approved drugs remain challenging,typically necessitating chemical modifications of the drugs to facilitate the gelation process.In this study,we report a novel type of supramolecular hydrogel through the direct assembly of two clinically approved drugs,tobramycin and mycophenolic acid,via combined electrostatic and hydrophobic interactions.The hydrogel shows adjustable bio-adhesiveness,zero-order release kinetics,good biocompatibility,and maintained antibacterial and immunosuppressive activities.It efficiently inhibits bacterial infections and foreign body responses,and accelerates tissue healing in several subcutaneous/intraosseous implantation models accompanied by bacteria infections.This work provides a facile and promising strategy to fabricate supramolecular hydrogels with stable drug release kinetics using clinically approved drugs.展开更多
Nifedipine(NF),a widely prescribed antihypertensive agent,necessitates long-term administration to maintain therapeutic efficacy.Although osmotic pump formulations,such as Bayer’s Adalat^(®),are well-established...Nifedipine(NF),a widely prescribed antihypertensive agent,necessitates long-term administration to maintain therapeutic efficacy.Although osmotic pump formulations,such as Bayer’s Adalat^(®),are well-established for achieving zero-order drug release,their complex manufacturing requirements significantly elevate production costs.In this study,we employed mesoporous silica as a drug carrier for nifedipine and incorporated it with an organic polymer matrix to construct an organic-inorganic hybrid nanocomposite(OIN).This nanostructured system demonstrated robust sustained-release properties in both in vitro and in vivo evaluations,with the in vitro release profile exhibiting classical first-order kinetics.To further optimize the release behavior,we combined OIN with conventional tablet-forming techniques to create an oral nanocomposite system(ONS)capable of achieving near-zero-order release.Remarkably,the cumulative release profiles of ONS closely mirrored those of the commercially available Adalat^(®)osmotic formulation across multiple time points.Moreover,we conducted a theoretical analysis of the release mechanisms underlying both OIN and ONS systems,offering novel mechanistic insights that could inform the future design of advanced sustained-release drug delivery platforms.展开更多
针对工业机器人末端作业时轴向低频隔振难的问题,设计一种由等边六边形拉簧装置和正刚度弹簧组构成的轴向准零刚度(Quasi Zero Stiffness,QZS)隔振器。首先,通过静力学分析初始高度对等边六边形拉簧装置负刚度性能和隔振器刚度特性的影...针对工业机器人末端作业时轴向低频隔振难的问题,设计一种由等边六边形拉簧装置和正刚度弹簧组构成的轴向准零刚度(Quasi Zero Stiffness,QZS)隔振器。首先,通过静力学分析初始高度对等边六边形拉簧装置负刚度性能和隔振器刚度特性的影响;其次,建立非线性动力学方程,应用谐波平衡法推导力传递率,通过数值仿真分析振动幅值、阻尼比、初始高度和负载对力传递率的影响。最后,在不同外部激励下对轴向QZS隔振器和线性隔振器进行实验研究,并将实验结果与四阶龙格库塔法求解的加速度响应进行对比。结果表明:轴向QZS隔振器在载荷为20~80 N时能隔离3.2~20 Hz的振动;相较于其对应的线性隔振器,该隔振器的固有频率降低到1.8 Hz,起始隔振频率降低76.6%,隔振频带增宽166.7%。展开更多
基金The Natural Science Foundation of Jiangsu Province (No.BK2006102)the National Natural Science Foundation of China(No.10772086)
文摘For eliminating the zero-order image in digital holography, a new method using the differential of the hologram intensity instead of the hologram itself for numerical reconstruction is proposed. This method is based on digital image processing. By analyzing the spatial spectrum of the off-axis digital hologram, it theoretically proves that the zero-order image can be effectively eliminated by differential before reconstruction. Then, the detected hologram is processed in the program with differential and reconstruction. Both the theoretical analysis and digital reconstruction results show that it can effectively eliminate the large bright spot in the center of the reconstructed image caused by the zero-order image, improve the image quality significantly, and render a better contrast of the reconstructed image. This method is very simple and convenient due to no superfluous optical elements and requiring only one time record.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.81527901,11604361,and 91630309)。
文摘Shell structures have increasingly widespread applications in biomedical ultrasound fields such as contrast agents and drug delivery,which requires the precise prediction of the acoustic radiation force under various circumstances to improve the system efficiency.The acoustic radiation force exerted by a zero-order quasi-Bessel-Gauss beam on an elastic spherical shell near an impedance boundary is theoretically and numerically studied in this study.By means of the finite series method and the image theory,a zero-order quasi-Bessel-Gauss beam is expanded in terms of spherical harmonic functions,and the exact solution of the acoustic radiation force is derived based on the acoustic scattering theory.The acoustic radiation force function,which represents the radiation force per unit energy density and per unit cross-sectional surface,is especially investigated.Some simulated results for a polymethyl methacrylate shell and an aluminum shell are provided to illustrate the behavior of acoustic radiation force in this case.The simulated results show the oscillatory property and the negative radiation force caused by the impedance boundary.An appropriate relative thickness of the shell can generate sharp peaks for a polymethyl methacrylate shell.Strong radiation force can be obtained at small half-cone angles and the beam waist only affects the results at high frequencies.Considering that the quasi-Bessel-Gauss beam possesses both the energy focusing property and the non-diffracting advantage,this study is expected to be useful in the development of acoustic tweezers,contrast agent micro-shells,and drug delivery applications.
文摘With derivative spectrophotometric method,the complexes of lanthanides with 2-(5-bromo-2-pyridylazo)-5-diethylaminophen- ol(5-Br-PADAP)in the presence of octylphenol poly(ethyleneg- lycol)ether(TX-100)were studied.It is found that the maximum absorption of fourth-order derivative spectra of the neodymium complex by 4f electron transitions is at 579(+)nm and 582(-)nm with molar derivative absorptivities of 5.2×10~3 1.mol^(-1).cm^(-1). The maximum absorption of the zero-order derivative spectra of the complexes for neodymium and praseodymium is at 580hm,the molar absorptivities are 1.47×10~5 l.mol^(-1).cm^(-1)for Nd and 1.26 ×10~5 l.mol^(-1).cm^(-1)for Pr.The component ratio of the complex is Nd:5-Br-PADAP=1:4.Beer's law is obeyed in the range of 0-3.75μg of Nd and Pr in 25ml of solution.The method has been used for the simultaneous determination of Nd and Pr in four synthetic samples and the results obtained are satisfactory.
文摘In this research, we have improved a relaxation method for triangular meshes intended for finite element fluid simulations which contain discrete element particles. The triangle edges are treated as springs which relax their lengths towards a “better” force equilibrium where the triangles are closer to equilateral shape. The actual kernel is an improved zero order integrator which is able to follow reconfigurations of the particles faster than earlier methods. The improved relaxation allows larger timesteps in the flow simulation and leads to more stable, faster mesh reconfigurations for fast moving particles in the flow. Additionally, this demonstrates how integrators of the same order zero can nevertheless have different convergence speeds towards
基金supported by the National Key R&D Program of China(grant nos.2022YFB3804400 and 2019YFA0904500).
文摘Supramolecular hydrogels demonstrate considerable potential in drug delivery owing to their distinctive features,including bio-adhesiveness,self-healing behaviors,biodegradability,and biocompatibility.Nevertheless,the fabrication of supramolecular hydrogels utilizing exclusively clinically approved drugs remain challenging,typically necessitating chemical modifications of the drugs to facilitate the gelation process.In this study,we report a novel type of supramolecular hydrogel through the direct assembly of two clinically approved drugs,tobramycin and mycophenolic acid,via combined electrostatic and hydrophobic interactions.The hydrogel shows adjustable bio-adhesiveness,zero-order release kinetics,good biocompatibility,and maintained antibacterial and immunosuppressive activities.It efficiently inhibits bacterial infections and foreign body responses,and accelerates tissue healing in several subcutaneous/intraosseous implantation models accompanied by bacteria infections.This work provides a facile and promising strategy to fabricate supramolecular hydrogels with stable drug release kinetics using clinically approved drugs.
基金The National Natural Science Foundation of China(Grant Nos.U20A20412,81821004,U22A20384,82225044,52273136)the National Key R&D Program of China(Grant Nos.2022YFC3501900,2023YFC2605004)+1 种基金the Beijing Natural Science Foundation(Grant Nos.L222127,L212013)the AI+Health Collaborative Innovation Cultivation Project(Grant No.Z211100003521002).
文摘Nifedipine(NF),a widely prescribed antihypertensive agent,necessitates long-term administration to maintain therapeutic efficacy.Although osmotic pump formulations,such as Bayer’s Adalat^(®),are well-established for achieving zero-order drug release,their complex manufacturing requirements significantly elevate production costs.In this study,we employed mesoporous silica as a drug carrier for nifedipine and incorporated it with an organic polymer matrix to construct an organic-inorganic hybrid nanocomposite(OIN).This nanostructured system demonstrated robust sustained-release properties in both in vitro and in vivo evaluations,with the in vitro release profile exhibiting classical first-order kinetics.To further optimize the release behavior,we combined OIN with conventional tablet-forming techniques to create an oral nanocomposite system(ONS)capable of achieving near-zero-order release.Remarkably,the cumulative release profiles of ONS closely mirrored those of the commercially available Adalat^(®)osmotic formulation across multiple time points.Moreover,we conducted a theoretical analysis of the release mechanisms underlying both OIN and ONS systems,offering novel mechanistic insights that could inform the future design of advanced sustained-release drug delivery platforms.
