The high-end equipment represented by high-end machine tools and aero-engines is the core component of the national intelligent manufacturing plan,and the mass unbalance is the main reason for its excessive vibration,...The high-end equipment represented by high-end machine tools and aero-engines is the core component of the national intelligent manufacturing plan,and the mass unbalance is the main reason for its excessive vibration,that seriously impacts the operation efficiency and running life of the equipment.In order to change the traditional way that the fault of equipment can only be repaired by human,the self-recovery mechanism of human and animal are given to the equipment in this paper,which forms the self-recovery regulation(SR)system for unbalance vibration of high-end equipment.The system can online generate the self-recovery force to restrain the unbalance vibration of the equipment in operation,which is an important direction for the development of the equipment to the advanced intelligent stage.Based on the basic principles of SR technique,the typical engineering application cases of this technique in the field of aeroengine and high-end machine tools are introduced,and four related studies promoting the development of this technique are summarized and analyzed in turn.It includes feature extraction,imbalance location,regulation method and balancing actuator.Self-recovery Regulation(SR)Technique is an important way to realize intelligent manufacturing and intelligent maintenance.Relevant research can lay a technical foundation for the development of high-end equipment with self-health function.展开更多
Stimuli-responsive hydrogels have become one of the most popular artificial soft materials due to their excellent adaption to complex environments. Thermoresponsive hydrogels triggered by temperature change can be eff...Stimuli-responsive hydrogels have become one of the most popular artificial soft materials due to their excellent adaption to complex environments. Thermoresponsive hydrogels triggered by temperature change can be efficiently utilized in many applications. However, these thermoresponsive hydrogels mostly cannot recover their mechanical states under large strain during the process. Herein, we utilize the heterogeneous comb-type polymer network with semicrystalline hydrophobic side chains to design self-recovery semi-crystalline hydrogels. Based on hydrophilic/hydrophobic cooperative complementary interaction and heterogeneous polymer network, hydrogels can be endowed with excellent thermosensitive properties and mechanical performance. The hydrogels exhibit high compressive strength(7.57 MPa) and compressive modulus(1.76 MPa) due to the semi-crystalline domains formed by association of the hydrophobic poly(ε-caprolactone) PCL. The melting-crystalline transition of PCL and elastic polymer network provide the hydrogels excellent thermomechanical performance and self-recovery property. Furthermore, the hydrogels exhibit shape memory behavior, which can be realized by simple process and smart surface patterning. With these excellent properties, our hydrogels can be applied in sensors, flexible devices and scaffolds for tissue engineering.展开更多
针对在原始图像中嵌入大量的水印(认证水印和参考水印)容易造成图像失真的问题,提出嵌入少量参考水印的方法。为了减小图像失真,提出将少量的参考水印信息嵌入在原始图像的边缘、轮廓等区域的方法。在恢复篡改区域时,提出利用图像修复...针对在原始图像中嵌入大量的水印(认证水印和参考水印)容易造成图像失真的问题,提出嵌入少量参考水印的方法。为了减小图像失真,提出将少量的参考水印信息嵌入在原始图像的边缘、轮廓等区域的方法。在恢复篡改区域时,提出利用图像修复算法将篡改块匹配问题转化为非局部自相似图像块的最小化问题,复制攻击图像本身的相似信息来恢复篡改区域。实验结果表明,在水印容量为0.015626的情况下,该算法得到嵌入水印后图像的峰值信噪比(peak signal to noise ratio,PSNR)均值超过60 dB,恢复图像的PSNR均值超过40 dB。展开更多
In this paper, we propose a secure semi-fragile watermarking technique based on integer wavelet transform with a choice of two watermarks to be embedded. A self-recovering algorithm is employed, that hides the image d...In this paper, we propose a secure semi-fragile watermarking technique based on integer wavelet transform with a choice of two watermarks to be embedded. A self-recovering algorithm is employed, that hides the image digest into some wavelet subbands for detecting possible illicit object manipulation undergone in the image. The semi-fragility makes the scheme tolerant against JPEG lossy compression with the quality factor as low as 70%, and locates the tampered area accurately. In addition, the system ensures more security because the embedded watermarks are protected with private keys. The computational complexity is reduced by using parameterized integer wavelet transform. Experimental results show that the proposed scheme guarantees safety of a watermark, recovery of image and localization of tampered area.展开更多
为满足发动机控制系统中燃油调节器的高可靠性和安全性要求,配套的燃调数字控制器除具备常规的燃调闭环控制能力外,更需具备自恢复能力。详细介绍了控制器的每个余度中各个组成部分的功能,同时阐述了控制器自恢复功能对燃油调节器可靠...为满足发动机控制系统中燃油调节器的高可靠性和安全性要求,配套的燃调数字控制器除具备常规的燃调闭环控制能力外,更需具备自恢复能力。详细介绍了控制器的每个余度中各个组成部分的功能,同时阐述了控制器自恢复功能对燃油调节器可靠运行的重要性。设计了一种以数字信号处理器(Digital Signal Processor,DSP)为核心,结合数字电源监控、外部看门狗和主控切换逻辑等硬件电路的自恢复双余度燃调控制器。与传统的双余度燃调控制器相比,所设计的控制器具有结构简单、成本较低、自恢复等优点。控制器样机测试结果表明了设计方案具有可行性和可靠性,具有良好的工程应用前景。展开更多
基金Supported by National Natural Science Foundation of China(Grant No.51875031)Youth Backbone Personal Project of Beijing(Grant No.2017000020124 G018).
文摘The high-end equipment represented by high-end machine tools and aero-engines is the core component of the national intelligent manufacturing plan,and the mass unbalance is the main reason for its excessive vibration,that seriously impacts the operation efficiency and running life of the equipment.In order to change the traditional way that the fault of equipment can only be repaired by human,the self-recovery mechanism of human and animal are given to the equipment in this paper,which forms the self-recovery regulation(SR)system for unbalance vibration of high-end equipment.The system can online generate the self-recovery force to restrain the unbalance vibration of the equipment in operation,which is an important direction for the development of the equipment to the advanced intelligent stage.Based on the basic principles of SR technique,the typical engineering application cases of this technique in the field of aeroengine and high-end machine tools are introduced,and four related studies promoting the development of this technique are summarized and analyzed in turn.It includes feature extraction,imbalance location,regulation method and balancing actuator.Self-recovery Regulation(SR)Technique is an important way to realize intelligent manufacturing and intelligent maintenance.Relevant research can lay a technical foundation for the development of high-end equipment with self-health function.
基金financially supported by the National Natural Science Foundation of China (21574004)the National Natural Science Funds for Distinguished Young Scholar (21725401)+2 种基金the Fundamental Research Funds for the Central Universitiesthe National ‘Young Thousand Talents Program’the China Postdoctoral Science Foundation (2017M620012)
文摘Stimuli-responsive hydrogels have become one of the most popular artificial soft materials due to their excellent adaption to complex environments. Thermoresponsive hydrogels triggered by temperature change can be efficiently utilized in many applications. However, these thermoresponsive hydrogels mostly cannot recover their mechanical states under large strain during the process. Herein, we utilize the heterogeneous comb-type polymer network with semicrystalline hydrophobic side chains to design self-recovery semi-crystalline hydrogels. Based on hydrophilic/hydrophobic cooperative complementary interaction and heterogeneous polymer network, hydrogels can be endowed with excellent thermosensitive properties and mechanical performance. The hydrogels exhibit high compressive strength(7.57 MPa) and compressive modulus(1.76 MPa) due to the semi-crystalline domains formed by association of the hydrophobic poly(ε-caprolactone) PCL. The melting-crystalline transition of PCL and elastic polymer network provide the hydrogels excellent thermomechanical performance and self-recovery property. Furthermore, the hydrogels exhibit shape memory behavior, which can be realized by simple process and smart surface patterning. With these excellent properties, our hydrogels can be applied in sensors, flexible devices and scaffolds for tissue engineering.
文摘针对在原始图像中嵌入大量的水印(认证水印和参考水印)容易造成图像失真的问题,提出嵌入少量参考水印的方法。为了减小图像失真,提出将少量的参考水印信息嵌入在原始图像的边缘、轮廓等区域的方法。在恢复篡改区域时,提出利用图像修复算法将篡改块匹配问题转化为非局部自相似图像块的最小化问题,复制攻击图像本身的相似信息来恢复篡改区域。实验结果表明,在水印容量为0.015626的情况下,该算法得到嵌入水印后图像的峰值信噪比(peak signal to noise ratio,PSNR)均值超过60 dB,恢复图像的PSNR均值超过40 dB。
基金This work was supported by the Higher Education Commission of the Government of Pakistan under the Indigenous Ph.D.Scholarship Program(Grant No.17-5-1(Cu-180)HEC/Sch/2004/4343).
文摘In this paper, we propose a secure semi-fragile watermarking technique based on integer wavelet transform with a choice of two watermarks to be embedded. A self-recovering algorithm is employed, that hides the image digest into some wavelet subbands for detecting possible illicit object manipulation undergone in the image. The semi-fragility makes the scheme tolerant against JPEG lossy compression with the quality factor as low as 70%, and locates the tampered area accurately. In addition, the system ensures more security because the embedded watermarks are protected with private keys. The computational complexity is reduced by using parameterized integer wavelet transform. Experimental results show that the proposed scheme guarantees safety of a watermark, recovery of image and localization of tampered area.
文摘为满足发动机控制系统中燃油调节器的高可靠性和安全性要求,配套的燃调数字控制器除具备常规的燃调闭环控制能力外,更需具备自恢复能力。详细介绍了控制器的每个余度中各个组成部分的功能,同时阐述了控制器自恢复功能对燃油调节器可靠运行的重要性。设计了一种以数字信号处理器(Digital Signal Processor,DSP)为核心,结合数字电源监控、外部看门狗和主控切换逻辑等硬件电路的自恢复双余度燃调控制器。与传统的双余度燃调控制器相比,所设计的控制器具有结构简单、成本较低、自恢复等优点。控制器样机测试结果表明了设计方案具有可行性和可靠性,具有良好的工程应用前景。
