针对物联网中传感网基础设施与应用程序分离将加重安全风险、认证机制不完善等问题,文中基于现存的互联网标准和数据包传输层安全协议DTLS(Datagram Transport Layer Security),提出了一个物联网环境下的端到端双向认证安全机制。该安...针对物联网中传感网基础设施与应用程序分离将加重安全风险、认证机制不完善等问题,文中基于现存的互联网标准和数据包传输层安全协议DTLS(Datagram Transport Layer Security),提出了一个物联网环境下的端到端双向认证安全机制。该安全机制主要利用DTLS协议的全认证握手过程实现对用户和节点身份的双向认证,并对数据进行加密和完整性封装。该机制工作在标准低功耗通信栈上面,在部署了相关协议的传感节点上对安全机制的性能参数进行了评估,如传输延时、能量消耗、内存消耗等。验证其可行性,证明了该安全机制具有低开销和高互操作性。展开更多
A compact interdigital H-mode drift-tube linac (IH-DTL) with the alternating-phase-focusing (APF) method, working at 325 MHz was designed for an injector of a proton medical accelerator. When fed in with a proper RF (...A compact interdigital H-mode drift-tube linac (IH-DTL) with the alternating-phase-focusing (APF) method, working at 325 MHz was designed for an injector of a proton medical accelerator. When fed in with a proper RF (radio frequency) power, the DTL cavity could establish the corresponding electromagnetic field to accelerate the ‘‘proton bunches’’ from an input energy of 3 MeV to an output energy of 7 MeV successfully, without any additional radial focusing elements. The gap-voltage distribution which was obtained from the CST■ Microwave Studio software simulations of the axial electric field was compared with that from the beam dynamics, and the errors met the requirements within ± 5%. In this paper, the RF design procedure and key results of the APF IH-DTL, which include the main RF characteristics of the cavity, frequency sensitivities of the tuners, and coupling factor of the RF power input coupler are presented.展开更多
A multisampling technique was introduced to the phase error detector of Conventional Digital Tanlocked Loop(C DTL). In this new technique a number of samples ( M ) were taken at nonuniform intervals within one peri...A multisampling technique was introduced to the phase error detector of Conventional Digital Tanlocked Loop(C DTL). In this new technique a number of samples ( M ) were taken at nonuniform intervals within one period of the input signal. The novel system is called Multisampling Digital Tanlocked loop(MS DTL). The simulated model on the computer shows that for M =4, the system has a faster locking speed and wider locking in range compared with C DTL.展开更多
The excessive energy of light,especially the invisible rays with lower wavelength,is basically absorbed by retinal pigment epithelium(RPE)and usually causes DNA damage.The molecular mechanism behind DNA damage repair ...The excessive energy of light,especially the invisible rays with lower wavelength,is basically absorbed by retinal pigment epithelium(RPE)and usually causes DNA damage.The molecular mechanism behind DNA damage repair response to this frequent stress in RPE is not clearly understood.In this study,we determined that the Fanconi anemia(FA)pathway was activated in human RPE ARPE-19 cells after ultraviolet(UV)B and C treatment.Moreover,immunoprecipitation(IP)of FANCD2 indicated that denticleless E3 ubiquitin protein ligase homolog(DTL)closely interacted with FANCD2.Knockdown of DTL weakened the activity of the FA pathway in ARPE-19 cells responding to UV treatment.Finally,the DTL promoter was incubated with a biotin-labeled probe and pulled down by streptavidin beads followed by the genomic DNA sonication.p53 was indicated by mass spectrum and further determined by chromatin IP assay.Taken together,our results demonstrated that DTL regulated by p53 could activate the FA pathway for UV-induced DNA damage repair in retinal pigment epithelial cells.展开更多
SSC-LINAC is as a linear injector for the cyclotron accelerator SSC. DTL2 RF cavity is designed to install in SSC-LINAC intermediate energy beam line, whose working frequency is 53.667 MHz and working mode is cw.DTL2 ...SSC-LINAC is as a linear injector for the cyclotron accelerator SSC. DTL2 RF cavity is designed to install in SSC-LINAC intermediate energy beam line, whose working frequency is 53.667 MHz and working mode is cw.DTL2 cavity adopts drift tube structure with IH-mode, which having high shunt impedance, high quality, etc.展开更多
文摘针对物联网中传感网基础设施与应用程序分离将加重安全风险、认证机制不完善等问题,文中基于现存的互联网标准和数据包传输层安全协议DTLS(Datagram Transport Layer Security),提出了一个物联网环境下的端到端双向认证安全机制。该安全机制主要利用DTLS协议的全认证握手过程实现对用户和节点身份的双向认证,并对数据进行加密和完整性封装。该机制工作在标准低功耗通信栈上面,在部署了相关协议的传感节点上对安全机制的性能参数进行了评估,如传输延时、能量消耗、内存消耗等。验证其可行性,证明了该安全机制具有低开销和高互操作性。
基金supported by the National Key Research and Development Program of China(No.2016YFC0105408)
文摘A compact interdigital H-mode drift-tube linac (IH-DTL) with the alternating-phase-focusing (APF) method, working at 325 MHz was designed for an injector of a proton medical accelerator. When fed in with a proper RF (radio frequency) power, the DTL cavity could establish the corresponding electromagnetic field to accelerate the ‘‘proton bunches’’ from an input energy of 3 MeV to an output energy of 7 MeV successfully, without any additional radial focusing elements. The gap-voltage distribution which was obtained from the CST■ Microwave Studio software simulations of the axial electric field was compared with that from the beam dynamics, and the errors met the requirements within ± 5%. In this paper, the RF design procedure and key results of the APF IH-DTL, which include the main RF characteristics of the cavity, frequency sensitivities of the tuners, and coupling factor of the RF power input coupler are presented.
文摘A multisampling technique was introduced to the phase error detector of Conventional Digital Tanlocked Loop(C DTL). In this new technique a number of samples ( M ) were taken at nonuniform intervals within one period of the input signal. The novel system is called Multisampling Digital Tanlocked loop(MS DTL). The simulated model on the computer shows that for M =4, the system has a faster locking speed and wider locking in range compared with C DTL.
文摘The excessive energy of light,especially the invisible rays with lower wavelength,is basically absorbed by retinal pigment epithelium(RPE)and usually causes DNA damage.The molecular mechanism behind DNA damage repair response to this frequent stress in RPE is not clearly understood.In this study,we determined that the Fanconi anemia(FA)pathway was activated in human RPE ARPE-19 cells after ultraviolet(UV)B and C treatment.Moreover,immunoprecipitation(IP)of FANCD2 indicated that denticleless E3 ubiquitin protein ligase homolog(DTL)closely interacted with FANCD2.Knockdown of DTL weakened the activity of the FA pathway in ARPE-19 cells responding to UV treatment.Finally,the DTL promoter was incubated with a biotin-labeled probe and pulled down by streptavidin beads followed by the genomic DNA sonication.p53 was indicated by mass spectrum and further determined by chromatin IP assay.Taken together,our results demonstrated that DTL regulated by p53 could activate the FA pathway for UV-induced DNA damage repair in retinal pigment epithelial cells.
文摘SSC-LINAC is as a linear injector for the cyclotron accelerator SSC. DTL2 RF cavity is designed to install in SSC-LINAC intermediate energy beam line, whose working frequency is 53.667 MHz and working mode is cw.DTL2 cavity adopts drift tube structure with IH-mode, which having high shunt impedance, high quality, etc.
文摘目的:探讨E3泛素连接酶DTL(dentideless E3 ubiquitin ligase)在肝细胞癌(hepatocellular carcinoma,HCC)组织中的表达及预后价值。方法:从癌症基因组图谱(The Cancer Genome Atlas,TCGA)数据库中下载获得374例HCC组织和50例癌旁正常组织的转录组数据;从基因表达综合数据库(Gene Expression Omnibus,GEO)下载GSE121248数据集,获得包括70例HCC组织和37例癌旁正常组织的转录组数据。比较HCC组织与癌旁正常组织中DTL的表达水平。采用Kaplan-Meier法进行生存分析,并采用log-rank检验比较DTL高表达组与DTL低表达组HCC患者总生存率、无进展间期生存率的差异。HCC患者不良预后的危险因素采用Cox回归分析。绘制DTL表达水平诊断HCC的受试者操作特征(receiver operator characteristic,ROC)曲线。利用基于多因素Cox回归分析的列线图预测DTL对HCC患者预后的影响。同时对DTL高表达组与DTL低表达组HCC组织的差异表达基因进行GSEA富集分析。结果:DTL在HCC组织中的表达水平高于癌旁正常组织(P<0.001)。DTL高表达组与DTL低表达组HCC患者年龄、人种、AFP水平、病理分级、病理分期、T分期差异均有统计学意义(P均<0.05)。Kaplan-Meier法生存分析结果显示,与DTL低表达组HCC患者相比,DTL高表达组HCC患者总生存率和无进展间期生存率均较短(P=0.005,P<0.001)。ROC曲线显示,DTL表达水平对HCC有较强的诊断能力[曲线下面积(area under the curve,AUC)为0.96]。通过构建列线图发现,DTL表达的C指数为0.663(95%CI为0.54~0.61)。GSEA富集分析结果显示,DTL可能通过影响细胞周期、染色体维持、DNA复制、G2/M检查点、有丝分裂期、TP53转录调控等通路影响HCC的发生发展。
