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51.
Yunjian Xu Dr. Menglong Zhao Licai Wu Feiyang Li Mingdang Li Mingjuan Xie Prof. Shujuan Liu Prof. Wei Huang Prof. Qiang Zhao 《ChemMedChem》2019,14(15):1378-1383
The development of efficient phototherapeutic agents (PTA) through rational and specific principles exhibits great potential to the biomedical field. In this study, a facile and rational strategy was used to design PTA through perturbation theory. According to the theory, both the intersystem crossing rate for singlet oxygen generation and nonradiative transition for photothermal conversion efficiency can be simultaneously enhanced by the rational optimization of donor–acceptor groups, heavy atom number, and their functional positions, which can effectively decrease the energy gap between the singlet and triplet states and increase the spin-orbit coupling constant. Finally, efficient PTA were obtained that showed excellent performance in multimode-imaging-guided synergetic photodynamic/photothermal therapy. This study therefore expands the intrinsic mechanism of organic PTA and should help guide the rational design of future organic PTA via perturbation theory. 相似文献
52.
53.
Ahlswede R. Ning Cai Zhen ZHang 《IEEE transactions on information theory / Professional Technical Group on Information Theory》1996,42(1):55-62
For the discrete memoryless channel (χ, y, W) we give characterizations of the zero-error erasure capacity Cer and the zero-error average list size capacity Cal in terms of limits of suitable information (respectively, divergence) quantities (Theorem 1). However, they do not “single-letterize.” Next we assume that χ⊂y and W(x|x)>0 for all x∈χ, and we associate with W the low-noise channel Wϵ, where for y +(x)={y:W(y|x)>0} Wϵ(y|x)={1, if y=x and |y+(x)|=1 1-ϵ, if y=x and |y+(x)|>1 e/|y +(x)|-1, if y≠x. Our Theorem-2 says that as ε tends to zero the capacities Cer(Wε) and Cal (Wε) relate to the zero-error detection capacity C de(W). Our third result is a seemingly basic contribution to the theory of identification via channels. We introduce the (second-order) identification capacity Coid for identification codes with zero misrejection probability and misacceptance probability tending to zero. Our Theorem 3 says that Coid equals the zero-error erasure capacity for transmission Cer 相似文献
54.
本文绘出了伞喷燃烧方式在135型试验机上进行的试验研究,性能参数表明该燃烧方式具有热预混合燃烧的特点,且改善了经济性、工作粗暴性和排入指标。 相似文献
55.
张群 《北京电子科技学院学报》2013,21(1):14-22
中国古人很早就认识到保密对维护国家安全和利益的重要性。秦汉以来,形成了以唐律“漏泄大事”罪和清代奏折为代表的保密制度。同时,中国古人也逐渐认识到保密的诸多弊端,并在明清时期形成了保密应当适度的可贵主张。但在当时的历史环境下,政务公开的社会需要和动力都显著不足,因而中国古代保密文化在整体上还停留于对国家秘密的消极保护,对如何处理保密与公开的关系,充分发挥信息资源的积极作用,还没有太多的思考与尝试。 相似文献
56.
Silicon nitridation mechanism in reaction‐bonded Si3N4–SiC and Si3N4‐bonded ferrosilicon nitride
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Menglong Long Yong Li Xiuming Jin Guisheng Yao Jialin Sun Ramachandran V. Kumar 《Journal of the American Ceramic Society》2018,101(9):4350-4356
Reaction‐bonded Si3N4–SiC and Si3N4‐bonded ferrosilicon nitride, with Si powder, SiC particles and Fe3Si–Si3N4 particles as raw materials, respectively, are prepared in flame‐isolation nitridation shuttle kiln with flowing N2 at 1723K. There is columnar β‐Si3N4 in both Si3N4–SiC and Si3N4‐bonded ferrosilicon nitride. However, fibrous α‐Si3N4 is only observed in Si3N4–SiC and Si3N4‐bonded ferrosilicon nitride contains much more Si2N2O than Si3N4–SiC. By analyzing the oxidation thermodynamics of Si and Si3N4, it is known that in the process of producing Si3N4–SiC, Si is oxidized first to gaseous SiO and fibrous α‐Si3N4 is generated with SiO and N2. The existence of SiO is the reason of low silicon nitridation rate. But in the process of producing Si3N4‐bonded ferrosilicon nitride, Si3N4 is easier to be oxidized than Si and Si2N2O is generated on the surface of Si3N4 hexagonal prisms in ferrosilicon nitride particles. Meanwhile, Si in raw materials forms new ferrosilicon alloys with Fe3Si, which decreases the temperature of liquid appearance and blocks some open pores in the samples, which stops the matter loss of nitridation. Liquid ferrosilicon alloys favors β‐Si3N4 generation from Si direct nitridation and fibrous α‐Si3N4 transformation, which used to exist in ferrosilicon nitride raw materials. 相似文献
57.
【目的】为应对超大规模计算系统所带来的监控数据风暴、作业调度稳定性及灵活性、网络复杂度及高效性等实际挑战,本文分享了近期真实实践的经验和解决办法。【应用背景】当计算系统从P级逐渐向E级过渡,节点数量可超过10000个。在计算系统设计之初就需要确定网络拓扑的选型,而在系统的具体使用中更是离不开高效的调度和及时的监控。【方法】本文采用了基于动态负载均衡的分布式监控架构设计,基于高速缓存的分布式告警架构设计,基于SLURM的源码和配置优化,以及nd-Torus网络拓扑仿真对比等相关技术手段,基本满足了实际业务使用需求。【结果】数据表明,对于~10000节点的计算系统,实时告警数据库表的数据量大小基本可以控制在100万条以内。优化后的SLURM调度系统,可满足系统的业务级调度需求。网络方面,6D-Torus网络由于网络直径低、平均通信距离短,性能和网卡线缆用量较Fat-Tree网络和3D-Torus有一定提升,饱和吞吐率超过40%。【结论】分布式监控架构和告警架构可以有效解决监控数据风暴问题。SLURM在优化后可以实现对超大规模计算系统的作业调度功能。就线缆和交换机使用数量而言,6D-Torus相对于传统Fat-Tree网络更加经济,且性能优于3D-Torus,更适合超大规模计算系统。 相似文献
58.
考虑到无线传感网络WSNs(Wireless Sensor Networks)的电源能量有限问题,提出基于模糊规则算法的分簇-能效-路由算法FLECR(Fuzzy Logic-based Energy-efficient Clustering Routing)。FLECR路由引用"分布簇头选举"方式,并采用按需方式进行簇重构。同时,FLECR路由利用相对剩余能量、距离以及中心度三个变量,并结合模糊规则算法选举簇头。仿真结果表明,相比于低功耗自适应层次路由LEACH(Low Energy Adaptive Clustering Hierarchy),FLECR路由的网络生存时间得到大幅度提升。 相似文献
59.
High‐Performance Organic Heterojunction Phototransistors Based on Highly Ordered Copper Phthalocyanine/para‐Sexiphenyl Thin Films
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Chuan Qian Jia Sun Ling‐An Kong Guangyang Gou Menglong Zhu Yongbo Yuan Han Huang Yongli Gao Junliang Yang 《Advanced functional materials》2017,27(6)
High‐performance organic heterojunction phototransistors are fabricated using highly ordered copper phthalocyanine (CuPc) and para ‐sexiphenyl (p ‐6P) thin films. The p ‐6P thin film plays an important role on the performance of CuPc/p ‐6P heterojunction phototransistors. It acts as a molecular template layer to induce the growth of highly ordered CuPc thin film, which dramatically improves the charge transport and decreases the grain boundaries. On the other hand, the p ‐6P thin film can form an effective heterojunction with CuPc thin film, which is greatly helpful to enhance the light absorption and photogenerated carriers. Under 365 nm ultraviolet light irradiation, the ratio of photocurrent and dark current and photoresponsivity of CuPc/p ‐6P heterojunction phototransistors reaches to about 2.2 × 104 and 4.3 × 102 A W?1, respectively, which are much larger than that of CuPc phototransistors of about 2.7 × 102 and 7.3 A W?1, respectively. A detailed study carried out with current sensing atomic force microscopy proves that the photocurrent is predominately produced inside the highly ordered CuPc/p ‐6P heterojunction grains, while the photocurrent produced at the boundaries between grains can be neglected. The research provides a good method for fabricating high‐performance organic phototransistors using a combination of molecular template growth and organic heterojunction. 相似文献
60.
Shaoyuan Li Menglong Wei Shengjun Huang 《International Journal of Software and Informatics》2022,12(2):213-230
Traditional supervised learning requires the groundtruth labels for the training data, which can be difficult to collect in many cases. In contrast, crowdsourcing learning collects noisy annotations from multiple non-expert workers and infers the latent true labels through some aggregation approach. In this paper, we notice that existing deep crowdsourcing work does not sufficiently model worker correlations, which is, however, shown to be helpful for learning by previous non-deep learning approaches. We propose a deep generative crowdsourcing learning approach to incorporate the strengths of Deep Neural Networks (DNNs) and exploit worker correlations. The model comprises a DNN classifier as a prior and an annotation generation process. A mixture model of workers'' capabilities within each class is introduced into the annotation generation process for worker correlation modeling. For adaptive trade-off between model complexity and data fitting, we implement fully Bayesian inference. Based on the natural-gradient stochastic variational inference techniques developed for the Structured Variational AutoEncoder (SVAE), we combine variational message passing for conjugate parameters and stochastic gradient descent for DNN parameters into a unified framework for efficient end-to-end optimization. Experimental results on 22 real crowdsourcing datasets demonstrate the effectiveness of the proposed approach. 相似文献