Research On Service Mode of Information Security in Post-construction Era

Based on information security service and its characteristics in the development of information technology, author comprehensively analyzes the current situation and development tendency of the industry. This paper puts forward the business mode of the information security operation, and analyzes its model composition, construction process and diffi culties that faced in this process. This article can provide certain model reference and theoretical support for the innovation and sustainable development in this business

Conception et étude de microsystèmes avancés pour la recherche de cellules souches et de cellules cancéreuses.

This work aimed to provide new tools and methods that can be used for advanced studies of stem cells and cancer cells. We first developed a patch method for off-ground culture and differentiation of human induced pluripotent stem cells (hiPSCs). The culture patch we proposed consists of crosslinked monolayer gelatin nanofibers on a honeycomb frame to ensure minimal exogenous material contact and maximum permeability. Then, we demonstrated the formation of cardiac tissue constructs and motor neurons on the patch, started from embryoid-body like and monolayer hiPSC colonies, respectively. We also developed a microfluidic device with integrated filter for isolation of circulating tumor cells (CTCs), showing high capture performances in terms of efficiency, selectivity and cell viability. Finally, we evaluated the anti-cancer drug effect on the formation of tumor spheroids by using microfabricated agarose multi-wells. All together, we progressed in micro-engineering toward large scale applications.Ce travail a pour but de mettre au point des nouvelles méthodes pour la recherche avancée sur les cellules souches et les cellules cancéreuses. Nous avons d'abord développé une méthode de patch pour la culture et la différentiation des cellules souches pluripotentes induites humain (hiPSCs) "hors sol". Ce patch de culture est constitué des monocouches de nanofibres réticulées de gélatine sur un support en nid d'abeilles pour assurer un minimum de contact de matériel exogène et un maximum de perméabilité. Puis, nous avons démontré la formation des tissues cardiaques et des neurones moteurs sur le patch, partis de colonies des hiPSCs en forme d'embryoïdes et de monocouches respectivement. Nous avons également développé un dispositif microfluidique avec filtre intégré pour isoler les cellules tumorales circulantes (CTCs), montrant une haute performance de capture en termes d'efficacité, de sélectivité et de viabilité cellulaire. Enfin, nous avons évalué l'effet de drogue anticancéreuse à la formation des sphéroïdes tumoraux en utilisant des multi-puits d'agarose micro-fabriqués. Tous ensembles, nous avons progressé dans la micro-ingénierie vers des applications à grande échelle

Modal and harmonic response analysis of key components of robotic arm based on ANSYS

To study the problem of vibration of harmonic response of robotic arm under the load, a three-dimensional model of the frame of the robotic arm was created in the Solidworks, then the model was imported into ANSYS for modal analysis. We obtained the frequency of natural vibration and the effect of response of the key components of robotic arm by above analysis. The natural frequency of the robotic arm can be kept away from the frequency of vibration of machine completely, and thus poor working conditions caused by resonance can be avoided. Next the analysis of harmonic response was also performed on the basis of modal analysis. According to the above analysis we obtained displacement diagram and stress distribution diagram of harmonic response. The analysis has a referenced value to design and improve the structure of robotic arm

A New Characteristic Nonconforming Mixed Finite Element Scheme for Convection-Dominated Diffusion Problem

A characteristic nonconforming mixed finite element method (MFEM) is proposed for the convection-dominated diffusion problem based on a new mixed variational formulation. The optimal order error estimates for both the original variable u and the auxiliary variable σ with respect to the space are obtained by employing some typical characters of the interpolation operator instead of the mixed (or expanded mixed) elliptic projection which is an indispensable tool in the traditional MFEM analysis. At last, we give some numerical results to confirm the theoretical analysis

Dirac-Surface-State Modulated Spin Dynamics in a Ferrimagnetic Insulator at Room Temperature

This work demonstrates dramatically modified spin dynamics of magnetic insulator (MI) by the spin-momentum locked Dirac surface states of the adjacent topological insulator (TI) which can be harnessed for spintronic applications. As the Bi-concentration x is systematically tuned in 5 nm thick (BixSb1-x)2Te3 TI film, the weight of the surface relative to bulk states peaks at x = 0.32 when the chemical potential approaches the Dirac point. At this concentration, the Gilbert damping constant of the precessing magnetization in 10 nm thick Y3Fe5O12 MI film in the MI/TI heterostructures is enhanced by an order of magnitude, the largest among all concentrations. In addition, the MI acquires additional strong magnetic anisotropy that favors the in-plane orientation with similar Bi-concentration dependence. These extraordinary effects of the Dirac surface states distinguish TI from other materials such as heavy metals in modulating spin dynamics of the neighboring magnetic layer

3GPP-Like THz Channel Modeling for Indoor Office and Urban Microcellular Scenarios

Terahertz (THz) communication is envisioned as the possible technology for the sixth-generation (6G) communication system. THz channel propagation characteristics are the basis of designing and evaluating for THz communication system. In this paper, THz channel measurements at 100 GHz and 132 GHz are conducted in an indoor office scenario and an urban microcellular (UMi) scenario, respectively. Based on the measurement, the 3GPP-like channel parameters are extracted and analyzed. Moreover, the parameters models are available for the simulation of the channel impulse response by the geometry-based stochastic model (GBSM). Then, the comparisons between measurement-based parameter models and 3rd Generation Partnership Project (3GPP) channel models are investigated. It is observed that the case with path loss approaching free space exists in the NLoS scenario. Besides, the cluster number are 4 at LoS and 5 at NLoS in the indoor office and 4 at LoS and 3 at NLoS in the UMi, which are much less than 3GPP. The multipath component (MPC) in the THz channel distributes more simpler and more sparsely than the 3GPP millimeter wave (mm-wave) channel models. Furthermore, the ergodic capacity of mm-wave and THz are evaluated by the proposed THz GBSM implementation framework. The THz measurement model predicts the smallest capacity, indicating that high carrier frequency is limited to the single transmission mechanism of reflection and results in the reduction of cluster numbers and ergodic capacity. Generally, these results are helpful to understand and model the THz channel and apply the THz communication technique for 6G.Comment: 13 pages, 12 figures, 3 table