摘要：We report the development of a metastasis-on-a-chip platform to model and track hepatocellular carcinoma(HCC)-bone metastasis and to analyze the inhibitory effect of an herb-based compound,thymoquinone(TQ),in hindering the migration of liver cancer cells into the bone *** bioreactor consisted of two chambers,one accommodating encapsulated HepG2 cells and one bone-mimetic niche containing hydroxyapatite(HAp).Above these chambers,amicroporous membrane was placed to resemble the vascular barrier,where medium was circulated over the *** was observed that the liver cancer cells proliferated inside the tumor microtissue and disseminated from the HCC chamber to the circulatory flow and eventually entered the bone *** number of metastatic HepG2 cells to the bone compartment was remarkably higher in the presence of HAp in the *** was then used as ametastasis-controlling agent in both free form and encapsulated nanoparticles,to analyze its suppressing effect on HCC *** indicated that the nanoparticle-encapsulated TQ provided a longer period of inhibitory *** summary,HCC-bone metastasis-on-a-chip platform was demonstrated to model certain key aspects of the cancer metastasis process,hence corroborating the potential of enabling investigations on metastasis-associated biology as well as improved anti-metastatic drug screening.

摘要：To minimize the deviation of the predicted creep curves obtained under constant load conditions by the original θ projection model, a new modified version that can be expressed by ε = θ_1(1-e^(-θ2t)) +θ3 (e^(θ_4e^θ5^εt)-1), was derived and experimentally validated in our last study. In the present study, the predictive capability of the modified θ projection model was investigated by comparing the simulated and experimentally determined creep curves of K465 and DZ125 superalloys over a range of temperatures and stresses. Furthermore, the linear relationship between creep temperature and initial stress was extended to the 5-parameter model. The results indicated that the modified model could be used as a creep life prediction method, as it described the creep curve shape and resulted in predictions that fall within a specified error interval. Meanwhile, this modified model provides a more accurate way of describing creep curves under constant load conditions. The limitations and future direction of the modified model were also discussed. In addition, this modified θ projection model shows great potential for the evaluation and assessment of the service safety of structural materials used in components governed by creep deformation.

摘要：A method to decide near optimal settings of the process parameters in friction welding was *** success of the friction welding process is based on various input parameters like friction pressure,friction time,upset pressure and upset time and output parameters like tensile strength,hardness and material ***-6Al-4V and SS304L(SS) materials were joined by friction welding process using interlayer *** Box-Behnken design and response surface methodology(RSM) were applied to deciding the number of experiments to be performed and identify the optimum process parameters for obtaining better joint *** results were highly *** strength of 523 MPa was obtained at a friction pressure of 12 N/mm^2,upset pressure of40 N/mm^2,friction time of 1.2 s and upset time of 7 s.

摘要：Estimating long-term creep deformation and life of materials is an effective way to ensure the service safety and to reduce the cost of long-term integrity evaluation of high temperature structural *** the 1980 s, the θ projection model has been widely used for predicting creep lives due to its ability to capture the characteristic transitions observed in creep curves obtained under constant true stress conditions. However, the creep rupture behavior under constant load or engineering stress conditions cannot be simulated accurately using this model because of the different stress states. In this paper, creep curves obtained under constant load conditions were analyzed using a modified θ projection model by considering the increase in true stress with creep deformation during the creep tests. This model is expressed as ε = θ_1(1-e^(-θ_2t)) + θ3 e^(θ_4e^θ5^εt)-1, and was validated using the creep curves of K465 and DZ125 superalloys tested at a range of temperatures and engineering stresses. Moreover, it was shown that the predictive capability of the modified θ projection model was significantly improved over the original one, as it reduces the prediction uncertainty from a range of 10% to 20% to below 5%. Meanwhile,it was shown that the model can be reasonably used for predicting constant stress creep conditions, when appropriate parameters are used. The prediction performance of the modified model will be discussed in another paper. The results of this study show great potential for the evaluation and assessment of the service safety of structural materials used in applications where designs are limited by creep deformation.

摘要：This paper considers the simultaneous attack problem of multiple missiles against a maneuvering target. Different from most of the existing literature in which the simultaneous attack problem is formulated as a consensus problem of missiles＇ time-to-go estimates, this paper formulates it as the consensus problem of missiles＇ ranges-to-go. Based on this strategy, novel distributed guidance laws are proposed to solve the simultaneous attack problem with the target of unknown *** control method is introduced to estimate the upper bound of the target＇s acceleration. The effectiveness of the proposed guidance laws is verified both theoretically and numerically.

摘要：Liquefied natural gas(LNG) is the most economical way of transporting natural gas(NG) over long distances. Liquefaction of NG using vapor compression refrigeration system requires high operating and capital cost. Due to lack of systematic design methods for multistage refrigeration cycles, conventional approaches to determine optimal cycle are largely trial-and-error. In this paper a novel mixed integer non-linear programming(MINLP)model is introduced to select optimal synthesis of refrigeration systems to reduce both operating and capital costs of an LNG plant. Better conceptual understanding of design improvement is illustrated on composite curve(CC) and exergetic grand composite curve(EGCC) of pinch analysis diagrams. In this method a superstructure representation of complex refrigeration system is developed to select and optimize key decision variables in refrigeration cycles(i.e. partition temperature, compression configuration, refrigeration features, refrigerant flow rate and economic trade-off). Based on this method a program(LNG-Pro) is developed which integrates VBA,Refprop and Excel MINLP Solver to automate the methodology. Design procedure is applied on a sample LNG plant to illustrate advantages of using this method which shows a 3.3% reduction in total shaft work consumption.

摘要：The design of a novel photonic crystal waveguide power splitter is *** proposed power splitter has three output ports,the coupling among three parallel photonic crystal waveguides can be considered as a multimode interference(MMI),and the positions of output waveguides are determined by those of twofold images which are formed by the self-imaging effect of multimode *** transmission characteristics of the splitter are investigated by using the finite-difference time domain(FDTD) and the plane wave expansion *** output optical power in each port can be controlled by adjusting the radius of the dielectric rods in the coupling region,and the coupling effect among output ports is decreased by using the T-shaped output *** results indicate that 1 × 1,1 × 2 and 1 × 3 type power splitters can be realized when the normalized radius of dielectric rods in the coupling region is 0.130,0.180,0.152 or 0.221,respectively.

摘要：Reproducibility of clinical output is important when investigating therapeutic efficacy in pre-clinical animal *** to its physiological relevance,a swine myocardial infarction(MI)model has been widely used to evaluate the effectiveness of stem cells or tissue-engineered constructs for ischemic heart *** methods are used to induce MI in the swine ***,it is difficult,using these approaches,to obtain a similar level of functional outcomes from a group of animals due to interpersonal variation,leading to increased experimental ***,in order to minimize human intervention,we developed an approach to use a customized occluder that has dimensional similarities with that of the coronary artery of animals in the case of the swine *** carried out angiography to measure the diameter of the middle left anterior descending artery of each individual animal to fabricate the customized occluder using a 3D-printing *** fabricated occluder contained a central hole smaller than that of the targeted middle left anterior descending artery to mimic an atherosclerotic coronary artery that has an approximately 20%blocked ***,the 3D-printed occluder can provide continuous blood flow through the central pore,indicating a high survival rate(88%)of up to 28 days *** method showed the possibility of creating consistent myocardial infarction induction as compared to the conventional representative closed-chest method(50%survival rate),thus highlighting how our method can have a profound effect on accelerating reliable experiments for developing new therapeutic approaches to ischemic heart diseases.

摘要：Clearly understanding the structure-function relationship and rational design of efficient CO2 electrocatalysts are still the *** article describes the molecular origin of high selectivity of formic acid on N-doped SnO2 nanoparticles,which obtained via thermal treatment of g-C3N4 and SnCl2·2H2O *** with density functional theory(DFT)calculations,we discover that N-doping effectively introduces oxygen vacancies and increases the charge density of Sn sites,which plays a positive role in CO2 *** addition,N-doping further regulates the adsorption energy of^*OCHO,^*COOH,^*H and promotes HCOOH *** from above modulation,the obtained N-doped SnO2 catalysts with oxygen vacancies(Ov-N-SnO2)exhibit faradaic efficiency of 93% for C1 formation,88% for HCOOH production and well-suppression of H2 evolution over a wide range of potentials.

摘要：This paper addresses double-loop robust tracking controller design of the miniaturized linear motor drive precision stage with mass and damping ratio uncertainties. As an inner-loop, a disturbance observer （DOB） is employed to suppress exogenous low frequency disturbances such as friction and cutting force. To further eliminate the residual disturbance and to guarantee the robust tracking to the reference input, μ-synthesis outer-loop controller is designed. For eliminating the steady state error, a technique is proposed to design the μ-synthesis outer-loop controller with an integrator. A guideline to select the bandwidth of the Q-filter in the DOB is provided. Simulations using a model of a prototype micro-milling machine indicate that the proposed outer-loop synthesis scheme is superior to the H∞ suboptimal control in disturbance rejection performance and steady state tracking performance. Furthermore, it is shown experimentally that the proposed double-loop robust tracking controller improves the tracking performance of the stage by 29.6% over PID control with a DOB inner-loop.