低雷诺数下翼型绕流的LBM数值模拟

Lattice Boltzmann Method (LBM)是一种近年来发展的基于分子动理论的数值方法,它具有计算简单、边界易于处理的特点。本文基于采用D2Q9模型的LBM方法对NACA0012翼型进行了数值模拟与分析,数值结果表明:对于简单翼型的低雷诺数、非定常湍流流场,LBM方法的数值结果与CFL3D参考值可以很好的吻合。因而,该方法对于低雷诺数下简单翼型流场计算是一种有效的计算手段。

A Maximum Likelihood Method for Estimating Probabilistic Strain Amplitude-Fatigue Life Curves

The fatigue lives of materials and structures at different strain levels show het- eroscedasticity. In addition when the number of test specimens is insufficient, the fatigue strength coefficient and fatigue ductility coefficient of the fitting parameters in the total strain life equa- tion may not have definite physical significance. In this work, a maximum likelihood method for estimating probabilistic strain amplitude fatigue life curves is presented based on the fatigue lives at different strain levels. The proposed method is based on the general basic assumption that the logarithm of fatigue life at an arbitrary strain level is normally distributed. The rela- tionship among the parameters of total strain life equation, monotonic ultimate tensile stress and percentage reduction of area is adopted. The presented approach is finally illustrated by two applications. It is shown that probabilistic strain amplitude-fatigue life curves can be eas- ily estimated based on the maximum likelihood method. The results show that fatigue lives at different strain levels have heteroscedasticity and the values of fatigue strength coefficient and fatigue ductility coefficient obtained by the proposed method are close to those of the true tensile fracture stress and true tensile fracture strain.

Mesoporous silica as micro/nano-carrier： From passive to active cargo delivery, a mini review

Mesoporous silica has been widely explored for biomedical applications due to its unique structure and good biocompatibility. In particular it exhibits superior properties as micro/nano-carriers in the biomedical field. We explore their potentials in controlled drug/gene co-delivery and photodynamic therapy for cancer treatment both in vitro and in vivo. By incorporating mesoporous silica nanoparticles（MSNP） with two-dimensional nanomaterial, graphene oxide nano-sheet, we utilize MSNP in cellular bio-imaging with squaraine dye. Meanwhile, through delicate combination between mesoporous silica micro/nano carriers with catalytic/bio-catalytic reactions, we manage to achieve self-propelled micro/nano-motors based on mesoporous silica that are capable of transporting cargos in an active manner. Especially, enzyme powered mesoporous silica motors can be powered by physiologically available fuels such as glucose and urea,which are advantageous for future biomedical use. Motion control on both velocity and movement direction provides a powerful tool for targeted drug delivery. Therefore, such mesoporous silica based active carriers pave way to the solution of targeted drug delivery for cancer treatment in future nano-medicine field.

Additively Manufactured Flexible Electronics with Ultrabroad Range and High Sensitivity for Multiple Physiological Signals'Detection

Flexible electronics can be seamlessly attached to human skin and used for various purposes, such as pulse monitoring, pressure measurement, tensile sensing, and motion detection. Despite their broad applications, most flexible electronics do not possess both high sensitivity and wide detection range simultaneously;their sensitivity drops rapidly when they are subjected to even just medium pressure. In this study, ultrabroad-range, high-sensitivity flexible electronics are fabricated through additive manufacturing to address this issue. The key to possess high sensitivity and a wide detection range simultaneously is to fabricate flexible electronics with large depth-width ratio circuit channels using the additive manufacturing inner-rinsing template method. These electronics exhibit an unprecedented high sensitivity of 320 kPa^(−1) over the whole detection range, which ranges from 0.3 to 30,000 Pa (five orders of magnitude). Their minimum detectable weight is 0.02 g (the weight of a fly), which is comparable with human skin. They can stretch to over 500% strain without breaking and show no tensile fatigue after 1000 repetitions of stretching to 100% strain. A highly sensitive and flexible electronic epidermal pulse monitor is fabricated to detect multiple physiological signals, such as pulse signal, breathing rhythm, and real-time beat-to-beat cuffless blood pressure. All of these signals can be obtained simultaneously for detailed health detection and monitoring. The fabrication method does not involve complex expensive equipment or complicated operational processes, so it is especially suitable for the fabrication of large-area, complex flexible electronics. We believe this approach will pave the way for the application of flexible electronics in biomedical detection and health monitoring.

Magnetic Nanomotor-Based Maneuverable SERS Probe

Surface-enhanced Raman spectroscopy(SERS)is a powerful sensing technique capable of capturing ultrasensitive fingerprint signal of analytes with extremely low concentration.However,conventional SERS probes are passive nanoparticles which are usually massively applied for biochemical sensing,lacking controllability and adaptability for precise and targeted sensing at a small scale.Herein,we report a“rod-like”magnetic nanomotor-based SERS probe(MNM-SP)that integrates a mobile and controllable platform of micro-/nanomotors with a SERS sensing technique.The“rod-like”structure is prepared by coating a thin layer of silica onto the self-assembled magnetic nanoparticles.Afterwards,SERS hotspots of silver nanoparticles(AgNPs)are decorated as detecting nanoprobes.The MNM-SPs can be navigated on-demand to avoid obstacles and target sensing sites by the guidance of an external gradient magnetic field.Through applying a rotating magnetic field,the MNM-SPs can actively rotate to efficiently stir and mix surrounding fluid and thus contact with analytes quickly for SERS sensing.Innovatively,we demonstrate the self-cleaning capability of the MNM-SPs which can be used to overcome the contamination problem of traditional single-use SERS probes.Furthermore,the MNM-SPs could precisely approach the targeted single cell and then enter into the cell by endocytosis.It is worth mentioning that by the effective mixing of intracellular biocomponents,much more informative Raman signals with improved signal-to-noise ratio can be captured after active rotation.Therefore,the demonstrated magnetically activated MNM-SPs that are endowed with SERS sensing capability pave way to the future development of smart sensing probes with maneuverability for biochemical analysis at the micro-/nanoscale.

Large-area flexible and transparent UV photodetector based on cross-linked Ag NW@ZnO NRs with high performance

A series of large-area,flexible and transparent ultraviolet(UV)photodetectors(PDs)based on Ag nanowire(NW)@ZnO nanorods(NRs)are fabricated by an inexpensive,facile and effective approach.These Ag NW@ZnO NRs are successfully synthesized using a two-step method in an oil bath with a high surface-to-volume ratio and good crystallinity.The PDs are fabricated by drop-coating with different drop-coating times on the surface of polyethylene terephthalate(PET)coupled with Au electrodes.By optimizing the cross-linked network of Ag NW@ZnO NRs,PD2 with a size greater than 25 mm exhibits excellent photoresponse under UV light illumination of 365 nm(1.3 m W cm^(-2))with a bias of 5 V:a high sensitivity of over 10^(3),and a much shorter rise/decay time of 2.6 s/2.3 s.Simultaneously,the detector exhibits an average transmittance of more than 70%in the visible light region,as well as good flexibility and excellent mechanical stability under a bending angle of 120°over 1000 circles bending.These integral advantages have significant potential for practical applications and mass production.

Porcine Picornavirus 3C Protease Degrades PRDX6 to Impair PRDX6-mediated Antiviral Function

Peroxiredoxin-6(PRDX6)is an antioxidant enzyme with both the activities of peroxidase and phospholipase A2(PLA2),which is involved in regulation of many cellular reactions.However,the function of PRDX6 during virus infection remains unknown.In this study,we found that the abundance of PRDX6 protein was dramatically decreased in foot-and-mouth disease virus(FMDV)infected cells.Overexpression of PRDX6 inhibited FMDV replication.In contrast,knockdown of PRDX6 expression promoted FMDV replication,suggesting an antiviral role of PRDX6.To explore whether the activity of peroxidase and PLA2 was associated with PRDX6-mediated antiviral function,a specific inhibitor of PLA2(MJ33)and a specific inhibitor of peroxidase activity(mercaptosuccinate)were used to treat the cells before FMDV infection.The results showed that incubation of MJ33 but not mercaptosuccinate promoted FMDV replication.Meanwhile,overexpression of PRDX6 slightly enhanced type I interferon signaling.We further determined that the viral 3Cprowas responsible for degradation of PRDX6,and 3Cpro-induced reduction of PRDX6 was independent of the proteasome,lysosome,and caspase pathways.The protease activity of 3Cprowas required for induction of PRDX6 reduction.Besides,PRDX6 suppressed the replication of another porcine picornavirus Senecavirus A(SVA),and the 3Cproof SVA induced the reduction of PRDX6 through its proteolytic activity as well.Together,our results suggested that PRDX6 plays an important antiviral role during porcine picornavirus infection,and the viral 3Cproinduces the degradation of PRDX6 to overcome PRDX6-mediated antiviral function.

Correction to: Porcine Picornavirus 3C Protease Degrades PRDX6 to Impair PRDX6-mediated Antiviral Function

Correction to:Virologica Sinica(2021)36:948-957 https://doi.org/10.1007/s12250-021-00352-4 Due to our negligence,the original version of this article,published online on March 15,2021,contained a mistake in Figure 2E(The Knockdown band of Western blotting was provided incorrectly).The correct Fig.2E is given below.We apologize for this error and state that this does not change the scientific conclusions of the article in any way.