磷化铁@碳纳米管制备及其锌空电池正极催化性能——本科综合化学实验设计

为响应“新工科”建设的需求,将碳基纳米材料与金属锌空电池相结合的前沿科研成果设计为本科综合化学实验。通过化学氧化聚合及高温热解制备磷化铁@碳纳米管,并考察其作为锌空电池正极催化材料的电化学性能,从而帮助学生了解新能源电池行业最新发展动态,熟悉锌空电池的组装及性能测试,将已学知识“学以致用”,培养分析、解决问题的能力和创新能力,提升综合素养。

Instability waves and low-frequency noise radiation in the subsonic chevron jet

Spatial instability frequency noise radiation at waves associated with low- shallow polar angles in the chevron jet are investigated and are compared to the round counterpart. The Reynolds-averaged Navier-Stokes equations are solved to obtain the mean flow fields, which serve as the baseflow for linear stability analysis. The chevron jet has more complicated instability waves than the round jet, where three types of instability modes are identified in the vicinity of the nozzle, corresponding to radial shear, azimuthal shear, and their integrated effect of the baseflow, respectively. The most unstable frequency of all chevron modes and round modes in both jets decrease as the axial location moves downstream. Besides, the azimuthal shear effect related modes are more unstable than radial shear effect related modes at low frequencies. Compared to a round jet, a chevron jet reduces the growth rate of the most unstable modes at down- stream locations. Moreover, linearized Euler equations are employed to obtain the beam pattern of pressure generated by spatially evolving instability waves at a dominant low frequency St = 0.3, and the acoustic efficiencies of these linear wavepackets are evaluated for both jets. It is found that the acoustic efficiency of linear wavepacket is able to be reduced greatly in the chevron jet, compared to the round jet.

Coherent structures and wavepackets in subsonic transitional turbulent jets

A large eddy simulation (LES) is performed for two subsonic jets with a Reynolds number of , which have different core temperatures, i.e., the cold and hot jet. The far-field overall sound pressure levels (OASPL) and noise spectra are well validated against previous experimental results. It is found that the OASPL is raised by heating at shallow angles. The most energetic coherent structures are extracted with specified frequencies using the filter based on the frequency domain variant of the snapshot method of proper orthogonal decomposition (POD). The modes have high coherence of near-field pressure for both jets, while the coherence of modes is enhanced greatly by heating. Based on the coherent structures, spatial wavepackets are educed and the characteristics of growth, saturation and decay are analyzed and compared between the two jets in detail. The results show that heating would enhance the linear growth rate for high frequency components, and nonlinear growth rates for low frequency components in general, which are responsible for higher OASPL in the hot jet. The far-field sound generated by wavepackets is computed using the Kirchhoff extrapolation, which matches well with that of LES at shallow angles. This indicates that the wavepackets associated with coherent structures are dominant sound sources in forced transitional turbulent jets. Additionally, the present POD method is proven to be a robust tool to extract the salient features of the wavepackets in turbulent flows.

Mode decomposition of a noise suppressed mixing layer

Noise is generated in a two-dimensional mixing layer due to the growing of instability waves and vortex pairings. The adjoint-based control methodology has shown to be a robust tool to suppress noise radiation. The mode decomposition algorithms such as the compressible version of proper orthogonal decomposition （POD） and dynamic mode decomposition （DMD） are employed to analyze the spatial/spatial-temporal coherent structures for a consecutive data sets of the controlled mixing layer and its uncontrolled counterpart. The analyses of POD indicate that the y-direction body force control mainly modify the most energetic spatial structures, and increase the uniformity of the flow. The analyses of DMD show us prevalent frequencies and corresponding mode structures, and the stability characteristics of each mode can be obtained from DMD-spectrum. The spectral signatures illustrate that a lot of neutral/slightly damping modes emerging in uncontrolled flow within the frequency range （w 〈 0.4） are suppressed due to control, relevant spatial-temporal structures are also varied, which is coincident with the change of far-field noise spectra. From the view of mode decomposition, the action of control redistribute the energy for frequency components of ~ 〈 0.4 by weakening nonlinearities and regularizing corresponding dynamic structures in streamwise direction, and thus suppress the noise radiation. Moreover, the POD- and DMD-analysis in this study demon- strate that DMD can serve as an important supplement for POD in analyzing a time-resolved physical process.

A Case of COPD with Left Endobronchial Hamartoma by Bronchoscopic Intervention

Objective: Exploration for chronic obstructive pulmonary disease with branched air lumen hamartoma by bronchoscoptic treatment. Material and Method: An old man was referred to our hospital with shortness of breath for many years. Clinical evidence emphysema on respiratory examination, lung function and chest X-ray gave rise to concern. He was diagnosed as COPD and treated with ICS + LABA. But the shortness of breath is still existed. Initial assessment by CT suggested a left lower lobe collapse. Then bronchoscope identified a solid abnormality in main left bronchus. The pathology showed a benign neoplasm. Because of intolerance of operation, the patient was treated by brochoscopic intervention. The endoscopic intervention included resection by electrosurgical snare, electrocautery, argon plasma coagulation (APC). Result: After intervention, the neoplasm was partly removed and the pathological result was endobrochial hematoma. After treatment, the patient’s panting had taken a turn for the better. After one month later, the patient’s lung function improved a lot. Conclusion: In conclusion, endobronchial hamartomas are one of benign neoplasms. It can cause persistent bronchial obstruction and recurrent pneumonias. In this case, invasive endoscopic treatment provides an excellent outcome.

A hybrid subcell-remapping algorithm for staggered multi-material arbitrary Lagrangian-Eulerian methods

A new flux-based hybrid subcell-remapping algorithm for staggered multimaterial arbitrary Lagrangian-Eulerian (MMALE) methods is presented. This new method is an effective generalization of the original subcell-remapping method to the multi-material regime (LOUBERE, R. and SHASHKOV,M. A subcell remapping method on staggered polygonal grids for arbitrary-Lagrangian-Eulerian methods. Journal of Computational Physics, 209, 105–138 (2005)). A complete remapping procedure of all fluid quantities is described detailedly in this paper. In the pure material regions, remapping of mass and internal energy is performed by using the original subcell-remapping method. In the regions near the material interfaces, remapping of mass and internal energy is performed with the intersection-based fluxes where intersections are performed between the swept regions and pure material polygons in the Lagrangian mesh, and an approximate approach is then introduced for constructing the subcell mass fluxes. In remapping of the subcell momentum, the mass fluxes are used to construct the momentum fluxes by multiplying a reconstructed velocity in the swept region. The nodal velocity is then conservatively recovered. Some numerical examples simulated in the full MMALE regime and several purely cyclic remapping examples are presented to prove the properties of the remapping method.

Linear stability analysis of supersonic axisymmetric jets

Stabilities of supersonic jets are examined with different velocities, momentum thicknesses, and core temperatures. Amplification rates of instability waves at inlet are evaluated by linear stability theory （LST）. It is found that increased velocity and core temperature would increase amplification rates substantially and such influence varies for different azimuthal wavenumbers. The most unstable modes in thin momentum thickness cases usually have higher frequencies and azimuthal wavenumbers. Mode switching is observed for low azimuthal wavenumbers, but it appears merely in high velocity cases. In addition, the results provided by linear parabolized stability equations show that the mean-flow divergence affects the spatial evolution of instability waves greatly. The most amplified instability waves globally are sometimes found to be different from that given by LST.

Central nervous system efficacy of aumolertinib versus gefitinib in patients with untreated,EGFR-mutated,advanced non-small cell lung cancer:data froma randomized phase III trial(AENEAS)

Background:The initial randomized,double-blinded,actively controlled,phase III ANEAS study(NCT03849768)demonstrated that aumolertinib showed superior efficacy relative to gefitinib as first-line therapy in epidermal growth factor receptor(EGFR)-mutated advanced non-small cell lung cancer(NSCLC).Metastatic disease in the central nervous system(CNS)remains a challenge in the management of NSCLC.This study aimed to compare the efficacy of aumolertinib versus gefitinib among patients with baseline CNS metastases in the ANEAS study.Methods:Eligible patients were enrolled and randomly assigned in a 1:1 ratio to orally receive either aumolertinib or gefitinib in a double-blinded fashion.Patients with asymptomatic,stable CNS metastases were included.Follow-up imaging of the same modality as the initial CNS imaging was performed every 6 weeks for 15 months,then every 12weeks.CNS responsewas assessed by a neuroradiological blinded,independent central review(neuroradiological-BICR).The primary endpoint for this subgroup analysis was CNS progression-free survival(PFS).Results:Of the 429 patients enrolled and randomized in the ANEAS study,106 patients were found to have CNS metastases(CNS Full Analysis Set,cFAS)at baseline by neuroradiological-BICR,and 60 of them had CNS target lesions(CNS Evaluable for Response,cEFR).Treatment with aumolertinib significantly prolonged median CNS PFS compared with gefitinib in both cFAS(29.0 vs.8.3 months;hazard ratio[HR]=0.31;95%confidence interval[CI],0.17-0.56;P<0.001)and cEFR(29.0 vs.8.3 months;HR=0.26;95%CI,0.11-0.57;P<0.001).The confirmed CNS overall response rate in cEFRwas 85.7%and 75.0%in patients treated with aumolertinib and gefitinib,respectively.Competing risk analysis showed that the estimated probability of CNS progression without prior non-CNS progression or death was consistently lower with aumolertinib than with gefitinib in patients with and without CNSmetastases at baseline.No new safety findings were observed.Conclusions:These results indicate a potential advantage of aumolertinib over gefitinib in terms of CNS PFS and the risk of CNS progression in patients with EGFR-mutated advanced NSCLC with baseline CNS metastases.

Establishment of a Genetic Transformation System and Its Application in Thermoanaerobacter tengcongensis

The whole-genome sequence of Thermoanaerobacter tengcongensis, an anaerobic thermophilic bacterium isolated from the Tengchong hot spring in China, was completed in 2002. However, in vivo studies on the genes of this strain have been hindered in the absence of genetic manipulation system. In order to establish such a system, the plasmid pBOL01 containing the replication origin of the T. tengcongensis chromosome and a kanamycin resistance cassette, in which kanamycin resistance gene expression was controlled by the tte1482 promoter from T. tengcongensis, was constructed and introduced into T. tengcongensis via electroporation. Subsequently, the high transformation efficiency occurred when using freshly cultured T. tengcongensis cells without electroporation treatment, suggesting that T. tengcongensis is naturally competent under appropriate growth stage. A genetic transformation system for this strain was then established based on these important components, and this system was proved to be available for studying physiological characters of T. tengcongensis in vivo by means of hisG gene disruption and complementation.

Endovascular revascularisation of acute tandem vertebrobasilar artery occlusion:seven case series with literature reviews

background The outcome of acute ischaemic stroke due to tandem vertebrobasilar artery occlusion was poor.Endovascular revascularisation may be a positive approach for acute basilar artery occlusion combined with vertebral ostium stenosis or occlusion.We reported seven patients with acute vertebrobasilar tandem occlusion by using angioplasty or stenting for proximal lesion and thrombectomy for distal occlusion.Materials and methods Consecutive patients with acute tandem vertebrobasilar artery occlusion at two centres were included in this study.We retrospectively analysed the clinical,technical and functional outcomes of the patients.results From March 2016 to March 2017,seven patients were included.The mean age and National Institute of Health Stroke Scale score at admission was 57 years and 22,respectively.A reverse approach was used in five patients.The Thrombolysis in Cerebral Infarction score 2b-3 was acquired in all patients.There were no procedural complications.The modified Rankin Scale score was 1-2 for three patients and 4 for one patient at 3 months.Three patients died at 3 months of follow-up.Conclusions Endovascular revascularisation may be feasible for acute tandem vertebrobasilar artery occlusion,and more researches are needed.

A 2D Staggered Multi-Material ALE Code Using MOF Interface Reconstruction

Hydrocodes are necessary numerical tools in the fields of implosion and high-velocity impact,which often involve large deformations with changing-topology interfaces.It is very difficult for Lagrangian or Simplified Arbitrary Lagrangian-Eulerian(SALE)codes to tackle these kinds of large-deformation problems,so a stag-gered Multi-Material ALE(MMALE)code is developed in this paper,which is the explicit time-marching Lagrange plus remap type.We use the Moment Of Fluid(MOF)method to reconstruct the interfaces of multi-material cells and present an adaptive bisection method to search for the global minimum value of the nonlinear objective function.To keep the Lagrangian computations as long as possible,we develop a ro-bust rezoning method named as Combined Rezoning Method(CRM)to generate the convex,smooth grids for the large-deformation domain.Regarding the staggered remap phase,we use two methods to remap the variables of Lagrangian mesh to the rezoned one.One is the first-order intersection-based remapping method that doesn’t limit the distances between the rezoned and Lagrangian meshes,so it can be used in the applications of wide scope.The other one is the conservative second-order flux-based remapping method developed by Kucharika and Shashkov[22]that requires the rezoned element to locate in its adjacent old elements.Numerical results of triple point problem show that the result of first-order remapping method using ALE computations is gradually convergent to that of second-order remapping method using Eulerian computations with the decrease of rezoning,thereby telling us that MMALE computations should be performed as few as possible to reduce the errors of the interface reconstruction and the remapping.Numerical results provide a clear evidence of the robustness and the accuracy of this MMALE scheme,and that our MMALE code is powerful for the large-deformation problems.