基于创新性内侧壁成型工艺的多光学通道微型碱金属原子气室

Existing microfabricated atomic vapor cells have only one optical channel,which is insufficient for supporting the multiple orthogonal beams required by atomic devices.In this study,we present a novel wafer-level manufacturing process for fabricating multi-optical-channel atomic vapor cells and an innovative method for batch processing the inner sidewalls of millimeter glass holes to meet optical channel requirements.Surface characterization and transmittance tests demonstrate that the processed inner sidewalls satisfy the criteria for an optical channel.In addition,the construction of an integrated processing platform enables multilayer non-isothermal anode bonding,the filling of inert gases,and the recovery and recycling of noble gases.Measurements of the absorption spectra and free-induction decay signals of xenon-129(^(129)Xe)and xenon-131(^(131)Xe)under different pump-probe schemes demonstrate the suitability of our vapor cell for use in atomic devices including atomic gyroscopes,dual-beam atomic magnetometers,and other optical/atomic devices.The proposed micromolding technology has broad application prospects in the field of optical-device processing.

Research progress on lung cancer stem cells in epidermal growth factor receptor–tyrosine kinase inhibitor targeted therapy resistance in lung adenocarcinoma

Lung cancer is the leading cause of cancer-related deaths globally.In recent years,with the widespread use of genetic testing,epidermal growth factor receptor–tyrosine kinase inhibitor(EGFR-TKI)–targeted drugs have been efficacious to patients with lung adenocarcinoma exhibiting EGFR mutations.However,resistance to treatment is inevitable and eventually leads to tumor progression,recurrence,and reduction in the overall treatment efficacy.Lung cancer stem cells play a crucial role in the development of resistance toward EGFR-TKI–targeted therapy for lung adenocarcinoma.Lung cancer stem cells possess self-renewal,multilineage differentiation,and unlimited proliferation capabilities,which efficiently contribute to tumor formation and ultimately lead to tumor recurrence andmetastasis.In this study,we evaluated the origin,markers,stemness index,relevant classic studies,resistance mechanisms,related signaling pathways,and strategies for reversing lung cancer stem cell resistance to EGFR-TKIs to provide new insights on delaying or reducing resistance and to improve the treatment efficacy of patients with EGFR-mutated lung adenocarcinoma in the future.

Catalytic conversion of guaiacol to alcohols for bio-oil upgrading

Guaiacol was chosen to represent O-containing chemicals with lower effective hydrogen carbon ratio（H/Ceff factor） in bio-oil,and the hydrodeoxygenation of guaiacol was investigated over non-precious and nonsulfided catalysts. Effects of metal composition,reaction temperature,and hydrogen pressure on conversion and selectivity were investigated systematically. Among various compositions of catalysts,Ni Co/CNT exhibited best performance of guaiacol conversion with higher selectivity towards desired alcohols with higher H/Cefffactor. The reaction pathways of guaiacol in aqueous were proposed based on the product analyzed.Results show that metal composition and temperature have great effects on the conversion of guaiacol and the yields of desired products.

Inversion of ocean-bottom seismometer(OBS) waveforms for oceanic crust structure: a synthetic study

The waveform inversion method is applied-- using synthetic ocean-bottom seismometer （OBS） data--to study oceanic crust structure. A niching genetic algorithm （NGA） is used to implement the inversion for the thickness and P-wave velocity of each layer, and to update the model by minimizing the objective function, which consists of the misfit and cross-correlation of observed and synthetic waveforms. The influence of specific NGA method parameters is discussed, and suitable values are presented. The NGA method works well for various observation systems, such as those with irregular and sparse distribu- tion of receivers as well as single receiver systems. A strategy is proposed to accelerate the convergence rate by a factor of five with no increase in computational complex- ity; this is achieved using a first inversion with several generations to impose a restriction on the preset range of each parameter and then conducting a second inversion with the new range. Despite the successes of this method, its usage is limited. A shallow water layer is not favored because the direct wave in water will suppress the useful reflection signals from the crust. A more precise calculation of the air-gun source signal should be considered in order to better simulate waveforms generated in realistic situa- tions; further studies are required to investigate this issue.

Multi-centric clinical study of the effect of intervention time on efficacy of gastroparesis external application prescription treatment of gastrointestinal tumor postsurgical gastroparesis

Objective:This intervention has been shown to be clinically efficacious and safe.The aim of this study was to determine the effect of different intervention times on the efficacy of gastroparesis external application prescription versus placebo for the treatment of gastrointestinal tumor postoperative,postsurgical gastroparesis.Methods:A multicenter,randomized,double-blind,placebo controlled phaseⅢclinical trial was designed to demonstrate superiority and conducted at four grade 3A hospitals in Beijing.Patients diagnosed with gastrointestinal tumor postsurgical gastroparesis and local cold syndrome in the abdomen were enrolled and received conventional treatment(nutritional support,gastrointestinal decompression,and prokinetic medication).Treatment and control groups respectively received gastroparesis external application prescription or placebo acupoint application over a treatment course of 14 days or until the primary efficacy endpoint(clinical efficiency)was achieved.Results:A total of 120 patients were enrolled in the treatment and control groups(n Z 60 per group),and 15 patients dropped out of the study because of skin allergies(n Z 7)or poor efficacy(nZ8).The efficacy among patients in Class B of Group A(treatment group)was marginally better than that of Group B(control group)(64.28%vs.55.56%)although the difference between the two groups was not significant.However,the efficacy among patients in Class C of Group A was significantly better than that of Group B(79.49%vs.43.33%).For Group A,the time for patients in the three classes to achieve the efficacy endpoint increased significantly with disease progression(3.00,6.78,and 8.29 days for Class A,B,and C,respectively).Conclusions:Gastroparesis external application prescription can effectively treat gastrointestinal tumor postsurgical gastroparesis and may be more efficacious in progressive disease compared placebo.Patients with gastrointestinal tumor postsurgical gastroparesis should therefore undergo intervention at an earlier stage.

Longitudinal Vibration Analysis of Marine Riser During Installation and Hangoff in Ultra Deepwater

This paper is concerned with the problem of longitudinal vibration of a 3,000 m long disconnected drilling riser during installation and hangoff operation.The natural frequency,amplitude of vibration displacement and vibration force of longitudinal vibration have been determined with consideration of the damping effect of the sea water.Results show the natural frequency of riser under these two situations are both decrease with the increase of water depth.The natural frequency of riser in installation operation is bigger than that in hangoff operation.The vibration displacement in hangoff configuration is bigger than that in installation while the vibration force in hangoff configuration is smaller than that in installation configuration.Under the condition of resonance,the vibration displacement increase along riser from top end to the bottom end while the vibration force increase along riser from riser bottom end to the top end.

A scheme to treat the singularity in global seismic wavefield simulation using pseudospectral method with staggered grids

The pseudospectral method has been applied to the simulation of seismic wave propagation in 2-D global Earth model. When a whole Earth model is considered, the center of the Earth is included in the model and then singularity arises at the center of the Earth where r=0 since the 1/r term appears in the wave equations. In this paper, we extended the global seismic wavefield simulation algorithm for regular grid mesh to staggered grid configuration and developed a scheme to solve the numerical problems associated with the above singularity for a 2-D global Earth model defined on staggered grid using pseudospectral method. This scheme uses a coordinate transformation at the center of the model, in which the field variables at the center are calculated in Cartesian coordinates from the values on the grids around the center. It allows wave propagation through the center and hence the wavefield at the center can be stably calculated. Validity and accuracy of the scheme was tested by compared with the discrete wavenumber method. This scheme could also be suitable for other numerical methods or models parameterized in cylindrical or spherical coordinates when singularity arises at the center of the model.

Crustal velocity structure of central Gansu Province from regional seismic waveform inversion using firework algorithm

The firework algorithm（FWA） is a novel swarm intelligence-based method recently proposed for the optimization of multi-parameter, nonlinear functions. Numerical waveform inversion experiments using a synthetic model show that the FWA performs well in both solution quality and efficiency. We apply the FWA in this study to crustal velocity structure inversion using regional seismic waveform data of central Gansu on the northeastern margin of the Qinghai-Tibet plateau. Seismograms recorded from the moment magnitude（MW） 5.4 Minxian earthquake enable obtaining an average crustal velocity model for this region. We initially carried out a series of FWA robustness tests in regional waveform inversion at the same earthquake and station positions across the study region,inverting two velocity structure models, with and without a low-velocity crustal layer; the accuracy of our average inversion results and their standard deviations reveal the advantages of the FWA for the inversion of regional seismic waveforms. We applied the FWA across our study area using three component waveform data recorded by nine broadband permanent seismic stations with epicentral distances ranging between 146 and 437 km. These inversion results show that the average thickness of the crust in this region is 46.75 km, while thicknesses of the sedimentary layer, and the upper, middle, and lower crust are 3.15,15.69, 13.08, and 14.83 km, respectively. Results also show that the P-wave velocities of these layers and the upper mantle are 4.47, 6.07, 6.12, 6.87, and 8.18 km/s,respectively.

Global SH-wave propagation in a 2D whole Moon model using the parallel hybrid PSM/FDM method

We present numerical modeling of SH-wave propagation for the recently proposed whole Moon model and try to improve our understanding of lunar seismic wave propagation. We use a hybrid PSM/FDM method on staggered grids to solve the wave equations and implement the calculation on a parallel PC cluster to improve the computing efficiency. Features of global SH-wave propagation are firstly discussed for a 100-km shallow and900-km deep moonquakes, respectively. Effects of frequency range and lateral variation of crust thickness are then investigated with various models. Our synthetic waveforms are finally compared with observed Apollo data to show the features of wave propagation that were produced by our model and those not reproduced by our models. Our numerical modeling show that the low-velocity upper crust plays significant role in the development of reverberating wave trains. Increasing frequency enhances the strength and duration of the reverberations.Surface multiples dominate wavefields for shallow event.Core–mantle reflections can be clearly identified for deep event at low frequency. The layered whole Moon model and the low-velocity upper crust produce the reverberating wave trains following each phases consistent with observation. However, more realistic Moon model should be considered in order to explain the strong and slow decay scattering between various phases shown on observation data.

In Situ Studies of Deformation and Fracture in Sputtering Copper Film

Nanocrystalline copper films were prepared by sputtering and then in situ straining experiments were performed using a trans- mission electron microscope. Macroscopically, these copper films exhibited very low ductility (<l%). Dislocation activity was limited in regions far from propagating cracks. Near stable growing cracks, considerable local plasticity was observed. The evidence of slip ac- tivity both within grain interiors and in grain boundaries was also observed. Although some dislocation; moved very fast, others showed rates much lower than those typically measured for bulk copper. Fracture was intergranular, but not brittle. It occurred by linking of microcracks. Microcracks formed within a micrometer or so ahead of the main crack tip, usually within a grain boundary. Linking then took place by the easiest available path.

Comparison of deterministic and stochastic approaches to crosshole seismic travel-time inversions

The Bayesian inversion method is a stochastic approach based on the Bayesian theory.With the development of sampling algorithms and computer technologies,the Bayesian inversion method has been widely used in geophysical inversion problems.In this study,we conduct inversion experiments using crosshole seismic travel-time data to examine the characteristics and performance of the stochastic Bayesian inversion based on the Markov chain Monte Carlo sampling scheme and the traditional deterministic inversion with Tikhonov regularization.Velocity structures with two different spatial variations are considered,one with a chessboard pattern and the other with an interface mimicking the Mohorovicicdiscontinuity(Moho).Inversions are carried out with different scenarios of model discretization and source–receiver configurations.Results show that the Bayesian method yields more robust single-model estimations than the deterministic method,with smaller model errors.In addition,the Bayesian method provides the posterior probabilistic distribution function of the model space,which can help us evaluate the quality of the inversion result.

Global SH-wavefield calculation for a two-dimensional whole-Earth model with the parallel hybrid PSM/FDM algorithm

We present a parallel hybrid algorithm based on pseudospectral method （PSM） and finite difference method （FDM） for two-dimensional （2-D） global SH- wavefield simulation. The whole-Earth model is taken as a cross section of spherical Earth, and corresponding wave equations are defined in 2-D cylindrical coordinates. Spatial derivatives in the wave equations are approximated with efficient and high accuracy PSM in the lateral and high-order FDM in the radial direction on staggered grids. This algorithm allows us to divide the whole-Earth into sub-domains in radial direction and implement efficient parallel computing on PC cluster, while retains high accuracy and efficiency of PSM in lateral direction. A transformation of moment tensor between 3-D spherical Earth and our 2-D model was proposed to give corre- sponding moment tensor components used in 2-D modeling. Comparison of modeling results with those obtained by direct solution method shows very good accuracy of our algorithm. We also demonstrate its feasibility with a lateral heterogeneous whole-Earth model with localized velocity perturbation.

Depth variation of the Conrad discontinuity in the Qaidam Basin, northwestern China, and its crustal dynamic implications

We use broadband records from a dense seismic network deployed in and around the Qaidam Basin in northwestern China to analyze the crustal phases and investigate the depth of the Conrad and Moho discontinuities as well as the P-wave velocity.Waveform cross-correlation is used to assist in the identification of the crustal phases and in determining their arrival times.Depth of the Conrad discontinuity is determined by fitting the travel times of Conrad-diffracted P-waves using a two-layer model.The depth of the Conrad discontinuity under the eastern part of the basin is shallower than the western part,which can be attributed to different crustal shortening mechanisms.The upper crust shortening in the western part of the basin leads to thickening of the upper crust,while multiple thrust faults result in the rise of the Conrad discontinuity in the east.These two different mechanisms determine the depth change of the Conrad discontinuity in the basin from the west to the east,which is supported by the results in this study.

Preface to special issue on recent advances in computational seismology and its applications

Computational seismology is a relatively new interdisciplinary field spanning computational techniques in theoretical and observational seismology. It studies numerical methods and their implementation in various theoretical and applied problems in seismology.

上颈椎骨折合并轻中型颅脑损伤的手术策略选择体会及效果

目的总结上颈椎骨折合并轻中型颅脑损伤手术策略选择的体会及其治疗效果.方法以2018年6月-2019年6月本院收治的上颈椎骨折合并轻中型颅脑损伤患者36例为研究对象,对其手术治疗进行回顾性分析.结果36例患者颈椎手术均顺利完成,未出现因为颈椎骨折处理不到位导致患者脊髓受伤的情况,术后患者颈部活动受限、枕部放射性疼痛等症状均得到有效缓解.出院时患者GOS评分V级25例,IV级11例,未出现患者死亡的情况.患者复查结果显示,全部病例骨折均得到良好愈合,颈椎稳定,未出现固定断裂、松动及脱出的情况.早期颈椎骨折漏诊5例,漏诊率为13.89%(15/36).结论颈椎骨折联合颅脑损伤在临床上比较常见,对于颅脑损伤患者应重点对其颈部进行检查和保护,早期进行骨科、脑外科联合手术临床效果较好,上颈椎骨折则应尽早进行手术,不能过分强调颅脑损伤的治疗而延误颈椎手术的时机.

New type of overrunning clutch based on curved-plate compression-torsion metamaterial

Overrunning clutches are unidirectional drive mechanisms that are widely used in transmission systems.However,existing overrunning clutches have complex structures,require high preparation accuracy,and fail after a certain degree of wear.To address these issues,we propose a new type of overrunning clutch consisting of a conical structure and novel compression-torsion conversion(CTC)metamaterial with curved plates.Theoretical calculations are employed to guide the material distribution and ensure the deformation coordination of the curved-plate CTC metamaterial for greater ultimate torque.The transmission mechanism of the proposed overrunning clutch is derived to guide the parameter selection of the CTC metamaterial and the conical structure.Experiments and finite element simulations reveal that the curved-plate CTC metamaterial features excellent CTC efficiency,flexibility,and transverse stiffness,which is conducive reducing the resistance of the overrunning state and ensures stability during operation.The unidirectional transmission system constructed with the new overrunning clutch shows reliable performances under working and overrunning states.The constructed overrunning clutch provides an effective one-way transmission method.The clutch with simple construction and self-compensated ability for wear exhibits great potential in miniaturized and lightweight equipment or robots.

A viral movement protein targets host catalases for 26S proteasome-mediated degradation to facilitate viral infection and aphid transmission in wheat

The infection of host plants by many different viruses causes reactive oxygen species(Ros)accumulation and yellowing symptoms,but the mechanisms through which plant viruses counteract RoS-mediated immunity to facilitate infection and symptom development have not been fully elucidated.Most plant viruses are transmitted by insect vectors in the field,but the molecular mechanisms underlying virus-host-insect interactions are unclear.In this study,we investigated the interactions among wheat,barley yellow dwarf virus(BYDV),and its aphid vector and found that the BYDV movement protein(MP)interacts with both wheat catalases(CATs)and the 26S proteasomeubiquitin receptor non-ATPase regulatorysubunit2homolog(PSMD2)to facilitate the 26S proteasome-mediateddegradation of CATs,promotingviral infection,disease symptom development,and aphid transmission.Overexpression of the BYDV MP gene in wheat enhanced the degradation of CATs,which leading to increased accumulation of ROS and thereby enhanced viral infection.Interestingly,transgenic wheat lines overexpressing BYDV MP showed significantly reduced proliferation of wingless aphids and an increased number of winged aphids.Consistent with this observation,silencing of CAT genes also enhanced viral accumulation and reduced the proliferation of wingless aphids but increased the occurrence of winged aphids.In contrast,transgenic wheat plants overexpressing TaCAT1 exhibited the opposite changes and showed increases in grain size and weight upon infection with BYDV.Biochemical assays demonstrated that BYDV MP interacts with PSMD2 and promotes 26S proteasome-mediated degradation of TaCAT1 likely in a ubiquitination-independent manner.Collectively,our study reveals a molecular mechanism by which a plant virus manipulates the Ros production system of host plants to facilitate viral infection and transmission,shedding new light on the sophisticated interactions among viruses,host plants,and insect vectors.

Ultrasensitive SERF atomic magnetometer with a miniaturized hybrid vapor cell

The chip-scale hybrid optical pumping spin-exchange relaxation-free(SERF)atomic magnetometer with a single-beam arrangement has prominent applications in biomagnetic measurements because of its outstanding features,including ultrahigh sensitivity,an enhanced signal-to-noise ratio,homogeneous spin polarization and a much simpler optical configuration than other devices.In this work,a miniaturized single-beam hybrid optical pumping SERF atomic magnetometer based on a microfabricated atomic vapor cell is demonstrated.Although the optically thin Cs atoms are spinpolarized,the dense Rb atoms determine the experimental results.The enhanced signal strength and narrowed resonance linewidth are experimentally proven,which shows the superiority of the proposed magnetometer scheme.By using a differential detection scheme,we effectively suppress optical noise with an approximate five-fold improvement.Moreover,the cell temperature markedly affects the performance of the magnetometer.We systematically investigate the effects of temperature on the magnetometer parameters.The theoretical basis for these effects is explained in detail.The developed miniaturized magnetometer has an optimal magnetic sensitivity of 20 fT/Hz^(1/2).The presented work provides a foundation for the chip-scale integration of ultrahighly sensitive quantum magnetometers that can be used for forward-looking magnetocardiography(MCG)and magnetoencephalography(MEG)applications.

Composition and luminescence properties of highly robust green-emitting LuAG:Ce/Al_(2)O_(3)composite phosphor ceramics for high-power solid-state lighting

The major advantage of laser lighting over white light-emitting-diode is the possibility to achieve ultra-high luminance.However,phosphors usually suffer laser-induced luminescence saturation,which limits the peak luminance of laser lighting devices.The aim of the present study is to develop LuAG:Ce/Al_(2)O_(3)composite ceramics(LACCs)with a high saturation threshold for high-luminance laser lighting.Owning to the rigid crystal structure,proper synthetic process,and optimized thermal design,the LACCs possess small thermal quenching(16%loss in luminescence at 225℃),high quantum yield(>95%),and excellent luminescence properties.When the LACCs are irradiated by blue laser diodes in a reflection mode,a high luminous flux of 4634 lm and luminous efficacy of 283 lm·W^(−1)are realized.Furthermore,they show no sign of luminescence saturation even when the power density reaches 20.5 W·mm^(−2).With these favorable properties,the designed LACCs show great potential in high-luminance laser lighting.

Reactive SPS of Al_(2)O_(3)–RE:YAG(RE=Ce;Ce+Gd)composite ceramic phosphors

Ultrafine-grained Al_(2)O_(3)–rare earth:yttrium aluminium garnet(Al_(2)O_(3)–RE:YAG)(RE=Ce;Ce+Gd)composite ceramics were obtained for the first time by reactive spark plasma sintering(SPS)using commercially available initial oxide powders.The effect of key sintering parameters(temperature,dwell time,and external pressure(P_(load)))on densification peculiarities,structural-phase states,and luminescent properties of composites was studied comprehensively.Differences in phase formation and densification between Ce-doped and Ce,Gd-codoped systems were shown.Parameters of reactive SPS,at which there is partial melting with the formation of near-eutectic zones of the Al_(2)O_(3)–YAG system/coexistence of several variations of the YAG-type phase,were established.Pure corundum–garnet biphasic ceramics with an optimal balance between microstructural and luminescence performance were synthesized at 1425℃/30 min/30–60 MPa.The external quantum efficiency(EQE)of the phosphor converters reached 80.7%and 72%with close lifetime of~63.8 ns,similar to those of commercial Ce:YAG materials,which is promising for further applications in the field of high-power white light-emitting diodes(WLEDs)and laser diodes(LDs).