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Single-arm trial refers to a clinical trial design that does not set up parallel control group, adopts open design, and does not involve randomization and blind method. These features, on the one hand, speed up the process of clinical trials, significantly shorten the time to market and meet the needs of patients with advanced malignancies, but also lead to the uncertainty of single-arm clinical trials themselves. Recently, the US Food and Drug Administration held a meeting of the oncologic drug advisory committee to discuss six tumor indications that have been accelerated approved, which once again triggered the discussion of single-arm trials. The basis of accelerated approval by single-arm trial is actually a compromise on the level of evidence-based medical evidence requirements after assessing the benefit risk. Therefore, the sponsor should strictly grasp the applicable conditions of single-arm trial in anti-tumor drugs and conduct single-arm trial scientifically. Post-marketing clinical trial should be implement as early as possible to ensure the benefit of patients. Based on the characteristics of single-arm trial, combined with two guidance relevant to single-arm trial issued by National Medical Products Administration recently, this article is supposed to propose and summarize the strategy of single-arm trial supporting the marketing of anti-tumor drugs.单臂试验是指在临床试验设计时，不设立平行对照组，并采用开放设计，不涉及随机与盲法的一种临床试验设计。单臂试验的特征一方面加速了临床试验的进程，缩短了药品的上市时间，使晚期恶性肿瘤患者更快获得治疗药物，但同时也具有试验结果不够稳定的局限性。2021年4月，美国食品药品监督管理局召开肿瘤药物咨询委员会会议，对6项已通过单臂加速批准上市的肿瘤适应证进行讨论，再次引发了各界对单臂试验的讨论。单臂试验所支持的药品加速上市，实际是在评估了获益风险后，对循证医学证据级别要求进行了一定程度的妥协，因此，研发单位应严格把握单臂试验支持抗肿瘤药物附条件上市的适用条件，并科学开展单臂试验，同时，及早开展上市后确证性研究，以确保患者获益。文章基于单臂试验的特点，结合国家药品监督管理局发布的《单臂试验支持上市的抗肿瘤药进入关键试验前临床方面沟通交流技术指导原则》和《单臂试验支持上市的抗肿瘤药上市许可申请前临床方面沟通交流技术指导原则》，对单臂试验支持抗肿瘤药物上市策略提出思考与总结。.

This paper presents a new rear-triggered vanadium-compensated 4H silicon carbide (4H-SiC) photoconductive semiconductor switch (PCSS) with aluminum nitride (AlN) anti-reflection coating on the back of PCSS device. Characteristics of PCSS are investigated by using semiconductor device simulation software Silvaco-TCAD. The switch substrates were doped with vanadium to make the substrates highly insulated. The on-state performance of the photoconductive switch was tested under pulsed light conditions with a wavelength of 532 nm and an optical power density of 6.8 MW/cm2 at a bias voltage of 2 kV. And the bias voltage was increased from 0 V to 10 kV in the absence of light trigger conditions, and its off-state characteristics were tested. Results show that the electric field strength between electrodes can be reduced by using rear-triggered structure, the switch breakdown voltage is over 80 kV DC, the maximum transient current is about 137 A, and the tail current almost disappears when the pulse light is turned off. In addition, the breakdown voltage of the rear-triggered PCSS to be higher than that of the front-triggered one. After adding AlN anti-reflection coating on the switch, the maximum transient of the switch and the optical utilization efficiency of laser energy are significantly improved, the maximum transient current of the switch was greatly improved from137 A to 150 A, which was increased by about 9.4 %. In addition, the effects of substrate thickness and optical power density on the switching performance were evaluated.

In this paper, the ZTC4/B/C titanium matrix composite containing 0·2–0·5 wt-%B and 0·5–2 wt-%C was fabricated using melting–casting process. The microstructure and mechanical properties of as cast ZTC4/B/C Ti matrix composite were investigated. The results indicate that the microstructures of as cast ZTC4/B/C were consisted of lamellar α, β at grain boundary and second phases of bar-like TiB and spherical-like TiC. The elastic modulus of ZTC4/B with 0·5 wt-%B is 145 GPa, 30% higher than that of the matrix alloy. The ultimate tensile strength of ZTC4/B/C with 0·5 wt-%B and 0·5 wt-%C reached 1300 MPa, 25% higher than that of the matrix alloy.

Tensile tests were carried out at ambient temperature on one kind of near α titanium alloy named Ti-600 before and after being exposed at 600°C for 100 h. Fractography morphologies were investigated and fracture mechanisms were analysed. The results indicate that, compared with the sample without thermal exposure, the strength of the sample without oxidising layers increases by 1% or so, while the elongation decreases by about 20·4% for the alloy after thermal exposure. For the sample with oxidising layers, the ultimate strength decreases somewhat and the elongation decreases by 48·9%, indicating that the plasticity decreases abruptly during the thermal exposure process. For the solutioned plus aged samples, cracks originated from the centre of the fracture, and dimple-type fractures could be found. After long thermal exposure, for the samples without oxidising layers, hybrid fractures (both dimples and cleavage facets) can be seen. However, for the samples with oxidising layers, only cleavage fac...

The two-stroke DI engine has distinct advantages such as high speed, high power density, and simple structure . LPG has a low boiling point and high saturation vapor pressure, which is very helpful in accelerating the fuel-air mixing. Owing to these characteristics and advantages, the two-stroke LPG engine is generally regarded as the preferred power source of the generator unit for extended-range electrical vehicles. The process of mixture formation is numerically simulated after the calculation model is validated by results from optical experiments. The results show that, under conditions of avoidance of fuel short-circuiting, an injection timing of 50° CA ABDC for engine start and warming (2000 rpm), and an 40° CA ABDC for running as the power source of the generator (4800 rpm) are appropriate. Further analysis of the velocity and concentration fields shows that the fresh mixture is locked in the cylinder when the exhaust port is closed (73° CA ABDC) and the homogeneous mixture can be formed at spark timing.

Slope radar which is based on the principles of synthetic aperture radar and differential interferometry can be used to the deformation monitoring in open pit mines, tailings, dump and other occasions. The existing slope radar systems mainly adopt stepping frequency continuous wave signal (SFCW) to achieve range resolution, and achieve azimuth resolution by stop-go motion mode along track direction. In this paper, frequency modulated continuous wave (FMCW) signal and continuous motion mode are applied in slope radar, which can reduce the acquisition time of each radar image from 5–10 minutes to 0.5–1 minutes. However, continuous motion mode will introduce errors in the echo model. This paper focuses on the imaging geometry model of continuous motion mode slope radar, and imaging algorithm with motion error compensation. In detail, the imaging geometry and echo model of continuous motion acquisition mode slope radar based on FMCW signal are established in Section 2. And Section 3 deduces the imaging algorithm with motion error compensation. In Section 4, numerical simulation on the relationship between velocity and imaging performance is carried out. And the motion error model and imaging algorithm of this paper are verified via mine slope measured data analysis in Section 5.

A switch uniform linear array (ULA) frequency-modulated continuous-wave (FMCW) synthetic aperture radar (SAR) system transmits and receives FMCW waveform by firing elements of the ULA sequentially under the control of a switch network. Resolution in range is achieved by range compression and in ULA direction is achieved by digital beamforming. Compared with a conventional SAR system, a switch ULA FMCW SAR has a lot of advantages, such as high-speed data acquisition, forward-looking/downard-looking 3D imaging mode and simpler hardward. However, it inevitably suffers from multi-channel amplitude/phase imbalance and sweep rate non-linearity error, which lead to resolution degradation and image defocussed. In practical system, the two kinds of errors coupled together so that the existing correction method is no longer suitable. This paper presents correction scheme to solve this problem. First, seperate the two kinds of errors by two calibration signal differential. Next, correct the sweep rate non-linearity error by residual video phase (RVP) filter. Then, correct the multi-channel amplitud/phase error by S parameters measurement and estimation from point-like target echo. At last, repeat the above procedure for each channel to complete the entire correction process. We develop a real switch ULA FMCW SAR system and validate the the effectiveness of the presented calibration scheme by real data processing.

Recently ground-based synthetic aperture radar (GB-SAR) has been an important technical means in remote sensing deformation monitoring. However, similar to spaceborne and airborne SAR, the accuracy of GB-SAR interferometry is also seriously affected by atmospheric phase disturbances. In this paper, a novel GB-SAR atmospheric phase correction (APC) algorithm based on coherent scatterers (CSs) is proposed. Firstly, coherent scatterers is selected by frequency interleaved sub-images entropy [1], which only use a single pair of echo data. Then spatial correlation is used for distinguish the stable control points among the coherent scatterers. Finally, the atmospheric phase screen (APS) can be obtained by spatial interpolation and polynomial fitting of the stable control points, which has zero deformation phase. Compared with the existing atmospheric phase correction algorithms, the proposed algorithm using short temporal characterized properties, which is more suitable for GB-SAR real-time deformation monitoring. And due to the spatial correlation of atmospheric phase, the new algorithm has strong robustness by combination of spatial interpolation and polynomial fitting.

To control fuel injection, optimize combustion and reduce emissions for LPG (liquefied petroleum gas) engines, it is necessary and important to understand the characteristics of LPG sprays. The present work investigates the geometry of LPG sprays, including spray tip penetration, spray angle, projected spray area and spray volume, by using schlieren photography and digital image processing techniques. Two types of single nozzle injectors were studied, with the same nozzle diameter, but one with and one without a double-hole flow-split head. A code developed to analyse the results directly from the digitized images is shown to be more accurate and efficient than manual measurement and analysis. Test results show that a higher injection pressure produces a longer spray tip penetration, a larger projected spray area and spray volume, but a smaller spray cone angle. The injector with the double-hole split-head nozzle produces better atomization and shorter tip penetration at medium and late injection times, but longer tip penetration in the early stage.

Dust particles from the Taklimakan Desert can be lofted vertically up to 10 km due to the unique topography and northeasterly winds associated with certain synoptic conditions. Then they can be transported horizontally to regions far downwind by westerlies. We combined data from the Multiangle Imaging Spectroradiometer (MISR) and the Cloud-Aerosol Lidar with Orthogonal Polarization to investigate the three-dimensional distribution of dust over the Taklimakan Desert and surrounding areas. During spring and summer, a dust belt with high aerosol optical depths (AOD) extends eastward from the Taklimakan Desert to the Loess Plateau along the Hexi Corridor and southward to the Tibetan Plateau. However, the dust extinction coefficients decrease rapidly from 0.340 km−1 near surface to 0.015 km−1 at 5 km in spring, while the extinction values vary within 0.100 ± 0.020 between the altitudes of 1.6 and 3.5 km and decrease to 0.023 km−1 at 5 km in summer, indicating that dust aerosol is relatively well mixed vertically. We further used MISR daily AOD to identify high- and low-dust days and then analyzed composite difference patterns of temperature, geopotential height, and wind between high- and low-dust days. It was found that although the synoptic situations of spring and summer are quite different, there are two common features: a strong anticyclonic wind anomaly over the Taklimakan at 500 hPa and an enhanced easterly wind over the Tarim Basin at 850 hPa for the two seasons. These conditions are favorable for dust entrainment from the dry desert surface, vertical lofting, and horizontal transport.

A combustion system consisting of a pent-roof type of combustion chamber, a flat-top piston and a center-located injector to form homogeneous mixture for LPG direct injection engine is presented. Taking advantage of the easy evaporation property of liquid phase LPG, the injection pressure of this system can be much less than that used in gasoline direct injection engine. The mixture formation processes for this system were simulated and validated at different engine loads. The correctness of the simulation method was confirmed by comparing the results with those obtained from schlieren experiment. The simulated results showed that, at high load conditions with two intake valves opened, the intake tumble would break into small-scale vortex (turbulence) near the end of compression stroke; while at part load conditions with one of the two intake valves closed, an inclined intake swirl was formed, which enhanced the turbulence in combustion chamber near the end of compression stroke. The results also showed that if the liquid phase LPG was injected at 60∼80°CA ATDC in intake stroke, the homogeneous mixture would form in spite of the engine load.

Nine bacterial strains isolated from root nodules of Astragalus sinicus were compared with 41 reference strains, including the type strains of the type species of the genera Rhizobium, Bradyrhizobium, and Agrobacterium, by performing a numerical analysis of 200 phenotype features. Representative strains belonging to different clusters were further compared with similar bacteria by using data from gel electrophoresis of whole-cell proteins, DNA G+C content data, and DNA-DNA hybridization data. The rhizobial strains isolated from nodules of A. sinicus constitute a distinct homology group that is quite different from previously described Rhizobium, Bradyrhizobium, and Agrobacterium species and from strains isolated from other Astragalus species. We propose the name Rhizobium huakuii sp. nov. for the strains isolated from A. sinicus. Type strain CCBAU 2609 (= 103) has been deposited in the Culture Collection of Beijing Agricultural University, Beijing, People's Republic of China.

Cavitation and flashing formed inside and outside of an injector, respectively, have significant effect on liquid phase LPG (Liquefied Petroleum Gas) injection. Numerical simulations of internal flow of the liquid phase LPG inside different injector nozzles were performed using the FIRE CFD code. The results showed that the cavitation always occurred at the inlet corner of the nozzle with negative pressure and higher velocity regardless the nozzle geometries. The relationships between vapor void fraction at the exit of the nozzle and injection pressure were also investigated for different nozzle geometries. The spray of the liquid phase LPG was further simulated by using the results of the internal flow as initial conditions. During the simulation of the spray, the effect of superheat degree on evaporation was considered and a modified evaporation equation was employed. The comparison of the simulation with experimental results showed that, with the injection pressure increasing, spray tip penetration increased but SMD (Sauter mean diameter) decreased.

The purpose of this research is to extend the theory of the concentrated thermo-elastohydrodynamic line contact to include the influence of the existence of solid lubricant dispersed in liquid-base lubricant. The combined effects of the rheological characteristics of the oil and the mechanical properties of the particles and those of the bounding surfaces are taken into consideration in theoretical development. Results are presented for the pressure distribution, the oil film thickness, the temperature rise, and the coefficient of friction for two commonly used solid lubricants namely MOS2 and graphite.

A theoretical study of the effectiveness of solid particles dispersed in oil in the elastohydrodynamic line contact is presented. The analysis includes the variation of the viscosity and density of the lubricant as a function of pressure. The deformation of solid particles and that of the bounding surfaces are taken into consideration. Results are presented for the variation of the film thickness and the load carrying capacity as a function of the particle size, concentration, and properties of various types of particles.