20 research outputs found

    Observational Investigation of the Effect of Turbulence on Microphysics and Precipitation in Warm Marine Boundary Layer Clouds

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    Abstract Turbulence is omnipresent in the marine boundary layer (MBL) and several mechanisms have been proposed regarding its role on MBL cloud microphysics. In particular, past modeling studies suggested that increasing turbulence broaden the droplet size distribution (DSD) and leads to precipitation initiation, this suggested relationship has not been evaluated yet using long‐term observations. Here, comprehensive retrievals from long‐term ground‐based observations are used to explore the impact of turbulence on microphysics and precipitation in drizzling MBL clouds. Our analysis supports that broader DSD and larger droplets are observed with strong turbulence, but interestingly, the precipitation is reduced instead of being enhanced. This suppression mechanism is mainly due to the entrainment and mixing process in which the entrained dry air evaporates cloud water. This study provides observational evidence to show the complex effect of turbulence on MBL cloud properties and implies the potential influence of turbulence on the clouds lifetime

    THz Radar Observations of Hydrometeors in a Spray Chamber

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    Abstract A THz radar, with its wide bandwidth, is capable of high‐resolution imaging down to the centimeter scale. In this study, a THz radar is applied to detect hydrometeors generated in a spray chamber. The observed backscattering signals show fluctuations at centimeter scales, indicating various hydrometeor distribution patterns along the radar beam. A co‐located High‐Speed Imaging (HSI) sensor is used to measure the Drop Size Distributions (DSD) in the spray chamber. The radar sampling beam is well aligned with the HSI probes, allowing an objective comparison between the remote sensing and in situ observations. In this study, the observed radar power is compared with the power estimated from the HSI measurements. Results show great consistency, with power difference smaller than 0.5 dB. This study demonstrates the feasibility and great potential of using a THz radar for ultra‐high‐resolution observations of clouds in a laboratory facility, and in the real atmosphere

    Design of Low Energy Beam Transport System for CSRe Molecular Ion Research Facility

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    <span style="color: rgb(51, 51, 51); font-family: arial, helvetica, sans-serif; font-size: 13px; line-height: 22px; background-color: rgb(248, 248, 248);">本文完成了 CSRe分子离子研究装置低能传输线的物理设计。采用Poisson/Superfish软件对150 kV倍压型高压加速器的电场分布进行了模拟,结果显示,加速器各区域空间电场强度均远低于击穿电场强度限值。利用Beampath程序对离子源引出的分子离子束在高压加速器中的传输进行了模拟,束流包络显示,加速区电场对分子离子束具有较强的聚焦作用,加速管出口束斑尺寸较小。采用Trace-3D 程序设计了高分辨能力的磁分析系统和RFQ加速器的注入匹配段。通过Beampath程序的模拟,分析出了质量数为150的分子离子束,并由三单元四极透镜实现了分析束流与直线加速器RFQ的注入匹配。</span><span style="color: rgb(51, 51, 51); font-family: arial, helvetica, sans-serif; font-size: 13px; line-height: 22px; background-color: rgb(248, 248, 248);">The design of a low energy beam transport system for CSRe molecular ion research facility was presented. The electric field distribution of the 150 kV high voltage accelerator was simulated by Poisson/Superfish code. The results show that the electric field strengths of various region spaces were far lower than the value of breakdown electric field. The transmission of the molecular ion beam from the ion source was simulated by Beampath in the high voltage accelerator. The beam envelope indicates that the electric field of acceleration section has a strong focusing effect on the molecular ion beam, and the beam size is small at the end of the accelerate tube. The Trace-3D code was used to design the magnetic analysis system with high resolution and the matching section for injecting into RFQ accelerator. Finally, through the simulation, the molecular ion beam with the mass number of 150 was analyzed and the injection matching of the RFQ accelerator by one triplet quadrupoles was achieved.</span

    High-precision and flexible magnetoelectric sensor operated at 25–330 °C

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    It is a big challenge to in situ monitor the health status of high-temperature magnetic equipment such as electric motors and generators since it is difficult to achieve a high-temperature magnetoelectric sensor. Here, the Pb(Zr0.52Ti0.48)O3 film with a ferroelectric Curie temperature of 400 °C and the Metglas alloy slice with a magnetic Curie temperature of 430 °C were combined by using a high-temperature inorganic glue to achieve a high-temperature magnetoelectric sensor. The magnetoelectric coefficient αE of the flexible sensor is as high as 104 V/(cm Oe) at 25 °C, 63.6 V/(cm Oe) at 200 °C, and 39.7 V/(cm Oe) at 330 °C. Besides, the magnetic sensor has a detection accuracy of ∼0.3 nT at 25–330 °C. Most importantly, the high-temperature sensor is flexible, high precision, low cost, light weight, and low power consumption simultaneously

    Novel CD123 polyaptamer hydrogel edited by Cas9/sgRNA for AML-targeted therapy

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    CD123 targeting molecules have been widely applied in acute myelocytic leukemia (AML) therapeutics. Although antibodies have been more widely used as targeting molecules, aptamer have unique advantages for CD123 targeting therapy. In this study, we constructed an aptamer hydrogel termed as SSFH which could be precisely cut by Cas9/sgRNA for programmed SS30 release. To construct hydrogel, rolling-circle amplification (RCA) was used to generate hydrogel containing CD123 aptamer SS30 and sgRNA-targeting sequence. After incubation with Cas9/sgRNA, SSFH could lose its gel property and liberated the SS30 aptamer sequence, and released SS30 has been confirmed by gel electrophoresis. In addition, SS30 released from SSFH could inhibit cell proliferation and induce cell apoptosis in vitro. Moreover, SSFH could prolong survival rate and inhibit tumor growth via JAK2/STAT5 signaling pathway in vivo. Additionally, molecular imaging revealed SSFH co-injected with Cas9/sgRNA remained at the injection site longer than free aptamer. Furthermore, once the levels of cytokines were increasing, the complementary sequences of aptamers injection could neutralize SS30 and relieve side effect immediately. This study suggested that CD123 aptamer hydrogel SSFH and Cas9/sgRNA system has strong potential for CD123-positive AML anticancer therapy

    A Single-photon Lidar Observes Atmospheric Clouds at Decimeter Scales: Resolving Droplet Activation within Cloud Base

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    Clouds, crucial for understanding climate, begin with droplet formation from aerosols, but observations of this fleeting activation step are lacking in the atmosphere. Here we use a time-gated time-correlated single-photon counting lidar to observe cloud base structures at decimeter scales. Results show that the air-cloud interface is not a perfect boundary but rather is a transition zone where transformation of aerosol particles into cloud droplets occurs. The observed distributions of first-arriving photons within the transition zone reflect vertical development of a cloud, including droplet activation and condensational growth. Further, the highly resolved vertical profile of backscattered photons above cloud base enables remote estimation of droplet concentration, an elusive but critical property to understand aerosol-cloud interactions. Our results show the feasibility of remotely monitoring cloud properties at submeter scales, thus providing much needed insights into impacts of atmospheric pollution on clouds, and aerosol-cloud interactions that influence climate
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