High-resolution visible imaging with piezoelectric deformable secondary mirror: experimental results at the 1.8-m adaptive telescope

Integrating deformable mirrors within the optical train of an adaptive telescope was one of the major innovations in astronomical observation technology,distinguished by its high optical throughput,reduced optical surfaces,and the incorporation of the deformable mirror.Typically,voice-coil actuators are used,which require additional position sensors,internal control electronics,and cooling systems,leading to a very complex structure.Piezoelectric deformable secondary mirror technologies were proposed to overcome these problems.Recently,a high-order piezoelectric deformable secondary mirror has been developed and installed on the 1.8-m telescope at Lijiang Observatory in China to make it an adaptive telescope.The system consists of a 241-actuator piezoelectric deformable secondary mirror,a 192-sub-aperture Shack-Hartmann wavefront sensor,and a multi-core-based real-time controller.The actuator spacing of the PDSM measures 19.3 mm,equivalent to approximately 12.6 cm when mapped onto the primary mirror,significantly less than the voicecoil-based adaptive telescopes such as LBT,Magellan and VLT.As a result,stellar images with Strehl ratios above 0.49 in the R band have been obtained.To our knowledge,these are the highest R band images captured by an adaptive telescope with deformable secondary mirrors.Here,we report the system description and on-sky performance of this adaptive telescope.

Repeated methamphetamine exposure decreases plasma brain-derived neurotrophic factor levels in rhesus monkeys

Background Brain-derived neurotrophic factor(BDNF)is known to prevent methamphetamine(METH)-induced neurotoxicity and plays a role in various stages of METH addiction.However,there is a lack of research with longitudinal design on changes in plasma BDNF levels in active METH-dependent individuals.Aims The aim of the study was to investigate changes in BDNF levels during METH self-administration in monkeys.Methods This study measured plasma BDNF levels in three male rhesus monkeys with continuous METH exposure and four male control rhesus monkeys without METH exposure.Changes in plasma BDNF levels were then assessed longitudinally during 40 sessions of METH self-administration in the three monkeys.Results Repeated METH exposure decreased plasma BDNF levels.Additionally,plasma BDNF decreased with long-term rather than short-term accumulation of METH during METH self-administration.Conclusions These findings may indicate that the changes in peripheral BDNF may reflect the quantity of accumulative METH intake during a frequent drug use period.

EAST-Educational Adaptive-optics Solar Telescope

For the public having a better understanding of solar activities,the Educational Adaptive-optics Solar Telescope(EAST)was built in July 2021 and is located at the Shanghai Astronomy Museum.The EAST consists of a 65 cm aperture solar telescope with a 177-element adaptive optics system and two-channel high resolution imaging system at the Hαand TiO bands,in addition to three full disk solar telescopes at CaK,Hαand TiO bands equipped on the tube of the main telescope.In this paper,the configuration of the EAST is described.Its performance and on-sky observational results are presented.The EAST,to our knowledge,is the most advanced solar telescope for the popularization of science in the world.Due to its excellent performance,the data acquired by the EAST can also be used for research on solar physics and space weather prediction.

Grain size regulation for balancing cycle performance and rate capability of LiNi_(0.9)Co_(0.055)Mn_(0.045)O_(2) single crystal nickel-rich cathode materials

It is challenging to balance the cyclability and rate capability of single crystal nickel-rich cathode materials(Ni>0.8).Multicomponent oxides by spray pyrolysis shows potential as highly-reactive precursors to synthesize single crystal nickel-rich cathode at lower temperature,yet Ni^(2+)will severely inhibit particle growth when Ni content exceeds 0.9.Herein,lithium nitrate(LiNO_(3))with low melting point and strong oxidation is introduced as collaborate lithium salts for fabrication of well-dispersed submicron and micron single crystal LiNi_(0.9)Co_(0.055)Mn_(0.045)O_(2)(NCM90)cathode without extra unit operation.By changing amount of LiNO_(3),particle size regulation is realized and cation disorder can be diminished.The as-prepared material with optimal content of 4 wt%LiNO_(3)(NCM90-4 LN)displays the most appropriate particle size(1μm)with approximately stoichiometric structure,and presents better kinetics characterization of lithium-ion diffusion(15%higher than NCM90)and good electrochemical performance with specific discharge capacity of 220.6 and 173.8 mAh g^(-1) at 0.1 C and 10 C at room temperature,respectively.This work broadens the conventional research methodology of size regulation for single crystal Ni-rich cathode materials and is indispensable for the development of designing principal of nickel-rich cathode materials for lithium-ion batteries.

Ground-layer adaptive optics for the New Vacuum Solar Telescope:Instrument description and first results

Ground-layer adaptive optics(GLAO)has shown its potential for use in solar observation owing to its wide field-of-view(FOV)correction.A high-order GLAO system that consists of a multiple direction Shack-Hartmann wavefront sensor(WFS),a realtime controller with a multi-CPU processor,and a 151-element deformable mirror was developed for the 1-m New Vacuum Solar Telescope at Yunnan Observatories,Chinese Academy of Sciences.A hexagonal microlens with 9×8 subapertures is employed in the WFS.The detection FOV is 42′′×37′′,in which 9(3×3)guide regions are extracted for multiple direction wavefront sensing with a frame rate of up to 2200 Hz.To our knowledge,this is the first professional solar GLAO system used as a regularly operating instrument for scientific observations.Its installation and adjustment were performed in the summer of 2021.In this article,a detailed account of the GLAO system and its first light results and a comprehensive analysis of the performance of the GLAO system are provided.The results show that this system can effectively improve the imaging quality after compensating for the wavefront aberration due to ground-layer turbulence.

Ultralarge layer spacing and superior structural stability of V_(2)O_(5)as high-performance cathode for aqueous zinc-ion battery

Aqueous zinc(Zn)-ion batteries(AZIBs)present safe and environmentally friendly features thereby emerging as an attractive energy storage device.The V_(2)O_(5)-based cathodes are promising because of their high theoretical capacity and energy density.However,insufficient interlayer distance,easy dissolution and structural collapse due to irreversible crystalline phase transition limit the development of V_(2)O_(5)cathodes in AZIBs.Herein,doubly modified V_(2)O_(5)-based cathode which was in-situ intercalated by polyaniline(PANI)and composited with MXene(Ti_(3)C_(2)T_(x))(denoted PVM)were synthesized by one-step method for the first time.The in situ intercalation of PANI provides a channel for the rapid diffusion of Zn2+and the heterogeneous structures effectively promote charge transfer and enable structural integrity of cathode during cycling.Meanwhile,the conductivity of PVM electrode is greatly improved.Specifically,the PVM electrode shows a superior rate performance of 82 mAh·g^(-1)after 2000 cycles at 10 A·g^(-1).And it shows high pseudocapacitance behavior(80.23%capacitor contribution ratio at 0.1 mV·s^(-1)).A novel method of intercalation composite modification for the cathode is proposed,which provides fundamental guidance for the development of high-performance cathodes for AZIBs.

氯胺酮快速抗抑郁的代谢影像学研究进展

重度抑郁症严重致残,目前的治疗方法及疗效有限。亚麻醉剂量的氯胺酮具有快速且持久的抗抑郁作用。本文对单次亚麻醉剂量氯胺酮给药24 h内的谷氨酸代谢、葡萄糖代谢及血流灌注的影像学评估进展进行综述,并对三者之间的关系进行阐述,为氯胺酮抗抑郁治疗提供证据。

碳纤维增强尼龙6复合材料的阴离子聚合反应注射成型工艺

以己内酰胺为原料,自制己内酰胺钠(C10)、双酰化内酰胺-1,6-己二胺(C20)分别为引发剂和活化剂,首先对适用于反应注射成型技术(RIM)的尼龙6(PA6)阴离子聚合工艺进行探究。实验结果表明,提高引发剂浓度可提升聚合反应速率,转化率受影响并不明显,但分子量有所降低;而提高活化剂浓度,会导致聚合反应不完全;随着聚合温度的升高,反应速率明显加快,同时分子量增大,结晶度呈下降趋势。最终选取1.5 mol%的C10、1 mol%的C20,浸胶温度100℃、聚合温度180℃的工艺参数,利用自行研制的反应注射设备成功制备了单向碳纤维增强尼龙6 (CF/PA6)复合材料单向板,其沿纤维方向的拉伸强度可达974.2 MPa,弯曲强度达786.9 MPa。

Ion exchange membranes from poly(2,6-dimethyl-1,4-phenylene oxide) and related applications

Ion exchange membranes(IEMs) play a significant role in fields of energy and environment, for instance fuel cells, diffusion dialysis, electrodialysis, etc. The limited choice of commercially available IEMs has produced a strong demand of fabricating IEMs with improved properties via facile synthetic strategies over the past two decades. Poly(phenylene oxide)(PPO) is considered as a promising polymeric material for constructing practical IEMs, due to its advantages of good physicochemical properties, low manufacturing cost and easy post functionalization. In this review, we present the accumulated efforts in synthetic strategies towards diverse types of PPO-based IEMs. Relation between polymer structures and the resulted features is discussed in detail. Besides, applying IEMs from PPO and its derivatives in fuel cell, diffusion dialysis and electrodialysis is summarized and commented.

RNF126 Quenches RNF168 Function in the DNA Damage Response

DNA damage response(DDR) is essential for maintaining genome stability and protecting cells from tumorigenesis. Ubiquitin and ubiquitin-like modi?cations play an important role in DDR, from signaling DNA damage to mediating DNA repair. In this report, we found that the E3 ligase ring ?nger protein 126(RNF126) was recruited to UV laser micro-irradiation-induced stripes in a RNF8-dependent manner. RNF126 directly interacted with and ubiquitinated another E3 ligase, RNF168. Overexpression of wild type RNF126, but not catalytically-inactive mutant RNF126(CC229/232 AA), diminished ubiquitination of H2 A histone family member X(H2AX),and subsequent bleomycin-induced focus formation of total ubiquitin FK2, TP53-binding protein1(53 BP1), and receptor-associated protein 80(RAP80). Interestingly, both RNF126 overexpression and RNF126 downregulation compromised homologous recombination(HR)-mediated repair of DNA double-strand breaks(DSBs). Taken together, our ?ndings demonstrate that RNF126 negatively regulates RNF168 function in DDR and its appropriate cellular expression levels are essential for HR-mediated DSB repair.

Layered K_(0.54)Mn_(0.78)Mg_(0.22)O_(2)as a high-performance cathode material for potassium-ion batteries

Layered Mn-based oxides are one of the promising cathode materials for potassium-ion batteries(KIBs)owing to their high theoretical capacities,abundant material supply,and simple synthesis method.However,the structural deterioration resulting from the Jahn-Teller effect of Mn ions hinders their further development in KIBs.Herein,a novel Mn-based layered oxide,K_(0.54)Mn_(0.78)Mg_(0.22)O_(2),is successfully designed and fabricated as KIBs cathode for the first time.It delivers smooth charging/discharging curves with high specific capacity of 132.4 mAh·g^(‒1)at 20 mA·g^(‒1)and good high-rate cycling stability with a capacity retention of 84%over 100 cycles at 200 mA·g^(‒1).Combining in-situ X-ray diffraction(XRD)and ex-situ X-ray photoelectron spectroscopy(XPS)analysis,the storage of K-ions by K_(0.54)Mn_(0.78)Mg_(0.22)O_(2)is revealed to be a solid-solution processes with reversible slip of the crystal lattice.The studies suggest that the rational doping of inactive Mg2+can effectively suppress the Jahn-Teller effect and provide outstanding structure stability.This work deepens the understanding of the structural evolution of Mn-based layered materials doped with inactive materials during de/potassiation processes.

Buckle Propagation in Steel Pipes of Ultra-high Strength:Experiments,Theories and Numerical Simulations

In this paper,experimental,theoretical and numerical approaches were employed to scrutinize the buckle propagation events occurring in pipes subjected to external pressure.Two groups of samples with different radius-to-thickness ratios were fabricated using steel pipes of ultra-high strength and were subjected to compression of external pressure in a sealed pressure vessel specially designed and customized for the experiment.Experimental results were recorded through a data acquisition system.For facilitating the theoretical calculations,uniaxial tensile tests were performed on tensile pieces cut from the same pipes to obtain the material properties.It was found from the experimental results that once a buckle is initiated in a pipe,the external pressure dropped to a specific value called buckle propagation pressure and kept at this level until the whole pipe is flattened into a dog-bone shape.Based on the measured material properties and geometric parameters,theoretical solutions were computed using established ring models and shell model,and finite element predictions were also obtained from ABAQUS software.The efficiency and accuracy of the shell model and finite element model were expounded by comparing various theoretical solutions and numerical predictions with the experimental results.With the authenticated shell model and finite element model,a deep insight into the phenomenon of buckle propagation of pressurized long pipes was provided by performing a series of parametric study.