On-orbit space optical communication demonstration with a 22†s acquisition time.

The inherent small divergence angle of space optical communication poses significant challenges to establishing communication links. Therefore, laser link acquisition becomes a crucial technology in optical communication, with a primary focus on reducing the acquisition time effectively. Conventional optical communication acquisition techniques fail to address the error effects caused by satellite insertion into the Earth orbit, thus unable to meet the rapid establishment demands of laser links in satellite optical communication networks. In this regard, we propose a novel, to the best of our knowledge, on-orbit calibration method for laser communication terminals to our knowledge. Leveraging stellar observations, this method achieves efficient on-orbit calibration with only a single observation. Theoretical analysis and on-orbit experimental results demonstrate that this approach effectively enhances an open-loop pointing accuracy, offering promising prospects for achieving a rapid establishment of optical communication links in ultra-long-distance optical communication missions.

On-orbit demonstration of inter-satellite free-space optical stable communication enabled by integrated optical amplification of HPA and LNA.

Satellite free-space optical (FSO) communication is very promising in improving the bandwidth and capacity of space information networks in the future. However, the inter-satellite transmission distance of over 1000 km leads to unstable optical beam pointing, acquisition, and tracking and then generates optical power jitter by a large margin before detection-demodulation. Therefore, it is difficult to realize high-stability and long-time FSO communication between satellites due to the generated bit error rate (BER) by jitter. In this paper, we report an autonomously self-designed and high-integration laser communication payload (LCP) and on-orbit-demonstrated inter-satellite 145 min, zero-BER FSO stable communication with a line rate of 2.8 Gbps. Moreover, based on the inter-satellite laser communication link, a video phone was clearly implemented for more than 10 min, and authentic user data transmitted 459,149 packets, achieving results of zero-packet loss. Summarily, this on-orbit experiment demonstrated an excellent performance of the LCP owing to the distinctive design of integrating a high-power amplifier and low-noise amplifier optical amplification function. Our space mission was successfully completed, and the on-orbit demonstration results may offer a significant reference for the field of satellite laser communication and space information networks.

Synthesis of Silica-Based Quaternized Adsorption Material and Study on Its Adsorption Behavior for Pu(IV).

In this research, we explored the synthesis optimization of the silica-based quaternized adsorption material (SG-VTS-VPQ) and its adsorption behavior for Pu(IV). By optimizing the synthesis process, the grafting amount of 4-vinylpyridine reached 1.25 mmol·g-1. According to the analysis of NMR and XPS, the quaternization rate of pyridine groups reached 91.13%. In the adsorption experiments, the thermodynamic experiment results show that the adsorption of Pu(IV) by SG-VTS-VPQ is more in line with the Langmuir adsorption model and the adsorption type is a typical chemical adsorption; the kinetic results show that adsorption process is more in line with the pseudo first-order kinetic model, and the larger specific surface area of SG-VTS-VPQ plays an important role in the adsorption. The results of the adsorption mechanism show that the adsorption of Pu(IV) by SG-VTS-VPQ is mainly complex anion Pu(NO3)62- and Pu(NO3)5-. This research provides in-depth and detailed ideas for the surface modification and application of porous silica gel, and at the same time provides a new way to develop the direction of the analysis of pretreatment materials in the spent fuel reprocessing field.

Study on the graft modification mechanism of macroporous silica gel surface based on silane coupling agent vinyl triethoxysilane.

In this research, the graft modification mechanism of coupling agent vinyl triethoxysilane (KH-151) to macroporous silica gel was studied using a combination of multiple methods. SEM, FTIR, RAMAN, NMR and XPS were used to characterize the silica gel before and after grafting, determining the mechanism of the grafting reaction of the silane coupling agent. On this basis, the grafting rate of the coupling agent was accurately calculated by TGA weight loss. From the results of characterization, it can be seen that the coupling agent molecules have two connection types on the surface of silica gel, and the ratio of the two types is 43.51% and 56.49% respectively. The influences of hydration degree of the silica gel, coupling agent dosage and reaction temperature on the grafting rate were explored, and the optimal reaction conditions for the modification of macroporous silica gel were determined by the coupling agent through orthogonal experiments, that is, the hydration degree of silica gel of 10%, a coupling agent dosage of 12 mL, and a reaction temperature of 80 °C. Under optimal reaction conditions, the average grafting rate of the coupling agent vinyl triethoxysilane (KH-151) on macroporous silica gel is as high as 91.03%.

A Multitask Cascading CNN with MultiScale Infrared Optical Flow Feature Fusion-Based Abnormal Crowd Behavior Monitoring UAV.

Visual-based object detection and understanding is an important problem in computer vision and signal processing. Due to their advantages of high mobility and easy deployment, unmanned aerial vehicles (UAV) have become a flexible monitoring platform in recent years. However, visible-light-based methods are often greatly influenced by the environment. As a result, a single type of feature derived from aerial monitoring videos is often insufficient to characterize variations among different abnormal crowd behaviors. To address this, we propose combining two types of features to better represent behavior, namely, multitask cascading CNN (MC-CNN) and multiscale infrared optical flow (MIR-OF), capturing both crowd density and average speed and the appearances of the crowd behaviors, respectively. First, an infrared (IR) camera and Nvidia Jetson TX1 were chosen as an infrared vision system. Since there are no published infrared-based aerial abnormal-behavior datasets, we provide a new infrared aerial dataset named the IR-flying dataset, which includes sample pictures and videos in different scenes of public areas. Second, MC-CNN was used to estimate the crowd density. Third, MIR-OF was designed to characterize the average speed of crowd. Finally, considering two typical abnormal crowd behaviors of crowd aggregating and crowd escaping, the experimental results show that the monitoring UAV system can detect abnormal crowd behaviors in public areas effectively.

Efficient Photocatalytic Reduction of Aqueous Perrhenate and Pertechnetate.

The pertechnetate anion (99TcO4-) is a long-lived radioactive species that is soluble in aqueous solution, in contrast to sparingly soluble 99TcO2. Results are reported for photocatalytic reduction and removal of perrhenate (ReO4-), a nonradioactive surrogate for 99TcO4-, using a TiO2 (P25) nanoparticle suspension in formic acid under UV-visible irradiation. Re(VII) removal up to 98% was achieved at pH = 3 under air or N2. The proposed mechanism is Re(VII)/Re(IV) reduction mediated by reducing radicals (·CO2-) from oxidation of formic acid, not direct reduction by photogenerated electrons of TiO2. Recycling results indicate that photocatalytic reduction of ReO4- exhibits excellent regeneration and high activity with >95% removal even after five cycles. 99Tc(VII) is more easily reduced than Re(VII) in the presence of NO3- with very slow redissolution of reduced 99Tc. This study presents a novel method for the removal of ReO4-/99TcO4- from aqueous solution, with potential application for deep geological disposal.

Preclinical development of GR1501, a human monoclonal antibody that neutralizes interleukin-17A.

Interleukin-17A (IL-17A) is a soluble pro-inflammatory cytokine, which is mainly secreted by Th17 cells. In humans, IL-17A mRNA and protein levels are increased in several autoimmune diseases, including psoriasis and rheumatoid arthritis. This study describes the preclinical in vitro and in vivo characterization of GR1501, a human IL-17A-neutralizing IgG4 monoclonal antibody. GR1501 binds human, rhesus and cynomolgus IL-17A with high affinity but does not bind to mouse IL-17A or other IL-17 family members. GR1501 effectively blocks the interaction between IL-17A and its receptor IL-17RA, thereby inhibiting IL-17A-induced CXCL1 and IL-6 release in cells and mice. In mouse air pouch model, GR1501 effectively inhibits IL-17A induced leukocytes infiltration into the air pouch. GR1501 also reduces joint swelling and inflammation in mouse arthritis model. These data suggest that GR1501 is a potent and selective IL-17A-neutralizing monoclonal antibody and will support the clinical investigation of this monoclonal antibody in psoriasis and rheumatoid arthritis.