Construction of a backpropagation starlight atmospheric refraction model based on ray tracing.

The atmospheric refraction model is a vital part of the refraction navigation system. A more accurate model needs to be constructed for the navigation algorithm design and simulation verification. Based on the Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics/Sounding of the Atmosphere using Broadband Emission Radiometry (TIMED/SABER) dataset and the geometrical ray propagation law, a ray tracing algorithm is proposed to calculate the atmospheric refraction angles. Moreover, a neural network starlight atmospheric refraction model (BP model) is constructed to better describe the relationship between time, location, and refraction angle. Compared with the experimental data, the bias error of the backpropagation (BP) model is 1.06 ' ' , which is better than the 3.75 ' ' of the traditional model. It indicates that the BP model is exact and has important guiding significance for the starlight refraction navigation technology.

Green Finance and Technological Innovation in Heavily Polluting Enterprises: Evidence from China.

There is an urgent need for countries worldwide to promote the green transformation of their economies and reduce environmental pollution. Based on China's Green Credit Guidelines policy in 2012 and the data of Chinese listed companies from 2007 to 2021, we conducted an empirical test using the difference-in-differences method. The results showed that green finance policies inhibit technological innovation in heavily polluting enterprises, and the stronger the enterprise's operating capacity, the weaker this inhibiting effect. The study also shows that bank loan, loan term, corporate management motivation, and business confidence have intermediation effects. Therefore, countries should improve green financial policies and promote technological innovation in heavily polluting enterprises in order to reduce environmental pollution and promote green growth.

Atomically dispersed Pb ionic sites in PbCdSe quantum dot gels enhance room-temperature NO2 sensing.

Atmospheric NO2 is of great concern due to its adverse effects on human health and the environment, motivating research on NO2 detection and remediation. Existing low-cost room-temperature NO2 sensors often suffer from low sensitivity at the ppb level or long recovery times, reflecting the trade-off between sensor response and recovery time. Here, we report an atomically dispersed metal ion strategy to address it. We discover that bimetallic PbCdSe quantum dot (QD) gels containing atomically dispersed Pb ionic sites achieve the optimal combination of strong sensor response and fast recovery, leading to a high-performance room-temperature p-type semiconductor NO2 sensor as characterized by a combination of ultra-low limit of detection, high sensitivity and stability, fast response and recovery. With the help of theoretical calculations, we reveal the high performance of the PbCdSe QD gel arises from the unique tuning effects of Pb ionic sites on NO2 binding at their neighboring Cd sites.

Design of off-axis three-mirror systems with ultrawide field of view based on an expansion process of surface freeform and field of view.

Unobscured reflective optical systems with a wide field of view (FOV) have significant application values. However, the aberration increases with the increase of the system FOV, so a wide FOV system is difficult to design. In this paper, a design method that is effective in achieving off-axis three-mirror systems with ultrawide FOV is proposed. In this method, the system FOV is expanded stepwise in the design process, and the surface optical freeform polynomial terms are extended based on the judgment of image quality and some constraint conditions, and to obtain a prospective ultrawide FOV system. A freeform off-axis three-mirror imaging system with a focal length of 1000 mm, an F-number of 10, and an ultrawide FOV of 80°×4° is designed as an example. This design result shows that the system has a high imaging quality of RMS wavefront error value of 0.040λ(λ=0.633 µm), and it demonstrates that the method is effective in achieving off-axis three-mirror systems with an ultrawide FOV.

Directing Reaction Pathways through Controlled Reactant Binding at Pd-TiO2 Interfaces.

Recent efforts to design selective catalysts for multi-step reactions, such as hydrodeoxygenation (HDO), have emphasized the preparation of active sites at the interface between two materials having different properties. However, achieving precise control over interfacial properties, and thus reaction selectivity, has remained a challenge. Here, we encapsulated Pd nanoparticles (NPs) with TiO2 films of regulated porosity to gain a new level of control over catalyst performance, resulting in essentially 100 % HDO selectivity for two biomass-derived alcohols. This catalyst also showed exceptional reaction specificity in HDO of furfural and m-cresol. In addition to improving HDO activity by maximizing the interfacial contact between the metal and metal oxide sites, encapsulation by the nanoporous oxide film provided a significant selectivity boost by restricting the accessible conformations of aromatics on the surface.

Subchronic exposure to arsenic induces apoptosis in the hippocampus of the mouse brains through the Bcl-2/Bax pathway.

OBJECTIVES: The aim of this study was to identify whether arsenic (As) exposure could induce hippocampal neural apoptosis in vivo. METHODS: Sixty-four mice were randomly divided into 4 groups of 16 each. Group 1 orally received drinking water alone as a control. Groups 2-4 were given arsenic trioxide (As2O3) orally at the doses of 1 ppm, 2 ppm and 4 ppm, respectively. All the treatments continued for 60 days. Morphological changes in the hippocampus were observed by HE staining. Apoptosis in the hippocampus was examined by TUNEL assay and transmission electron microscopy. The expression levels of Bcl-2 and Bax genes and their proteins in the hippocampus were determined by real-time PCR and Western blotting. The activity of caspase-3 was determined by spectrophotometry. RESULTS: Abnormal histopathological changes and apoptosis were found in the hippocampus of As-exposed mice. The expressions of the Bcl-2 gene and its protein in the hippocampus of As-exposed mice were significantly lower than those in the control group (p<0.05). However, the expressions of the Bax gene and its protein, and the expression ratio of Bax/Bcl-2 in the hippocampus were significantly higher in the groups exposed to As than in the control group (p<0.05). Moreover, the activity of caspase-3 in the hippocampus of mice exposed to As was higher than that in the control (p<0.05). CONCLUSIONS: These results indicate that subchronic exposure to As induces apoptosis in the hippocampus of mice by disturbing normal Bax/Bcl-2 regulatory pathways. Meanwhile, it is suggested that the induced apoptosis in the hippocampus may be at least partly responsible for As-induced neurotoxicity.

[Curative effect observation of plasma eardrum perforation homochronous with palatoplasty in the treatment of chronic secretory otitis media].

OBJECTIVE: To investigate the effect of plasma eardrum perforation homochronous with palatoplasty on hearing and tympanic cavity pressure in cleft palate children with secretory otitis media. METHOD: Fifty-six cases of cleft palate children with secretory otitis media were randomly divided into observation group and control group. For the control group, palatoplasty was carried out alone. For the observation group, homochronous with palatoplasty, plasma eardrum perforation was performed with the diameter of the aperture 2-3 mm, which was decided by observing viscosity of tympanum fluid under microscope or otoscope. RESULT: Compared with the simple cleft palate repairing palatoplasty, the perforation in the observation group could keep for 6-8 weeks after the surgery. Followed up 6 months later, the children in observation group improved better in terms of hearing restoration and tympanometry. CONCLUSION: By means of plasma eardrum perforation homochronous with palatoplasty, the children of cleft palate with secretory otitis media could improve hearing and tympanometry in a short period, recovering the function of middle ear.

Greenhouse gas flux and crop productivity after 10 years of reduced and no tillage in a wheat-maize cropping system.

Appropriate tillage plays an important role in mitigating the emissions of greenhouse gases (GHG) in regions with higher crop yields, but the emission situations of some reduced tillage systems such as subsoiling, harrow tillage and rotary tillage are not comprehensively studied. The objective of this study was to evaluate the emission characteristics of GHG (CH4 and N2O) under four reduced tillage systems from October 2007 to August 2009 based on a 10-yr tillage experiment in the North China Plain, which included no-tillage (NT) and three reduced tillage systems of subsoil tillage (ST), harrow tillage (HT) and rotary tillage (RT), with the conventional tillage (CT) as the control. The soil under the five tillage systems was an absorption sink for CH4 and an emission source for N2O. The soil temperature positive impacted on the CH4 absorption by the soils of different tillage systems, while a significant negative correlation was observed between the absorption and soil moisture. The main driving factor for increased N2O emission was not the soil temperature but the soil moisture and the content of nitrate. In the two rotation cycle of wheat-maize system (10/2007-10/2008 and 10/2008-10/2009), averaged cumulative uptake fluxes of CH4 under CT, ST, HT, RT and NT systems were approximately 1.67, 1.72, 1.63, 1.77 and 1.17 t ha(-1) year(-1), respectively, and meanwhile, approximately 4.43, 4.38, 4.47, 4.30 and 4.61 t ha(-1) year(-1) of N2O were emitted from soil of these systems, respectively. Moreover, they also gained 33.73, 34.63, 32.62, 34.56 and 27.54 t ha(-1) yields during two crop-rotation periods, respectively. Based on these comparisons, the rotary tillage and subsoiling mitigated the emissions of CH4 and N2O as well as improving crop productivity of a wheat-maize cropping system.

[Effects of different maize straw-returning modes on the soil respiration in a winter wheat field].

By using static chamber-TGC method, an in situ observation was conducted in a 10-year conservation tillage winter wheat field to study the effects of different maize straw-returning modes on the soil respiration. The soil respiration had a significant positive correlation with the stubble height of maize straw, and two peaks were observed in wheat growth period. Under no tillage and no straw-returning, the soil respiration was 72.5% of that under no tillage with all straw-returning, and the soil respiration under conventional tillage and no straw- returning was 76.5% of that under conventional tillage with all straw-returning. The soil respiration was significantly positively correlated with the soil temperature and soil organic carbon at 20 cm depth, but no significant correlation with the soil organic carbon at 40 cm depth. A correlation was also observed between the soil respiration and soil moisture. The diurnal soil respiration in the treatments of all straw-returning presented a single-peak curve, with the peak at 18:00. There was a similar variation trend of soil temperature and soil respiration at the depth of 20 cm. Among the treatments of different straw-returning amounts, straw-returning with the stubble of 1 m height could reduce the soil respiration significantly, being a reasonable straw-returning mode.

Response of CH4 and N2O emissions and wheat yields to tillage method changes in the North China plain.

The objective of this study was to quantify soil methane (CH(4)) and nitrous oxide (N(2)O) emissions when converting from minimum and no-tillage systems to subsoiling (tilled soil to a depth of 40 cm to 45 cm) in the North China Plain. The relationships between CH(4) and N(2)O flux and soil temperature, moisture, NH(4) (+)-N, organic carbon (SOC) and pH were investigated over 18 months using a split-plot design. The soil absorption of CH(4) appeared to increase after conversion from no-tillage (NT) to subsoiling (NTS), from harrow tillage (HT) to subsoiling (HTS) and from rotary tillage (RT) to subsoiling (RTS). N(2)O emissions also increased after conversion. Furthermore, after conversion to subsoiling, the combined global warming potential (GWP) of CH(4) and N(2)O increased by approximately 0.05 kg CO(2) ha(-1) for HTS, 0.02 kg CO(2) ha(-1) for RTS and 0.23 kg CO(2) ha(-1) for NTS. Soil temperature, moisture, SOC, NH(4) (+)-N and pH also changed after conversion to subsoiling. These changes were correlated with CH(4) uptake and N(2)O emissions. However, there was no significant correlation between N(2)O emissions and soil temperature in this study. The grain yields of wheat improved after conversion to subsoiling. Under HTS, RTS and NTS, the average grain yield was elevated by approximately 42.5%, 27.8% and 60.3% respectively. Our findings indicate that RTS and HTS would be ideal rotation tillage systems to balance GWP decreases and grain yield improvements in the North China Plain region.

Effects of sea buckthorn (Hippophaë rhamnoides L.) seed and pulp oils on experimental models of gastric ulcer in rats.

Oils from sea buckthorn (Hippophaë rhamnoides L.) seeds and berries have traditionally been used in the treatment of disorders of skin and mucosa in China. Compared with the negative control, oral administration of CO(2)-extracted seed and pulp oils, 7.0 ml x kg(-1) x day(-1) significantly reduced ulcer formation in water-immersion (P < 0.05) and reserpine-induced (P < 0.01) models in rats. In addition, administration of the two oils, 3.5 ml x kg(-1) x day(-1), significantly reduced the index of pylorus ligation-induced gastric ulcer (P < 0.05) and sped up the healing process of acetic acid-induced gastric ulcer (P < 0.01). The results suggested that the CO(2)-extracted sea buckthorn seed and pulp oils have both preventive and curative effects against experimental gastric ulcers in rats.