Ammonia (NH3) emission inventories are an essential input in chemical transport models and are helpful for policy-makers to refine mitigation strategies. However, current estimates of Chinese NH3 emissions still have large uncertainties. In this study, an improved inversion estimation of NH3 emissions in China has been made using an ensemble Kalman filter and the Nested Air Quality Prediction Modeling System. By first assimilating the surface NH3 observations from the Ammonia Monitoring Network in China at a high resolution of 15 km, our inversion results have provided new insights into the spatial and temporal patterns of Chinese NH3 emissions. More enhanced NH3 emission hotspots, likely associated with industrial or agricultural sources, were captured in northwest China, where the a posteriori NH3 emissions were more than twice the a priori emissions. Monthly variations of NH3 emissions were optimized in different regions of China and exhibited a more distinct seasonality, with the emissions in summer being twice those in winter. The inversion results were well-validated by several independent datasets that traced gaseous NH3 and related atmospheric processes. These findings highlighted that the improved inversion estimation can be used to advance our understanding of NH3 emissions in China and their environmental impacts.

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A wideband slot antenna with frequency-and pattern-reconfigurable characteristics for TD-LTE (3.4-3.8 GHz) and C-band (3.7-4.2 GHz) applications is proposed. The antenna consists of two symmetric slots that are fed by a fork-shaped microstrip line. Two PIN diodes are loaded in the slots to produce two different frequency bands. Meanwhile, two additional PIN diodes are inserted in the feed line to achieve the pattern reconfigurability. The wideband operation is realized by using the symmetric slots and fork-shaped feed line. Simulated and measured results show that the antenna provides 25°and 20°beam-steering in 3.4-3.8 and 3.7-4.2 GHz bands, respectively. Also, an impedance bandwidth of at least 12.8% is obtained in the operating bands.

We derive sufficient conditions on the Bézier net of a Bernstein-Bézier polynomial defined on a triangle in the plane to insure that the corresponding surface is monotone. We then apply these conditions to construct a new algorithm for fitting a monotone surface to gridded data. The method uses C 1 cubic splines defined on the triangulation obtained by drawing both diagonals of each subrectangle. In addition, we present an algorithm for the monotone scattered data interpolation problem which is based on a method for creating gridded data from the scattered data. Numerical results for several test examples are presented.

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A differential dual-band antenna-in-package (AiP) with multilayer structure is proposed. Compared to the normal antenna, the introduced package structure changes the impedance of the antenna, such that the new resonant frequency is excited. Then, a dual-band antenna is realized. Also, in order to improve the radiation pattern in higher band, two symmetrical T-shaped slots are etched on the patch. The T-slots can help to widen the bandwidths. The realized AiP can work at 2.49 and 5.8 GHz. The 10-dB relative bandwidth is 1.61% (2.47 2.51 GHz) and 5.51% (5.67 5.99 GHz), respectively.