[en] Graphical abstract: - Highlights: • Cd_0.65Zn_0.35S-TiO₂ nanotube is fabricated by a hydrothermal sulfuration method. • The hydrothermal temperature affects the composite's crystallinity and morphology. • Hydrothermal treated sample at 120 °C shows superior H₂ evolution activity. • Enhanced activity is due to the increased crystallinity and 1-D tubular structure. - Abstract: Titania nanotube-Cd_0.65Zn_0.35S nanocomposite (Cd_0.65Zn_0.35S-TiO₂) was synthesized from titanate nanotubes for ion change of Cd²⁺ and Zn²⁺ followed by hydrothermal sulfuration treatment using thiourea as sulfur source. The Cd_0.65Zn_0.35S-TiO₂ with enhanced crystallinity of TiO₂ nanotube can be obtained by increasing hydrothermal temperature from 90 °C to 120 °C. And further increasing hydrothermal temperature to 150 °C, TiO₂ nanotubes collapse and transform into irregular shaped particles. The photocatalytic activity for hydrogen production of the prepared Cd_0.65Zn_0.35S-TiO₂ with different hydrothermal temperature was investigated under visible-light irradiation. The result shows that the Cd_0.65Zn_0.35S-TiO₂ with hydrothermal temperature of 120 °C presents the highest hydrogen evolution rate and photostability, which can be attributed to a rapid charge transfer at the interface between Cd_0.65Zn_0.35S and TiO₂ nanotube due to the increased crystallinity and unique 1-D nanotubular structure of TiO₂

[en] This paper presents an algorithm that can adaptively select the intermediate frequency (IF) and compensate the IQ mismatch according to the power ratio of the adjacent channel interference to the desired signal in a low-IF GSM receiver. The IF can be adaptively selected between 100 and 130 kHz. Test result shows an improvement of phase error from 6.78° to 3.23°. Also a least mean squares (LMS) based IQ mismatch compensation algorithm is applied to improve image rejection ratio (IRR) for the desired signal along with strong adjacent channel interference. The IRR is improved from 29.1 to 44.3 dB in measurement. The design is verified in a low-IF GSM receiver fabricated in SMIC 0.13 μm RF CMOS process with a working voltage of 1.2 V. (semiconductor integrated circuits)

[en] A generally improved recycling folded cascode (IRFC) is analyzed and implemented. Analysis and comparisons among the IRFC, the original recycling folded cascode (RFC) and the conventional folded cascode (FC) are made, and it is shown that with the flexible structure of IRFC, significant enhancement in transconductance, slew rate and noise can be achieved. Prototype amplifiers were fabricated in 0.13 μm technology. Measurement shows that IRFC has 3× enhancement in gain-bandwidth and slew rate over conventional FC, and the enhancement is 1.5× when compared with the RFC. (semiconductor integrated circuits)

[en] A new expression is proposed to analyze the linearization effectiveness of derivative superposition (DS) with large and small signal inputs, and different optimization methods of DS are found for different input magnitudes. A power amplifier driver (PAD) with large-signal optimized DS was implemented in 0.13 μm technology within a reconfigurable RF transmitter. The PAD is compatible with the GSM band at 900 MHz and the WCDMA band at 1.95 GHz, and it has a gain range of 44 dB with a step of 2 dB. Measurement results show that the overall OIP3 of the transmitter is better than 19 dBm, and the output referred 1-dB compression point is better than 7.5 dBm. (semiconductor integrated circuits)

[en] This paper describes a low-pass reconfigurable baseband filter for GSM, TD-SCDMA and WCDMA multi-mode transmitters. To comply with 3GPP emission mask and limit TX leakage at the RX band, the out-of-band noise performance is optimized. Due to the distortion caused by the subthreshold leakage current of the switches used in capacitor array, a capacitor bypass technique is proposed to improve the filter's linearity. An automatic frequency tuning circuit is adopted to compensate the cut-off frequency variation. Simulation results show that the filter achieves an in-band input-referred third-order intercept point (IIP3) of 47 dBm at 1.2-V power supply and the out-of-band noise can meet TX SAW-less requirement for WCDMA and TD-SCDMA. The baseband filter incorporates -40 to 0 dB programmable gain control that is accurately variable in 0.5 dB steps. The filter's cut-off frequency can be reconfigured for GSM/TD-SCDMA/WCDMA multi-mode transmitter. The implemented baseband filter draws 3.6 mA from a 1.2-V supply in a 0.13 μm CMOS process. (semiconductor integrated circuits)

[en] Ecological vulnerability analysis (EVA) is vital for ecological protection, restoration, and management of wetland-type national parks. In this study, we assessed the ecological vulnerability of Beidagang National Park based upon remote sensing (RS) and geographic information system (GIS) technologies. To quantify the ecological vulnerability, 10 indices were collected by the ‘exposure-sensitivity-adaptive capacity’ model and spatial principal component analysis (SPCA) was then applied to calculate the ecological vulnerability degree (EVD). Based on the numerical values, EVD of the study area was classified into five levels: moderate, light, medium, strong, and extreme. Results showed that the average EVD value was approximately 0.39, indicating overall good ecological vulnerability in Beidagang National Park. To be specific, 80.42% of the whole area was assigned to a moderate level of EVD with the highest being the tourism developed areas and the lowest being the reservoirs and offshore areas. Ecological vulnerability of the region was determined to be affected by the natural environment and anthropogenic disturbance jointly. The primary factors included tourism disturbance, traffic interference, exotic species invasion, land use/land cover, and soil salinization. We expected to provide some insights of the sustainable development of Beidagang National Park and would like to extend the results to other wetland-type national parks in the future.

[en] This paper describes the analysis and design of a 0.13 μm CMOS tunable receiver front-end that supports 8 TDD LTE bands, covering the 1.8-2.7 GHz frequency band and supporting the 5/10/15/20 MHz bandwidth and QPSK/16QAM/64QAM modulation schemes. The novel zero-IF receiver core consists of a tunable narrowband variable gain low-noise amplifier (LNA), a current commutating passive down-conversion mixer with a 2nd order low pass trans-impedance amplifier, an LO divider, a rough gain step variable gain pre-amplifier, a tunable 4th order Chebyshev channel select active-RC low pass filter with cutoff frequency calibration circuit and a fine gain step variable gain amplifier. The LNA can be tuned by reconfiguring the output parallel LC tank to the responding frequency band, eliminating the fixed center frequency multiple LNA array for a multi-mode receiver. The large various gain range and bandwidth of the analog baseband can also be tuned by digital configuration to satisfy the specification requirement of various bandwidth and modulation schemes. The test chip is implemented in an SMIC 0.13 μm 1P8M CMOS process. The full receiver achieves 4.6 dB NF, -14.5 dBm out of band IIP3, 30-94 dB gain range and consumes 54 mA with a 1.2 V power supply. (semiconductor integrated circuits)

[en] Highlights: • Various organic additive (OA) co-pyrolytic sewage sludge biochars (SSB) were made. • C content increased, ratios of H/C, N/C, and O/C decreased for SSB with OA addition. • OA addition increased available nutrients (Olsen P, K, and NH₄⁺-N) contained in SSB. • OA addition boosts SSB's benefits in nutrient supply and carbon sequestration. Sewage sludge (SS) has been suggested as a priming feedstock for biochar production that could simultaneously benefit the solid waste reuse and agricultural production. However, effects of organic additive (OA) addition on nutrient characteristic of SS biochar (SSB) are still unclear. Herein, a series of SSBs were produced from the co-pyrolysis of SS and OA with different types [reed straw (RS), brewers' spent grain (BSG), and sawdust (SD)] and addition rates (10%, 30%, and 50%) at 350 and 700 °C, respectively, and their basic physicochemical and nutrient properties were also analyzed. The results indicated that OA addition greatly increased the carbon (C) content, while significantly decreased the yield, ash content, pH, electrical conductivity, and elemental ratios of H/C, N/C, and O/C of SSB. These changes in SSB physicochemical properties would be more beneficial to its potentials of soil improvement and C sequestration. Furthermore, OA co-pyrolytic SSBs generally demonstrated similar nutrient retention rate and higher available nutrient content (e.g., Olsen P, K, and NH₄⁺ − N) in relative to the SSBs from SS alone, indicating their excellent nutrient recovery capacity and higher nutrient utilization efficiency. Lastly, the SSBs produced from co-pyrolysis of SS and SD, BSG, and RS, respectively, with 50% addition rate and at 700 °C were suggested as the best SSB kinds used for soil application due to their highest comprehensive quality scores. In sum, co-pyrolysis of SS and OA is recommended as a promising strategy to increase the benefits of SSB in both agricultural production and environment.

[en] For composite electromagnetic (EM) scattering from rough surface and target above it in near-field condition, modified shooting and bouncing ray (SBR) method and integral equation method (IEM), which are analytic methods combined with two-scale model for rough surface, are proposed to solve the composite near-field scattering problems. And the modified method is verified in effectiveness and accuracy by comparing the simulation results with measured results. Finally, the composite near-fielding scattering characteristics of a slanted plane and rough water surface below are obtained by using the proposed methods, and the dynamic tendency of composite scattering characteristics versus near-fielding distance is analyzed, which may have practical contribution to engineering programs in need of radar targets near-field characteristics under extra-low-altitude conditions. (paper)

[en] Highlights: • Simulated devices are built to simulate the tidal cycle. • Tidal cycle has significant effect on the release of DOM, N and P. • Tidal cycle changes the microbial richness and diversity. • Microbial diversity explains the mechanism of nutrient release. • A model is introduced to predict the short-term release of N and P. Tide drives salt mixing processes, erosion, deposition, and nutrient circulation in sediments, which is critical to the estuarine systems. This study aims to investigate the effects of tidal cycle intensity on sediment dissolved organic matter (DOM), nitrogen and phosphorus release. In this study, the effects of tide are investigated by simulating different intensity of tidal disturbance with tidal simulator devices. The microbial community changes under different tidal cycle are disclosed to explain the mechanism of nutrient release. In addition, the short-term release of nitrogen and phosphorus under simulated tidal cycle is predicted by stepwise regression method. Results show that the higher the tidal cycle intensity, the stronger the DOM mineralization in sediments and diffusion into overlying water, leading to a sustained increase of fluorescence intensity in DOM. Besides, the tidal disturbance promotes the NH₄⁺-N and NO₃⁻-N release and the tidal disturbance is helpful for ammonification. While the greater the tidal intensity, the lower the NO₃⁻-N release. Content of released total phosphorus (TP) maintains at a low level and fluctuates over time under different simulated tidal intensity. In addition, tidal cycle greatly changes the microbial richness and diversity. Gammaproteobactere has the ability of denitrification and can reduce nitrate to nitrite. Besides, tidal environment greatly affects the abundance of Marinobacter which can enhance the N, P, and C migration transformation ability. The research on microbial community further explains the mechanism of nutrient release. The model of nitrogen and phosphorus release contributes to providing basic data for predicting the short-term release of nutrients under different simulated tidal intensity.