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Manipulation of the spin state holds great promise to improve the electrochemical activity of transition metal-based catalysts. However, the underlying relationship between the nonplanar metal coordination environment and spin states remains to be explored. Herein, we report the precise regulation of nonplanar Fe atomic d-orbital energy level into an irregular tetrahedral crystal field configuration by introducing P atoms. With the increase of P coordination number, the spin magnetic moment decreases linearly from 3.8 μB to 0.2 μB, and the high spin content decreases linearly from 31% to 5%. Significantly, a volcanic curve between the spin states of Fe-based catalysts (Fe–NxPy) and oxygen reduction reaction (ORR) activity has been unequivocally established based on the thermodynamic results. Thus, the Fe–N3P1catalyst with a 19% medium spin state experimentally exhibits the optimal reaction activity with a high half-wave potential of 0.92 V. These findings indicate that regulating electron spin moments through coordination engineering is a promising catalyst design strategy, providing important insights into spin catalysis.

Tailoring the local microenvironment of a single-atom active site is an effective pathway to promote electrocatalytic performance. Herein, we introduced a sulfur site to address the undesirable electron selectivity of a single-atom Fe-N4catalyst for oxygen reduction reaction (ORR). Comprehensive X-ray spectroscopic results, coupled with theoretical calculations, reveal that the introduction of a second-shell S site optimizes the local electron distribution of the Fe-N4moiety, enhancing its ORR activity. Furthermore, in situsynchrotron spectroscopy demonstrates that the presence of S in the Fe-N4moiety facilitates the breakage of the O-O bonding by reinforcing the adsorption of *OOH intermediates, accounting for enhanced ORR activity and four-electron selectivity. The well-designed catalyst exhibits satisfactory alkaline ORR activity, featuring a half-wave potential of 0.93 V versus reversible hydrogen electrode. Importantly, it effectively suppresses the yield of hydrogen peroxide to 4%, achieving a maximum power density of 241.1 mW cm-2in a Zn–air battery.

Rational design of well-defined active sites is crucial for promoting sluggish oxygen reduction reactions. Herein, leveraging the surfactant-oriented and solvent–ligand effects, we develop a facile self-assembly strategy to construct a core–shell catalyst comprising a high-index Pt shell encapsulating a PtCu3intermetallic core with efficient oxygen-reduction performance. Without undergoing a high-temperature route, the ordered PtCu3is directly fabricated through the accelerated reduction of Cu2+, followed by the deposition of the remaining Pt precursor onto its surface, forming high-index steps oriented by the steric hindrance of surfactant. This approach results in a high half-wave potential of 0.911 V versus reversible hydrogen electrode, with negligible deactivation even after 15000-cycle operation. Operandospectroscopies identify that this core–shell catalyst facilitates the conversion of oxygen-involving intermediates and ensures antidissolution ability. Theoretical investigations rationalize that this improvement is attributed to reinforced electronic interactions around high-index Pt, stabilizing the binding strength of rate-determining OHadsspecies.

Durability is an issue for selective catalytic reduction (SCR) catalysts due to their susceptibility to sulfur and water poisoning. In this study, Nano-Ce10-PSDCHF/ZrO2was prepared by the hydrothermal method using sintering dust, and the impact of SO2or water vapor on its SCR performance was investigated. The denitrification performance of Nano-Ce10-PSDCHF/ZrO2was better than that of 0.25-Ce10-PSDCHF/ZrO2prepared by the impregnation method in the entire temperature interval from 80 to 400 °C. The highest denitrification rate of 93.6% was achieved at 280 °C. Nano-Ce10-PSDCHF/ZrO2had a smaller particle size and uniform dispersion but also formed a high concentration of Ce3+and adsorbed oxygen Oαon the surface. Additionally, it showed better resistance to water and sulfur than 0.25-Ce10-PSDCHF/ZrO2. Even when exposed to 8% H2O and 400 ppm SO2, the denitrification rate of Nano-Ce10-PSDCHF/ZrO2remained at 82.1% after 4 h. SO2is more toxic to SCR catalysts than H2O. The effect of water on catalyst activity is partially reversible. Deactivation of SCR by SO2is primarily caused by the formation of ammonium sulfate species, with some contribution from competitive adsorption between SO2and NOx. In conclusion, the Nano-Ce10-PSDCHF/ZrO2catalyst exhibited the best SCR performance, with water and sulfur resistance, and effectively utilized sintering dust, which has potential application value.

Accurate channel state identification can improve the accuracy of ultrawideband (UWB) indoor positioning. In complex indoor environments, existing channel state identification methods suffer from high costs. Meanwhile, these methods pay little attention to the different localization errors caused by weak -non-line-of-sight (WLOS) and non-line-of-sight (NLOS). In this letter, a channel state identification method that can identify line-of-sight (LOS), WLOS, NLOS is proposed for use in a single indoor scenario based on the Stockwell transform and convolutional neural networks (ST-CNN). Moreover, combined with transfer learning (TL), ST-CNN can reduce the cost of identification in complex indoor environments. Simulations based on open source datasets show that ST-CNN can achieves F2 scores of 97.17% and 97.14% in NLOS and WLOS. For complex indoor environments consisting of multiple indoor scenarios, compared with the ST-CNN, the ST-CNN+TL method can reduce the training time by 62% and the training data by 40%.

Orthogonal time frequency space (OTFS), as a novel 2-D modulation technique, has been proposed to achieve better BER performances over delay-Doppler channels. In this paper, we propose two different power allocation (PA) algorithms in OTFS systems with zero forcing (ZF) or minimum mean square error (MMSE) equalization, where general formulas with PA are derived in advance under the condition of minimum BER (MBER) criterion. On one hand, a suboptimal MBER power allocation method is put forward to achieve better BER performances, and then analytical BER expressions are derived with proposed PA strategy. Considering the case of MMSE equalization, a combined subsymbol allocation (SA) and PA strategy is raised, where some subsymbols may be abandoned due to worse channel conditions, and then it is proven effectively to improve BER performances through theoretical and simulation results. Furthermore, BER performances with proposed joint SA and PA strategy are also investigated in delay-Doppler channels, where an improved message passing (MP) receiver based on equivalent channel matrix with PA is given.

The production of light olefins by catalytic cracking is a research hotspot in the petrochemical industry. Herein, nickel was used to modify IM-5 zeolite to improve the performance in catalytic cracking. Properties of the Ni/IM-5 zeolites with different nickel loadings were characterized. It was demonstrated that nickel species were mainly located on the external surface of impregnated IM-5 zeolite, only a few Ni2+ions were distributed in the ion exchange site as compensation cations. Pyridine infrared results indicated that the introduction of nickel could modulate the acidity of IM-5 zeolite and increase the amount of Lewis acid sites. Compared with IM-5, Ni/IM-5 exhibited higher olefin selectivity, especially ethylene, in n-hexane cracking reactions. It was considered that nickel could provide dehydrogenation active sites and promote the formation of light olefins. Thus, the selectivity of light olefins can be improved by controlling the amount and distribution of nickel in IM-5 zeolite.

Multiple secondary users (SUs) perform collaborative spectrum sensing (CSS) in cognitive radio networks to improve the sensing performance. However, this system severely degrades with spectrum sensing data falsification (SSDF) attacks from a large number of malicious secondary users, i.e., massive SSDF attacks. To mitigate such attacks, we propose a joint spectrum sensing and spectrum access framework. During spectrum sensing, each SU compares the decisions of CSS and independent spectrum sensing (IndSS), and then the reliable decisions are adopted as its final decisions. Since the transmission slot is divided into several tiny slots, at the stage of spectrum access, each SU is assigned with a specific tiny time slot. In accordance with its independent final spectrum decisions, each node separately accesses the tiny time slot. Simulation results verify effectiveness of the proposed algorithm.

Graphical abstract: In this work, an efficient nanocomposite photocatalyst of TiO2@MIL-101(Cr) were synthesized by hydrothermal method. The toluene removal efficiency of TiO2@MIL-101(Cr) was 23.28% higher than that of MIL-101(Cr), and 26.88% higher than that of bare TiO2.

Sine Non-linear Chirp Keying (SNCK) is a kind of high-efficient modulation scheme, which provides a potential new beamforming method in communication and radar systems. It has been proved to have advantages in some parameter estimation issues over conventional modulation schemes. In this paper, a novel transform termed as Discrete Sinusoidal Frequency Modulation transform (DSFMT) is proposed. Then, the DSFMT of SNCK signal is deduced and classified into three types, based on which, the time-bandwidth product is estimated by the proposed algorithm. Simulation results show that the noise has a significant impact on the localization of the peak value and the time-bandwidth product can be estimated by using local ratio values when 5 NR > 5dB.

Intrinsically high mobility and large absorption coefficient endow inorganic halide perovskites (IHPs) with great promise for high-performance photodetectors (PDs), which, however, are being hindered by the low carrier extraction and transport efficiency of the solution assembled films. Here, we report on a general strategy to enhance the perovskite film conductivity that carbon nanotubes (CNTs) conductive nanonets are constructed from to provide fast carrier tracks. Resultantly, the CsPbBr3nanosheet/CNT composite films exhibit both high light harvesting and high conductivity, such advantages are demonstrated by the high performances of corresponding planar PDs. Specifically, the highest external quantum efficiency (EQE) of 7488% and the highest responsivity of 31.1 A W–1under a bias of 10 V among IHP PDs with planar structure are achieved, which are almost 125-fold over the previous best results. Besides, the efficient charge extraction and transport also remarkably contribute to the fast response speed where a rise time of 16 μs is achieved, which is also superior to state-of-the-art IHP PDs. Furthermore, the composite films exhibit impressive flexibility due to the ultrathin 2D and 1D structural characteristic of perovskites and CNTs. By deploying the PD as a point-like detector, we acquire clear images. The results indicate the promising potentials of the perovskite/CNT composites for solution and ambient condition processed flexible devices, and this strategy is general for all kinds of perovskite optoelectronic devices including photodetectors, phototransistors, and even LEDs.

Toluene, as a strong carcinogen, is widely found in the newly renovated rooms, shopping malls, and workshops. Photocatalytic oxidation has great superiority and application prospects for the degradation of toluene. However, low photocatalytic efficiency under visible-light irradiation arising from easy agglomeration of the solid catalysts hinders their photodegradation of toluene gas. In this work, heterostructured TiO2/WO3 photocatalysts were fabricated via an electrospinning technology combining the hydrothermal treatment. The special microstructure and composition allowed the photogenerated electrons quickly transfer from the TiO2 nanofibers to the WO3 nanorods, and thus effectively reduced the recombination of photogenerated electrons and holes. Coupling TiO2 with the narrow band-gap WO3 broadened the spectral response range of TiO2. The heterostructured TiO2/WO3 photocatalysts exhibited a remarkably higher degradation rate of toluene gas than that of the bare TiO2 nanofibers under visible-light irradiation. The photocatalysts were deposited onto the inner walls of the photoreactor and some nylon meshes. The meshes were also placed in the photoreactor in a direction perpendicular to the air flow. The meshes increased the contact between photocatalysts in solid phase and toluene in gas phase, and about 85.3% of the toluene had been degraded in the experimental conditions.

Heterostructured TiO2/SnO2 fibrillar nanocomposites were synthesized by using electrospinning technology with the setup composed of a syringe pump with two parallel syringes on it and a rotating collector. The heterojunctions were formed between TiO2 and SnO2 nanofibers fast and efficiently on a large scale, after the fiberizing carrier polyvinylpyrrolidone (PVP) on the as-spun composite nanofibers was burnt away at 500degC. The samples were characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflection spectroscopy (DRS), and photoluminescence spectra (PL), respectively. The results indicated that two kinds of small nanofibers with different diameters were interconnected to form heterojunctions. Photocatalytic tests displayed that the heterostructured TiO2/SnO2 nanofibers exhibited a much higher degradation rate of methylene blue (MB), rhodamine B (RhB), and 4-chlorophenol (4-CP) than that of bare TiO2 nanofibers or Evonik P25 under UV light irradiation. The enhanced photocatalytic activity could be attributed to the effective charge separation derived from the coupling effect of TiO2 and SnO2 nanocomposites.

Patient-derived xenografts (PDXs) and patient-derived organoids (PDOs) have been shown to model clinical response to cancer therapy. However, it remains challenging to use these models to guide timely clinical decisions for cancer patients. Here, we used droplet emulsion microfluidics with temperature control and dead-volume minimization to rapidly generate thousands of micro-organospheres (MOSs) from low-volume patient tissues, which serve as an ideal patient-derived model for clinical precision oncology. A clinical study of recently diagnosed metastatic colorectal cancer (CRC) patients using an MOS-based precision oncology pipeline reliably assessed tumor drug response within 14 days, a timeline suitable for guiding treatment decisions in the clinic. Furthermore, MOSs capture original stromal cells and allow T cell penetration, providing a clinical assay for testing immuno-oncology (IO) therapies such as PD-1 blockade, bispecific antibodies, and T cell therapies on patient tumors.

Diffusion tensor imaging (DTI) can non-invasively examine the molecular diffusion of water in vivoand directly reflects the anatomical integrity of neural fibers in white matter. Fractional anisotropy (FA) can be calculated from DTI data, and utilized to evaluate white matter integrity. DTI was performed on 30 patients with schizophrenia and 19 healthy controls, and their FA values were subsequently measured in multiple brain regions. Statistical analyses revealed that FA values were decreased in the anterior cingulum of schizophrenia subjects. There were no significant differences between patients and controls in any other regions. This study supports the hypothesis that schizophrenia is associated with abnormal white matter integrity of the anterior cingulum.

Abstract: The residual stress induced in assembly is a common concern in electronic packaging, especially for those chips sensitive to residual stress. On chip-on-board (COB) packages, bisphenol A-type epoxy adhesive is applied to attach the chip to the substrate board. Silicon piezoresistive sensors are used to record residual stresses and stress evolution during adhesive curing. After 20-days storage in air at room temperature after curing, the residual stresses accumulate significantly in the recuring process, and after additional curing, the residual stress stabilizes at a relatively low level. Thermal analysis of the adhesive was performed to identify the incomplete cure of the adhesive after the first curing process.

Light-responsive carriers have been used for the controlled release of antitumor drugs in recent years. However, most light-responsive vectors require high-energy ultraviolet or visible light to achieve local drug release, and ultraviolet light would cause cellular damage. Near-infrared light has a deeper tissue-penetration depths and minimal harm to tissues, but it is difficult to cleave the chemical bond directly. The aim of this study is to develop a novel near-infrared light-responsive carrier for local release of antitumor drugs. Unsaturated phospholipids can be oxidized by singlet oxygen to achieve liposomal drug release, and singlet oxygen can be produced by photosensitizer under light irradiation. A new near-infrared light-responsive nanoliposome was designed that imparts light-triggered local drug release. Nanoliposomes, which were composed of matrix phospholipids and unsaturated phospholipids, were prepared by ammonium sulfate gradient method, and loaded with antitumor drug doxorubicin (DOX) and photosensitizer 1,4,8,11,15,18,22,25-octabutoxypalladium phthalocyanine. Under near-infrared light, photosensitizers could produce singlet oxygen and damage tumor cells by photodynamic therapy. Simultaneously, the unsaturated phospholipids were oxidized by singlet oxygen and result in DOX release, causing sustained cell damage by chemotherapy. Near-infrared light-responsive nanoliposomes exhibit enhanced anticancer activity owing to combined treatment of photodynamic therapy and chemotherapy. A new platform is thus offered for designing effective intracellular drug-release systems, holding great promise for future cancer therapy.

In recent years, high‐speed railway and subway are being built rapidly in China. Tunnel scenario is a major scenario in some of the high‐speed railways and most of the subways. Channel characteristic is the decisive condition of wireless communication system design in tunnel. The availability of multiple‐input multiple‐output (MIMO) in tunnel is an important issue in the next generation communication network. This paper presents results from a wideband measurement campaign at center frequency of 1.4725 and 6 GHz in a tunnel laboratory. The path loss, root‐mean‐square delay spread (RMS‐DS) characteristics by single‐input single‐output (SISO) measurement and the angle spread, channel matrix singular values, and MIMO capacity at various link distances by MIMO measurement are illustrated. and these provide insights for MIMO system deployment. And also, the threshold of singular value for channel matrix rank reduction is given. Wideband virtual multiantenna measurements are taken for straight tunnel channelsLarge‐ and small‐scale fading characteristics, including path loss, rms delay spread, angular characteristics, singular values, and MIMO capacity of straight tunnel channels at 1.4725 and 6 GHz are comparedThe threshold of singular value for channel matrix rank reduction is given at both 1.4725 and 6 GHz

In this work, diffident additives (sodium citrate, sodium acetate and KCl) are used to solve the problem that the CO2 absorption capacity of limestone decreases rapidly with the increase of cyclic calcination/carbonation reactions times. The results reflected that after adding 0.5% sodium acetate, the absorption rate and decomposition rate of CO2 in CaO are 1.01 times and 2.08 times higher than that without adding, and the absorption rate and decomposition rate are 2.65 times higher than those without adding after 10 cycles, and the decomposition rate is increased by 95.8%. After the addition of 1.0% sodium citrate, the first absorption rate increased by 28%, the 10 cycles increased by 38%, and the decomposition rate of the first calcium carbonate increased by 2.4 times. After adding 0.8% KCl, although the first absorption rate decreased by 36%, the decomposition rate of CaCO3 increased by 2.08 times after 10 cycles, and by 95.1% after 10 cycles. Therefore the use of additives improves obviously the CO2 absorption of CaO.

Toluene, as a strong carcinogen, is widely found in the newly renovated rooms, shopping malls, and workshops. Photocatalytic oxidation has great superiority and application prospects for the degradation of toluene. However, low photocatalytic efficiency under visible-light irradiation arising from easy agglomeration of the solid catalysts hinders their photodegradation of toluene gas. In this work, heterostructured TiO2/WO3photocatalysts were fabricated via an electrospinning technology combining the hydrothermal treatment. The special microstructure and composition allowed the photogenerated electrons quickly transfer from the TiO2nanofibers to the WO3nanorods, and thus effectively reduced the recombination of photogenerated electrons and holes. Coupling TiO2with the narrow band-gap WO3broadened the spectral response range of TiO2. The heterostructured TiO2/WO3photocatalysts exhibited a remarkably higher degradation rate of toluene gas than that of the bare TiO2nanofibers under visible-light irradiation. The photocatalysts were deposited onto the inner walls of the photoreactor and some nylon meshes. The meshes were also placed in the photoreactor in a direction perpendicular to the air flow. The meshes increased the contact between photocatalysts in solid phase and toluene in gas phase, and about 85.3% of the toluene had been degraded in the experimental conditions.

Heterostructured TiO2/SnO2fibrillar nanocomposites were synthesized by using electrospinning technology with the setup composed of a syringe pump with two parallel syringes on it and a rotating collector. The heterojunctions were formed between TiO2and SnO2nanofibers fast and efficiently on a large scale, after the fiberizing carrier polyvinylpyrrolidone (PVP) on the as-spun composite nanofibers was burnt away at 500°C. The samples were characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflection spectroscopy (DRS), and photoluminescence spectra (PL), respectively. The results indicated that two kinds of small nanofibers with different diameters were interconnected to form heterojunctions. Photocatalytic tests displayed that the heterostructured TiO2/SnO2nanofibers exhibited a much higher degradation rate of methylene blue (MB), rhodamine B (RhB), and 4-chlorophenol (4-CP) than that of bare TiO2nanofibers or Evonik P25 under UV light irradiation. The enhanced photocatalytic activity could be attributed to the effective charge separation derived from the coupling effect of TiO2and SnO2nanocomposites.