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In this paper, FIB/STEM/EELS characterized methods are used to study the 28 nm integrated circuit chip structure and chemical analysis. The newly developed EELS analysis method can distinguish different overlapping elements, which were used in HK-MG structure, but these cannot be separated with normal methods. With this high spatial resolution physical and chemical analysis capability, the detail process steps, which can improve the chip yield and the reliability are analyzed and discussed. A structure related to SiO2 thinner defect was also observed and studied.

Despite the large reduction in anthropogenic activities due to the outbreak of COVID-19, air quality in China has witnessed little improvement and featured great regional disparities. Here, by combining observational data and simulations, this work aims to understand the diverse air quality response in two city clusters, Yangtze River Delta region (YRD) and Pearl River Delta region (PRD), China. Though there was a noticeable drop in primary pollutants in both the regions, differently, the maximum daily 8 h average ozone (O3) soared by 20.6–76.8% in YRD but decreased by 15.5–28.1% in PRD. In YRD, nitrogen oxide (NOx) reductions enhanced O3 accumulation and hence increased secondary aerosol formation. Such an increment in secondary organic and inorganic aerosols under stationary weather reached up to 36.4 and 10.2%, respectively, which was further intensified by regional transport. PRD was quite the opposite. The emission reductions benefited PRD air quality, while regional transport corresponded to an increase of 17.3 and 9.3% in secondary organic and inorganic aerosols, respectively. Apart from meteorology, the discrepancy in O3–VOCs–NOx relationships determined the different O3 responses, indicating that future emission control shall be regionally specific, instead of one-size-fits-all cut. Overall, the importance of regionally coordinated and balanced control strategy for multiple pollutants is highly emphasized.

Purpose: To explore the efficacy of carrelizumab in the treatment of metastatic castration-resistant prostate cancer (mCRPC), and the significance of circulating tumor DNA (ctDNA) fraction in the process.Methods: 100 mCRPC patients who were treated in the Oncology Department of Harbin Medical University Cancer Hospital in a time frame of January 2018 to January 2019 were enrolled and assigned (1:1) into control and study groups and were given a regimen consisting of a combination of docetaxel and prednisone. Prognosis of patients with high and low ctDNA fractions relative to baseline ctDNA level, was compared.Results: The study group obtained considerably higher objective response rate (ORR) in relation to the control group (p < 0.05). Serum levels of prostate-specific antigen (PSA) and testosterone (TTE) were significantly lower in the study group versus control group. Better quality of life and bladder function were witnessed in the study group when compared to control group (p < 0.05). The proportion of patients with ctDNA fraction < 2 % in the study group significantly increased, but there was no significant change in ctDNA in the control group. The clinical prognosis of patients with low ctDNA fraction was significantly better than that of patients with high fraction (p < 0.05).Conclusion: Combined use of carrelizumab and docetaxel-prednisone regimen for mCRPC patients substantially improved clinical efficacy, quality of life, and long-term prognosis, while reducing ctDNA levels. Thus, the combination regimen has promise for the treatment of mCRPC patients.

A novel sandwich-like structure material was exploited for the fabrication of an effective corrosion resistance system. An environmentally friendly composite material was synthesized by installing 8-hydroxyquinoline (8-HQ) on the surface of graphene oxide (GO). In order to prevent leakage of corrosion inhibitor 8-HQ, GO/8-HQ was modified by polydopamine (PDA), denoted as GO/8-HQ/PDA. A sandwich-like structure (GO/8-HQ/PDA) enables long-term stable storage of corrosion inhibitor in the protective matrix. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were utilized to verify the sandwich-like structure of GO/8-HQ/PDA. The electrochemical tests in a 3.5 wt% NaCl solution showed that the addition of well-dispersed GO/8-HQ/PDA into epoxy system (GO/8-HQ/PDA-EP) remarkably improved corrosion protection of AZ31b magnesium alloy compared with pure epoxy (EP) coating. The sandwich structure protects the activity and structural integrity of the corrosion inhibitor (8-HQ). The corrosion inhibitor (8-HQ) of the GO/8-HQ/PDA sandwich structure cuts off the ion exchange between the metal alloy and the electrolyte solution, which hinders the electrochemical corrosion of the metal. A possible corrosion resistance mechanism of GO/8-HQ/PDA is fully discussed. This study provides feasibilities for the immobilization of corrosion inhibitors on the metal surface.

Incorporating visible light into sulfide oxidation is an emerging desirable strategy to produce versatile sulfoxides. We introduce the design and synthesis of multilayered wrinkled C3N4 nanosheets and demonstrate their unprecedented sulfide oxidation activity. Due to the wrinkled surfaces with a large SBET (208.6 m2g−1), wrinkled C3N4 nanosheets exhibit a sensitive optical response, facilitating the electron photoexcition. Layer structure confinement enables robust e−-h+ interactions and valid photoexcited excitons formation, allowing rapid 1O2 reactive species production. Integrating the sensitive optical response with robust e−-h+ interactions, photoexcited electrons and excitons are jointly produced, giving large yields of ⋅O2− and 1O2 reactive species that are conductive to O2− and 1O2 cocatalysis with an activity that is up to 33-fold that of bulk C3N4. In the cocatalysis mechanism, both O2− and 1O2, can produce peroxysulfoxide intermediates, resulting in target sulfoxides. This is the first report on sulfide oxidation via O2− and 1O2 cocatalysis and a promising study on catalyst exploitation for high-efficiency and high-selectivity production process.

BACKGROUND: Programmed death-1 (PD-1) inhibitors have been approved and are currently widely used to treat lung cancer patients. However, comparative data on the adverse events (AEs) associated with different PD-1 inhibitors are very limited. METHODS: Patients with histologically confirmed lung cancer who had been treated with at least 1 dose of PD-1 inhibitors between January 2017 and December 2019 at a tertiary cancer hospital were included in the study. Data on treatment-related AEs (tr-AEs) were collected from their electronic medical records. RESULTS: A total of 227 lung cancer patients treated with nivolumab (n=83), pembrolizumab (n=65), camrelizumab (n=27), sintilimab (n=31), and toripalimab (n=21) were included. In relation to nivolumab, pembrolizumab, camrelizumab, sintilimab, and toripalimab, the incidence rates of all-grade tr-AEs were 37.34%, 24.62%, 62.96%, 29.03% and 9.52%, respectively (P=0.01), and the incidence rates of grade 3–4 tr-AEs were 2.41%, 3.08%, 22.22%, 3.23% and 0%, respectively (P=0.05). The most common all-grade tr-AEs were capillary hemangioma (22.22%) and abnormal liver function (22.22%) for camrelizumab, pneumonitis for nivolumab (12.05%), pembrolizumab (6.15%) and nausea/vomiting (12.9%) for sintilimab, and pneumonitis (4.76%), rash/pruritus (4.76%) and shingles (4.76%) for toripalimab. Sex, age, PD-1 inhibitors, histology type and PD-1 cycles were significantly associated with tr-AEs. CONCLUSIONS: There were significant differences in the incidence and most common tr-AEs among the different PD-1 inhibitors. Different monitoring priorities should be given to different PD-1 inhibitors during treatment cycles.

A new design method of highly reliable thermally conductive packaging material is proposed for the heat dissipation problem of high-density packaging of chips. The high reliability is obtained by high temperature condensation of AlN particles suspension of PAA. Focusing on the influence law of the content of AIN on the electronic packaging material, the experimental results show that the thermal conductivity reaches 3.8 W/(m⋅K) when the mass percentage of AIN reach more than 60%. The Td in N2 is 524°C. The surface of AIN is modified by the macromolecular coupling agent GBM to increase the compatibility of AIN with the Polymeric materials. The tensile strength of PI/AlN composite is 170 MPa, and the material has good insulation performance when the temperature rises to 200°C under 120 kV/mm electric field, which meets the application requirements of high-density chip packaging.

This study aimed to evaluate the effect of aging on the color stability and bond strengths of dual-cured resin cements containing amine or amine-free self-initiators. Three dual-cured and one light-cured resin cements were used. The covered (by lithium disilicate ceramic disks) and uncovered groups (n=10) were included. Color measurements were tested after 24 h, 10,000 and 20,000 thermal cycles (TCs). Micro-shear bond strengths (µSBS) were tested after 24 h, 10,000 and 20,000 TCs, and failure modes were analyzed (n=14). Two-way ANOVA and Tukey's test were implemented for color difference (ΔE*ab) and µSBS (α=0.05). The mean ΔE*ab difference was significant among groups (p

In recent years, most of the communication places are using business English manual simultaneous interpretation or electronic equipment translation. In the context of diverse cultures, the way English is used and its grammar vary from country to country. In the face of this situation, how to optimize business English translation technology and improve the accuracy of business communication content is one of the research contents of scholars all over the world. This paper first introduces the purpose of business English translation and the gap between business English translation and general English translation. Secondly, a genetic algorithm is used to optimize the structure of the BP neural network, and the combination of the two improves the ability of translation search. This paper compares the influence of the traditional BP algorithm and the BP algorithm optimized by genetic algorithm on the construction of a business English translation model. The results show that BP neural network optimized by the genetic algorithm can improve the speed of business English text translation, reduce the impact of semantic errors on the accuracy of the translation model, and improve the efficiency of translation.

In order to explore the influence of interlayer between dielectric layer and channel layer on performance of thin film transistors (TFTs), the single layer titanium doped zinc oxide (TiZO) TFTs and the dual layer indium tin oxide (ITO)/TiZO TFTs were fabricated successfully in this work. The effects of interlayer thickness on the performance of TFTs were studied and the optimal thickness condition was obtained. The experimental results indicate that the introduction of interlayer contributes to the improvement of TFT characteristics. In addition, the dual-layer ITO/TiZO TFTs also present a good uniformity, which is suitable for large-area display applications.

The feeder terminal unit (FTU) is a critical component of any electric power system that works in a complex electromagnetic environment. However, innovative research of theoretical analysis of electromagnetic–thermal practices inside the FTU system is missing in the literature. This work presents the theoretical methodologies for calculating and analyzing the electromagnetic–thermal influence of FTUs in a high-power electromagnetic (HPEM) environment. The numerical outcomes reveal that the surface of the FTU and connecting cables under powerful electromagnetic pulses (EMP) induce significant electromagnetic fields and high temperatures. Significantly, the electromagnetic pulse and injection of heat through the wires into the FTU may cause interference and possibly damage to the FTU’s circuits and electronics. This work serves as a reference for electromagnetic compatibility (EMC) design of FTUs and provides numerical analysis for ensuring the normal operation of FTU devices under harsh electromagnetic environments.

During the COVID-19 lockdown, ambient ozone levels are widely reported to show much smaller decreases or even dramatical increases under substantially reduced precursor NOx levels, yet changes in ambient precursor volatile organic compounds (VOCs) have been scarcely reported during the COVID-19 lockdown, which is an opportunity to examine the impacts of dramatically changing anthropogenic emissions on ambient VOC levels in megacities where ozone formation is largely VOC-limited. In this study, ambient VOCs were monitored online at an urban site in Guangzhou in the Pearl River Delta region before, during, and after the COVID-19 lockdown. The average total mixing ratios of VOCs became 19.1% lower during the lockdown than before, and those of alkanes, alkenes and aromatics decreased by 19.0%, 24.8% and 38.2%, respectively. The levels of light alkanes (C6) decreased by only 13.0%, while those of higher alkanes (C ≥ 6) decreased by 67.8% during the lockdown. Disappeared peak VOC levels in morning rush hours and the drop in toluene to benzene ratios during the lockdown suggested significant reductions in vehicle exhaust and industrial solvent emissions. Source apportioning by positive matrix factorization model revealed that reductions in industrial emissions, diesel exhaust (on-road diesel vehicles and off-road diesel engines) and gasoline-related emissions could account for 48.9%, 42.2% and 8.8%, respectively, of the decreased VOC levels during the lockdown. Moreover, the reduction in industrial emissions could explain 56.0% and 70.0% of the reductions in ambient levels of reactive alkenes and aromatics, respectively. An average increase in O

It is well known that the vertical tunnel field effect transistor (TFET) is easier to fabricate than the conventional lateral TFETs in technology. Meanwhile, a lightly doped pocket under the source region can improve the subthreshold performance of the vertical TFETs. This paper demonstrates a dual material gate heterogeneous dielectric vertical TFET (DMG-HD-VTFET) with a lightly doped source-pocket. The proposed structure adopts a GaSb/GaAs0.5Sb0.5 heterojunction at the source and pocket to improve the band-to-band tunneling (BTBT) rate, at the same time, the gate electrode is divided into two parts, namely a tunnel gate (M1) and control gate (M2) with work functions ΦM1 and ΦM2, where ΦM1 &gt, ΦM2. In addition, further performance enhancement in the proposed device is realized by a heterogeneous dielectric corresponding to a dual material gate. Simulation results indicate that DMG-HD-VTFET and HD-VTFET possess superior metrics in terms of DC (Direct Current) and RF (Radio Frequency) performance as compared with conventional VTFET. As a result, the ON-state current of 2.92 × 10−4 A/μm, transconductance of 6.46 × 10−4 S/μm, and average subthreshold swing (SSave) of 18.1 mV/Dec at low drain voltage can be obtained. At the same time, DMG-HD-VTFET could achieve a maximum fT of 459 GHz at 0.72 V gate-to-source voltage (Vgs) and a maximum gain bandwidth (GBW) of 35 GHz at Vgs = 0.6 V, respectively. So, the proposed structure will have a great potential to boost the device performance of traditional vertical TFETs.

Vehicle emission is an important source of ammonia (NH3) in urban areas. To better address the role of vehicle emission in urban NH3 sources, the emission factor of NH3 (NH3-EF) from vehicles running on roads under real-world conditions (on-road vehicles) needs to update accordingly with the increasingly tightened vehicle emission standards. In this study, laser-absorption based measurements of NH3 were conducted during a six-day campaign in 2019 at a busy urban tunnel with a daily traffic flow of nearly 40,000 vehicles in south China’s Pearl River Delta (PRD) region. The NH3-EF was measured to be 16.6 ± 6.3 mg km−1 for the on-road vehicle fleets and 19.0 ± 7.2 mg km−1 for non-electric vehicles, with an NH3 to CO2 ratio of 0.27 ± 0.09 ppbv ppmv−1. Multiple linear regression revealed that the average NH3-EFs for gasoline vehicles (GVs), liquefied petroleum gas vehicles, and heavy-duty diesel vehicles (HDVs) were 18.8, 15.6, and 44.2 mg km−1, respectively. While NH3 emissions from GVs were greatly reduced with enhanced performance of engines and catalytic devices to meet stricter emission standards, the application of urea selective catalytic reduction (SCR) in HDVs makes their NH3 emission an emerging concern. Based on results from this study, HDVs may contribute over 11% of the vehicular NH3 emissions, although they only share ∼4% by vehicle numbers in China. With the updated NH3-EFs, NH3 emission from on-road vehicles was estimated to be 9 Gg yr−1 in the PRD region in 2019, contributing only 5% of total NH3 emissions in the region, but still might be a dominant NH3 source in the urban centers with little agricultural activity.

The general preparation method of large-area, continuous, uniform, and controllable vdW heterostructure materials is provided in this paper. To obtain the preparation of MoS2/h-BN and WS2/h-BN heterostructures, MoS2 and WS2 material are directly grown on the insulating h-BN substrate by atmospheric pressure chemical vapor deposition (APCVD) method, which does not require any intermediate transfer steps. The test characterization of MoS2/h-BN and WS2/h-BN vdW heterostructure materials can be accomplished by optical microscope, AFM, Raman and PL spectroscopy. The Raman peak signal of h-BN material is stronger when the h-BN film is thicker. Compared to the spectrum of MoS2 or WS2 material on SiO2/Si substrate, the Raman and PL spectrum peak positions of MoS2/h-BN heterostructure are blue-shifted, which is due to the presence of local strain, charged impurities and the vdW heterostructure interaction. Additionally, the PL spectrum of WS2 material shows the strong emission peak at 1.96 eV, while the full width half maximum (FWHM) is only 56 meV. The sharp emission peak indicates that WS2/h-BN heterostructure material has the high crystallinity and clean interface. In addition, the peak position and shape of IPM mode characteristic peak are not obvious, which can be explained by the Van der Waals interaction of WS2/h-BN heterostructure. From the above experimental results, the preparation method of heterostructure material is efficient and scalable, which can provide the important support for the subsequent application of TMDs/h-BN heterostructure in nanoelectronics and optoelectronics.

In this paper, polyacrylate (PA) was modified by waterborne polyurethane (WPU) to synthesize waterborne polyurethane-acrylate coating material. The structural changes of each component before and after modification, emulsion performance, film performance and printing performance were studied. The effects of raw material ratio and process conditions on application performance of printing emulsion were explored. The results showed that under the conditions of drying temperature and time of 150 °C and 3 min, the optimal formula was resin coating (WPU : PA=4 : 6), mixed solvent, deionized water and pigment content of 25 %, 15 %, 45 % and 15 %, respectively. The obtained emulsion was stable, the water absorption and solvent resistance of the film were good, and the rubbing fastness of printing could reach 4–5 grade. The structural analysis showed that the polyacrylate emulsion was synthesized, and the modified emulsion had the composite structure of WPU/PA.

Worldwide, non-alcoholic fatty liver disease (NAFLD) is a common chronic liver disease closely associated with obesity, diabetes and other metabolic diseases. Shenling Baizhu powder (SLBZP), a formulation of a variety of natural medicinal plants, has hepatoprotective properties and clinical efficacy in treating non-infectious intestinal disease. SLBZP has improved NAFLD symptoms; however, its mechanism of action is unknown.We established an NAFLD model in rats given a high-fat diet (HFD), administered different interventions and measured serum biochemical indices and inflammatory factors. Liver tissues were stained with hematoxylin and eosin (HE) and oil red O, and colon tissues were analyzed by immunohistochemistry. The expression profiles of liver TLR4 pathway related protein was confirmed by western blotting. Changes in intestinal microbiota composition were analyzed using a 16S rDNA sequencing technique.Of note, SLBZP effectively reduced body weight in HFD-fed rats (p 0.05). Serum biochemical analysis indicated that SLBZP decreased the serum level of total cholesterol (TC) and improved liver function. Additionally, SLBZP decreased the serum level of endotoxin, tumor necrosis factor α (TNF-α), interleukin-1β (IL-β) (p 0.05), and decreased the expression of TLR4 pathway related protein. Pathological examination showed that SLBZP alleviates hepatic steatosis and repairs colon mucosa. Microbiome analysis revealed that SLBZP improved the abundance of intestinal microbiota. In taxonomy-based analysis, compared with control rats, SLBZP-treated rats showed obvious changes in intestinal microbiota composition. Moreover, SLBZP increased the relative abundance of short-chain fatty acid (SCFA)-producing bacteria, including Bifidobacterium and Anaerostipes.Taken together, these results suggest that the effects of SLBZP against NAFLD may be related to the increased abundance of beneficial gut microbiota and decreased levels of LPS in the portal vein.

The paper compares HydroChina’s involvement in Adama Wind Farm in Ethiopia as a case of South-South technology transfer to that of Vergnet, a French firm involved in the construction and financing of Ashegoda Wind Farm, as a case of North-South technology transfer. The impact of technology transfer is evaluated along four dimensions: capital goods and equipment, direct skill transfer, indirect skill transfer, and knowledge and expertise. In recent years, rise of south-south technology transfer led by Chinese-financed overseas renewable energy projects in developing countries has rekindled debate on motivations and impacts of China’s increasing engagements. However, the literature on impact of technology transfer in renewable energy is scarce and non-comparative in nature. This paper aims to fill in the gap. Through interviews with key stakeholders and detailed analysis of the negotiation and construction processes in both projects, the research shows although HydroChina shared a higher level of knowledge and expertise to local engineers and university scholars during the construction phase, Vergnet formed stronger long-term skill transfer linkages with local university students and employed a larger share of local workers than HydroChina. It is crucial to note the research presented here shows that host government, rather than donor country, has considerable capacity and can play a vital role in negotiating and maximizing technology transfer. In fact, the host government’s expectations and demands contributed to the variations in technology transfer patterns. The paper concludes with a discussion of potential opportunities and challenges, and policy recommendations to facilitate international technology transfer.

The present study investigates the potential therapeutic mechanism underlying the effects of the Chinese herbal formula Hongqijiangzhi Fang (HJF) on nonalcoholic fatty liver disease (NAFLD) in rats. Male Sprague Dawley (SD) rats were randomly divided into 4 groups (n=8): control group was fed a normal diet, three other groups were fed high-fat diets (HFD), and the two treatment groups were intragastrically given a compound probiotic or HJF during the molding time. After 16 w, related indices were detected. The results showed that HJF significantly reduced abdominal aorta serum cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL), IL-1β, and IL-18, portal venous serum lipopolysaccharide (LPS), and liver TC and TG levels in HFD-fed rats. HJF ameliorated hepatic steatosis in the liver and improved the intestinal barrier in HFD-fed rats. Activation of the NLRP3 inflammasome was reduced by HJF in HFD-fed rats. Additionally, the abundances of A. muciniphila (Verrucomicrobiaceae), F. rappini (Helicobacteraceae), and Enterobacteriaceae bacteria significantly decreased in HJF-treated HFD-fed rats. In conclusion, these result suggested that the Chinese herbal formula HJF reduced hepatic steatosis maybe through decreasing certain gut bacteria (such as Enterobacteriaceae bacteria and F. rappini), alleviating intestinal endotoxemia and reducing NLRP3 inflammasome activation.

This work presents a monolithically integrated temperature and humidity sensor based on microelectromechanical systems technology. The temperature sensor working on the “bi-metallic” effect has the advantages of wide temperature range, high sensitivity, and fast detection. The humidity sensor has a polyimide parallel plate capacitive structure with the microporous array on the upper electrode designed for high sensitivity and fast response. Numerical analysis and COMSOL simulation showed that the temperature detection sensitivity is 0.2 mV/°C in the range of 193–393 K and humidity sensitivity is 0.405 pF/% relative humidity (RH) with the response time of 34 s in the humidity range of 0%–100% RH. The integrated temperature and humidity sensor has the advantages of small dimension, wide detection range, high precision, and fast response.

Carbonyls play a vital role in atmospheric photochemistry. Vehicle emission is among most important primary emission sources of carbonyls in urban areas, yet knowledge is quite scarce about real-world emissions of carbonyls with the changing on-road vehicle fleets. In this study, emissions of carbonyls were characterized based on tests in a busy urban tunnel in south China. Emission factor (EF) of carbonyls was measured to be 9.89 ± 0.65 mg km−1 on average, in which formaldehyde alone shared 53.1% with an EF of 5.25 ± 0.35 mg km−1, followed by acetaldehyde with an EF of 1.47 ± 0.13 mg km−1. Glyoxal and methylglyoxal showed identical EFs of 0.18 ± 0.02 mg km−1. Multiple linear regression retrieved total carbonyl EFs of 5.68, 47.71 and 35.09 mg km−1 and ozone formation potentials (OFPs) of 38.4, 329.3, and 242.4 mg km−1 for gasoline, diesel and liquefied petroleum gas vehicles (LPGVs), respectively. The unexpectedly high carbonyl emissions from LPGVs were largely attributed to the lack of after-treatment systems or the inefficiency of the after-treatment systems. Among vehicle-emitted non-methane hydrocarbons and carbonyls, carbonyls could contribute ~20% of the total OFPs while they only accounted for 7.1% of the total mass.

The degradation mechanism of Ti/Pt/Au ohmic contacts to p-GaAs was identified experimentally under high direct-current density stress in detail. A revised measuring structure was designed based on the circular transfer length method (CTLM), in which the high current density of $0.8\times 10^{5}$ A/cm2 was applied vertically, while the contact resistance was measured horizontally between two contact electrodes. According to revised CTLM, the specific contact resistance was measured during stress. The results indicated that specific contact resistance showed an exponential dependence on the aging time. The depth profiling results obtained from the Auger electron spectroscopy showed that Pt penetrated into the Au layer during stress. Furthermore, some voids were observed at the Au/Pt interface, and intermixing began to form within metal layer during stress. These results demonstrated that the degradation of Ti/Pt/Au ohmic contacts to p-GaAs was attributed mainly to the electromigration and Joule heating along the current direction under high current density.

This study demonstrated a dye-sensitized TiO 2 -polyoxometalate system (denoted TiO 2 -(PW 12 -TH) 8 , where PW 12 = PW 12 O 40 3− and TH = thionine) for selective oxidation of alcohols under visible light. The results showed that various substituted alcohols were transformed into their corresponding aldehydes with high selectivity. Due to more efficient electrons transfer, large surface area, and enhanced visible light absorption, the photocatalytic activity of TiO 2 -(PW 12 -TH) 8 was superior to any other dye-sensitized system reported to date. The response in the photocurrent-time curves over several on/off cycles of intermittent irradiation showed good reproducibility. The photocurrent response of TiO 2 -(PW 12 -TH) 8 was much higher than that of TiO 2 /TH (physical mixture of TiO 2 and TH), SiO 2 -(PW 12 -TH) 8 or P25-(PW 12 -TH) 8 (P25 = Degussa P25), attributed to the more efficient transfer and longer lifetime of photoexcited electrons. This photocatalytic process confirmed that efficient electron transfer during photocatalytic oxidation plays a vital role in determining the reaction conversion and obtaining good selectivity. Electron paramagnetic resonance (EPR) spectra and radical scavenging experiments proved that superoxide radicals and electrons were the main reactive species in the proposed system, the absence of hydroxyl radicals and holes is demonstrated to be the key of high reaction selectivity.

Great progress has been made recently in the understanding of the sources and formation mechanisms of atmospheric aerosols at the ground level. However, vertical profiles and sources of size-resolved particulate matter within the urban boundary layer are still lacking. In this study, vertical distribution characteristics of size-segregated particles were investigated at three observation platforms (ground, 118 m and 488 m) on the 610-meter-high Canton Tower in Guangzhou, China. Size-segregated aerosol samples were simultaneously collected at the three levels on the Canton Tower in autumn and winter, respectively. Major aerosol components, including water-soluble ions, organic carbon and elemental carbon, were measured. The results showed that daily average fine-particle concentrations generally decreased with height. Concentrations of sulfate and ammonium in fine particles displayed small vertical gradients and nitrate concentrations increased with height in autumn, while the above chemical components showed greater variations in winter than in autumn. The size distributions of sulfate and ammonium in both seasons were characterized by dominant unimodal droplet modes with a peak at the size range of 0.44–1.0 μm. In autumn, the nitrate size distribution was bi-modal, peaking at 0.44–1.0 μm and 2.5–10 μm, while it was unimodal in winter, implying that the formation mechanisms for nitrate particles were different in the two seasons. Our results suggest droplet mode sulfate and nitrate are likely formed from aqueous-phase reactions and coarse mode nitrate formation is attributed to heterogeneous reactions of gaseous nitric acid on existing sea-derived coarse particles in autumn at the measurement site. The results from pollution cases study further showed that atmospheric aqueous-phase and heterogeneous reactions together with adverse weather conditions, such as temperature inversion and calm wind, resulted in the autumn and winter haze pollution in the PRD region.