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Abstract: We report the synthesis of MoV2O8 nanowires of high quality using spin coating followed by the thermal annealing process. Transmission electron microscopy (TEM) reveals the average diameter of synthesized nanowire about 100 nm, and average length ranges from 1 to 5 μm. The TEM analysis further confirms the <001> growth direction of MoV2O8 nanowires. The electrochemical properties of synthesized nanowires using cyclic voltammetry show the specific capacitance 56 Fg−1 at the scan rate of 5 mV s−1 that remains 24 Fg−1 at 100 mV s−1. The electrochemical measurements suggest that the MoV2O8 nanowires can be used as a material for the future electrochemical capacitors (energy storage devices). [Copyright &y& Elsevier]

Abstract: Ultrathin nanoflakes of Ni(OH)2 were synthesized onto multi-walled carbon nanotubes (MWCNTs) by simple low cost chemically precipitation method for high performance electrochemical supercapacitor applications. The synthesized ultrathin Ni(OH)2 exhibit high specific capacitance of 1735Fg−1 at a scan rate of 5mVs−1 with excellent rate capability. This high performance of Ni(OH)2 nanoflakes was attributed to its complete accessibility to the electrolyte and maximum utilization of metal hydroxides. Findings of this work suggest that synthesized electrodes offer low-cost and scalable solution for high-performance energy storage devices. [Copyright &y& Elsevier]

Electrodeposition (ED) presents a substantially technical advantage over other methods, conducted with a simply equipped nonvacuum green process. Zn deposition is recognized as the biggest challenge in the process of electrodepositing CuZnSn‐based photovoltaic materials, due to the fiercely competitive reaction with H2O. Herein, Cu‐promoted Zn deposition from a preferred Cu/Sn/Zn stacked electrodeposition process is proposed. Intermetallic diffusion is confirmed to be positively reinforced during Zn electrodeposition, leading to a dense prefabricated alloyed layer with a reversed elemental distribution. Thus, a high‐quality Cu2ZnSnSe4 (CZTSe) absorber layer with up–down microsized grains is achieved by a two‐step sequence selenization, thereby reducing the Voc deficit and space‐charge‐region (SCR) recombination. With these sequential positive effects, a power conversion efficiency of 9.1% is achieved, accompanied with a depressed Voc deficit of 556 mV, to be the highest efficiency on electrodeposited CZTSe‐based devices. Additional processes of antireflective coating or surface treatments are expected to further improve the efficiency. This work highly contributes to the progress of high‐performance Cu‐kesterite solar cells by the low‐cost green electrodeposition process. [ABSTRACT FROM AUTHOR]

The changes of hydrological regimes, resulted from the anthropogenic and natural influences, inevitably altered ecological pattern and processes. Momoge wetland is a National Nature Reserve acted as an important habitat for the Siberian crane due to its capability of providing plenty food, the tuber of S. Planiculmis. Recent years, ecohydrological pattern has been dramatic altered by the anthropogenic activities, which also altered the habitat of Siberian crane. In present study, suitable water level depth for two types of vegetation, P. Communis and S. Planiculmis, were assessed, and then response of vegetation to different water level scenarios were simulated. The results showed that: (i) the suitable water levels for flood, normal and dry flow years were deduced from the relationship between annual precipitation and vegetation cover in the Baihe Lake, which are 1.23, 0.99 and 0.81m, respectively; (ii) The optimal ecological water level for P. Communis ranged from 30 to 50 cm, while it ranged from -5 to 30 cm for S. planiculmis; (iii) the spatial distribution of P. Communis and S. planiculmis, simulated using vegetation evolution model, exhibited that P. Communis and S. planiculmis both extended, while open water area decreased with decreases in water level; and (iv) the area for S. planiculmis in dry flow years are almost 2.8 times than that in high flow years, which can provide more food for Siberian crane. The results indicated that ecohydrological pattern varied with the water level, which also altered the habitat for Siberian crane. All of these would help address wetland degradation by providing suitable water level in high, normal and dry flow years/period. [ABSTRACT FROM AUTHOR]

A novel idea was presented by using patterned honeycomb-like ZnO cavities to enhance the light harvesting of Cu(In,Ga)Se 2 (CIGS) thin film solar cells in a broadband wavelength range. Large-scale patterned honeycomb-like ZnO cavities were fabricated through the versatile colloidal lithograhpy technique combined with the subsquent hydrothermal growth reaction. The growth mechanism was proposed based on the structural evolution of the patterned ZnO cavities. By introducing the patterned honeycomb-like ZnO cavities into CIGS solar cells, the performances of the device can be remarkabley improved due to the enhanced light harvesting. Photovoltaic device with a standard soda lime glass (SLG)/Mo/CIGS/CdS/i-ZnO/AZO/ZnO cavities/Ag grid structure exhibited a maximum power conversion efficiency of 11.4% under the standard AM 1.5 global illumination with a light intensity of 100 mW/cm 2 . An improvement of over 9.0% in the short-circuit photocurrent density and a 10.6% enhancement in the energy conversion efficiency were achieved compared with the standard reference device without ZnO cavities. More importantly, the device with patterned ZnO cavities exhibited omnidirectional behavior within a wide incident angle range. The enhancement of light harvesting is originating from the novel “negative” configuration of patterned ZnO cavities, which can realize high-efficient light trapping by multiple scattering and light coupling. [ABSTRACT FROM AUTHOR]

Sb 2 Se 3 solar cells deposited by rapid thermal evaporation (RTE) have drawn extensive attention owing to their compatibility with the commercial production line of CdTe solar cells and can be used to fabricate high-quality Sb 2 Se 3 films with high reproducibility. However, the deposition pressure during the RTE process has not been clearly explored, although it has a significant effect on the Sb 2 Se 3 film quality. A novel two-step deposition strategy is proposed that finely regulates the deposition pressure to improve the quality of Sb 2 Se 3 absorber layers, thereby improving the device performance of Sb 2 Se 3 solar cells. This novel method includes a rapid deposition process under a low pressure (5 mTorr) and an in situ annealing process under a relatively high pressure (200 Torr). The maximum power conversion efficiency (PCE) of Sb 2 Se 3 solar cells fabricated by two-step deposited approach is up to 8.12%. The PCE enhancement is attributed to the increased grain size, reduced grain boundaries, modified surface Fermi level gradient of the absorber layer, and improved defect performance. This innovative deposition technique is expected to benefit other low-melting-point metal sulfoselenides for solar cell applications., (© 2023 Wiley-VCH GmbH.)

As a systematic research at basin scale, this study explored the composition and concentration characteristics of 16 priority polycyclic aromatic hydrocarbons (PAHs) in sediments, water, and suspended particulate matter (SPM) in the water systems (rivers, lakes, and reservoirs) in the Hai River Basin through literature review. The sources and the ecosystem risks of PAHs in the sediments in the entire basin were specially discussed with diagnostic ration, PAHs composition, and an improved risk quotient method. Results showed that the total concentration of PAHs varied from 99.65 to 25,303 ng g(-1) dry weight in sediments, from 51.0 to 559.1 ng L(-1) in water, and from 4528 to 51,080 ng g(-1) dry weight in SPM, respectively. The dominant PAHs in the three examined phases were 2-3 rings in most waterbodies. PAHs in the rivers were from mixed sources (petrogenic and pyrolytic inputs), whereas those in lakes and reservoirs were mainly from biomass combustion and petroleum combustion. PAHs in the entire basin exhibited moderate to high ecological risk, and the rivers (especially Hai River, Jiyun River, Chaobai River, and Beiyun River) suffered higher ecological risk than reservoirs and lakes. Most of the rivers with higher PAHs risk flow through or around megacity Beijing and Tianjin.

Phthalate esters (PAEs) are widely used in the manufacturing of plastics, and the demand for PAEs has grown rapidly, especially in China. This trend will lead to much more environmental PAE contamination. PAEs are listed as priority substances in the European Union and are therefore subject to ecological risk assessments. This paper reviews the literature concerning the pollution status of PAEs and their ecological risk to aquatic environments. Risk quotients (RQs) based on the predicted no effect concentration and PAE concentrations in aquatic environments demonstrated significant (10 ≤ RQ < 100) or expected (RQ ≥ 100) potential adverse effects for algae, Daphnia, and fish in aquatic environments near PAE-based industrial and urban areas. Thus, the ecological risk of PAEs in Chinese aquatic environments should be considered, especially in areas where commercial plastics are produced.

Hematite (α-Fe2O3) thin films with various nanostructures were synthesized through self-assembly between iron oxide hydroxide particles, generated by hydrolysis and condensation of Fe(NO3)3 · 6H2O, and a Pluronic triblock copolymer (F127, (EO)106(PO)70(EO)106, EO = ethylene oxide, PO = propylene oxide), followed by calcination. The self-assembly structure can be tuned by introducing water in a controlled manner through the control of the humidity level in the surrounding of the as-cast films during aging stage. For the given Fe(NO3)3 · 6H2O:F127 ratio, there appear to be three different thermodynamically stable self-assembly structures depending on the water content in the film material, which correspond to mesoporous, spherical micellar, and rod-like micellar structures after removal of F127. Coupled with the thermodynamic driving forces, the kinetics of the irreversible reactions of coalescence of iron oxide hydroxide particles into larger ones induce diverse nanostructures of the resultant films. The length scale of so-obtained nanostructures ranges from 6 nm to a few hundred nanometers. In addition to water content, the effects of other experimental parameters such as aging temperature, spin rate during spin coating, type of substrate, and type of iron reagent were investigated.

The pollution loads continuously increased in Haihe estuary, of Tianjin, China, due to intensive human activities, especially the construction of the Haihe Gate and Lingang Industrial Area. In 2011, hydrological variability in Haihe estuary was investigated and sediments were collected. Total organic carbon (TOC), particle size, total polycyclic aromatic hydrocarbons (ΣPAHs), heavy metals (Cd, Cr, Cu, Ni, Pb, and Zn), and benthic diatom community were analyzed. The highest concentrations of ΣPAHs and heavy metals were found near the Haihe Gate. The Shannon diversity index and the relative abundance of Coscinodiscus perforatus (RC) indicated a decreasing trend seaward. Results of Pearson correlation analysis illustrated significant relations between water current velocity and ΣPAHs (p < 0.01), Cr (p < 0.05), and RC (p < 0.05). Path analysis further indicated that water current played an important role in the distribution of PAH, Cr, and RC.

The variations and associations of abiotic and biotic variables in Baiyangdian Lake, China, were analyzed in situ. Abiotic variables included eleven water quality parameters, and were characterized by water quality index (WQI). Biotic variables included periphyton function and diversity metrics. WQI differed in different seasons at sampling sites and the highest value of WQI was observed in October 2009. Periphyton function metrics, expressed by extracellular enzyme activities of alkaline phosphatase, β-glucosidase and leucine aminopeptidase, gross primary productivity and daily respiration rate, and diversity indices, in terms of Shannon diversity index and Berger-Parker abundance index, showed significantly temporal and spatial variations. Regression linear analysis illustrated a fairly good correlation of WQI with periphyton function and diversity indices, Shannon diversity index was the best correlated with WQI (r = 0.904, P < 0.01), followed by leucine aminopeptidase (r = -0.847, P < 0.01) and Berger-Parker abundance index (r = -0.840, P < 0.01), alkaline phosphatase, β-glucosidase and gross primary productivity also showed a good inverse correlation with WQI. Redundancy analysis suggested that eleven environmental variables explained a significant amount of the variation in the periphyton community data. The study was helpful for us to understand chemical and ecological status of water quality, and give us messages for monitoring water quality accurately.

The Haihe River Basin is a semiarid water resources area of China. River ecosystem was degraded for high population density and intensive water resources development activities. To assist in the improvement of the ecological integrity of this river ecosystem, an environmental flow assessment model was developed that consider both spatial structure and dominant eco-function parameters. River ecosystem was divided into three sub-ecosystems which including river reach, wetland and estuary based on the spatial structure of river ecosystem. River reach was divided into three types which including habitat restoration type (HR), water quality restoration type (WQR) and vegetation restoration substitute water quantity restoration type (VRSWQR) according to their dominant eco-function. The spatio-temporal distribution of environmental flow (EF) for the river ecosystem in the Haihe River Basin was assessed based on the model. The results indicate that the EF for the river reach, wetland, and estuary are 2.267, 1.532, and 0.972 billion m(3), respectively. The EF for HR type of river reach, the WQR type of river reach and VRSWQR type of river reach are 1.140, 1.138, and 0.154 billion m(3), which are equal to 4.320, 4.312, and 0.584 % of the average annual flow of 26.39 billion m(3), respectively. EF for river ecosystem in wet period (June-September), normal period (October-January) and dry period (February-May) are 2.999, 0.951, and 0.821 billion m(3), respectively. Annual EF for river ecosystem of the Basin are 4.771 billion m(3), which accounts for 18 % of the average annual flows of 26.39 billion m(3).

Heavy metals may adversely affect the structure and function of the periphyton community in lake ecosystems. We carried out samplings of three habitats at eight sites located in the Lake Baiyangdian that is strongly influenced by wastewater discharge (Sites 1 and 2), aquaculture and densely populated villages (Sites 3, 6, and 8), and the least disturbed (Sites 4, 5, and 7). Cu, Ni, Pb, Zn, Hg, Cd, and Cr were determined in these samples, and the periphyton community was simultaneously studied. The contamination factor (C f (i) ) was estimated for every metal as the ratio between pre-industrial records from sediments (C n (i) ) and present concentration values (C (i) ), and the individual potential risk (E r (i) ) was calculated by multiply the toxic response factor (Tr (i) ) and C f (i) for a given substance were based on Hakanson's methodology. The RI was obtained for each sampling site by summing the values of E r (i) first and the average was calculated across the sampling sites. The results showed that the RI for all three habitats was lower than 94, and they are in decreasing order: wastewater discharge, aquaculture and densely populated villages, and the least anthropogenic impacted. When the three sampling seasons were compared, August appeared to show the highest risk, followed by April and November. The RI values showed negative correlations (r = -0.444 to -0.851, p < 0.05) with the structural and functional metrics. The best correlation was detected between chlorophyll c/chlorophyll a (Chl c/a) ratio and E r (i) Hg (r = -0.851, p < 0.01). Our results suggest the periphyton community can be used in bio-monitoring.

Based on the international standards about implantable pacemakers, designing the static magnetic field testing coil in accordance with the requirements of the standards. The testing result demonstrates that the designed coil could be used for the static magnetic field strength test of implantable pacemakers.

We describe a genetic transformation method of secondary somatic embryogenesis in alfalfa through cotyledon-stage somatic embryos of alfalfa infected by Agrobacterium strain GV3101. The Agrobacterium strain GV3101 contained binary vector pCAMBIA2301 that had gus gene as reporter and npt II gene as selectable marker. The infected primary embryos were induced through series of medium under 75 mg/L kanamycin selection. We obtained the transgenic alfalfa plants. Then, GUS expression in different tissue of transgenic alfalfa was tested by GUS histochemical analysis. Further, the stable integration and transformation efficiency were tested by polymerase chain reaction and Southern blotting hybridization. The result showed that GUS expression was different in different organs of transgenic alfalfa; the copy number of integrated npt II gene was from 1 to 4; the transformation efficiency via primary somatic embryogenesis was 65.82%.

This paper reveals the EMC quality situation of China's medical electrical equipment and the existing security risks in order to arouse the concerns of the government supervision departments, technical inspection units, the production enterprises and the users. It also serves as a reference when formulating related policies and measures.

Eutrophication is caused by hydrological, physical or chemical factors such as temperature, illumination, or shapes of waters. It is very important to identify the main factors to understand and control the process of eutrophication. In this paper, Beijing north circle water system was divided into river subsystem and lake subsystem by cluster analysis. Factor analysis indicated that the main factors of river subsystem eutrophication were TP, TN and NH4-N, while those for lake subsystem were TN and NH4-N, which meant that in the study area, the main cause for eutrophication was the overload of nutrients. Stepwise regression was introduced to build forecasting model, and the choice results of independent variables in the regression model inferred that the type of eutrophication in river subsystem was P limited, while that of lake was N limited. Two main causes for nutrient load were found from water quantity and quality analysis of the study area, one was the ecological water demands be not able to satisfy from 1990 to 1998 except 1998, and the other was the increase of nutrient load coming from domestic waste and non-point pollutant, resulting from the rapid population increase and city expansion. The measures to control the eutrophication process were put forward.