The desktop slot exhaust hood has been widely used, but it is calculated by empirical formula. Axial velocity change rule of desktop slot exhaust hood can effectively provide the basis of the wind ...speed needed in order to control the poison. According to gas motion mathematical model, the geometry model and boundary conditions of desktop slot exhaust hood was established, and the influence of the hood sizes to axial velocity were analyzed by Fluent simulation. The changes of relationship between the axial velocity (V) and the distance from the hood mouth (L), the short edge of the hood mouth (a), the long edge of the hood mouth (b), the equivalent diameter of the hood mouth (d) and the square root of the hood mouth area (√A) were comparative analyzed by dimensionless processing. The result is the V/V0 with L/d have better change rule. The axial velocity change rule of different axial velocity were also analyzed using V/V0 with L/d change rule, and the change rule of V/V0 with L/d of desktop slot exhaust hood was obtained, which was verified by experiment.
In recent years, the issue of invasive alien species brought on by ballast water has drawn increasing attention, and advances in ballast water treatment technologies have been made. One of the most ...popular combined ballast water treatment technologies utilized in ballast water management systems (BWMSs) globally is filtration + UV-C radiation. During the actual voyage of the ship, ballast water is treated by the BWMS and then enters the dark ballast tanks until the ballast water is discharged. Marine organisms are able to complete DNA damage caused by UV radiation in dark ballast tanks. Therefore, the length of holding time affects the effectiveness of the BWMS in treating ballast water. The objective of this study was to examine the efficacy of filtration + UV-C irradiation treatment at different holding times for the removal or inactivation of phytoplankton and zooplankton populations during simulated ballast water treatment. Results indicate that the holding time after the filtration + UV-C radiation treatment increased the inactivating efficacy, especially for zooplankton in natural seawater. For phytoplanktons in ballast water, the strongest impact on the treatment efficacy was reached with a holding time of 24 h.
This paper addresses the problem of joint carrier frequency offset (CFO) and channel estimation in multiuser multiple-input-multiple-output (MIMO) orthogonal frequency-division multiplexing (OFDM) ...systems. To choose the optimal training sequences with the goal of providing the smallest estimation mean square error (MSE), the asymptotic Cramer-Rao bounds (asCRBs) are derived. The optimal training sequences are designed that minimize the asCRBs for both CFO and channel estimation under the constraint that the asCRBs being channel independent. A joint CFO and channel estimator is derived based on the maximum likelihood (ML) criterion. A computationally efficient method using importance sampling technique is proposed to solve the highly demanding multidimensional exhaustive search required by the ML multi-CFO estimation. Simulation results illustrate the merits of the proposed training sequences and also verify the effectiveness of the proposed estimation scheme.
A multi-residue analysis of six diacylhydrazine insecticides in water, sediment, and aquatic products was established by liquid chromatography triple quadrupole tandem mass spectrometry (LC-MS/MS). ...The water sample was extracted with acetonitrile by low-temperature enrichment liquid-liquid extraction technology. The sediment and aquatic products were prepared using QuEChERS technique. Method validation showed perfect linearity with correlation coefficients (R) more than 0.9992 for all insecticides, and the matrix effects were nearly negligible (−1.42% to −0.27%) for water, sediment and aquatic products. The recoveries were 80.0–99.7% at three spiked levels (0.02 ng·mL−1, 0.1 ng·mL−1, 0.5 ng·mL−1; 2.0, 10, and 50 ng·g−1) and the precisions (intra-day and inter-day precision) were lower than 5.28%, with the low LODs (3.8 ~ 9.6 pg·mL−1; 0.38–0.96 ng·g−1) and LOQs (12.7 ~ 32.0 pg·mL−1; 1.27–3.20 ng·g−1) for water, sediment, and aquatic products, indicating the good accuracy and precision of the proposed method. The applicability, efficiency, and sensitivity of this method have been proved in the analysis of six diacylhydrazine insecticides in water, sediment, and crucian carp in Rice- crucian carp - integrated planting system.
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•A multi-residue analysis of six diacylhydrazine insecticides in water, sediment, and aquatic products was established by HPLC-MS/MS for the first time.•The water sample was extracted with acetonitrile by low-temperature enrichment liquid-liquid extraction technology.•The sediment and aquatic products were prepared using modified QuEChERS technique.•Method validation showed perfect linearity, recovery, accuracy, precision, and sensitivity.•The application of the method validation exhibited excellent results in water, sediment, and crucian carp in Rice- crucian carp - integrated planting system.
Clostridial neurotoxins, including tetanus and botulinum neurotoxins, generally target vertebrates. We show here that this family of toxins has a much broader host spectrum, by identifying PMP1, a ...clostridial-like neurotoxin that selectively targets anopheline mosquitoes. Isolation of PMP1 from Paraclostridium bifermentans strains collected in anopheline endemic areas on two continents indicates it is widely distributed. The toxin likely evolved from an ancestral form that targets the nervous system of similar organisms, using a common mechanism that disrupts SNARE-mediated exocytosis. It cleaves the mosquito syntaxin and employs a unique receptor recognition strategy. Our research has an important impact on the study of the evolution of clostridial neurotoxins and provides the basis for the use of P. bifermentans strains and PMP1 as innovative, environmentally friendly approaches to reduce malaria through anopheline control.
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•Interactions of 3 pheasants were studied using a new model based on long-term data.•And considered habitat filtering and indirect species interactions together.•Both positive and ...negative interactions existed among 3 pheasants.•Species interactions varied with habitat heterogeneity and stress levels in 11 years.
As the lack of a general understanding of how interspecific interactions change along varying environmental gradients exists, predicting the response of ecological communities to habitat and climate change becomes an arduous task. Researchers generally assess interspecific interactions by investigating species co-occurrence patterns. However, habitat filtering and indirect interspecific interactions can interfere with interspecific interaction signals in co-occurrence data, and these two factors have rarely been considered jointly in previous studies. By using the Markov random fields model which can control the indirect interaction, based on the 11-year co-occurrence data, we analyzed the effects of environmental factors on the interaction of three sympatric pheasant species (Chinese Bamboo Partridge Bambusicola thoracicus, Sichuan Hill Partridge Arborophila rufipectu, Temminck's Tragopan Tragopan temminckii) in Laojunshan National Nature Reserve, China. To eliminate the interference of habitat filtering, we took the environmental change during the 11-year period as the environmental variable instead of the environmental spatial gradient commonly used in previous studies. We found that the positive interaction increased with the increase of temperature, and decreased with the increase of precipitation, and with the increase of EVI heterogeneity, the positive interaction increased and the negative interaction decreased. The results are consistent with the predictions of habitat heterogeneity hypothesis and stress gradient hypothesis. Our study provides an idea for the follow-up studies of how to eliminate the interference of habitat filtering and indirect interaction in interspecific interaction analysis.
During the construction of tunnels subjected to high temperatures (here called high-temperature tunnels), ventilation cooling is an essential requirement. A high-temperature section of a construction ...tunnel on the Sichuan-Tibet Railway was used as a test case to study the heat exchange on both sides of the ventilation duct during active cooling. We used theoretical analysis and numerical simulation to establish a model for calculating the temperatures associated with the ventilation duct, and studied the influence of different factors on the convection heat exchange on the inside and outside the duct during the ventilation cooling process. According to simulation and field measurement results, the airflow temperature inside the duct rose with the distance from the inlet, and the temperature near the duct's wall was higher than the temperature in the center. After analyzing different influencing factors, it was found that duct material and thickness have little effect on the convection heat transfer inside the duct. But the convection heat transfer intensity would rise when the temperature difference between the inside and the outside of the duct increased, and the heat flux (q) through the wall increased by 1.5 W/m2. The average air temperature trend of the ventilation duct section was stable as the ventilation distance increased. It increased linearly as ventilation distance increased. While the effect of ventilation cooling gradually declined, and the overall temperature of the air of the tunnel rose when the ventilation distance increased. As a result, heat exchange along the duct should be fully considered in the design and application of the ventilation cooling process to ensure that the airflow temperature reaching the excavation face at the head of the tunnel meets the operational requirements.
Aedes cadherin (AaeCad, AAEL024535) has been characterized as a receptor for Bacillus thuringiensis subsp. israelensis (Bti) Cry11A toxins. However, its role in development is still unknown. In this ...study, we modified the cadherin gene using ZFN and TALEN. Even though we obtained heterozygous deletions, no homozygous mutants were viable. Because ZFN and TALEN have lower off-targets than CRISPR/Cas9, we conclude the cadherin gene is essential for Aedes development. In contrast, in lepidopteran insects loss of a homologous cadherin does not appear to be lethal, since homozygous mutants are viable. To analyze the role of AaeCad in vivo, we tagged this protein with EGFP using CRISPR-Cas9-mediated homologous recombination and obtained a homozygous AaeCad-EGFP line. Addition of Aedes Rad51 mRNA enhanced the rate of recombination. We then examined AaeCad protein expression in most tissues and protein dynamics during mosquito development. We observe that AaeCad is expressed in larval and adult midgut-specific manner and its expression pattern changed during the mosquito development. Confocal images showed AaeCad has high expression in larval caecae and posterior midgut, and also in adult midgut. Expression of AaeCad is observed primarily in the apical membranes of epithelial cells, and not in cell-cell junctions. The expression pattern observed suggests AaeCad does not appear to play a role in these junctions. However, we cannot exclude its role beyond cell-cell adhesion in the midgut. We also observed that Cry11A bound to the apical side of larval gastric caecae and posterior midgut cells exactly where AaeCad-EGFP was expressed. Their co-localization suggests that AaeCad is indeed a receptor for the Cry11A toxin. Using this mosquito line we also observed that low doses of Cry11A toxin caused the cells to slough off membranes, which likely represents a defense mechanism, to limit cell damage from Cry11A toxin pores formed in the cell membrane.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The method of flow ratio
is often used for designing parallel push-pull ventilation. The
value is mostly selected empirically and is difficult to determine accurately, resulting in an imprecise ...design of the push-pull ventilation system. Therefore, parallel push-pull ventilation was taken as the research object in this paper. The push-pull ventilation studied consists of a square uniform supply hood and a square uniform exhaust hood, and the side length of pull hood and pull hood was same. A workbench was set between the push hood and pull hood, and the source of toluene pollutions was set in the center of the worktable surface. The optimal
values for different distances between push hood and pull hood were studied by numerical simulation using Ansys Fluent, which were obtained base on the distribution of wind speed and toluene concentration. The results showed that parallel push-pull ventilation is not suitable for applications when
/
≥ 6. The changing patterns of
value with
/
is proposed in the range of 1.5 ≤
/
≤ 5 for the parallel square push-pull ventilation, which can be used to estimate
value relatively accurately under the condition that
/
is known, so as to guide the determination of the exhaust air volume of the parallel push-pull ventilation system.
Solution-processed organic‒inorganic halide perovskite (OIHP) single crystals (SCs) have demonstrated great potential in ionizing radiation detection due to their outstanding charge transport ...properties and low-cost preparation. However, the energy resolution (ER) and stability of OIHP detectors still lag far behind those of melt-grown inorganic perovskite and commercial CdZnTe counterparts due to the absence of detector-grade high-quality OIHP SCs. Here, we reveal that the crystallinity and uniformity of OIHP SCs are drastically improved by relieving interfacial stress with a facial gel-confined solution growth strategy, thus enabling the direct preparation of large-area detector-grade SC wafers up to 4 cm with drastically suppressed electronic and ionic defects. The resultant radiation detectors show both a small dark current below 1 nA and excellent baseline stability of 4.0 × 10
nA cm
s
V
, which are rarely realized in OIHP detectors. Consequently, a record high ER of 4.9% at 59.5 keV is achieved under a standard
Am gamma-ray source with an ultralow operating bias of 5 V, representing the best gamma-ray spectroscopy performance among all solution-processed semiconductor radiation detectors ever reported.
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