Regulated emission characteristics of in-use LNG and diesel semi-trailer towing vehicles under real driving conditions using PEMS

On-road driving emissions of six liquefied natural gas(LNG) and diesel semi-trailer towing vehicles(STTVs) which met China Emission Standard IV and V were tested using Portable Emission Measurement System(PEMS) in northern China.Emission characteristics of these vehicles under real driving conditions were analyzed and proved that on-road emissions of heavy-duty vehicles(HDVs) were underestimated in the past.There were large differences among LNG and diesel vehicles, which also existed between China V vehicles and China IV vehicles.Emission factors showed the highest level under real driving conditions, which probably be caused by frequent acceleration, deceleration, and start-stop.NOx emission factors ranged from 2.855 to 20.939 g/km based on distance-traveled and 6.719–90.557 g/kg based on fuel consumption during whole tests, which were much higher than previous researches on chassis dynamometer.It was inferred from tests that the fuel consumption rate of the test vehicles had a strong correlation with NOx emission, and the exhaust temperature also affected the efficiency of Selected Catalytic Reduction(SCR) aftertreatment system, thus changing the NOx emission greatly.THC emission factors of LNG vehicles were 2.012–10.636 g/km, which were much higher than that of diesel vehicles(0.029–0.185 g/km).Unburned CH4 may be an important reason for this phenomenon.Further on-road emission tests, especially CH4 emission test should be carried out in subsequent research.In addition, the Particulate Number(PN) emission factors of diesel vehicles were at a very high level during whole tests, and Diesel Particulate Filter(DPF)should be installed to reduce PN emission.

Emission characteristics of offshore fishing ships in the Yellow Bo Sea, China

Maritime transport has been playing a decisive role in global trade. Its contribution to the air pollution of the sea and coastal areas has been widely recognized. The air pollutant emission inventories of several harbors in China have already been established. However,the emission factors of local ships have not been addressed comprehensively, and thus are lacking from the emission inventories. In this study, on-board emission tests of eight diesel-powered offshore fishing ships were conducted near the coastal region of the northern Yellow Bo Sea fishing ground of Dalian, China. Results show that large amounts of fine particles（ 0.5 μm, 90%） were found in maneuvering mode, which were about five times higher than those during cruise mode. Emission rates as well as emission factors based on both distance and fuel were determined during the cruise and maneuvering modes（including departure and arrival）. Average emission rates and distance-based emission factors of CO, HC and PM were much higher during the maneuvering mode as compared with the cruise mode. However, the average emission rate of Nitrous Oxide（NOx） was higher during the cruise mode as compared with the maneuvering modes. On the contrary, the average distance-based emission factors of NOxwere lower during the cruise mode relative to the maneuvering mode due to the low sailing speed of the latter.

Natural variations in grain length 10(GL10)regulate rice grain size

Grain size is an important determinant of grain weight and yield in rice.Although several genes related to grain size have been identified,natural variations in these genes that affect grain size are poorly characterized.Here,we describe the grain length QTL GL10,encoding MADS56,which positively regulates grain length and grain weight.A natural allelic variation of NIL-gl10,containing an~1.0-kb deletion in the first exon that abolishes its transcription,results in shorter grain length,lower grain weight and delayed flowering in gl10 plants.The knockout of GL10 in the HJX74 background leads to grain phenotypes similar to that of NIL-gl10,while overexpression of GL10 results in increased grain length and weight and earlier heading date.GL10 regulates grain length by promoting greater longitudinal cell growth in the grain glume.Additionally,GL10 participates in the regulation of gibberellic acid(GA)signaling pathway genes in young panicle tissues.Analysis of GL10 haplotypes shows obvious divergence between the japonica and indica lineages.Our findings reveal an allelic variation of GL10 that may explain differences in grain length among modern cultivars and could be used to breed rice varieties with optimized grain shape.

Seasonal variations of soil bacterial communities in Suaeda wetland of Shuangtaizi River estuary, Northeast China

Estuarine wetland is the transitional interface linking terrestrial with marine ecosystems,and wetland microbes are crucial to the biogeochemical cycles of nutrients.The soil samples were collected in four seasons(spring,S1;summer,S2;autumn,S3;and winter,S4)from Suaeda wetland of Shuangtaizi River estuary,Northeast China,and the variations of bacterial community were evaluated by high-throughput sequencing.Soil properties presented a significant seasonal change,including p H,carbon(C)and total nitrogen(TN),and the microbial diversity,richness and structure also differed with seasons.Canonical correspondence analysis(CCA)and Mantel tests implied that soil p H,C and TN were the key factors structuring the microbial community.Gillisia(belonging to Bacteroidetes)and Woeseia(affiliating with Gammaproteobacteria)were the two primary components in the rhizosphere soils,displaying opposite variations with seasons.Based on PICRUSt(Phylogenetic Investigation of Communities by Reconstruction of Unobserved States)prediction,the xenobiotics biodegradation related genes exhibited a seasonal decline,while the majority of biomarker genes involved in nitrogen cycle showed an ascending trend.These findings could advance the understanding of rhizosphere microbiota of Suaeda in estuarine wetland.

Carbonyl emissions from heavy-duty diesel vehicle exhaust in China and the contribution to ozone formation potential

Fifteen heavy-duty diesel vehicles were tested on chassis dynamometer by using typical heavy duty driving cycle and fuel economy cycle. The air from the exhaust was sampled by 2,4- dinitrophenyhydrazine cartridge and 23 carbonyl compounds were analyzed by high performance liquid chromatography. The average emission factor of carbonyls was 97.2 mg/km, higher than that of light-duty diesel vehicles and gasoline-powered vehicles. Formaldehyde, acetaldehyde, acetone and propionaidehyde were the species with the highest emission factors. Main influencing factors for carbonyl emissions were vehicle type, average speed and regulated emission standard, and the impact of vehicle loading was not evident in this study. National emission of carbonyls from diesel vehicles exhaust was calculated for China, 2011, based on both vehicle miles traveled and fuel consumption. Carbonyl emission of diesel vehicle was estimated to be 45.8 Gg, and was comparable to gasolinepowered vehicles （58.4 Gg）. The emissions of formaldehyde, acetaldehyde and acetone were 12.6, 6.9, 3.8 Gg, respectively. The ozone formation potential of carbonyls from diesel vehicles exhaust was 537 mg O3/km, higher than 497 mg O3/km of none-methane hydrocarbons emitted from diesel vehicles.

Decoding and calibration method on focused plenoptic camera

The ability of light gathering of plenoptic camera opens up new opportunities for a wide range of computer vision applications. An efficient and accurate method to calibrate plenoptic camera is crucial for its development. This paper describes a 10-intrinsic-parameter model for focused plenoptic camera with misalignment. By exploiting the relationship between the raw image features and the depth–scale information in the scene, we propose to estimate the intrinsic parameters from raw images directly,with a parallel biplanar board which provides depth prior. The proposed method enables an accurate decoding of light field on both angular and positional information, and guarantees a unique solution for the 10 intrinsic parameters in geometry. Experiments on both simulation and real scene data validate the performance of the proposed calibration method.

Optical fiber amplifiers for space-division multiplexing

最近，空间部门 multiplexing (SDM ) 技术使用多核心纤维(MCF ) 和很少模式纤维(FMF ) 被介绍了进光纤维通讯增加传播能力。光纤维放大器的二种主要类型基于 Erbiumdoped 纤维(EDF ) 和拉曼效果被开发了在 MCF 和 FMF 放大信号。在这份报纸，我们考察了这些放大器的原则和配置。

Same impact momentum causes different degrees of spinal cord injury

The weight-drop impact is widely used in making animal model of spinal cord injury(SCI).But there has not yet been an appropriate unit for the quantification of the impact.In this study,we compared the degrees of the spinal cord injury caused by weight-drop impact with the same momentum but different combinations of drop weight and drop height,in order to test whether‘‘momentum’’is capable of being the unit for the quantification of weightdrop impact.Thirty adult rats were randomly allocated to three groups and were injured with 5 g–10 cm(group A),10 g–2.5 cm(group B)and 15 g–1.11 cm(group C)impacts with the same momentum to the spinal cord,respectively.Open-field locomotor function was evaluated using the Basso–Beattie–Bresnahan(BBB)locomotor rating scale.The percentage of spared tissue area(STA)at the epicenter,and 500,1000 and 1500 lm from the epicenter was calculated using serial sections stained by hematoxylin and eosin.As a result,the behavioral recovery(BBB scores)and the STA percentage were similar in group B and group C.However,the BBB score in group A was significantly lower than that in groups B and C at the same time point post injury.The STA percentage was significantly less and the lesion/cavity length was significantlygreater in group A than in groups B and C.These suggested that the 5 g–10 cm weight-drop impact,compared with the other two impacts with different weights and heights,caused a greater damage of the spinal cord when the momentum was the same.So,these impacts with the same momentum but different weights and drop heights cause different degrees of spinal cord injury.Momentum alone is inadequate to be the unit for the qualification of weightdrop impact and to be used to predict the extent of injury.

Quick fabrication of aeronautical complicated structural parts based on stereolithography

Investment casting based on stereolithography(SL)has the characteristics of short production cycle and low cost,which is especially suitable for fabricating complex aeronautical parts without metal dies.But there are some problems during the fabrication process,such as low surface accuracy caused by the staircases of resin prototype,shell cracking caused by higher thermal stress during the sintering process and so on.Taking an engine turbine stator as a fabrication example,the surface accuracy of resin prototype under the effect of coating method was investigated using the laser confocal microscopy;what’s more,both theoretical analysis and finite element analysis(FEA)were combined and compared to reveal the thermal stress field of ceramic shell during pyrolyzing and sintering process under different situation.It was founded that the surface staircases of the resin prototype was eliminated and the surface quality was improved after coating process,the thermal stress was decreased and shell cracking was avoided by sintering the ceramic shell with the inner hollow resin prototype under the heating rate of 51C/min.The result showed that,the metal turbine stator had high dimensional accuracy of CT4-CT6 and had a good surface finish within Ra 3.2.

Multi-UAV Collaborative Edge Computing Algorithm for Joint Task Offloading and Channel Resource Allocation

Unmanned aerial vehicle (UAV)-based edge computing is an emerging technology that provides fast task processing for a wider area. To address the issues of limited computation resource of a single UAV and finite communication resource in multi-UAV networks, this paper joints consideration of task offloading and wireless channel allocation on a collaborative multi-UAV computing network, where a high altitude platform station (HAPS)is adopted as the relay device for communication between UAV clusters consisting of UAV cluster heads (ch-UAVs) and mission UAVs (m-UAVs). We propose an algorithm, jointing task offloading and wireless channel allocation to maximize the average service success rate (ASSR)of a period time. In particular,the simulated annealing(SA)algorithm with random perturbations is used for optimal channel allocation,aiming to reduce interference and minimize transmission delay.A multi-agent deep deterministic policy gradient (MADDPG) is proposed to get the best task offloading strategy. Simulation results demonstrate the effectiveness of the SA algorithm in channel allocation. Meanwhile,when jointly considering computation and channel resources,the proposed scheme effectively enhances the ASSR in comparison to other benchmark algorithms.