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Previous surface topography prediction models for external spline shaping do not consider the relationship between the tool and workpiece geometry and cutter edge wear. In this work, by considering the tool–workpiece geometry correlation, a model for the tooth surface topography of the external spline is established based on the micro-element method. Combined with adhere model, a gear shaper wear model is founded on the wear mechanism of cutter edge micro-element derived from the abrasive wear mechanism. The distribution characteristics of tooth topography are analysed through an external spline shaping experiment, which verifies the validity of the presented model. For the uneven distribution of tooth surface topography, a shaping process optimisation algorithm is proposed based on the advance-and-retreat method, which can obtain tooth surfaces with uniform surface topography distribution and reduce tool wear. This work can guide the optimisation of the external spline shaping process, improve the integrity of the tooth surface and prolong the serviceable life of gear shaper.

This study aims to: (1) evaluate the concentration distribution of particulate matter in the Guangzhou metro system; (2) Compare particulate matter concentrations under different conditions, including time, season, location, subway lines, and sampling height; (3) Compare the concentrations with existing research and propose future improvement measures. The analysis showed that spatial factors were significantly correlated with the particulate matter concentration. We also identified the stratification of PM10at various heights in both carriages and platforms, with a more notable effect observed in carriages. The PM10average concentration at 80cm is 14 % higher than at 120cm and 13 % higher than at 150cm. We suggest mitigation measures for particulate matter in both carriage and platform environments.

With the development of convolutional neural networks (CNNs), their high computational complexity and energy consumption become significant problems. Many CNN inference accelerators are proposed to reduce the consumption. Most of them are based on 32-bit float-point matrix multiplication, where the data precision is over-provisioned. This paper presents Laius, an 8-bit fixed-point LeNet inference engine implemented on FPGA. To achieve low-precision computation and storage, we introduce our fixed-point training framework called FixCaffe. To economise FPGA resources, we proposed a methodology to find the optimal bit-length for weight and bias in LeNet. We use optimisations of pipelining, tiling, and theoretical analysis to improve the performance. Experiment results show that Laius achieves 44.9 Gops throughputs. Moreover, with only 1% accuracy loss, 8-bit Laius largely reduces 31.43% in delay, 87.01% in LUT consumption, 66.50% in BRAM consumption, 65.11% in DSP consumption and 47.95% in power compared to the 32-bit version with the same structure.

This paper reports our developments for Micro LED laser lift‐off which is a very important step in Micro LED mass transfer process. By selecting the temporary bonding material, optimizing laser power intensity and other process parameters, the yield of Micro LED laser lift‐off can reach 99.87% for more than 1500 LEDs. This technical developments is of great potential for promoting high‐yield mass transfer technology to realize commercial Micro‐LED displays.

This paper reports our developments for Micro LED laser lift‐off which is a very important step in Micro LED mass transfer process. By selecting the temporary bonding material, optimizing laser power intensity, and using PSS structure, the yield of Micro LED laser lift‐off can reach 99% for more than 5000 LEDs. This technical developments is of great potential for promoting high‐yield mass transfer technology to realize commercial Micro‐LED displays.

This paper reports our developments for Micro LED laser lift‐off which is a very important step in Micro LED mass transfer process. By selecting the temporary bonding material, optimizing laser power intensity and other process parameters, the yield of Micro LED laser lift‐off can reach 99.87% for more than 1500 LEDs. This technical developments is of great potential for promoting high‐yield mass transfer technology to realize commercial Micro‐LED displays.

As natural gas exploration expands to deep, ultra-deep and unconventional areas, more and more complex exploration targets are encountered. In this circumstance, it is necessary to improve the existing basic natural gas geological theories for guiding the exploration and discovery of more giant gas fields. In this paper, the researches on basic natural gas geological theories since the beginning of the 12th Five-Year Plan were engaged, and then the key exploration target zones were analyzed. Some results were obtained. (1) The theory of whole-process hydrocarbon generation of organic matters was improved and the geologic theories of organic matter hydrocarbon generation (e.g. the thermal evolution model of kerogen degradation and the successive gas generation of organic matters) were developed. (2) Multi-element natural gas genesis identification method, quantitative evaluation method for different types of seals/caprocks, tight sandstone gas accumulation theory for low hydrocarbon generation intensity region, and hydrocarbon accumulation theory for giant ancient carbonate gas field were established, and the geological theories of gas generation, genesis identification and hydrocarbon accumulation were developed to provide the effective guidance for the exploration breakthrough and discovery of giant gas fields in the key basins of China recently. Four conclusions were reached: (1) ancient carbonate rock, tight sandstone, foreland region, shale and volcanic rock are primary exploration targets for discovering giant gas fields; (2) craton and foreland basins are still the key exploration areas, and ancient uplift, gentle slope and thrust belt are the main enrichment zones; (3) ancient strata and deep formations are critical gas exploration targets in the future; (4) oil cracking gas in marine basins, tight sandstone gas and shale gas are the important replacement resources for future gas reserves and production growth.

Epileptic networks are characterized by two states, seizures or more prolonged interictal periods. Here, we present the procedure for labeling seizure-activated and interictal-activated neuronal ensembles in mouse hippocampal kindling model using an enhanced-synaptic-activity-responsive element. We describe the seizure model establishment, tamoxifen induction, electrical stimulation, and calcium signal recording of labeled ensembles. This protocol has demonstrated dissociated calcium activities in the two ensembles during focal seizure dynamics and can be applied to other animal models of epilepsy.

A novel trizine ring-based phosphorus–nitrogen flame retardant, 1,3,5-tris(3-(diphenylphosphoryl)propyl)-1,3,5-triazinane-2,4,6-trione (PN), was synthesized by the reaction of diphenylphosphine oxide and triallyl isocyanurate with triethylborane as catalyst. Chemical structure of the target compound was confirmed by Flourier transform infrared spectrum, nuclear magnetic resonances, matrix-assisted laser desorption/ionization time-of-flight mass spectrum measurements. The newly developed PN was used in the flame retardancy of o-cresol novolac epoxy/phenolic novolac hardener system. For comparison, another analogous phosphorus–silicon flame retardant, [(1,1,3,3-tetramethyl-1,3-disiloxanediyl)-di-2,1-ethanediyl]-bis(diphenylphosphine oxide) (PSi), was also applied in the same system. Experimental results revealed that PN showed superior flame retardant efficiency to that of PSi. In addition, the incorporation of flame retardants was in favor of the char formation during the thermal degradation process of epoxy thermosets. With the same flame retardant content, the char residue of epoxy thermosets with PSi was higher than that of epoxy thermosets with PN at 750 °C. Cone calorimeter results indicated that PN contributed to gas phase flame retardancy while PSi was more likely to take part in flame retardancy in the condense phase. X-ray photoelectron spectroscopy data revealed that the binding energies of phosphorus changed in different ways in PN and PSi after combustion. This implied that phosphorus exhibited different combustion behaviors when combined with nitrogen or silicon.

Retracted.

Epileptic networks are characterized as having two states, seizures or more prolonged interictal periods. However, cellular mechanisms underlying the contribution of interictal periods to ictal events remain unclear. Here, we use an activity-dependent labeling technique combined with genetically encoded effectors to characterize and manipulate neuronal ensembles recruited by focal seizures (FS-Ens) and interictal periods (IP-Ens) in piriform cortex, a region that plays a key role in seizure generation. Ca2+activities and histological evidence reveal a disjointed correlation between the two ensembles during FS dynamics. Optogenetic activation of FS-Ens promotes further seizure development, while IP-Ens protects against it. Interestingly, both ensembles are functionally involved in generalized seizures (GS) due to circuit rearrangement. IP-Ens bidirectionally modulates FS but not GS by controlling coherence with hippocampus. This study indicates that the interictal state may represent a seizure-preventing environment, and the interictal-activated ensemble may serve as a potential therapeutic target for epilepsy.

In many cities, the building envelope is deteriorating and aging. Understanding the defect characteristics of the envelope is essential to increasing the safety of the house and reducing the loss of energy. A 3-day infrared thermography (IRT) experiment was conducted on 5 buildings (11 rooms) in an urban village in Guangzhou, China. The analysis includes qualitative analysis and quantitative analysis. In qualitative analysis, three types of building defects were found, namely, conduction thermal defects, ventilation defects and moisture. In terms of quantitative analysis, (1) an improved temperature factor framework (ITF) is proposed to evaluate conduction thermal defects, (2) the influence of different influencing factors on the thermal performance of the building envelope is analyzed. Qualitative analysis results showed that conduction thermal defects were the most common thermal defects in Nanting Village and occurred 28 times in five residential buildings. It is mainly distributed in the joints of different walls and the joints of walls and other structures. Ventilation defects and moisture were the other two causes of envelope defects. Quantitative analysis showed that orientation has an important effect on thermal defects. The temperature distribution of walls at different heights is different to some extent. Thermal bridges are more likely to occur on extended floors built on the original building.

An atomically resolved study of an adsorbate photoreaction on the surface of an isolated TiO2nanocrystal is reported. The crystal is grown in situon Au(111) in an ultrahigh-vacuum chamber. The experiments use scanning tunneling microscopy (STM) backed by temperature-programmed desorption (TPD) to determine the surface coverage of trimethylacetic acid (TMAA) on the nanocrystal surfaces before and after irradiation with monochromated 305 nm UV light. A detailed determination of the surface structure of the 1–3 nm thick and 10–30 nm wide nanocrystals is presented and the importance of moiré effects in controlling the reaction sites shown. The normalized TMAA photodesorption quantum efficiency from Au-supported TiO2nanocrystals was found to be ∼4 times lower compared to the same reaction on rutile TiO2(110) surface, a result consistent with the lower fraction of light adsorbed in the nanocrystals.

Oil-cracked gas, as the main type of high-over mature marine natural gas in China, is mainly derived from occluded hydrocarbon. So it is significant to carry out quantitative study on occluded hydrocarbon. In this paper, the occluded hydrocarbon volume of the main basins in China was calculated depending on their types, abundances and evolution stages by means of the forward method (experimental simulation) and the inversion method (geologic profile dissection). And then, occluded hydrocarbon evolution models were established for five types of source rocks (sapropelic, sapropelic prone hybrid, humic prone hybrid, humic and coal). It is shown that the hydrocarbon expulsion efficiency of sapropelic and sapropelic prone hybrid excellent source rocks is lower than 30% at the low-maturity stage, 30%–60% at the principal oil generation stage, and 50%–80% at the high-maturity stage, which are all about 10% higher than that of humic prone hybrid and humic source rocks at the corresponding stages. The resource distribution and cracked gas expulsion of occluded hydrocarbon since the high-maturity stage of marine source rocks in the Sichuan Basin were preliminarily calculated on the basis of the evolution models. The cracked gas expulsion is 230.4 × 1012 m3at the high evolution stage of occluded hydrocarbon of the Lower Cambrian Qiongzhusi Fm in this basin, and 12.3 × 1012 m3from the source rocks of Sinian Doushantuo Fm, indicating good potential for natural gas resources. It is indicated that the favorable areas of occluded hydrocarbon cracked gas in the Qiongzhusi Fm source rocks in the Sichuan Basin include Gaoshiti–Moxi, Ziyang and Weiyuan, covering a favorable area of 4.3 × 104 km2.

The application of elastic lattice strain is a promising approach for tuning material properties, but the attainment of a systematic approach for introducing a high level of strain in materials so as to study its effects has been a major challenge. Here we create an array of intense locally varying strain fields on a TiO2(110) surface by introducing highly pressurized argon nanoclusters at 6–20 monolayers under the surface. By combining scanning tunneling microscopy imaging and the continuum mechanics model, we show that strain causes the surface bridge-bonded oxygen vacancies (BBOv), which are typically present on this surface, to be absent from the strained area and generates defect-free regions. In addition, we find that the adsorption energy of hydrogen binding to oxygen (BBO) is significantly altered by local lattice strain. In particular, the adsorption energy of hydrogen on BBO rows is reduced by ∼35 meV when the local crystal lattice is compressed by ∼1.3%. Our results provide direct evidence of the influence of strain on atomic-scale surface chemical properties, and such effects may help guide future research in catalysis materials design.

We report an experimental and theoretical investigation of the decomposition (partial oxidation) of deuterated methanol (CD3OD) on a single-crystal Fe3O4(111) surface. The crystal surface contains majority areas of a Fe-terminated Fe3O4(111) surface as well as smaller regions of O-terminated FeO(111) or biphase surface reconstruction. Our investigation uses a combination of scanning tunneling microscopy, temperature-programmed desorption, and density functional theory calculations to examine the surface reactions and adsorbates as a function of coverage. Our studies show that the reaction of methanol on this iron–oxide surface is highly sensitive to atomic-level surface reconstructions.

Surface phenomena: Measurements of absolute probabilities are reported for the vibrational excitation of NO(v=0→1,2) molecules scattered from a Au(111) surface. These measurements were quantitatively compared to calculations based on ab initio theoretical approaches to electronically nonadiabatic molecule–surface interactions. Good agreement was found between theory and experiment (see picture; Ts=surface temperature, P=excitation probability, and E=incidence energy of translation).

Absolute Wahrscheinlichkeitenfür die Schwingungsanregung von an einer Au(111)‐Oberfläche gestreuten NO(v=0→1,2)‐Molekülen wurden gemessen. Die Messungen wurden mit Berechnungen, die auf Ab‐initio‐Theorien zur Beschreibung der elektronisch nichtadiabatischen Wechselwirkungen zwischen Molekül und Oberfläche beruhen, verglichen. Theorie und Experiment stimmten gut überein (siehe Bild; Ts=Oberflächentemperatur, P=Anregungswahrscheinlichkeit und E=Stoßenergie).

We have studied the adsorption and tip-induced chemistry of 2-chloroanthracene on TiO2(110). STM images show that at 135 K and low coverage, i.e., ∼0.1 ML, these molecules are physisorbed along the five-coordinated titanium rows on the rutile(110) surface as a result of electrostatic interaction. Applying electric pulses >2.5 V from the STM tip to individual molecules causes either desorption or dissociation of the molecules, as indicated by the changes in the STM images. We have observed dissociative electron capture of a single 2-chloroanthracene molecule, which leaves behind a surface chlorine atom adsorbed in the on-top configuration on a surface Ti atom. The threshold energy required for the dissociation was found to be ∼2.7 eV.

Abstract: The light hydrocarbon geochemical characteristics of biogenic gases from Sebei 1 gas field in the Qaidam Basin, Baoshan gas field in the Baoshan Basin and Alaxin gas field, Puqian gas pool, Aonan gas pool in the Songliao Basin are studied and the origin is discussed based on the composition and isotope data of gases. The isoalkane contents among light hydrocarbons in natural gas show a negative relationship with δ13C1 values. The isoalkane contents of the gases with δ13C1 values of less than −60‰ are also high with more than 40% among light hydrocarbons in Sebei 1 gas field and Puqian gas pool. Moreover, the 2,2-dimethylbutane and 2-methylpentane, mainly sourced from bacteria, have predominance among isoalkanes, which suggests that light hydrocarbons in biogenic gases from these gas fields or pools were probably generated by microbial action. However, the cycloalkane contents among light hydrocarbons in biogenic gas are related to δ13C1 values positively. In Alaxin gas field and Aonan gas pool, where δ13C1 values of biogenic gases are less than −60‰, the average contents of cycloalkane are higher than 44%. Light hydrocarbons among biogenic gases from these gas fields were probably generated by catalysis. The isoalkane and cycloalkane contents among light hydrocarbons from biogenic gases in the Baoshan gas field are both high, which might be generated by these two actions. The results show that the data of light hydrocarbons in biogenic gas can provide important information for understanding the generation mechanisms of light hydrocarbons during geological evolution and identifying biogenic gas and low mature gas.

The Qinshui Basin is an important favorable locale for Coalbed Methane (CBM) exploration and development in China. The Qinshui coalbed methane field was discovered in the southeastern part of the basin. We have carried out an experiment of canister desorption of methane from two fresh coal samples collected from two wells of the field. The experimental results indicate that the coal desorption rate in the area is high, the amount of desorbed gas may reach 60%–85% of the total amount of desorbed gas over 96 hours of desorption, and the whole desorption process was practically ended in 720 hours. The amount of desorbed gas is more than 18 m3/t on average. The fractionation of carbon isotope occurs during the process of canister desorption, and the change in δ13C1 values in methane appears to be linearly related to the desorption rates. According to this linear correlation and regularly monitoring the change in δ13C1 values in the process of coalbed gas production, we can deduce the desorption rates of coalbed methane from the gas field and forecast the recovery percentage and production life. Based on the change in δ13C1 values during the trial production in A1 and A1-3 wells, it is deduced that the produced coal gas probably is mainly free gas coming from fissures in the coal. This demonstrates that the stable yielding quality of CBM is good and the exploration potential of coalbed methane in this basin is high.