用AVP300型烟支自动通气度仪测定滤嘴棒吸阻

通过对英国菲尔创纳(Filtrona)仪器及自动化有限公司生产的AVP300型烟支自动通气度仪的分析和大量的实验,对仪器进行了局部技术处理,使之所测滤棒吸阻的数据与LJY-1型滤棒压降仪测定的数据基本相同。

鼻腔通气度检测的研究进展

很早以前,人们就已经注意到研究鼻腔通气功能的重要性,并随之研究出多种测量鼻腔通气度的方法,这在很大程度上促进了鼻科学的发展。目前,新的检测方法不断出现,虽各有优点,但仍有不足。现对鼻腔通气度检测的研究进展概述如下。 1 检测流量的方法 早在1882年Paulsen等撰写了许多关于鼻腔气流的著作。其后Zwaardemaker(1889)和Glatzel(1903)先后采用带有刻度的金属板置于鼻孔之前,根据呼出气流中水蒸气在金属板上凝集范围的大小和时间来判断鼻腔通气度。Heetderks(1927)

混凝土屋面聚氨酯通气缓冲施工方法及其防水层性能试验

混凝土屋面防水维修时,如不拆除原防水层而采用聚氨酯防水涂料外露工法,易出现涂膜防水层起鼓发泡等现象。本文提出了自粘通气施工方法,利用自粘通气垫层作通气缓冲层,做成的聚氨酯外露防水层适合各种气温和湿度条件下的现场施工,是目前外露防水翻修工程的理想选择之一。

Sea Surface Temperature Simulation of Tropical and North Pacific Basins Using a Hybrid Coordinate Ocean Model (HYCOM)

A Hybrid Coordinate Ocean Model （HYCOM） is used to simulate the sea surface temperature of the Tropical and North Pacific. Based on the different combinations of two air-Sea flux data sets （COADS and ECMWF） and two bulk parameter formulas （non-constant and constant）, four numerical experiments are carried out. The following conclusions can be deduced from the numerical results. （1） The numerical results using non-constant bulk parameter formula are much better than those using constant one. In the Pacific area from 40°N to 20°S, the annual average SST obtained from the experiment using non-constant bulk parameter formula is 0.21 ℃ higher than that from the satellite-based SST climatology （the pathfinder data）. However, the difference is 0.63 ℃ for the experiment when the using constant one. （2） HYCOM successfully simulates the monthly variation of climatological SST in tropical and north Pacific basins and monthly spatial variation of Western Pacific Warm Pool. Especially in the Pacific area from 40°N to 20°S, the difference of the seasonal averaged SST between pathfinder data and the result of experiment 2 （using COADS data set and non-constant bulk parameter formula） is only about 0.02 ℃. （3）The simulation results using different Air-Sea flux data are different and the difference is very large in some regions. In the northwest of the model region, the annual average SST obtained from experiment 2 （using COADS data set） is 1℃ higher than that obtained from experiment 4 （using ECMWF data set）. Contrarily, the result of experiment 4 is 1 ℃ larger than that of experiment 2 in the southeast of the model region. The largest difference is about 4 ℃ occurred near the area of 58°N, 140°E and the Bohai sea.

机械深耕的优越性

机械深耕就是利用深耕犁进行耕地作业,将耕深由原来常规耕作深度逐年加深,以打破犁底层,提高土壤的通透性能。改善作物根系下扎的条件,促进作物生长发育,达到增产增收的效果。现在大部分土地连年施用化学肥料,有机肥减少,秸秆还田机械化技术还不能普及,造成土壤板结,直接影响作物的丰产丰收。实施机械化深耕,便能克服这一弊病,其优越性如下: 一、能够打破犁底层。

Analysis of atmospheric turbulence in the upper layers of sea fog

Atmospheric turbulence plays a vital role in the formation and dissipation of fog. However,studies of such turbulence are typically limited to observations with ultrasonic anemometers less than 100 m above ground. Thus,the turbulence characteristics of upper fog layers are poorly known. In this paper,we present 4-layers of data,measured by ultrasonic anemometers on a wind tower about 400 m above the sea surface; we use these data to characterize atmospheric turbulence atop a heavy sea fog. Large differences in turbulence during the sea fog episode were recorded. Results showed that the kinetic energy,momentum flux,and sensible heat flux of turbulence increased rapidly during the onset of fog. After onset,high turbulence was observed within the uppermost fog layer. As long as this turbulence did not exceed a critical threshold,it was crucial to enhancing the cooling rate,and maintaining the fog. Vertical momentum flux and sensible heat flux generated by this turbulence weakened wind speed and decreased air temperature during the fog. Towards the end of the fog episode,the vertical distribution of sensible heat flux reversed,contributing to a downward momentum flux in all upper layers. Spatial and temporal scales of the turbulence eddy were greater before and after the fog,than during the fog episode. Turbulence energy was greatest in upper levels,around 430 m and 450 m above mean sea level(AMSL),than in lower levels of the fog(390 m and 410 m AMSL); turbulence energy peaked along the mean wind direction. Our results show that the status of turbulence was complicated within the fog; turbulence caused fluxes of momentum and sensible heat atop the fog layer,affecting the underlying fog by decreasing or increasing average wind speed,as well as promoting or demoting air temperature stratification.

Variability of Surface Sensible Heat Flux over Northwest China

The present study documents the variability of surface sensible heat flux over Northwest China using station observations for the period 1961 2000.It is found that the afternoon and nighttime sensible heat flux variations are remarkably different.The variability of the instant flux in the afternoon is much larger than in the nighttime.The afternoon and nighttime flux anomalies tend to be opposite.The diurnal and seasonal dependence of sensible heat flux variations is closely related to the diurnal cycle of mean land-air temperature difference.The relationship of sensible heat flux with land-air temperature difference based on the instant value differs from that based on the daily mean.The present study indicates the importance for the models to properly simulate mean land-air temperature difference and its diurnal and seasonal variations in order to capture surface sensible heat flux variability over Northwest China and predicts its plausible impacts on climate.

A quasi-synoptic interpretation of water mass distribution and circulation in the western North Pacific:I.Water mass distribution

With high-resolution conductivity-temperature-depth （CTD） observations conducted in Oct.-Nov. 2005, this study provides a detailed quasi-synoptic description of the North Pacific Tropic Water （NPTW）, North Pacific Intermediate Water （NPIW） and Antarctic Intermediate Water （AAIW） in the western North Pacific. Some novel features are found. NPTW enters the western ocean with highest-salinity core off shore at 15°-18°N, and then splits to flow northward and southward along the western boundary. Its salinity decreases and density increases outside the core region. NPIW spreads westward north of 15°N with lowest salinity off shore at 21°N, but mainly hugs the Mindanao coast south of 12°N. It shoals and thins toward the south, with salinity increasing and density decreasing. AAIW extends to higher latitude off shore than that in shore, and it is traced as a salinity minimum to only 10°N at 130°E. Most of the South Pacific waters turn northeastward rather than directly flow northward upon reaching to the Mindanao coast, indicating the eastward shift of the Mindanao Undercurrent （MUC）.

Interdecadal Variability of Spring Precipitation over South China and Its Associated Atmospheric Water Vapor Transport

The characteristics of spring precipitation and water vapor transport in South China were analyzed by using observational data and the National Centers for Environmental Prediction (NCEP) reanalysis data. The results show that, during the spring, each component of the water cycle (precipitation, wind field, specific humidity, water vapor transport, etc.) in South China exhibits a notable interdecadal variability. An abrupt increase in spring precipitation occurred in the early 1970s. During the dry period from 1958 to 1971, a water vapor flux divergence (positive divQ) existed in South China, which may have led to the deficiency in rainfall. However, during the wet period from 1973 to 1989, there was a remarkable water vapor flux convergence (negative divQ) in South China, which may have resulted in the higher rainfall. The interdecadal variability of water vapor transport is closely related to the interdecadal variability of wind fields, although the interdecadal variability of specific humidity also plays a role to some extent, and the interdecadal variability of the zonal water vapor transport contributes much more to the interdecadal variability of spring precipitation than the meridional water vapor transport.

Flotation characteristics of Shenfu coal macerals

The flotation characteristics of Shenfu coal macerals was researched. Taking flotation recovery and enrichment of macerals as the evaluation objects, the influence of the agent dosage, pulp concentration, impeller speed and aeration rate on the separating effect was investigated. And the optimum process conditions of flotation were confirmed. The results show that the agent dosage, pulp concentration, impeller speed and aeration rate have a significant impact on flotation recovery and en- richment of macerals. The float recovery was 73.28% and enrichment ratio of vitrinite was 83.89% when CTAB dosage of 1.0 kg/t, pulp concentration of 100 g/L, impeller speed of 1 700 r/min and aeration rate of 0.25 m3/（m2·min） were used. The tailings yield was 60.30% and enrichment ratio of inertinite was 61.44% when CTAB dosage of 0.5 kg/t, pulp concentration of 100 g/L, impeller speed of I 700 r/min and aeration rate of 0.20 m3/（m2·min） were used.

Numerical analysis of aerated heap bioleaching with variable irrigation and aeration combinations

Forced aeration is an effective way to accelerate the heap bioleaching process.To reveal the effects of different irrigation and aeration combinations on bioleaching performance of copper sulfides,numerical simulations with COMSOL were carried out.Results showed the oxygen concentration is the highest at the bottom with forced aeration,the airflow transports spherically from the aeration pipeline to the slope,and the horizontal diffusion distance is further than vertical value.When the irrigation-to-aeration ratio is higher,the average heap temperatures are mainly decided by aeration rates;otherwise,temperature distributions are the equilibrium of mineral reaction heat,the livixiant driven heat and the airflow driven heat.When the aeration rate is higher than 0.90 m3/(m2·h),oxygen concentration is no longer a limiting factor for mineral dissolution.Additionally,on the premise of sufficient oxygen supply,Cu recovery rate is higher at the bottom with low irrigation rate;while it is higher at upper regions with high irrigation rate.The numerical analysis uncovered some insights into the dynamics and thermodynamics rules in bioleaching of copper sulfides with forced aeration.

Airflow adjustment and minimization of the air power of ventilation network

It is often required to know which roadway （adjustment roadway） resistances and how much values of the resis- tances should be changed to make the airflow rates in roadways （target roadways） to certain required values in the practice of mine ventilation. In this case, the airflow rates of the target roadways and the resistances of the roadways other than the ad- justment roadways are the given conditions and the resistances of the adjustment roadways are the solutions to be found. No straightforward method to solve the problem has been found up to now. Therefore, trial and error method using the ventilation network analysis program is utilized to solve the problem so far. The method takes long calculation time and the best answer is not necessarily obtained. The authors newly defined ＂airflow element＂ as an element of the ventilation network analysis. The resistances that satisfy the airflow requirements can be calculated straight forwardly by putting the function of the airflow element into the ventilation network analysis. The air power required for the ventilation can be minimized while meeting the airflow requirements by the advanced application of the method. The authors made the computer program fulfill the method. The program was applied to actual ventilation network and it was found that the method is very practical and the time required for the analysis is short.

Terminal Traffic Flow Prediction Method Under Convective Weather Using Deep Learning Approaches

In order to improve the accuracy and stability of terminal traffic flow prediction in convective weather,a multi-input deep learning(MICL)model is proposed.On the basis of previous studies,this paper expands the set of weather characteristics affecting the traffic flow in the terminal area,including weather forecast data and Meteorological Report of Aerodrome Conditions(METAR)data.The terminal airspace is divided into smaller areas based on function and the weather severity index(WSI)characteristics extracted from weather forecast data are established to better quantify the impact of weather.MICL model preserves the advantages of the convolution neural network(CNN)and the long short-term memory(LSTM)model,and adopts two channels to input WSI and METAR information,respectively,which can fully reflect the temporal and spatial distribution characteristics of weather in the terminal area.Multi-scene experiments are designed based on the real historical data of Guangzhou Terminal Area operating in typical convective weather.The results show that the MICL model has excellent performance in mean squared error(MSE),root MSE(RMSE),mean absolute error(MAE)and other performance indicators compared with the existing machine learning models or deep learning models,such as Knearest neighbor(KNN),support vector regression(SVR),CNN and LSTM.In the forecast period ranging from 30 min to 6 h,the MICL model has the best prediction accuracy and stability.

Hydrodynamics features of dispersed bubbles in the ventilated wake flow of a cylinder

An experimental study was conducted to investigate the 2 D bubbly flow downstream of a cylinder. Sparsely distributed bubbles were produced using the ventilation method. The carrier flow was measured using the particle image velocimetry(PIV) technique. The shadow imaging technique was used to capture instantaneous bubbly flow images. An image-processing code was compiled to identify bubbles in acquired image, calculate the bubble equivalent diameter and the bubble velocity. The effects of Reynolds number and the flow rate of the injected air were considered. The result indicates that the carrier flow is featured by distinct flow structures and the wake region is suppressed as the upstream velocity increases. Regarding the bubbles trapped in the wake flow, the number of small bubbles increases with the upstream velocity. On the whole, the bubble velocity is slightly lower than that of the carrier flow. The consistency between small bubbles and the carrier flow is high in terms of velocity magnitude, which is justified near the wake edge. The difference between the bubble velocity and the carrier flow velocity is remarkable near the wake centerline. For certain Reynolds number, with the increase in the air flow rate, the bubble equivalent diameter increases and the bubble void fraction is elevated.

Heating and Cooling Performance of Earth-Tube Heat Exchanger in a Mechanical Ventilated Farrowing House

Earth tempering of stable air has attracted great attention as a sustainable air conditioning method in pig houses. At summer time air cooling of income air strongly reduces heat stress and required ventilation rate. At winter time heating costs can be reduced. The effect of air condition using geothermal energy was investigated in a farrowing house. Underneath the foundation of the farrowing house 88 non perforated ribbed tubes （diameter： 20 cm） were piped in a depth of 1.6-2.0 m. Over a period of 12 month following data were recorded at hourly intervals and analyzed： outside air temperature, as well as air temperature in the air supply duct and in the compartments. Incoming air （supply duct） was heated up to 20 ℃ during winter time and in summer time cooled by up to 15 ℃ compared to the outside air temperature. In contrast to the outside air diurnal variation, temperature fluctuations of the incoming air were reduced by 90%. Due to cooling of the incoming air at summer time the stable inside temperature could be limited to maximal 29 ℃（maximum outside temperature was 35℃）. Earth-tube heat exchangers with non perforated ribbed tubes were very efficient for air conditioning in farrowing houses. They were a cost effective supplement for sustainable cooling and heating of farrowing houses.

Transpiration Rates of Carex Meyeriana in Relation to Micrometerological Factors in a Mountain Valley Wetland

In order to reveal transpiration rates of wetland plants and its relationships to micro-meterological factors in a mountain valley wetland, relative humidity, air temperature, leaf temperature, soil temperature, photo flux density and transpiration rates were measured once two hours in a Carex meyeriana wetland of the Changbai Mountain valley in dry (July) and wet (September) of 2003, respectively. Results showed that the tendency of "decreasing after increasing" was obvious in wet season. However, a relatively stable trend was observed for the transpiration in dry season.. Generally, the photon flux density of Carex meyeriana was higher in wet season than that in dry season. However, the variabilities of leaf temperature, air temperature and relative humidity were similar in both seasons. Higher transpiration rates of Carex meyeriana leaves were observed in July (varied from 40 to 150 mol·m-2·s-1) compared to those (varied from 7 to 14 mol·m-2·s-1) in September. Transpiration rates were significantly correlated with air temperature (P<0.01), leaf temperature (P<0.01), and wind speed (P<0.05), but correlationship between relative humidity and photo flux density was not significant (P<0.05).

Numerical Analysis on Ventilating and Air Conditioning Scheme of Shenyang Subway Station

Different cities have different climate conditions and outdoor temperature and humidity, so the scheme of an environment control in subway should be analyzed by considering objective conditions, project cost and operating status. In this paper, a physical and mathematical model is built according to the design of Shenyang subway (line 1), the boundary conditions of the model are defined by the design and experiments, the numerical analysis of ventilating scheme and air conditioning scheme is introduced individually, and the temperature field and air flow field of the two schemes are compared, so that the feasibility of using a ventilating scheme in subway of northeast cities is discussed. Considering comfort and economy, it can be concluded that mechanical ventilation is feasible in subway of northeast cities because the air temperature there is not very high in summer.

The stability indexes of branched airflow of ventilation network in coal mine

The stability of branched airflow of ventilation network is guarantee of safety in production of coal mine. Two indexes which stand for the stability of branches of ventilation network in coal mine were put forward in this paper, that are airflow intensity and sta- bility index of branched airflow, The airflow stability of working place was divided into different grade according to the stability index. The conclusion has great significance for safety in production of coal mine.

Difference in the Interdecadal Variability of Spring and Summer Sensible Heat Fluxes over Northwest China

The present study investigates the difference in interdecadal variability of the spring and summer sensible heat fluxes over Northwest China by using station observations from 1960 to 2000. It was found that the spring sensible heat flux over Northwest China was greater during the period from the late 1970s to the 1990s than during the period from the 1960s to the mid-1970s. The summer sensible heat flux was smaller in the late 1980s through the 1990s than it was in the 1970s through the early 1980s. Both the spring and summer land-air temperature differences over Northwest China displayed an obvious interdecadal increase in the late 1970s. Both the spring and summer surface wind speeds experienced an obvious interdecadal weakening in the late 1970s. The change in the surface wind speed played a more important role in the interdecadal variations in sensible heat flux during the summer, whereas the change in the land-air temperature difference was more important for the interdecadal variations in sensible heat flux in the spring. This difference was related to seasonal changes in the mean land-air temperature difference and the surface wind speed. Further analysis indicated that the increase in the spring land surface temperature in Northwest China was related to an increase in surface net radiation.