Spatial Distributions of Atmospheric Radiative Fluxes and Heating Rates over China during Summer

The latitude-altitude distributions of radiative fluxes and heating rates are investigated by utilizing CloudSat satellite data over China during summer. The Tibetan Plateau causes the downward shortwave fluxes of the lower atmosphere over central China to be smaller than the fluxes over southern and northern China by generating more clouds. The existence of a larger quantity of clouds over central China reflects a greater amount of solar radiation back into space. The vertical gradients of upward shortwave radiative fluxes in the atmosphere below 8 km are greater than those above 8 km. The latitudinal-altitude distributions of downward longwave radiative fluxes show a slantwise decreasing trend from low latitudes to high latitudes that gradually weaken in the downward direction. The upward longwave radiative fluxes also weaken in the upward direction but with larger gradients. The maximum heating rates by solar radiation and cooling rates by longwave infrared radiation are located over 28 40°N at 7 8 km mean sea level (MSL), and they are larger than the rates in the northern and southern regions. The heating and cooling rates match well both vertically and geographically.

Study of the Photon Flux and the Dose Rate in the Vicinity of a 60Co Gamma Irradiator

The present work presents an overview of the study of some dosimetric quantities in the vicinity of the Tunisian Gamma Irradiation Facility. Firstly, we have confirmed our previous calculation of the photon flux and the dose rates, using a simulation with GEANT 4. A good agreement between calculation and simulation was obtained, which well confirmed the modeling of the CNSTN extended source by a pencil-like source. Secondly we have determined the isodose curves in the vicinity of the irradiator using a straightforward calculation. Finally, we have presented many comments for some published work concerning the methods used to determine these dosimetric quantities.

光解速率测量技术研究进展

光解反应作为大气中链式反应的引发反应,是产生二次污染物的重要原因,光解速率作为描述光解反应强度的关键参数,其数值的准确测量愈加重要。光解速率的测量技术自被研发起不断发展,截至目前常见的测量技术有化学光度计测量技术、滤波辐射计测量技术,以及光谱辐射计测量技术等。其中:化学光度计测量技术是最直接测量光解速率的方法,不过由于其操作流程烦琐、仪器复杂,多用于实验室测量;滤波辐射计测量技术是一种简化的测量技术,具有较宽的光谱覆盖,并且仪器体积小、重量轻,缺点是测量气体种类有限,测量误差较大,多用于机载测量;光谱辐射计测量技术是最通用的测量方法,能够同时测量多种气体的光解速率,并且目前已利用该原理生产出商业化的光解光谱仪,然而光谱辐射计测量技术对光谱仪要求较高,多用于外场实验。除此之外,还可以用经验公式法与脉冲(闪过或激光)光解法来获得特定情况下的光解速率。该文总结了光解速率测量技术在各方面的应用,并对可能的研究重点进行了展望。

长江口滨海湿地有机碳循环过程及影响因素研究进展

滨海湿地是“蓝碳生态系统”的重要组成部分。综述了长江口滨海湿地土壤有机碳时空分布及含量、碳汇速率、有机碳横向输入输出通量及量化方法、有机碳循环定量分析模型以及有机碳储量和组分对不同影响因素所做出的动态响应规律,发现在土壤有机碳水平空间分布上,崇西湿地>崇明东滩>九段沙>南汇潮滩;有机碳通量和浓度变化主要受到植物生物量和结构、水和土壤的理化性质、陆源输入和潮汐动力、间隙水交换以及人类活动和全球气候变化的影响。未来应加强长江口湿地土壤碳库和有机碳输运通量统一观测,准确量化各主要因素对有机碳的贡献,这对研究盐沼湿地的碳循环机理和碳汇评估具有重要意义。

Preparation of ultrafine WC-Co powder via fluidized bed

In this study,the effects of reaction parameters on the deep-reduction and carbonization process of WO_(2)-Co to WC-Co were studied.The results indicate that the oxygen loss rate of WO_(2) is positively correlated with temperature and methane partial pressure.The partial pressure of methane has no significant effect on the formation rate of WC.The carbon content and particle size of the product increase with the increase of CH_(4) partial pressure.By synergistically regulating the reaction temperature to 950℃,the CH_(4) partial pressure to 1.25%,and the reaction time to 60 min,ultrafine WC-Co powder without h phase can be obtained.The particle size of the composite powder is 128 nm,with total carbon content of 6.16%,free carbon content of 0.4%,and residual oxygen content of 0.05%,respectively.The growth rate relationship of tungsten carbide is as follows:δ(t)=1.21×10^(-13)exp(-12809.72/T)√t.

吐鲁番市高昌区不同固沙植物的防风固沙效益

为了解不同防风固沙林对风速、输沙通量和土壤蚀积程度的影响,以期为荒漠化地区植物选择和配置提供技术支持,以吐鲁番市高昌区恰特喀勒乡公相村为实验地,利用气象站、风速仪、集沙仪等监测不同高度下梭梭林、柽柳林以及梭梭-柽柳混交林的风速、地表粗糙度、输沙通量等指标,分析比较不同固沙林的风速廓线、风速增加率、地表蚀积量及风沙堆积物变化规律。结果表明:随着风速的增加,输沙通量逐渐增加,地表粗糙度和蚀积深度呈现降低趋势;不同固沙林不同高度(h)的风速增加率均表现为中层(50 cm<h≤100 cm)最大,低层(10 cm<h≤50 cm)最小,说明固沙植物对低层风速有显著降低作用,增强了中层风速;不同固沙林输沙通量随着高度增加逐渐减小;柽柳林、梭梭-柽柳混交林后出现堆积现象,梭梭林前后为侵蚀现象。梭梭林、柽柳林以及梭梭-柽柳混交林均降低了近地表风速,有效拦截了风沙流,改变了表层风沙堆积物物质组成,梭梭-柽柳混交林防风固沙效果较好。

施氮对陇中黄土高原旱作麦田N_(2)O和CO_(2)排放的影响

【目的】探究陇中黄土高原半干旱区旱作麦田土壤N_(2)O和CO_(2)排放对不同施氮量的响应,阐明旱作麦田N_(2)O和CO_(2)排放特征及其主要影响因素,以期为该地区旱作麦田温室气体减排和氮肥管理提供依据。【方法】以陇中黄土高原旱作麦田为研究对象,采用大田定位试验和室内指标测定相结合的方法,布设CK(不施肥)、LN(低量氮肥)、MN(中量氮肥)和HN(高量氮肥)共4个施氮梯度,分析不同施氮量对旱作麦田土壤硝态氮(NO_(3)^(-)-N)、铵态氮(NH_(4)^(+)-N)、有机碳(SOC)、土壤温度、含水量及土壤N_(2)O和CO_(2)排放的影响。【结果】0~10 cm土层土壤中,HN、MN、LN较CK处理,NO_(3)^(-)-N平均含量增幅为21.55%、26.06%和34.11%;NH_(4)^(+)-N平均含量增幅为21.77%、31.42%和39.20%;SOC平均含量增幅为20.43%、25.80%和35.9%。HN、MN、LN较CK处理,N_(2)O累计排放量增幅为78.63%、130.47%、217.51%;CO_(2)累计排放量增幅为5.73%、10.63%、21.75%。皮尔逊相关关系表明,不同施氮处理中,麦田0~10 cm土层土壤中NO_(3)^(-)-N、NH_(4)^(+)-N和SOC平均含量与N_(2)O、CO_(2)累计排放量呈极显著正相关关系(P<0.001),土壤温度与N_(2)O和CO_(2)累计排放量呈显著正相关关系(P<0.05),土壤含水量与N_(2)O累计排放量呈显著的负相关关系(P<0.05),与CO_(2)累计排放量相关关系不显著。【结论】施氮可以增加黄土高原旱作麦田表层土壤中NO_(3)^(-)-N、NH_(4)^(+)-N和SOC含量,进而增加了N_(2)O和CO_(2)累计排放量,是该地区麦田N_(2)O和CO_(2)排放的主要驱动因子,表层土温和土壤含水量也一定程度上影响着N_(2)O和CO_(2)的排放。

基于逻辑斯谛方程对纳滤膜污染预测的建模分析

为了解决目前应用较广泛的膜种纳滤膜的膜污染极大地限制了纳滤膜工艺发展的问题,从而在错流过滤条件下更好地预测纳滤膜污染的过程,对减缓纳滤膜污染进行指导,基于逻辑斯谛方程,对纳滤膜通量衰减曲线进行拟合,建立逻辑斯谛纳滤膜污染预测模型;利用所建立模型对不同型号纳滤膜的膜通量衰减曲线进行拟合,考察污染物种类、纳滤膜型号、跨膜压差、错流速率、水力条件等关键因素对纳滤膜通量衰减速率的影响。结果表明:所建立模型通过了显著性检验,实验数据与所建立模型拟合数据的拟合度较高,决定系数R2大于0.95;纳滤膜通量衰减速率越小,则过滤稳定后的纳滤膜通量累积衰减率越大,进而通过调整运行条件和原水质条件等因素,达到调整纳滤膜通量衰减速率,减少纳滤膜污染的目的。

反应堆中子注量率对数测量技术研究

反应堆核仪表系统通过一系列布置在堆外的中子探测器进行反应堆中子注量率测量,为反应堆启动、运行和安全提供初始测量信号。中间量程中子注量率测量范围超过6个量级,同时探测器输出的电流十分微弱,最小达到10 pA,对测量技术要求较高。线性电流测量方法会产生由量程切换带来的测量跳变,影响反应堆周期测量稳定性,从而影响反应堆安全。本文详细分析了对数测量原理,利用对数放大电路具有宽动态范围的特点,实现了很宽的动态范围的中子注量率快速测量,避免了量程切换带来的测量数值跳变,提高了中子注量率测量和周期计算的精度。模拟探测器信号输入10 pA~100μA的微电流进行测量,结果表明,对于范围达7个数量级的输入电流,测量的相对误差低于0.5%,该方案适用于反应堆中子注量率的中间量程测量。

测试条件对超滤膜截留率和通量的影响

以50kD和100kD超滤膜为研究对象,牛血清白蛋白为测试的标准物质,测试不同的过滤方式、运行时间、测试压力和料液浓度对超滤膜截留率和通量的影响。结果表明:50kD超滤膜的截留率,不同测试条件对其影响小,偏离值<±10%;100kD超滤膜的截留率,不同测试条件对其影响较大,偏离值可以达到50%。50kD和100kD超滤膜的通量受测试条件影响都较大,实验表明截留物质相对分子质量与超滤膜截留相对分子质量之间的相对大小对通量有较大的影响;长时间的过滤(>20 min),超滤膜采用错流过滤的方式比死端过滤更有优势,通量衰减慢且更稳定。

PTFE中空纤维膜蒸馏高盐废水浓缩实验研究

文章选择工业生产中常见的含氯化钠(NaCl)高盐废水,以疏水性PTFE中空纤维膜组件为载体,采用真空膜蒸馏的方式进行浓缩处理实验研究,研究各操作条件对膜通量和截盐率的影响,并验证实验可行性。实验结果表明,膜下游侧压力增加,膜通量会逐渐降低;废水料液流量和料液温度的增加均有助于提高膜通量;废水料液浓度的增加,会抑制传质过程,降低膜通量。各操作条件对膜截盐率的影响很小,膜截盐率一直保持在99.8%以上,说明PTFE中空纤维膜蒸馏用于高盐废水浓缩具备可行性。

热管置入式墙体供暖季传热性能分析

墙体是建筑的主要组成部分之一,其热损失占据了冬季供暖能耗的一大部分,因此降低墙体热损失是建筑节能领域的研究重点.热管置入式墙体(wall implanted with heat pipes,WIHP)是一种新型的太阳能被动式利用技术.通过TRNSYS软件建立了一个新的WIHP传热部件,并通过实验测试进行模型验证.对WIHP不同方向的传热性能进行分析,并提出两种WIHP的优化方式.结果表明,在工作期间,南向WIHP、西向WIHP和东向WIHP均可以提高内表面温度,减少墙体热损失,节能效果显著.

生活垃圾焚烧灰渣代砂混凝土的抗氯离子渗透性能研究

为探究生活垃圾焚烧灰渣代砂混凝土的抗氯离子渗透性能,采用3种代砂率(0,20%,40%)和3种水胶比(0.30,0.45,0.60)进行配合比设计,并养护至标准、中长、长期龄期,基于电通量法测试不同配合比在不同龄期下的抗氯离子渗透性能。结果表明:与普通混凝土类似,焚烧灰渣混凝土的抗氯离子渗透性能随着水胶比的增加而减少,焚烧灰渣代砂率的提高可促进抗氯离子渗透性能,且高水胶比下的效果更好;由于硫化物和氧化镁组分的存在,焚烧灰渣化学反应活性将在后期缓慢发挥,并进一步减少氯离子扩散系数;综合考虑环境效益,0.45水胶比+40%替代率下的具有最佳的抗氯离子渗透性能,可满足工程实践需求。

高通量血液透析疗法对糖尿病肾病患者Ccr、BUN等指标的影响研究

目的分析高通量血液透析疗法对糖尿病肾病患者肌酐清除率(Ccr)、尿素氮(BUN)等指标的影响。方法将2021年5月—2022年4月本院收治的80例糖尿病肾病患者纳入研究,采取随机数字表法将其分为研究组和对照组,每组40例。研究组采取高通量血液透析疗法,对照组采取低通量血液透析疗法。对比两组肾功能指标、炎性因子、血糖相关及胰岛素指标。结果治疗后,研究组的Ccr较对照组更高,BUN和Scr值较对照组更低(P<0.05);研究组的炎症因子较对照组更低(P<0.05);研究组血糖相关及胰岛素水平较对照组更低(P<0.05)。结论将高通量血液透析疗法应用于糖尿病肾病患者的治疗中,可改善其肾功能,减轻炎症反应,降低血糖水平,值得临床推广应用。

Effect of Carbon Properties on Melting Behavior of Mold Fluxes for Continuous Casting of Steels

During continuous casting of steel, the properties of mold fluxes strongly affect the casting performance, steel quality and environment of casting operation. The high temperature microscopy technique was used to investigate the melting behaviour of mold fluxes, and drip test method was used to determine their melting rate. The results showed that free carbon is a dominant factor in governing the melting behaviour of fluxes, and the melting rate is increased with increasing carbon reactivity and decreasing carbon content.

Study on extraction phenol from coal tar with high flux centrifugal extractor

Solvent extraction phenol from coal tar were carried out with novel composite YH-3 as extraction agent, and the high flux centrifugal extractor was used as extraction device. Under the premise of high phenol extraction rate, composite YH-3 extraction agent reduces n-n interaction between phenolic compounds and aromatic hydrocarbons, thus decreasing the entrainment of neutral oil. The optimization of operation conditions, such as the diameter of heavy phase weir HWD, the flow ratio, the total flow rate and the rotation speed, are necessary. For single stage extraction experiment, the mass transfer efficiency was up to 84% while the rate of extraction agent loss was lower than 0.28% with the operation conditions of 29 mm of the heavy phase weir diameter （HWD）, 1：1-1.4：1 of the flow ratio range, 160-200 mL/min of the total flow rate and the rotation speed varied from 2200 to 2600 r/min. For three stage counter-current test, the mass transfer efficiency reached up to 92.6% with the optimum operation condition of 29 mm of the HWD, 1：1 of the flow ratio, 200 rnL/min of the total flow rate and 2400 r/rain of the rotation speed. The results indicated that phenol could be extracted effectively from coal tar in the process of multistage continuous count current centrifugal extraction.

Surface Roughness of Flux Film in Continuous Casting Mold

The corundum plates with a groove were used to freeze molten flux into solid slice to simulate the flux film formed in continuous casting mold,and thereby to study the formation mechanism of flux film with different surface roughness.The effect of some factors on the surface roughness of flux film,such as reheating rate,cooling rate,flux film thickness and crystallization ratio,was discussed.

Parameterization of Sheared Entrainment in a Well-developed CBL.PartⅡ:A Simple Model for Predicting the Growth Rate of the CBL

Following the parameterization of sheared entrainment obtained in the companion paper, Liu et al. （2016）, the present study aims to further investigate the characteristics of entrainment, and develop a simple model for predicting the growth rate of a well-developed and sheared CBL. The relative stratification, defined as the ratio of the stratification in the free atmosphere to that in the entrainment zone, is found to be a function of entrainment flux ratio （Ae）. This leads to a simple expression of the entrainment rate, in which Ae needs to be parameterized. According to the results in Liu et al. （2016）, Ae can be simply expressed as the ratio of the convective velocity scale in the sheared CBL to that in the shear-free CBL. The parameterization of the convective velocity scale in the sheared CBL is obtained by analytically solving the bulk model with several assumptions and approximations. Results indicate that the entrainment process is influenced by the dynamic effect, the interaction between mean shear and environmental stratification, and one other term that includes the Coriolis effect. These three parameterizations constitute a simple model for predicting the growth rate of a well-developed and sheared CBL. This model is validated by outputs of LESs, and the results show that it performs satisfactorily. Compared with bulk models, this model does not need to solve a set of equations for the CBL. It is more convenient to apply in numerical models.

A Numerical Sirnulation of Gas-Particle Two-Phase Flow in a Suspension Bed Using DifFusion Flux Model

A mathematical modei of two-dimensional turbulent gas-particle twophase flow based on the modified diffusion flux modei (DFM) and a numerical simulation method to analyze the gas-particle flow structures are developed. The modified diffusion flux modei, in which the acceleration due to various forces is taken into account for the calculation of the diffusion velocity of particles, is applicable to the analysis of multi-dimensional gas-particle two-phase turbulent flow. In order to verify its accuracy and efficiency, the numerical simulation by DFM is compared with experimental studies and the prediction by k-ε-kp two-fluid modei, which shows a reasonable agreement. It is confirmed that the modified diffusion flux modei is suitable for simulating the multi-dimensional gas-particle two-phase flow.

STUDY ON THE DISSOLVED OXYGEN FLUX IN THE SOUTH CHINA SEA

The seawater box model for the South China Sea (SCS) was used to calculate the fluxes of dissolved oxygen in Box I, Box Ⅱand Box Ⅲ for establishing the box model of dissolved oxygen (DO)in the SCS.The total input flux of oxygen to the SCS was calculated to be 280.4×104 mol/s, of which 49.2% was transported into the sea by outer oceans, 30.3% came from organisms photosynthesis, 3% from rainfall, 0.4% from rirers, and 17.0% from the atmosphere.