多级A/O工艺设计及其在应急污水处理工程中的应用

为有效缓解资阳市第二污水处理厂现状处理能力不足导致的污水溢流问题,改善周边水生态环境,新建了规模为5000 m 3/d的应急污水处理工程。该工程采用“多级A/O+磁混凝沉淀”组合工艺,对其中的多级A/O工艺段进行了深化设计,并对本项目的实际运行效果进行了分析。深化设计结果表明,多级A/O反应器级数宜采用2级,流量分配比宜为7∶3,污泥回流比宜为100%。运行期间的监测数据表明,出水指标均满足《四川省岷江、沱江流域水污染物排放标准》(DB51/2311-2016),其中的COD Cr、TP和TN的去除率分别为96.6%、97.6%和87.2%。通过设置初段硝化液回流,充分发挥初级缺氧池的脱氮能力,使多级A/O工艺的脱氮效率得到了强化。该项目采用的组合工艺简单有效,出水效果好,为城市溢流污水的高标准排放提供了一种更优选择。

A^(2)/O一体化设备在农村生活污水处理中的应用

随着我国大力实施乡村振兴战略,农村生活污水治理不断推进。本研究基于A^(2)/O一体化设备处理农村生活污水的调试数据,考察DO浓度、硝化液回流比、污泥回流比等参数对工艺的影响,分析各参数相互影响规律,探究最佳运行参数。研究结果表明:A^(2)/O工艺处理农村生活污水最佳运行参数应控制DO浓度区间2~3 mg/L,硝化液回流比200%,污泥回流比100%。调控最佳工艺参数后,经处理后,出水满足《农村生活污水集中处理设施水污染物排放标准》(DB33/973-2021)表1中的一级标准,对A^(2)O一体化设备在农村生活污水治理中的应用提供案例支撑和经验借鉴。

Prognostic significance of neutrophil to lymphocyte ratio in pancreatic cancer: A meta-analysis

AIM:To conduct a meta-analysis evaluating theassociation between the peripheral blood neutrophil to lymphocyte ratio(NLR) and the outcome of patients with pancreatic cancer.METHODS:Studies evaluating the relationship between the peripheral blood NLR and outcome of patients with pancreatic cancer published up to May 2014 were searched using electronic databases, including Pub Med, Web of Science, Embase and Ovid.A meta-analysis was performed to pool the hazard ratios(HRs) or odds ratios(ORs) and their 95% confidence intervals(CIs) using either a fixed-effects model or a random-effects model to quantitatively assess the prognostic value of NLR and its association with clinicopathological parameters.RESULTS:Eleven studies containing a total of 1804 patients were eligible according to our selection criteria, and combined hazard ratios indicated that high NLR was a poor prognostic marker for pancreatic cancer patients because it had an unfavorable impact on the overall survival(OS)(HR =2.61, 95%CI:1.68-4.06, P =0.000) and cancer specific survival(HR =1.66, 95%CI:1.08-2.57, P =0.021).Subgroup analysis revealed that high NLR was associated with poor OS in patients with mixed treatment(HR =4.36, 95%CI:2.50-7.61, P =0.000), chemotherapy(HR =2.08, 95%CI:1.49-2.9, P =0.000), or surgical resection(HR =1.2, 95%CI:1.00-1.44, P =0.048).Additionally, high NLR was significantly correlated with tumor metastasis(OR =1.69, 95%CI:1.10-2.59, P =0.016), poor tumor differentiation(OR =2.75, 95%CI:1.19-6.36, P =0.016), poor performance status(OR =2.56, 95%CI:1.63-4.03, P =0.000), high cancer antigen 199(OR =2.62, 95%CI:1.49-4.60, P =0.000), high C-reactive protein(OR =4.32, 95%CI:2.71-6.87, P =0.000), and low albumin(OR =3.56, 95%CI:1.37-9.27, P =0.009).CONCLUSION:High peripheral blood NLR suggested a poor prognosis for patients with pancreatic cancer,and it could be a novel marker of survival evaluation and could help clinicians develop therapeutic strategies for pancreatic cancer patients.

The influence of nitrified supernate’s recycle ratio on the removal of coking wastewater

The influence of the recycle ratio on the removal of coking wastewater has been researched using the anaerobicanoxic-aerobic （A/A/O） biofilm process. The research indicates that the concentrations of chemical oxygen demand （COD） and NO3 -N in the water are the lowest when the recycle ratio is 3：1 ,but the removal efficiency of total cyanide （TCN） is the highest when the recycle ratio is 1： 1. The removal efficiency of NH4^＋ -N is more than 99% at all three different recycle ratios. Compared with Grade A of the National Discharge Standard （GB 8978--1996）, the effluent NH4 -N is standard,but COD and TCN can not meet the requirements and further treatment processes are needed.

超临界CO_(2)/H_(2)O混合流体吞吐提高页岩油采收率实验研究

针对页岩储层压裂后一次衰竭开发原油采收率低的问题,基于页岩储层的低孔、超低渗透特征,提出了超临界CO_(2)/H_(2)O混合流体吞吐提高页岩油采收率实验方法。通过自主设计的室内岩心实验评价超临界CO_(2)/H_(2)O混合流体吞吐页岩油的效果,并对实验过程中注入介质、焖井时间、注入压力、吞吐轮次对提高采收率的影响规律进行研究,同时通过核磁共振技术明确超临界CO_(2)/H_(2)O混合流体对不同孔隙类型中原油的动用程度。结果表明:超临界CO_(2)/H_(2)O混合流体吞吐可以有效提高页岩油采收率;对于物性较差的页岩岩心,焖井时间对提高采收率有较大影响;注入压力与超临界CO_(2)/H_(2)O混合流体的扩散速度和渗流能力密切相关,混相条件下提高采收率效果显著;增加吞吐轮次大孔隙中的原油动用效果较好,但无法通过增加吞吐轮次动用更多微小孔隙中的原油。

Structural Changes of Y Zeolites with Different Initial SiO_2/Al_2O_3 Ratios during Hydrothermal Treatment

The effects of the initial framework SiO2/Al2O3 ratio and temperature on the structural changes of NaY zeolites during hydrothermal treatments are studied. Two samples with different framework SiO2/Al2O3 ratios are subjected to hydrothermal treatment at four different temperatures. For zeolite with a lower initial SiO2/Al2O3 ratio of 4.2, mesopores are easily formed because more framework aluminum is detached. Moreover, two kinds of mesopores are produced at a higher temperature due to the interconnection of vacancies and smaller mesopores. For zeolite with a higher initial SiO2/Al2O3 ratio of 6.0, there are less mesopores formed as compared with the lower initial SiO2/Al2O3 ratio sample, but there are some macropores formed. This may be attributed to the isolation of vacancies and the different distributions of aluminum in the crystal lattice of the zeolite. The experiment data show that NaY with the SiO2/Al2O3 ratio of 6.0 retains a high relative crystallinity during the hydrothermal treatment. This proves that a high framework SiO2/Al2O3 ratio benefits the stability of zeolite.

Zn/O ratio and oxygen chemical state ofnanocrystalline ZnO films grown atdifferent temperatures

ZnO nanocrystalline films are prepared on Si substrates at different temperatures by using metal-organic chemical vapour deposition （MOCVD）. It is observed that when the growth temperature is low, the stoichiometric ratio between Zn and 0 atoms has a large deviation from the ideal ratio of 1：1. The ZnO grains in the film have small sizes and are not well crystallized, resulting in a poor photoluminescence （PL） property. When the temperature is increased to an appropriate value, the Zn/O ratio becomes optimized, and most of Zn and 0 atoms are combined into Zn-O bonds. Then the film has good crystal quality and good PL property. If the temperature is fairly high, the interracial mutual diffusion of atoms between the substrate and the epitaxial film appears, and the desorption process of the oxygen atoms is enhanced. However, it has no effect on the film property. The film still has the best crystal quality and PL property.

A^(2)/O-BAF工艺短程硝化模式下反硝化除磷效能

采用厌氧/缺氧/好氧-曝气生物滤池(A^(2)/O-BAF)工艺处理低C/N城市污水,研究硝化液回流比为0、50%、100%、150%和200%时该工艺脱氮除磷效能。结果表明,在A^(2)/O中控制污泥龄(SRT)为15d,水力停留时间(HRT)为10h,好氧段溶解氧(DO)为2.0mg/L;BAF中控制HRT为3h、好氧/缺氧曝停时间比为50min∶10min以及硝化液回流比R=200%的条件下,进水COD、TN、NH_(4)^(+)-N和PO_(4)^(3-)-P的浓度分别为232.61mg/L、53.99mg/L、52.20mg/L和5.54mg/L,系统出水中COD、TN、NH_(4)^(+)-N和PO_(4)^(3-)-P的浓度分别为34.11mg/L、12.44mg/L、1.01mg/L和0.34mg/L,亚硝积累率(Ni AR)高达95.20%。出水NO_(2)^(-)-N回流至A^(2)/O缺氧段后,缺氧段出水的PO_(4)^(3-)-P含量下降至2.68mg/L,反硝化除磷(DPR)对系统PO_(4)^(3-)-P的去除贡献达75.42%。批次试验表明,A^(2)/O反应器中的除磷菌在厌氧120min后释磷量达到36.35mg/L,缺氧条件下以NO_(2)^(-)-N为电子受体的反应中吸磷量为26.28mg/L,吸磷率为72.30%,以NO_(2)^(-)-N为电子受体的反硝化除磷菌(DPB)占总除磷菌的72.91%。

水下连接器球面密封沟槽对O形圈密封性能的影响分析

一种可以实现水下连接角度补偿的球形法兰连接器采用O形圈作为主要的密封元件,位于球面上的密封槽通过影响O形圈的伸长率和压缩率来实现密封效果。槽宽b与槽深h是密封沟槽的主要尺寸,在满足球面沟槽设计准则的前提下,对O形圈球面密封沟槽的尺寸进行了设计计算。基于标准沟槽与球面沟槽体积大小一致的原则,确定了球面密封槽的具体尺寸。密封圈沟槽的尺寸设计主要改变了O形圈的压缩率大小。通过研究压缩率对O形圈密封效果的影响可以确定,17.6%左右的压缩率能够使密封圈的密封效果达到最佳。

Effect of O_2/CH_4ratio on the optimal specific-energy-input (SEI) for oxidative reforming of biogas in a plasma-shade reactor

In a novel plasma-shade reactor for oxidative reforming of biogas(CH4/CO2=3/2),the effects of specific-energy-input (SEI) on CH4 and CO2 conversions and energy cost of syngas were investigated at O2/CH4ratios ranged from 0.42 to 0.67.At each of O2/CH4 ratios,V-shape profiles of energy cost of syngas increasing with SEI were observed,reaching the lowest value at the optimal SEI(Opt-SEI).With the increase of O2/CH4 ratio,the Opt-SEI decreased significantly.Moreover,at the Opt-SEI,O2 and CH4 conversions and dry-basis concentration of syngas increased and energy cost of syngas decreased greatly with the increase of O2/CH4 ratio.

水硅比调控有机-无机杂化SiO_(2)膜制备与乙酸脱水渗透汽化性能

以1,2-双(三乙氧基硅基)乙烷(BTESE)为硅源前驱体,通过酸催化溶胶-凝胶法制备了BTESE有机-无机杂化SiO_(2)膜。为了提高其渗透汽化乙酸脱水性能,通过溶胶合成中水硅比(H_(2)O/BTESE)对硅网络进行调控。随着水含量的增大,水解的Si-OH增多,形成的凝胶孔径得到了有效降低,在膜进行渗透汽化乙酸脱水中,分离因子增大,通量降低.水硅比为180制备出的BTESE膜具有最佳综合分离指数,75℃下渗透汽化分离质量分数90%乙酸/10%水溶液,渗透通量和分离因子分别为1.25 kg/(m^(2)·h)和1050.将该膜分别浸泡在乙酸溶液和暴露在空气中,在长达80 d的时间里膜的乙酸脱水分离性能基本保持稳定,具有较好的长期耐酸稳定性和耐氧化化学稳定性.

Infiltration of Black Carbon Particles from Residential Woodsmoke into Nearby Homes

In many communities, residential wood burning is the source of a significant fraction of wintertime PM2.5 and produces exposures to nearby residents inside their homes. To evaluate the magnitude of this effect, black carbon particles were measured as a proxy for woodsmoke indoors and outdoors in a community where residential woodsmoke is the only significant particle source. Thirteen indoor/outdoor measurement pairs were obtained at 4 different residences and showed an average indoor/outdoor concentration ratio of 0.78 ± 0.21 for residences without indoor generation. In addition, a time dependent mass balance model was used in conjunction with aethalometer measurements taken over 16 nights at a single residence to estimate an average air exchange rate of 0.26 ± 0.08 h-1, an average deposition loss rate of 0.08 ± 0.03 h-1, and an average penetration factor of 0.97 ± 0.02. Using a mechanistic approach which utilizes these average values in a steady state model, the predicted average infiltration factor was 0.74 for the residence studied. The high values for both measured I/O ratio and modeled infiltration factor show that residential environments provide inhabitants with relatively little protection from recently generated wood smoke particles.

The Paradigm of Surgical Ellipse Dimensions: Are the Length-to-Width Ratio of 3 to 4 and a Vertex Angle of 30ºCorrect?

Background: It has been postulated that elliptical cutaneous excisions must possess a length-to-width ratio of 3 to 4 and a vertex angle of 30o or less in order to be closed primarily without creating a “dog ear”. These dimensions became axiomatic in cutaneous surgery and have been taught in the apprenticeship model for years. The present article examines the validity of that paradigm. Methods: We collected data from two sources: ellipses described in the literature (57 cases);and elliptical excisions performed at the authors’ outpatient clinic (83 cases). The surgical ellipse lengths, widths, and vertex angles were analyzed, and the data were compared to a mathematical formula used to generate a fusiform ellipse. Results: The length-to-width ratio of 3 - 4 was found to be inconsistent with the recommended vertex angle of 30o. In fact, a length-to-width ratio of 3 - 4 determines a vertex angle of 48o - 63o. A 30o vertex angle is only feasible with long length-to-width ration of about 7.5. Conclusions: The paradigm that surgical ellipses should have a vertex angle of 30o with length-to-width ratio of 3 - 4 is incorrect. Evidence from actual surgical practice and from mathematical formulation shows that either the length-to-width ratio must be larger than 3 - 4 or the vertex angle must be larger than 30 degrees.

MOLECULAR BEAM STUDIES ON OXIDATION OF CO ON Pd WITH DIFFERENT MIXED RATIOS OF P_(CO) TO P_(O2) ~*

Here some steady-state experiments on oxidation of CO on Pd were performed on a molecular beam apparatus. It is found that the characteristics of the rate of CO_2 formation r versus substrate temperature T are dependent on the ratio P=P_(CO)/P_(O2) in the mixed beam. These characteristics are related to the complicated interactions of co-adsorbed CO and O particles on Pd surface.

高压法兰内开孔金属O形环密封性能及变形失效分析

针对某压力容器法兰内开孔金属O形环在高压工况下,因法兰结构设计不合理导致O形环过度变形而引起的密封失效问题,建立了三维周期非线性弹塑性模型,分析了法兰侧壁间隙和压缩率对O形环接触应力周向分布和环体变形的影响。试验测试了工作压力下的O形环在不同法兰侧壁间隙和压缩率时的泄漏率,分析了O形环的变形特征,探讨了O形环在高压大侧壁间隙下的变形失效原因。结果表明:建立的有限元模型能准确地模拟O形环的力学行为和变形,计算曲线与试验曲线吻合程度良好;O形环的接触应力对法兰侧壁间隙更敏感,减小法兰侧壁间隙和增加压缩率都能提高O形环密封的可靠性;O形环在高压工况下容易产生颈缩变形,造成接触应力在周向不连续导致泄漏,控制O形环的预紧间隙并发挥法兰侧壁的约束作用能够改善此类变形。研究结果可为高压内开孔金属O形环密封的法兰结构设计提供参考。

Relationship Between Outdoor and Indoor Ozone Pollution Concentration

This paper analyses the changing rule of indoor ozone concentration and its influencing factors.A formula of indoor-outdoor concentration ratio(I/O ratio) was deduced based on the indoor ozone mass-balance equation.The ozone I/O ratio in different kinds of buildings was studied.Results show that I/O ratio is much related to air-exchange rate,which is well compatible with the theoretical calculation results.

不同Si/Al条件下Na_(2)O对煤灰熔融温度及硅酸盐结构的影响

以淮南本地高灰熔点煤为原料,通过调控煤灰硅铝比,改变煤灰中Na_(2)O含量,利用灰熔点测定仪、XRD及FTIR,探究Na_(2)O对不同硅铝比条件下煤灰熔融温度及硅酸盐结构的影响。实验结果表明:Na_(2)O明显改善煤灰熔融温度,且对高硅铝比煤灰影响较为显著,对低硅铝比煤灰熔融温度呈先降低后增加趋势,氧化钠含量为15%、Si/Al=2.0时煤灰流动温度(TF)降至最低,为1 292℃。不同硅铝比条件下原煤灰主要矿物为石英,在高温下煤灰中的Na_(2)O会与灰中的SiO2,Al2O3反应生成熔融温度较低的霞石,导致煤灰熔融温度的明显降低。Na_(2)O含量增加会导致架状和层状硅酸盐结构解聚形成更多的链状硅酸盐结构和环状硅酸盐结构,促进煤灰由复杂结构向简单结构转化。

Cavitation Increases the Ratio of Ortho/Para-H2O Isomers in Water and Reduces Its Viscosity

For the first time, we found that cavitation treatment of water increases the number of ortho-H2O isomers by 12% - 15%, which was confirmed in experiments on a tomograph. From this, it was suggested that the O/P ratio is a key factor in reducing the viscosity of water. The most significant decrease in the viscosity of an aqueous suspension of hemoglobin molecules with an increase in its concentration was measured earlier in the vicinity of a temperature of 37°C. The mechanism of the observed phenomena is discussed.

Effects of Film Thickness and Ar/O2 Ratio on Resistive Switching Characteristics of HfOx-Based Resistive-Switching Random Access Memories

Cu/HfOx/n^＋Si devices are fabricated to investigate the influence of technological parameters including film thickness and Ar/02 ratio on the resistive switching （RS） characteristics of HfOx films, in terms of switch ratio, endurance properties, retention time and multilevel storage. It is revealed that the RS characteristics show strong dependence on technological parameters mainly by altering the defects （oxygen vacancies） in the film. The sample with thickness of 2Onto and Ar/O2 ratio of 12：3 exhibits the best RS behavior with the potential of multilevel storage. The conduction mechanism of all the films is interpreted based on the filamentary model.

浅析计数器中O形圈对湿式液封水表性能的影响

研究不同压缩量下O形圈对湿式液封水表计量特性的影响,通过减小O形圈黏弹性引起的摩擦力,提高湿式液封水表的量程比。结果表明:计数器中的O形圈压缩量越小,则摩擦力越小,各流量点的测量误差有不同程度的降低;选择合适的O形圈压缩量,可大幅降低湿式液封水表最小流量的测量误差。减小计数器中O形圈的压缩量以提升湿式液封水表的量程比,可有效减少水计量损失。