Health Risk Assessment of Employees Exposed to Chlorination By-products of Recreational Water in Large Amusement Parks in Shanghai

Objective Chlorination is often used to disinfect recreational water in large amusement parks;however,the health hazards of chlorination disinfection by-products(DBPs)to occupational populations are unknown.This study aimed to assess the exposure status of chlorinated DBPs in recreational water and the health risks to employees of large amusement parks.Methods Exposure parameters of employees of three large amusement parks in Shanghai were investigated using a questionnaire.Seven typical chlorinated DBPs in recreational water and spray samples were quantified by gas chromatography,and the health risks to amusement park employees exposed to chlorinated DBPs were evaluated according to the WHO's risk assessment framework.Results Trichloroacetic acid,dibromochloromethane,bromodichloromethane,and dichloroacetic acid were detected predominantly in recreational water.The carcinogenic and non-carcinogenic risks of the five DBPs did not exceed the risk thresholds.In addition,the carcinogenic and non-carcinogenic risks of mixed exposure to DBPs were within the acceptable risk limits.Conclusion Typical DBPs were widely detected in recreational water collected from three large amusement parks in Shanghai;however,the health risks of DBPs and their mixtures were within acceptable limits.

Structure and electrical properties of polysilicon films doped with ammonium tetraborate tetrahydrate

Here,p-type polysilicon films are fabricated by ex-situ doping method with ammonium tetraborate tetrahydrate(ATT)as the boron source,named ATT-pPoly.The effects of ATT on the properties of polysilicon films are comprehensively analyzed.The Raman spectra reveal that the ATT-pPoly film is composed of grain boundary and crystalline regions.The preferred orientation is the(111)direction.The grain size increases from 16−23 nm to 21−47 nm,by~70%on average.Comparing with other reported films,Hall measurements reveal that the ATT-pPoly film has a higher carrier concentration(>10^(20)cm^(−3))and higher carrier mobility(>30 cm2/(V·s)).The superior properties of the ATT-pPoly film are attributed to the heavy doping and improved grain size.Heavy doping property is proved by the mean sheet resistance(Rsheet,m)and distribution profile.The R_(sheet,m)decreases by more than 30%,and it can be further decreased by 90%if the annealing temperature or duration is increased.The boron concentration of ATT-pPoly film annealed at 950℃ for 45 min is~3×10^(20)cm^(−3),and the distribution is nearly the same,except near the surface.Besides,the standard deviation coefficient(σ)of Rsheet,m is less than 5.0%,which verifies the excellent uniformity of ATT-pPoly film.

Progress in Analytical Methods of Halogenated Disinfection By-Products

Ensuring the health and safety of drinking water is crucial for both nations and their citizens.Since the 20th century,the disinfection of drinking water,effectively controlling pathogens in water sources,has become one of the significant advances in public health.However,the disinfectants used in the process,such as chlorine and chlorine dioxide,react with natural organic matter in the water to produce disinfection by-products(DBPs).Most of these DBPs contain chlorine,and if the source water contains bromine or iodine,brominated or iodinated DBPs,collectively referred to as Halogenated disinfection byproducts(X-DBPs),are formed.Numerous studies have found that X-DBPs pose potential risks to human health and the environment,leading to widespread concern.Mass spectrometry has become an important means of discovering new types of X-DBPs.This paper focuses on the study of methods for analyzing X-DBPs in drinking water using mass spectrometry.

基于by-production技术的中国绿色发展效率测度及差异化研究

在资源环境约束日益严峻的背景下,如何推动绿色发展,促进人与自然和谐共生成为中国发展道路上的关键问题。通过对中国绿色发展效率进行测度和差异化研究,能更好地把握中国绿色发展现状,进而加快实现经济可持续发展。首先,以中国30个省份为研究对象,引入了DEA框架下by-production技术测度中国绿色发展效率,该技术考虑了非期望产出只由能源投入产得的特征,更加符合实际生产过程。其次,采用Dagum基尼系数进一步探究中国绿色发展效率空间差异及其来源。通过研究发现:样本考察期内,基于by-production技术的中国绿色发展效率整体较高,绿色发展效率均值为0.84,但仍有提升空间;绿色发展效率的地区差距显著,且呈上升趋势。其中,区域间差距是最主要来源,平均贡献率为44.12%;西部地区区域内绿色发展效率差异最大;东部地区和东北地区区域间差异最大。因此,要加强区域间绿色发展交流合作,实现区域绿色协同发展。最后,针对所得结论提出了对策建议,为经济社会发展全面绿色转型提供决策参考,有助于推动实现经济效益与环境效益相统一。

多晶硅装置尾气回收工艺研究进展

综述了改良西门子法多晶硅制备工艺及尾气回收研究现状,从回收率、回收效果及能耗等方面阐述了湿法回收、膜分离回收和干法回收3种尾气回收工艺。重点概述了多晶硅尾气干法回收工艺各个单元的研究进展,并根据现状总结了未来的研究方向。

碳中和背景下我国多晶硅产业现状及发展趋势

在碳中和、碳达峰的重大时代背景下,加速能源结构转型、改变当前能源结构已成共识。本文简述了目前多晶硅主要的生产工艺流程,从多方面对比了各工艺的优缺点,详述了改良西门子法与硅烷流化床法工艺的发展趋势,指出硅烷流化床法仍有巨大改进空间,有望给我国多晶硅行业带来崭新局面。多晶硅产业逐渐向我国转移,我国市场占有率不断提升,推动双碳目标的实现也更加离不开多晶硅产业的发展。

42对棒环形布棒还原炉能量耗散研究

由于无法对大型还原炉环状硅棒排布方式对能耗的影响做出准确判断,对42对棒西门子多晶硅还原炉进行仿真模拟计算,建立两种环状硅棒布棒方式(三环排布、四环排布)的还原炉模型。通过对还原炉的炉行为及棒行为分析发现,硅棒直径加大能耗也会相应加大,且这种变化受炉内流场和温度场共同影响;同时,还原炉内内环硅棒辐射能耗随硅棒直径的增大呈先增大后减小的变化趋势,而排列在外环的硅棒辐射损耗则随硅棒直径的增大而不断增大。针对42对棒西门子还原炉内硅棒的排布方法,提出选用硅棒三环排布的方式可达到降低该还原炉总能耗的目的。

多晶硅企业事故大气环境次生污染物影响分析

本文以某企业三氯氢硅储罐泄漏、燃烧引发次生污染物氯化氢气体在大气环境中扩散的风险事故情形为例,利用AFTOX模型进行大气环境风险的分析、预测,为此类风险事故的防范、应急与减缓措施提供了建议。

多晶硅安全生产风险分析和事故预防

随着光伏产业的迅猛发展,主要生产原料多晶硅的需求增长迅速。国内多晶硅生产以三氯氢硅西门子法为主,硅烷流化床法为辅。介绍了多晶硅行业的发展概况和安全形势,以三氯氢硅西门子法为例分析了多晶硅生产过程的危险性,对行业近年来发生的安全生产事故进行了分析,剖析事故形成的原因,提出预防事故发生的措施和建议。

乙酸改性γ-Al_(2)O_(3)高效去除痕量PCl_(3)的研究

在多晶硅生产过程中,为了不影响产品性能,必须将杂质PCl_(3)的含量降低到ppb的水平,然而,这目前仍旧是一个巨大的挑战。本研究提出了一种可高效去除痕量PC13的方法,即利用乙酸改性γ-Al_(2)O_(3)作为吸附剂,其可去除ppb级别的PCl_(3),去除率高达84.2%。Boehm滴定实验表明,改性后的γ-Al_(2)O_(3)表面羧基含量大幅增加,从而增加了吸附PCl_(3)的活性位点,使其对PCl_(3)的吸附性能显著提升。表征分析和DFT模拟计算表明,乙酸与γ-Al_(2)O_(3)主要是通过γ-Al_(2)O_(3)中的羟基H和乙酸中的羰基O形成氢键而相互作用的;除了物理吸附外,γ-Al_(2)O_(3)中的Al与PCl_(3)中的Cl,以及乙酸中的羰基O与PCl_(3)中的P之间还可通过电荷转移相互作用。连续五次循环实验表明,该吸附剂在低温下具有优异的再生性能。本研究开发的吸附剂由于其高效、易于再生和低成本等特点,在去除痕量PCl_(3)方面具有潜在的应用前景。

气相色谱与质谱联用在多晶硅生产上的应用进展

多晶硅是推动国家战略能源结构和新能源产业改革,发展太阳能光伏行业的重要原材料。气相色谱技术以其卓越的分离能力和准确的测量结果,在化学分析领域发挥着至关重要的作用。研究综述了气相色谱技术及气质联用技术在多晶硅分析方面的应用进展,介绍了气相色谱的分离机理,并结合具体应用实例对气相色谱及质谱联用技术在多晶硅生产中所涉及方面的应用进行了详细阐述。

Fabrication of n^+ Polysilicon Ohmic Contacts with a Heterojunction Structure to n-Type 4H-Silicon Carbide

Polysilicon ohmic contacts to n-type 4H-SiC have been fabricated. TLM （transfer length method） test patterns with polysilicon structure are formed on n-wells created by phosphorus ion （P^＋） implantation into a Si-faced p-type 4H-SiC epilayer. The polysilicon is deposited using low-pressure chemical vapor deposition （LPCVD） and doped by phosphorous ions implantation followed by diffusion to obtain a sheet resistance of 22Ω/□. The specific contact resistance pc of n^＋ polysilicon contact to n-type 4H-SiC as low as 3.82 × 10^-5Ω· cm^2 is achieved. The result for sheet resistance Rsh of the phosphorous ion implanted layers in SiC is about 4.9kΩ/□. The mechanisms for n^＋ polysilicon ohmic contact to n-type SiC are discussed.

Resistivity Instability in Polysilicon Resistors Under Metal Interco-nnects and Its Suppression by Compensating Ion Implantation

The resistivity instability of the boron-doped polysilicon resistors being a line resistance element of ICs is within the range of several kΩ's,especially when our running the underneath metal interconnects.Polysilicon resistors have been fabricated under various processing conditions as well as some electrical and crystallographic characteristics have been obtained.It is shown the resistivity instability mainly results from the variational carrier mobility.By analyzing the Seto's model,the barrier height and trapped charge density are observed reducing under the Al over layer.Therefore,the resistance instability is also caused by both the charge trapping/detrapping occurring at polysilicon grain boundaries and the resultant variation in the potential barrier height.The formation of high-stability polysilicon resistors in the range of several kΩ's has been decided by compensating the ion implantation,which makes the charge trapping/detrapping at the grain boundary less susceptible to the hydrogen annealing.

Polysilicon Over-Etching Time Control of Advanced CMOS Processing with Emission Microscopy

The emission microscopy （EMMI） test is proposed as an effective method to control the polysilicon over-etching time of advanced CMOS processing combined with a novel test structure, named a poly-edge structure. From the values of the breakdown voltage （Vbd） of MOS capacitors （poly-edge structure） ,it was observed that,with for the initial polysilicon etching-time, almost all capacitors in one wafer failed under the initial failure model. With the increase of polysilicon over-etching time, the number of the initial failure capacitors decreased. Finally, no initial failure capacitors were observed after the polysilicon over-etching time was increased by 30s. The breakdown samples with the initial failure model and intrinsic failure model underwent EMMI tests. The EMMI test results show that the initial failure of capacitors with poly-edge structures was due to the bridging effect between the silicon substrate and the polysilicon gate caused by the residual polysilicon in the ditch between the shallow-trench isolation region and the active area, which will short the polysilicon gate with silicon substrate after the silicide process.

Recycling of Local Qatar’s Steel Slag and Gravel Deposits in Road Construction

Every year,the State of Qatar generates about 400,000 tons of steel slag and another 500,000 tons of gravel as a result of steel manufacturing and washing sand,respectively.The two materials(by-products)are not fully utilized to their best market values.At the same time,infrastructural renewal will take place in Qatar over the next ten years,and there will be a greater demand for aggregates and other construction materials as the country suffers from the availability of good aggregates.This paper presents results obtained on the use of steel slag,gravel and gabbro(control)in HMAC(hot mix asphalt concrete)paving mixtures and road bases and sub-bases.Tests were conducted in accordance with QCS-2010(Qatar Construction Specifications)and results were compared with QCS requirements for aggregates used in these applications.Based on the data obtained in this work,steel slag and gravel aggregates have a promising potential to be used in HMAC paving mixtures on Qatar’s roads,whether in asphalt base and asphalt wearing courses or as unbound aggregates in the base and sub-base pavement structure.

三层液精炼法提纯多晶硅的研究

在高温下利用密度差别,以熔硅、熔渣和熔铁(或铜)构建Si/Slag/Me三层液体系。冶金硅中的B和P杂质扩散到熔渣和底层金属中,达到提纯冶金硅的目的。热力学计算结果证明了这种方法具有可行性。实验研究分析了底层金属类型、炉渣成分及反应温度对B和P去除率的影响。结果表明:底层金属可有效吸收冶金硅中的P,其中铁比铜有更好的P吸收效果。底层金属对B的吸收效果不佳,B的去除主要归功于造渣提纯过程。在炉渣中加入10 wt%的CaF_(2),降低了渣黏度,可显著提高B和P的去除率。1600~1700℃温度范围内,提高反应温度有利于B的去除,对P的去除无显著作用。

定向凝固进程与相变界面预测模型的解析研究与实验——以太阳能级多晶硅为例

在封闭的定向凝固过程中,监控和预测凝固进程和相变界面形态是业内的难点。文章采用解析法对太阳能级多晶硅定向凝固过程进行求解,获得一种高精度凝固进程数学模型,由易于测得的散热温度和凝固时间推算凝固高度、瞬时凝固速率和熔体温度分布;通过求解Poisson(泊松)方程,建立三维的相变界面模型,揭示了熔体侧壁热流密度q值是影响界面形态的关键因素,为凝固工艺过程控制提供定量分析依据。以Si3303工业硅为原料,采用YITIPV型真空铸锭炉进行大尺寸(0.90 m×0.90 m×0.35 m)铸锭实验。对于几何对称的相变界面,凝固进程数学模型与实验曲线的最大偏差为4.43%;而对于不规则的相变界面,最大偏差为8.68%,根据实验结果修正了凝固进程模型。通过检测杂质含量、电阻率和少数载流子寿命等参数,并比较4种铸锭的典型相变界面形态,验证了三维相变界面模型的预测准确性和可靠性。该模型可以为多晶硅提纯、其他金属、非金属的精密铸造和晶体生长工艺控制提供参考。

光伏多晶硅定向凝固不平衡散热的数值研究与实验

定向凝固是物理法提纯光伏多晶硅的重要工艺方法。为改进传统定向凝固一维散热产生较大热应力和应变的缺点,提出一种新型不平衡散热结构和工艺方案,利用特定热阻设计和散热通道来降低热应力和应变。采用ProCAST软件对一维散热与不平衡散热进行三维数值建模,通过对比表明,不平衡散热方案较一维散热,热应力平均降幅可达52.56%,平均凝固速率增长20.67%,凝固时间减少17.10%,并且能在非一维温度场中保持相变界面的稳定。采用YITIPV型真空铸锭炉和3303工业硅原料,进行大尺寸铸锭(1 m×1 m×0.3 m)对照实验。实验证明,不平衡散热方案可以提高凝固速率和成品质量,制备的硅锭顶部更平整,实际总凝固时间减少15.75%,提纯单位重量硅的能耗降低17.86%,铸锭裂纹更少,有效体积更大。样片分析还表明,硅片平均电阻率提高7.86%,B、P、Al三种元素的杂质含量分别降低了28.6%、15.2%和83.3%。实验不但证实了不平衡散热结构和工艺的有效性,也验证了数值模型的适配性。该新型结构和工艺提高了铸锭质量和生产效率,降低了裂锭风险和成本,具备推广应用价值。

光总线控制系统在多晶硅项目中的应用

为解决多晶硅项目控制系统规模大、电缆敷设困难带来的设计和施工问题,基于光总线控制技术优点,结合多晶硅项目控制系统特点,提出了光总线控制系统的设计方案。以某多晶硅项目为例,介绍了该控制系统的信号传输、供电、接地的具体设计方案,以及数据光处理单元的安装保护方案,阐述了该控制系统相较于传统DCS的优势。应用表明,该控制系统能够简化工程设计,有效降低项目建设成本,提高自动化控制水平。

超高效液相色谱法测定化妆品中聚硅氧烷-15等7种脂溶性防晒剂的含量

建立了一种超高效液相色谱法测定聚硅氧烷-15等7种脂溶性防晒剂含量的方法,样品使用乙醇-四氢呋喃(体积比3∶1)混合溶剂超声提取,经Waters Symmetry C18(150×4.6 mm,3.5μm)色谱柱分离,以异丙醇-四氢呋喃(体积比90∶10)-水为流动相进行梯度洗脱,流速0.7 mL/min,柱温为25℃,检测波长311 nm。结果表明,7种脂溶性防晒剂在相应的质量浓度范围内线性关系良好(r≥0.9999),不同基质类型的样品在低、中、高3个浓度水平的平均加标回收率为94.4%~103.0%,相对标准偏差为0.4%~4.4%,检出限和定量限范围分别为0.002%~0.009%和0.005%~0.03%,各成分在48 h内稳定。采用该方法测定市售30批化妆品中的防晒剂,测定结果与《化妆品安全技术规范》(2015版)方法相比,检出的亚甲基双-苯并三唑基四甲基丁基酚、双-乙基己氧苯酚甲氧苯基三嗪等脂溶性防晒剂提取效果优于《规范》方法。该方法准确、快速、灵敏度高、稳定性好,可用于化妆品中脂溶性防晒剂的测定。