Impact of posture and upper-limb muscle activity on grip strength

Purpose. The current research was carried out to determine grip strength (GS) with change in posture and upper-limb muscle activity of manual workers and investigate the impacts of these changes. Methods. For the current research, 120 male and 80 female participants were selected and GS was assessed using a digital hand grip dynamometer in various conditions. Results. The outcomes showed that male participants had higher GS as compared to female participants. Maximum GS was found in a standing posture with the fixed forward shoulder at 45°, elbow at 90° and a neutral position of the wrist and forearm for all participants. Conclusions. Higher values of GS were attained in standing postures which may result in attainment of higher performance levels by the workers. The outcomes justify the importance of correct postures during manual work in industries employing traditional methods.     

Changes in fetal heart rate pattern after intrauterine paracentesis in one twin with meconium peritonitis

We report a case of in utero paracentesis of ascites in a fetus with meconium peritonitis due to volvulus at 34 weeks which resulted in the correction of an abnormal fetal heart rate pattern and enabled vaginal delivery by preventing abdominal dystocia. The intrauterine intervention also helped to establish the diagnosis and potentially reduced the respiratory compromise after birth. Copyright © 2001 John Wiley & Sons, Ltd.     

加入SOA示踪的深圳大气PM2.5受体模型源解析

为厘清包括二次有机气溶胶（SOA）在内的深圳市区PM_2.5各种一次和二次来源贡献,本文于2017年9月2日~2018年8月29日在深圳市大学城点位开展PM_2.5样品采集,并进行化学组分和水溶性有机物（WSOM）质谱测量,共获得162组有效数据.观测期间深圳市大气PM_2.5平均质量浓度为26μg/m³,在传统PMF源解析的基础上加入羧基离子碎片（CO₂⁺）作为SOA的示踪物,加入水溶性有机氧（WSOO）用于计算各因子O/C,验证有机物解析效果.结果表明,SOA可以被独立解析出,其O/C明显高于其他一次污染源中有机物;机动车、二次硫酸盐、二次硝酸盐、SOA为最主要的4个源,对PM_2.5质量浓度的贡献分别为25%、23%、17%和10%,船舶、地面扬尘、老化海盐、建筑尘、生物质燃烧、燃煤和工业贡献均在5%以内.各个源的变化特征表明,机动车、二次硫酸盐、二次硝酸盐、SOA等源贡献呈现冬高夏低的季节特征,与冬季季风条件下源自内陆的污染传输密切相关.污染天气时,二次硝酸盐和SOA的贡献增加相对最显著,因此NOx和挥发性有机物是减排的关键.     

人工智能技术对长江流域水污染治理的思考

随着经济的快速发展和城市化进程的不断加速,促使水污染严重的长江流域需从污染物去除过程的建模与优化、污水处理过程的优化控制、水污染监测系统的构建开展水污染治理研究.传统的水污染处理技术存在污染物去除效率预测精度较低、污水优化控制成本较高、水污染监测滞后效应严重的问题.人工智能技术能够有效克服上述问题,因此通过梳理国内外学者利用人工智能技术在污水污染物去除过程的建模与优化、污水处理过程的优化控制及水污染监测系统的构建等方面的研究成果,为全面加强长江流域水污染治理能力提供科学可靠的技术指导.结果表明:①利用人工神经网络技术（径向基神经网络、多层前馈网络-人工神经网络、多层感知器神经网络）对污水污染物去除过程进行建模与优化,为精确预测长江流域重金属（Cr、Cu）、营养盐（TN、TP）、持久性有机污染物〔PBDEs（多溴二苯醚）、HCH（六氯环己烷）〕的去除率提供重要参考价值.②采用污水处理的自动控制技术与人工智能技术（递归神经网络、支持向量机、模糊神经网络等）构建污水智能控制系统,为长江流域实现高效节能的污水优化控制提供重要的技术指导.③利用在线监测仪器和人工智能技术（小波神经网络、多元线性回归-人工神经网络、叠层去噪自动编码器等）建立水污染智能监测系统,为解决长江流域水污染监测响应滞后问题提供有力的技术支持.因此,人工智能技术对长江流域提高污水污染物去除率,降低污水优化控制成本,提升水污染监测时效性具有重要的推广价值.      

2018年秋冬季长江三角洲区域PM2.5污染来源数值研究

使用WRF-Chem和WRF-FLEXPART模式定量研究了2018年秋冬季,尤其是在明显冷空气影响时的长江三角洲PM_2.5来源贡献.结果表明：2018年秋冬季长江三角洲以外的跨区域输送对长江三角洲PM_2.5的贡献占15.9%,长江三角洲内部排放贡献占84.1%,长江三角洲区域内部排放及污染相互传输的影响比长江三角洲外跨区域输送的影响更为显著.而在冷空气影响时段中,跨区域输送对长江三角洲PM_2.5的贡献率为33.1%,约为整个秋冬季长江三角洲外部跨区域平均输送贡献率的2倍,输送影响更为明显;输送对长江三角洲三省一市的贡献为46.2%~56.2%,其中跨区域输送的贡献10.2%~38.6%,也明显大于各自秋冬季的平均水平.在冷空气影响时段,长江三角洲四座重点城市（上海、合肥、南京、杭州）的污染潜在输送路径主要以中东路为主;上海、南京受到长江三角洲以外的污染潜在贡献较多,超过30%;杭州受到长江三角洲以外的污染潜在贡献较少,为16.1%.     

近10年中国三大经济区太阳总辐射特征及其与O3、PM2.5的关系

采用中国地面气象观测站网2007~2016年的辐射日值数据集和中国空气质量在线监测平台2014~2016年逐日观测数据,分析了京津冀、长三角和珠三角近10a太阳总辐射年际和季节变化,近3a臭氧日最大8h平均（O_{3_8h_max}）和细颗粒物（PM_2.5）的污染过程频次变化,通过不同因子及其不同强度等级的分型统计,探讨PM_2.5、O_{3_8h_max}与太阳总辐射的关系.结果表明：京津冀近10a太阳总辐射显著上升,京津冀春季和珠三角夏季太阳总辐射显著上升.三大经济区PM_2.5污染过程年频次均呈现逐年递减,且从北到南递减;O₃污染过程年频次时间上呈现先减后增,空间上京津冀多于长三角和珠三角.三大经济区O_{3_8h_max}与太阳总辐射相关系数均在0.71以上,有较强的正相关;而PM_2.5与太阳总辐射的相关性具有区域差异性.三大经济区不同季节不同太阳总辐射下O_{3_8h_max}与PM_2.5的相关关系差异显著,其中京津冀春夏秋三季O_{3_8h_max}与PM_2.5在强太阳总辐射下有较好的正相关,冬季则存在一定的负相关;长三角四季两者相关性均较弱;珠三角夏季两者正相关最为显著;不同PM_2.5浓度下O_{3_8h_max}与太阳总辐射的线性拟合效果较好,体现出较强的正相关关系,各经济区拟合曲线的倾向率均随PM_2.5升高而增大.PM_2.5>75μg/m³时拟合优度均达到最大.     

海洋平台阴极保护与监测技术的应用

针对海洋平台全浸区的腐蚀情况,着重介绍了阴极保护及其原理、种类及特点,监测系统的组成及设计,探讨阴极保护及监测系统对海洋平台水下防腐的应用意义。     

海洋环境低水位加速腐蚀研究进展

以海洋环境中一个非常重要的局部腐蚀形式——低水位加速腐蚀(ALWC)为对象,自其检测、发生原因、防护三个方面就国内外的文献报告进行综述分析。在检测方面,首先介绍了常用的宏观观察这一被动形式,并突出其特征,然后介绍了利用海水中可溶性无机氮含量作为ALWC发生概率预测这一主动形式,分析其优势与不足。在发生原因方面,在对将ALWC认定为一种典型的微生物腐蚀(MIC)形式的认知过程进行介绍之后,重点分析了微生物对ALWC作用机制不清晰的原因,并建议在后续研究中突出动态演变过程,结合高通量测序等分子生物学技术,确定在不同的阶段影响ALWC的关键微生物,且进一步在大气-海水体系下研究典型菌株及其协同作用的影响,提出微生物对ALWC的作用机制。在防护方面,根据新建和已建钢结构设施分别对传统和针对ALWC所具有的MIC与局部腐蚀特性的新型高效防护方法进行了介绍,并分析了防护方法的优缺点。     

Development of monitoring technology for airborne particulate matter

Particulate matter suspended in the air has adverse effects onhuman health. Its level of concentration is an important parameter in evaluating the degree of hazard it poses to the atmosphere. Conventional methods used in measuring particulatematter are often filter-based, which indicates some disadvantagesbecause such a base requires labor and time. In this study, to achieve real-time measurements, a new electrical method was developed for measuring PM10 and PM2.5 concentrations. The basicprinciple is to electrically charge particles passing through thePM inlet using a corona charger and measure the currents createdby charged particles to obtain the number concentration of particulate matter. A new type inlet based on the particle cupimpactor configuration was designed and its performance was evaluated. A unipolar diffusion charger was developed and thecharger's efficiency was determined experimentally in terms ofPn, which represents the penetration through the charger,P, times the average charge number acquired by a particle,n, for different particle sizes. The correlation was constructed between the PM10 (or the PM2.5) mass concentrationsand the electrical currents due to particles, which were chargedby the diffusion charger.     

Monitoring Air Quality in Mountains: Designing an Effective Network

A quantitatively robust yet parsimonious air-quality monitoring network in mountainous regions requires special attention to relevant spatial and temporal scales of measurement and inference. The design of monitoring networks should focus on the objectives required by public agencies, namely: 1) determine if some threshold has been exceeded (e.g., for regulatory purposes), and 2) identify spatial patterns and temporal trends (e.g., to protect natural resources). A short-term, multi-scale assessment to quantify spatial variability in air quality is a valuable asset in designing a network, in conjunction with an evaluation of existing data and simulation-model output. A recent assessment in Washington state (USA) quantified spatial variability in tropospheric ozone distribution ranging from a single watershed to the western third of the state. Spatial and temporal coherence in ozone exposure modified by predictable elevational relationships ( 1.3 ppbv ozone per 100 m elevation gain) extends from urban areas to the crest of the Cascade Range. This suggests that a sparse network of permanent analyzers is sufficient at all spatial scales, with the option of periodic intensive measurements to validate network design. It is imperative that agencies cooperate in the design of monitoring networks in mountainous regions to optimize data collection and financial efficiencies.