Results 51 to 60 of about 833,358 (231)

From Indicator to Prediction: Five Decades of Biochemical Oxygen Demand Research in Tropical Freshwaters

open access: yesWorld Water Policy, Volume 12, Issue 4, November 2026.
ABSTRACT Biochemical oxygen demand (BOD) remains a core indicator of organic pollution in freshwater monitoring, but its role in water policy and practice is changing as water‐quality assessment moves toward predictive, integrative, and decision‐support approaches.
Isadora Favero Roque Cenci   +5 more
wiley   +1 more source

络合滴定法测定废水中铅离子的浓度

open access: yesGongye shui chuli, 2002
介绍了一种测定铅离子浓度的新方法,克服了常用方法 (双硫腙比色法、原子吸收分光光度法 )要使用剧毒物质KCN、绘制标准曲线、操作过程复杂及仅适合低浓度测定等局限性。该方法测定过程简单,测定结果准确(相对误差为 0.0 18%,相对标准偏差为 0.4 1 ...
李方文   +4 more
doaj   +2 more sources

泥料水分快速测定器(硬度计) 附视频

open access: yesDianci bileiqi, 1979
根据弹性体、虎克定律的原理试制成泥料水分快速测定器.本文介绍了测定器的基本结构,测量方法及测定值的对比.
doaj  

一种测定离子的传感器及其监测方法

open access: yes, 2010
本发明涉及传感器,具体地说是一种测定离子的传感器及其检测方法。控制电位仪通过导线分别连接工作电极和外参比电极;工作电极和外参比电极插入容器中,容器下设有磁铁;工作电极由聚氯乙烯管和插于之中的内参比电极组成,聚四氟乙烯管底部设有敏感膜;检测:将功能化磁性纳米材料的检测液与待测样品混合并发生反应,然后抽取混合溶液加入到工作电极中,在磁场的作用下,磁性纳米材料将被吸引到膜上同时产生电位变化,根据电位变化速率检测待测溶液中所测物质的含量。本发明具有灵敏度高、操作成本低、适合现场监测,可以在环境监测 ...
*秦伟, 宋德安
core  

There Is Always a Bigger Fish. Determinants of Power Perceptions in Swiss Biodiversity Policy

open access: yesPolicy Studies Journal, Volume 54, Issue 4, November 2026.
ABSTRACT The Advocacy Coalition Framework (ACF) views power as crucial in policy processes, but the nature of coalition power, its determinants, and how to empirically measure it remain understudied. In this article, we use a mixed method approach and social network analysis to explore power relationships in the biodiversity policy subsystem in ...
Alix d'Agostino   +2 more
wiley   +1 more source

水质中钙、镁和硬度的在线监测

open access: yesGongye shui chuli, 1998
对水质中钙、镁和硬度的在线监测方法进行了研究.利用稳定性好、灵敏度高的偶氮氯膦Ⅲ作显色剂,在pH70时,加入EGTA掩蔽钙,测定镁;在pH为25,掩蔽镁的干扰,测定钙,在线分析时,采用混合分析流程,加三通分流消除气泡干扰,测定数据稳定可靠,镁的测试范围1×10-3~48×10-3mmol/L,钙的测试范围1×10-3~50×10-3mmol/L,钙镁的检测限05×10-3mmol/L,该方法开发成在线仪器,可单独测定钙、镁,又可根据水样得到水质硬度,具有较好的实用性.
杨铸, 孙原
doaj   +2 more sources

滇池非封闭围隔水体底栖动物的监测调查

open access: yes, 2004
报道了昆明滇池蓝藻水华污染控制技术中,非封闭围隔水体试验区马村湾、海东湾底栖动物1年的定量、定性监测结果。调查中共采到底栖动物27科、68种;定量采样点底栖动物全年平均密度为7198.11条/m2,生物量为60.16g/m2;分析了本底调查与监测调查中种类的消长、分布 ...
王丽珍,刘永定,肖帮定
core  

Compliance in Regulatory Gray Areas: The Case of the Organic Seed Standard

open access: yesPolicy Studies Journal, Volume 54, Issue 4, November 2026.
ABSTRACT Adaptive regulations, designed to balance flexibility with accountability, can embed provisions that unintentionally leave room for firms to shirk on their responsibilities by exploiting flexibility. We call these provisions “regulatory gray areas,” and ask: how should we understand (non‐)compliance in adaptive regulatory settings?
Liza Wood   +3 more
wiley   +1 more source

血糖测定的影响因素研究

open access: yesZhongguo shiyan zhenduanxue, 2006
目的研究己糖激酶法和葡萄糖氧化酶法测定血液血糖含量时的干扰因素及其影响程度。方法应用己糖激酶法和葡萄糖氧化酶法试剂盒对临床标本进行血糖的测定,观察其时间反应曲线,同时测定其它24项常用生化示,分析对血糖测定产生干扰的物质及其影响程度。结果通过对临床标本的测定,我们发现体内的代谢产物对己糖激酶法血糖测定产生两种干扰,一种是在胆红素增高时伴随的快速干扰,一种是在革些病理情况下产生的慢反应干扰。结论血糖测定是临床最常用的检测指标,准确测定血糖浓度对指导临床治疗非常重要,所以研究血糖测定的干扰因素是非常有意义的。
王连明   +3 more
doaj  

反相氨基酸专用色谱柱及其紫外吸收定量测定法

open access: yes, 1994
一种反相氨基酸专用色谱柱及紫外吸收定量测定法,采用如下结构的填料填充色谱柱。$X为硅烷基#RY为长链烷基#R&用l-氟-2,4-二硝基苯和待测氨基酸反应,生成氨基酸的衍生物。将该衍生物用带紫外吸收检测器和装有上述色谱柱的普通高效液相色谱仪进行分析,即可得到氨基酸衍生物的色谱图,根据该色谱图可定量地测定氨基酸的含量 ...
于亿年, 周良模, 商振华
core  

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