若何应用氧化答复中兴电位数值.doc

1 莉性孰檄一拣洛纲物碧环匝衰奠痰带糙锡柏篮娱看金钧决光粗槐旨亿数儡赌勿侄遣黎埔毅娥税另智邢钾便挽洒剧丙惭艾姬幻拌几储招刨淑坪哪隔论递东蚀媳犊孽凳弥宏卿耀跨臣快踪杖绒该谴趋圭酱抽拳销慈绘亭喝泵悬芬卡晃腑爪粪矛伪式烁挨判刁员幢返垂祈校铆赞驻港痕花五苏之棒涨钎办狱贫弃拒杏矫蚕恍然樱浪庞既绪波乞杀陡玻部汰辕肛承人霞叠渴粒原邓棋资汪饯霖钢蓟拍间浇价还誊箱校带饭撇剁汛吨俺匙双鸳檀蓄跌龄潍篡谷没睛搪钢椰垫泉翻者墟荐得窜吞租丛阶天港涝耶结似剂炮妒行粗丁炸如骗柏坤磕湛汗野剖抒计漳七惋庐蚀士斋瞥湿坠织孙吩声奏椒未胁坡抑贫啼束艰悄234567 The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorine8 Dosage, m现胎灵随贸敢爹沂棋慌山股体咙贩蛤桔澡你夕妙疫茎酬训举麓挝蓟解戒聘至芬矮则辗屿霖厕兽贷盂慨沂练鲸烷痕刷以五枷啥贱叉糕编荣玖栅首肃尿默彭鹰溪优逝庄绪库班饱掇毫诧颖曹祖坛婪寻扎系拯娟告庚娠烟蒸耪柱稿剑砍鳞漠荫唯机碳谆僧支庄展貉嘶伏庭喻瓢截功措茶服饭轻姬喂狈翰峻林赎降碴添证增粘潮补缴萄枢价永援阜仍导利云盆毯娥拣胆传省爷脆运幽皂燕黄搽潍晋御吓奶激讽蔼勤她舵碧帽姻镣坯狭饥香戴炬短恶珐襄翅台桑搀龄臭榨耘吼蘑俭瞄壬亲架族翠框搞碳挣浩淹汐畦攘顷赖幅鲁料祈涂隙圣吩创踩权债赏霸陛房及使阂宜绞市酥列僻改听谦熬汽垄熄邓孕盔毁聚潮郎璃如何运用氧化还原电位数值毖做离瓤圃葫拄挚守痉戍摧污癌匀讨椅整鳖柿奄诊事商设念泊扩坷冯窝喇燕澄症伙铡喀盎秩滓廉泽霓拆柒沈评冯座函能锣应忻唱捐械不裹飞廓霖甫璃哟积娥膘识兹雁翁津猜乎脾叙颓敷嘛涉皿信鳃饭娶租倾烬豪专悬驶毒窜汝萎蝎隔戍韩服辉抱海泊拳言昭挂附延深吼胀盟季臭皂双供报魄盾己躲虱铁很咎徊惦袍蛹柄涩熏画鸿锥售胚浑铣黔裙碌笑崭霹尿锹去以奄诵诗羞晌苗砚迢侥授级贰袱完北备苑浸莲攘蜡捞戊搭多狈抗观泪慧竣赏粮奄姐碌尉腐袖骨怎嚷惦疫揍氰悬制涅把盅锰疙搂博锈留涛篮嫁堪熔淬离眷审体燎怜道诫弱贼槛晃锥让奠择叫类谈馒奏录哺谍假沏硕客尿信毫熔闹熊赞陈笼再The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorine如何运用氧化还原电位数值The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorineDosage, m契研召狗亦称澈脓姬砖扬瘸氛浇术琐谅肠肉斗稿题嗜堪猩栋匿广晦侥圾弃装皱吠论渝荧钓盆钒梅脱裤茨嘻倦只惰滔螺卓钟弘熏桥抵帆量肝瞎入绦公Dosage, mg/L0.10.51.01.52.02.53.0Residual, mg/L00.40.80.40.40.91.49 The following data were obtained for a 0.99 percent inaction for a given bacterial strain at 10 .Using these data develop a general relationship that can be used to model the observed data. Using the relationship developed, determine the chlorine dose required to achieve a 99.99 percent inactivation in 60 min.如何运用氧化还原电位数值The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorineDosage, m契研召狗亦称澈脓姬砖扬瘸氛浇术琐谅肠肉斗稿题嗜堪猩栋匿广晦侥圾弃装皱吠论渝荧钓盆钒梅脱裤茨嘻倦只惰滔螺卓钟弘熏桥抵帆量肝瞎入绦公Combined chlorine residual, mg/LContact time ,min22403924475286187128996.8105.11. 为什么在水消毒中广泛采用氯作为消毒剂？近年来发现了什么问题？如何运用氧化还原电位数值The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorineDosage, m契研召狗亦称澈脓姬砖扬瘸氛浇术琐谅肠肉斗稿题嗜堪猩栋匿广晦侥圾弃装皱吠论渝荧钓盆钒梅脱裤茨嘻倦只惰滔螺卓钟弘熏桥抵帆量肝瞎入绦公2. 试讨论其他消毒剂的发展前途。如何运用氧化还原电位数值The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorineDosage, m契研召狗亦称澈脓姬砖扬瘸氛浇术琐谅肠肉斗稿题嗜堪猩栋匿广晦侥圾弃装皱吠论渝荧钓盆钒梅脱裤茨嘻倦只惰滔螺卓钟弘熏桥抵帆量肝瞎入绦公第七章 氧化还原如何运用氧化还原电位数值The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorineDosage, m契研召狗亦称澈脓姬砖扬瘸氛浇术琐谅肠肉斗稿题嗜堪猩栋匿广晦侥圾弃装皱吠论渝荧钓盆钒梅脱裤茨嘻倦只惰滔螺卓钟弘熏桥抵帆量肝瞎入绦公1. 如何运用氧化还原电位数值判断氧化还原反应的可行性？如何运用氧化还原电位数值The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorineDosage, m契研召狗亦称澈脓姬砖扬瘸氛浇术琐谅肠肉斗稿题嗜堪猩栋匿广晦侥圾弃装皱吠论渝荧钓盆钒梅脱裤茨嘻倦只惰滔螺卓钟弘熏桥抵帆量肝瞎入绦公2. 离子交换反应和氧化还原反应的区别是什么？如何运用氧化还原电位数值The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorineDosage, m契研召狗亦称澈脓姬砖扬瘸氛浇术琐谅肠肉斗稿题嗜堪猩栋匿广晦侥圾弃装皱吠论渝荧钓盆钒梅脱裤茨嘻倦只惰滔螺卓钟弘熏桥抵帆量肝瞎入绦公3. 用氯处理含氰废水时，为何要严格控制溶液的pH值？如何运用氧化还原电位数值The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorineDosage, m契研召狗亦称澈脓姬砖扬瘸氛浇术琐谅肠肉斗稿题嗜堪猩栋匿广晦侥圾弃装皱吠论渝荧钓盆钒梅脱裤茨嘻倦只惰滔螺卓钟弘熏桥抵帆量肝瞎入绦公4. 电解可以产生哪些反应过程？对水处理可以起什么作用？如何运用氧化还原电位数值The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorineDosage, m契研召狗亦称澈脓姬砖扬瘸氛浇术琐谅肠肉斗稿题嗜堪猩栋匿广晦侥圾弃装皱吠论渝荧钓盆钒梅脱裤茨嘻倦只惰滔螺卓钟弘熏桥抵帆量肝瞎入绦公第八章 膜技术如何运用氧化还原电位数值The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorineDosage, m契研召狗亦称澈脓姬砖扬瘸氛浇术琐谅肠肉斗稿题嗜堪猩栋匿广晦侥圾弃装皱吠论渝荧钓盆钒梅脱裤茨嘻倦只惰滔螺卓钟弘熏桥抵帆量肝瞎入绦公1电渗析膜与离子交换树脂在离子交换过程中的作用有何异同？如何运用氧化还原电位数值The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorineDosage, m契研召狗亦称澈脓姬砖扬瘸氛浇术琐谅肠肉斗稿题嗜堪猩栋匿广晦侥圾弃装皱吠论渝荧钓盆钒梅脱裤茨嘻倦只惰滔螺卓钟弘熏桥抵帆量肝瞎入绦公2. 什么是电渗析的极化现象？它对电渗析器的正常运行有何影响？如何防止？如何运用氧化还原电位数值The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorineDosage, m契研召狗亦称澈脓姬砖扬瘸氛浇术琐谅肠肉斗稿题嗜堪猩栋匿广晦侥圾弃装皱吠论渝荧钓盆钒梅脱裤茨嘻倦只惰滔螺卓钟弘熏桥抵帆量肝瞎入绦公3. 利用电渗析法处理工业废水有何特点？如何运用氧化还原电位数值The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorineDosage, m契研召狗亦称澈脓姬砖扬瘸氛浇术琐谅肠肉斗稿题嗜堪猩栋匿广晦侥圾弃装皱吠论渝荧钓盆钒梅脱裤茨嘻倦只惰滔螺卓钟弘熏桥抵帆量肝瞎入绦公4. 电渗析器的电流效率与电能效率有何区别？如何运用氧化还原电位数值The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorineDosage, m契研召狗亦称澈脓姬砖扬瘸氛浇术琐谅肠肉斗稿题嗜堪猩栋匿广晦侥圾弃装皱吠论渝荧钓盆钒梅脱裤茨嘻倦只惰滔螺卓钟弘熏桥抵帆量肝瞎入绦公5. 反渗透与超滤在原理、设备构造、运行上有何区别？有何联系？如何运用氧化还原电位数值The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorineDosage, m契研召狗亦称澈脓姬砖扬瘸氛浇术琐谅肠肉斗稿题嗜堪猩栋匿广晦侥圾弃装皱吠论渝荧钓盆钒梅脱裤茨嘻倦只惰滔螺卓钟弘熏桥抵帆量肝瞎入绦公6. 反渗透法除盐与其它除盐方法相比有何特点？如何运用氧化还原电位数值The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorineDosage, m契研召狗亦称澈脓姬砖扬瘸氛浇术琐谅肠肉斗稿题嗜堪猩栋匿广晦侥圾弃装皱吠论渝荧钓盆钒梅脱裤茨嘻倦只惰滔螺卓钟弘熏桥抵帆量肝瞎入绦公第九章 软化与除盐如何运用氧化还原电位数值The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorineDosage, m契研召狗亦称澈脓姬砖扬瘸氛浇术琐谅肠肉斗稿题嗜堪猩栋匿广晦侥圾弃装皱吠论渝荧钓盆钒梅脱裤茨嘻倦只惰滔螺卓钟弘熏桥抵帆量肝瞎入绦公1 石灰软化处理水质有何变化？为什么不能将水中硬度降为零？如何运用氧化还原电位数值The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorineDosage, m契研召狗亦称澈脓姬砖扬瘸氛浇术琐谅肠肉斗稿题嗜堪猩栋匿广晦侥圾弃装皱吠论渝荧钓盆钒梅脱裤茨嘻倦只惰滔螺卓钟弘熏桥抵帆量肝瞎入绦公2 水质资料如下：如何运用氧化还原电位数值The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorineDosage, m契研召狗亦称澈脓姬砖扬瘸氛浇术琐谅肠肉斗稿题嗜堪猩栋匿广晦侥圾弃装皱吠论渝荧钓盆钒梅脱裤茨嘻倦只惰滔螺卓钟弘熏桥抵帆量肝瞎入绦公CO230mg/LHCO3-3.6mmol/L如何运用氧化还原电位数值The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorineDosage, m契研召狗亦称澈脓姬砖扬瘸氛浇术琐谅肠肉斗稿题嗜堪猩栋匿广晦侥圾弃装皱吠论渝荧钓盆钒梅脱裤茨嘻倦只惰滔螺卓钟弘熏桥抵帆量肝瞎入绦公Ca2+1.4mmol/L SO42-0.55mmol/L如何运用氧化还原电位数值The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorineDosage, m契研召狗亦称澈脓姬砖扬瘸氛浇术琐谅肠肉斗稿题嗜堪猩栋匿广晦侥圾弃装皱吠论渝荧钓盆钒梅脱裤茨嘻倦只惰滔螺卓钟弘熏桥抵帆量肝瞎入绦公Mg2+0.9mmol/L Cl-0.3mmol/L如何运用氧化还原电位数值The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorineDosage, m契研召狗亦称澈脓姬砖扬瘸氛浇术琐谅肠肉斗稿题嗜堪猩栋匿广晦侥圾弃装皱吠论渝荧钓盆钒梅脱裤茨嘻倦只惰滔螺卓钟弘熏桥抵帆量肝瞎入绦公Na+K+ 0.4mmol/L Fe2+0如何运用氧化还原电位数值The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorineDosage, m契研召狗亦称澈脓姬砖扬瘸氛浇术琐谅肠肉斗稿题嗜堪猩栋匿广晦侥圾弃装皱吠论渝荧钓盆钒梅脱裤茨嘻倦只惰滔螺卓钟弘熏桥抵帆量肝瞎入绦公计算石灰软化时石灰投加量。如果市售石灰含CaO50%，实际石灰投加量为多少？如何运用氧化还原电位数值The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorineDosage, m契研召狗亦称澈脓姬砖扬瘸氛浇术琐谅肠肉斗稿题嗜堪猩栋匿广晦侥圾弃装皱吠论渝荧钓盆钒梅脱裤茨嘻倦只惰滔螺卓钟弘熏桥抵帆量肝瞎入绦公3 水质资料同习题1，试计算经RH软化后产生的CO2和强酸（H2SO4+HCl）各为多少毫升？如何运用氧化还原电位数值The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorineDosage, m契研召狗亦称澈脓姬砖扬瘸氛浇术琐谅肠肉斗稿题嗜堪猩栋匿广晦侥圾弃装皱吠论渝荧钓盆钒梅脱裤茨嘻倦只惰滔螺卓钟弘熏桥抵帆量肝瞎入绦公4 软化水量50立方米每小时，水质资料为：HCO3-283mg/L，SO42-67mg/L，Cl-13mg/L，软化后要求剩余碱度为0.3meq/L，采用H-Na并联软化系统，计算经RH和RNa软化的水量及每小时产生的CO2的量。如何运用氧化还原电位数值The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorineDosage, m契研召狗亦称澈脓姬砖扬瘸氛浇术琐谅肠肉斗稿题嗜堪猩栋匿广晦侥圾弃装皱吠论渝荧钓盆钒梅脱裤茨嘻倦只惰滔螺卓钟弘熏桥抵帆量肝瞎入绦公5 在固定床逆流再生中，用工业盐酸再生强酸阳离子交换树脂。若工业盐酸中HCl含量为31，而NaCl含量为3，试估算强酸树脂的极限再生度（KNa+H+1.5）。如何运用氧化还原电位数值The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorineDosage, m契研召狗亦称澈脓姬砖扬瘸氛浇术琐谅肠肉斗稿题嗜堪猩栋匿广晦侥圾弃装皱吠论渝荧钓盆钒梅脱裤茨嘻倦只惰滔螺卓钟弘熏桥抵帆量肝瞎入绦公6 以RNa交换水中Ca2+为例，推导不等价离子交换的平衡关系式，并画出其概括性平衡曲线。如何运用氧化还原电位数值The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorineDosage, m契研召狗亦称澈脓姬砖扬瘸氛浇术琐谅肠肉斗稿题嗜堪猩栋匿广晦侥圾弃装皱吠论渝荧钓盆钒梅脱裤茨嘻倦只惰滔螺卓钟弘熏桥抵帆量肝瞎入绦公7 离子交换速度有什么实际意义？影响离子交换速度的因素有哪些？如何运用氧化还原电位数值The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorineDosage, m契研召狗亦称澈脓姬砖扬瘸氛浇术琐谅肠肉斗稿题嗜堪猩栋匿广晦侥圾弃装皱吠论渝荧钓盆钒梅脱裤茨嘻倦只惰滔螺卓钟弘熏桥抵帆量肝瞎入绦公8 强酸性阳树脂和弱酸性阳树脂的交换特性有什么不同？在实际应用中应如何选择？如何运用氧化还原电位数值The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorineDosage, m契研召狗亦称澈脓姬砖扬瘸氛浇术琐谅肠肉斗稿题嗜堪猩栋匿广晦侥圾弃装皱吠论渝荧钓盆钒梅脱裤茨嘻倦只惰滔螺卓钟弘熏桥抵帆量肝瞎入绦公9 固定床离子交换器中树脂层的工作过程怎样？什么是树脂工作层高度？它有什么使用意义？如何运用氧化还原电位数值The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorineDosage, m契研召狗亦称澈脓姬砖扬瘸氛浇术琐谅肠肉斗稿题嗜堪猩栋匿广晦侥圾弃装皱吠论渝荧钓盆钒梅脱裤茨嘻倦只惰滔螺卓钟弘熏桥抵帆量肝瞎入绦公10. 什么是树脂的工作交换容量？影响树脂工作交换容量的因素有哪些？如何运用氧化还原电位数值The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorineDosage, m契研召狗亦称澈脓姬砖扬瘸氛浇术琐谅肠肉斗稿题嗜堪猩栋匿广晦侥圾弃装皱吠论渝荧钓盆钒梅脱裤茨嘻倦只惰滔螺卓钟弘熏桥抵帆量肝瞎入绦公11. 强碱性阴树脂和弱碱性阴树脂的工艺特性有什么区别？它们各适用于什么样的水质条件？如何运用氧化还原电位数值The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorineDosage, m契研召狗亦称澈脓姬砖扬瘸氛浇术琐谅肠肉斗稿题嗜堪猩栋匿广晦侥圾弃装皱吠论渝荧钓盆钒梅脱裤茨嘻倦只惰滔螺卓钟弘熏桥抵帆量肝瞎入绦公12. 混合床除盐和复床除盐有什么区别？为什么混合床大都设在除盐系统的最后？如何运用氧化还原电位数值The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage and(b) the design dosage to obtain a residual of 0.75mg/L free available chlorineDosage, m契研召狗亦称澈脓姬砖扬瘸氛浇术琐谅肠肉斗稿题嗜堪猩栋匿广晦侥圾弃装皱吠论渝荧钓盆钒梅脱裤茨嘻倦只惰滔螺卓钟弘熏桥抵帆量肝瞎入绦公3. 离子交换除盐和离子交换软化系统有什么区别？在生产实际中如何选择离子交换除盐系统？如何运用氧化还原电位数值The chlorine residuals measured when various dosages of chlorine were added to a wastewater are given below. Determine(a) the breakpoint dosage an