光化学氧化剂测定实验中的模拟采样装置

本文对在光化学氧化剂测定实验教学中遇到的采样问题进行了探讨，并利用自制的模拟采样装置很好地解决了这一实验教学难题。     

碘量法快速测定烟气SO2

烟气SO2的测定,无论是碘量法还是光度法,都需要先采样后分析,费时较多。本文在碘量法的基础上,提出一种烟气SO2快速测定方法,采样、分析同时完成,操作简便、快速,现场适应性强。     

蓬溪县赤城湖藻类植物的组成调查

2006年8月至2007年3月分4次对蓬溪县赤城湖进行了藻类植物定性样品和定量样品的采集,共设置11个采样点,并对各采样点的水温、气温、pH、透明度等指标进行了测定。经鉴定和分析,结果表明：赤城湖水生藻类植物共有8门,38科,81属,220种（含变种和变型）。     

利用intel8253芯片确定电网参数采样时间的方法探讨

针对电网频率不稳定给电网参数采样测量带来的影响,详细分析讨论利用定时计数器芯片intel8253及相应电路准确测定电网周期,进而准确确定电网参数采样时间的原理﹑方法,以及具体的实现电路.     

微波消解及ICP-AES同时测定土壤中多种元素含量

在盐碱土壤改良等项目进行过程中,需要进行大量的土壤采样和测试工作。为此,需要提供一种能够快速测定土壤中主要元素含量的测试方法。采用微波消解仪将土壤样品全消解,ICP-AES同时测定其中多种元素。对微波消解条件、酸体系等进行了分析和实验优化,确定了最佳条件。该方法样品消解完全、用酸量小、方便快速、测定结果满意。     

微弱周期信号频率检测的一种改进方法

微弱信号的频率检测是微弱信号处理的一个重要内容,也是判定微弱信号幅度和相位的重要前提.文章提出一种方法,将AD采样数据先用结构函数算法粗略判定信号频率,然后进行数字预滤波,最后再次使用结构函数算法准确测定频率.该方法完全数字化,在带AD采样和存储器的微处理器系统上均可实现,编程简单,且不要求实时性,很容易在本科生的微弱信号检测实验中实施.实验证明,该算法对于信噪比为-20 dB以上的信号都具有很好的频率检测精度.在实验中提高采样AD的位数、采样频率、采样点数可进一步提高检测精度.     

煤炭采样器的设计与开发

自主研发的煤炭采样器具有广阔市场前景。分析了现有短螺旋、长螺旋和爪式采样头的结构和工作原理,发现现有的采样头存在一些设计缺陷,如短螺旋采样头破碎能力不强、长螺旋采样头螺旋叶片耐磨性差、爪式采样头强度刚度不足等。通过对采样头升降机构、旋转机构和采样装置进行创新设计,形成了一套结构简单、操作方便、可靠性高,而且能有效克服现有采样头设计缺陷的新型采样头,完成了采样头尺寸设计及零部件强度校核。新型采样头上线使用之后,各项指标都达到了现场采样要求,并实现了极寒天气条件下的破冰和自动取样,效果良好。     

南京市六合区农田土壤中PAHs的含量及评价

文章研究采集了江苏省南京市六合区农田土壤的表层土(0—15cm),用高效液相色谱测定了土壤中16种多环芳烃(PAHs)的含量.结果表明,采样点土壤中PAHs总量在45.6μg/kg~210.9μg/kg之间.在检测的PAHs中,二环、三环、四环的PAHs含量之和约为总量的51.0%~92.5%.采用PAHs总量和内梅罗综合污染指数方法评价污染水平,南京市六合区农田采样点土壤中PAHs含量基本上是处于安全水平.     

连续监测大气中二氧化硫甲醛吸收液稳定性对分析结果影响

通过测定大气中二氧化硫甲醛吸收液稳定性分析测试 ,探讨吸收液稳定性对 2 4小时监测结果的影响 ,及采样时间、流量和吸收液用量等因素对结果偏底的影响的揭示     

FPD-4A凝固点降低测定仪测定方法建立及应用示例

对FPD-4A凝固点降低测定仪的冷冻室进行了绝热改造,设计了智能化的凝固点测定软件,该软件可自动判断和告知凝固点。对仪器性能进行了测试,对冷冻功率测试结果的分析,发现最佳冷冻电压应该是刚好能使系统凝固的最低电压;对采样周期测试结果的分析,发现将采样周期的默认值设为15s比较合适;对环己烷凝固点3次测定结果的分析,发现仪器的重现性较好,其平均偏差为0.004℃。在对仪器性能考察的基础上,建立了逐步冷冻的测定方法,依该法测得萘的分子量为128.559,相对误差为0.30%。这些对该仪器的使用具有指导作用。     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

Sister Carrie, an Adherent of Desires

Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.     

Improvement of one-cycle controller by use of proportional integral differential controller

1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec…     

库克斯顿城堡

城堡, 是欧洲典型的建筑之一, 每个城堡都有一个美丽的传说或是一段历史。从本期开始, 我们将推出“城堡之旅”, 带各位读者去浏览、观赏欧洲各地的城堡, 开始一段文化与历史的旅途!     

胡主席在印度,我却在中国

Today, Sunday morning, I sit thinking and typing at my computer. My thoughts are in my homeland, India and my body is in China. The body is here and mind there for a good reason. Mr. Hu is president and I am resident and both are in each other's countries (what a difference the absence of one small letter makes!). Mr. Hu will return in a few days and I will stay on longer.