用缓冲的甲醛吸收液测定大气中二氧化硫方法的探讨

在国内外研究甲醛吸收液测定大气中二氧化硫的基础上，进一步较全面对其操作条件做了探讨，并与传统方法四氯汞钾吸收液进行对比，其灵敏度、精密度均高于传统方法，效果令人满意。吸收液中的氮氧化物、臭氧、重金属等掩蔽后不影响测定。     

鉴定K~+时用甲醛法消除NH_4~+干扰是可行的

本刊1987年第2期发表了题为《消除铵离子对鉴定钾离子干扰方法的比较》一文(以下简称《比较》).文中摘要部分写到:“甲醛掩蔽法我们觉得不可行”.于正文第4标题一甲醛掩蔽法中写到:“取分析纯的六次甲基四胺水溶液两份,分别加入奈氏试剂和亚硝酸     

高效液相色谱法测定啤酒中微量甲醛方法研究

ＨＰＬＣ测定啤酒中微量甲醛方法是将甲醛用水蒸馏后用０．２％２．４－二硝基苯肼吸收,氯仿提取,ＨＰＬＣ测定,根据Ｒｔ定性、峰高定量。此法效果好,灵敏度高,准确性高。     

应该反思的不仅是媒体

据报道,针对最近有媒体热炒"啤酒甲醛超标"的情况,国家质检总局、国务院国资委、国家工商总局、卫生部、中国食品工业协会等七部门7月16日联合召开"关于啤酒甲醛问题情况说明会".会议重申,"用甲醛提高啤酒的非生物稳定性",没有造成成品啤酒中的甲醛残留量超标,不构成啤酒的卫生安全问题.同时,国家食品质量监督检验中心相关负责人还明确指出,是幕后黑手制造了"甲醛风波".     

应该反思的不仅是媒体

据报道,针对最近有媒体热炒“啤酒甲醛超标”的情况,国家质检总局、国务院国资委、国家工商总局、卫生部、中国食品工业协会等七部门7月16日联合召开“关于啤酒甲醛问题情况说明会”。会议重申,“用甲醛提高啤酒的非生物稳定性”,没有造成成品啤酒中的甲醛残留量超标,不构成啤酒的卫生安全问题。同时,国家食品质量监督检验中心相关负责人还明确指出,是幕后黑手制造了“甲醛风波”。     

盐酸副玫瑰苯胺光度法测定二氧化硫

通过四氯汞钾溶液和甲醛缓冲吸收液对二氧化硫的不同吸收比较，指出用甲醛缓冲吸收液测定二氧化硫的可行性。     

大理市米线和饵丝中甲醛及吊白块含量检测

目的：检测大理市市售米线和饵丝中甲醛和吊白块含量。方法：采用乙酰丙酮法检测甲醛,盐酸副玫瑰苯胺法（GB／T5009．34—2003）检测二氧化硫;根据甲醛和亚硫酸氢钠（以二氧化硫计）含量及其比值判定吊白块的含量,并依据食品添加剂使用卫生标准（GB2760—1996）进行评价。结果：60份样品中,甲醛检出率100％,含量范围0．37～5．07mg／kg;二氧化硫检出率60％,含量范围0．14～11．88mg／kg;吊白块未检出。结论：本次检测样品中都没有添加吊白块,但可能存在违法违规使用甲醛和亚硫酸盐的情况,应加强监督检测。     

香菇中二氧化硫的快速测定方法

通过蒸馏方法提取香菇中的二氧化硫,用四氯汞钠溶液吸收蒸馏出的游离二氧化硫,使形成的络合物与甲醛及盐酸副玫瑰苯胺作用呈紫红色的显色反应,在550nm处测定吸光度,与标准系列比较定量。是一种快速、准确测定香菇中二氧化硫的方法。     

氢化物—原子荧光法测定果蔬类中的微量砷

提出了以氢化物－原子荧光法测定果蔬类中砷的新方法,研究了酸介质、还原剂用量、还原掩蔽剂等因素对测定的影响,并选择出仪器的最佳工作条件,采用硫脲－抗血酸－酒石酸为还原掩蔽剂,有效地消除了共存离子的干扰,方法的检出限为1.23ng/g,相对标准偏差在3％以内。     

"甲醛风波"疑为业内企业幕后策划95%国产啤酒甲醛超标纯属误导--国家七部门联合声明国产啤酒甲醛含量安全,消费者可放心饮用

编者按:七月初,因某媒体发表了一篇根据读者来信撰写的文章--<95%的啤酒都加了甲醛绝大多数消费者毫不知情>,引起了巨大反响,不仅国内一片哗然,韩国、日本也相继对其进口的中国啤酒作出检查、停售等反应;并且,事件暴光后的几天,上市啤酒公司股票也都出现了下跌,"甲醛风波"给中国啤酒工业造成了极其恶劣的影响.事情真相究竟如何,在国家七部门随后发表的声明中称,抽查的中国啤酒均符合产品质量要求,消费者可放心饮用,并且指出本事件疑有幕后黑手操作.为通报事情原委,以正视听,本刊特综合各方面有关资讯,编发如下.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-