Application of polymeric aluminum salts in remediation of soil contaminated by Pb,Cd,Cu,and Zn

Soil contaminated with typical heavy metals (Pb,Cd,Cu,and Zn) was remedied by using the polymeric aluminum salt coagulants including polyaluminum chloride (PAC) and polyaluminum sulfate (PAS).The remediation efficiencies are influenced by reaction time,water amount,and dosage of remediation agent.The optimal remediation conditions are as follows:6 h of reaction time,1 kg/kg of water addition amount,and 0.25 kg/kg of remediation agent dosage.After PAC addition,the remediation efficiencies of diethylenetriamine-pentaacetic acid (DTPA)-extractable Pb,Cd,Cu,and Zn reach 88.3%,85.1%,85.4%,and 73.7%,respectively;and those for PAS are 89.7%,88.7%,83.5%,and 72.6%,respectively.The main remediation mechanism of the polymeric aluminum salt may contribute to the ionization and hydrolysis of PAC and PAS.H + released from ionization of polymeric aluminum salt can cause the leaching of heavy metals,while the multinuclear complex produced from hydrolysis may result in the immobilization of heavy metals.For PAC,the immobilization of heavy metals is the main remediation process.For PAS,both leaching and immobilization are involved in the remediation process of heavy metals.

Viscosity of Kaolin Slurries:Effects of Dispersant and Urea-Intercalation

Good fluidity（low viscosity） of highly concentrated kaolin is highly needed in paper-coating industry.We put forward an effective route to improve the viscosity concentration of Beihai kaolin slurries.The effects of various factors such as solid content,pH,dispersant content,and urea-intercalation on the viscosity of kaolin slurries were investigated.The results revealed that the viscosity of kaolin slurries significantly decreased with decreasing solid content or with increasing pH and dispersant content.It was worth noting that ureaintercalation was proven to be an efficient method for promoting the dispersion of highly concentrated kaolin as compared with adding dispersant.The intercalation ratio of urea-intercalated kaolin was increased from 17.36%with 2%of urea addition to 81.30%with 6%of urea addition.Meanwhile,the viscosity concentration of raw kaolin slurry was improved from 65.0%to 70.13%after the intercalation of urea with 6%addition,which was attributed to finer particle size,increased pH value and more negative charges of urea-intercalated kaolin.Therefore,the route is effective to improve the dispersion of highly concentrated kaolin for paper-coating.

Genetic Diversity of MHC Gene and Molecular Phylogeny in Wanbei Cattle

[Objective] To investigate the genetic diversity, molecular phylogeny and origination in Wanbei cattle. [Methedl Blood samples were collected from 50 Wanbei cattle and 14 local cattle breeds. According to the bovine MHC gene sequence, one pair of primers was designed and used for PCR amplification. The sequences of amplified MHC genes were aligned to detect MHC haplotypes and nucleotide polyrnorphisms. A phy- Iogenetic tree based on the MHC gene was also constructed. [Result] A total of 24 polymorphic loci covering 7.86% of the entire length of the se- quences and seven MHC haplotypes were detected. Among these polymorphic loci, there were 18 transitions, 1 tranversions and 5 transition / tran- version. The difference in nucleotide sequence was 0.26% -4.53% between the haplotypes. The nucleotide diversity （π value） and haplotype di- versity （H） were 0.012 - 0.019 and 0.602 - 0.617, respectively. [ Conclusion ] Wanbei cattle do not have rich MHC genetic diversity. They have closer aenetic relationship with Luxi cattle, and both are within the same sister group.

Falstaff: A Signifier Above and Beyond

This paper investigates the character of Falstaff in Shakespeare’s Henry IV Part I and Henry IV Part II,using philosophical concepts drawn from the thought of Jacques Lacan.Here,Falstaff is treated as signifying the complete satisfaction of desire for eating,drinking,love-making,and the primitive and ideal states of the ego.Thus,Falstaff is beyond the pleasure principle.To satisfy his desire and become the ideal ego,Falstaff manipulates signifiers,facts,time,and common logic.Falstaff is above signifying chains,in that he uses others around him and disobeys the others(God,the king,and the Chief Justice).However,Falstaff cannot be reduced to nothing because he represents the primitive nature and existential desire of human beings.To allow people to enjoy Falstaff’s pleasures is a task in social development.Due to the excesses he reaches in satisfying his desires,Falstaff can only be allowed to exist in fantasy.Falstaff is thus a signifier haunted above and beyond.

A Comparative Study on the Audiolingual Approach and the Communicative Approach

Audiolingual approach and communicative approach are two major teaching methods in the history of language teach ing.This paper aims to compare these two teaching methods to conclude their benefits for teaching foreign languages in our country.

A Study on the Strength Surplus Coefficient of Cement

This study considers P.O42.5 cement from different sources and evaluates the related surplus coefficient(defined as the proportionality factor linking the measured compressive strength value of the cement after 28 days to the“standard”value of cement strength).The needed tests have been conducted using a mixer,a pressure testing machine,a flexural testing machine,a vibrating table a ramming rod,a feeder and a metal ruler.The average value of the measured cement strength surplus coefficient of cement produced by five distinct cement manufacturers has been found to be 1.16.These results can be used as the basis to reduce the production cost and improve the performance of commercial concrete.

QUALITATIVE ANALYSIS FOR A CLASS OF SECOND-ORDER NONLINEAR SYSTEM WITH DELAY

The second-order nonlinear system with delay x ' (t) + f(x(t),x ' (t)) + g(x(t),x ' (t))psi (x(t-tau)) = p(t) being considered. Four theorems on the stability of zero solution, the boundedness of the solutions, the existence of the periodic solutions, the existence and uniqueness of the stationary oscillation are obtained by means of the Liapunov's second method, The conclusion in the literatures are generalized.

动态报表的打印对象的控制设计

每个信息系统的功能大多不相同,但一般都要把表或视图的联接集作为数据集进行报表打印。由于数据库不同,表结构不同,因此每个报表数据集的字段类型、宽度都不可能完全相同,这导致报表的多样性与复杂性,给报表设计带来诸多不便,通过控制报表的打印对象实现动态报表是一个有效解决该问题的方法。在水晶报表中先创建若干个打印对象,程序运行时对SQL语句获取的动态打印数据集的元素进行枚举,使每个元素与水晶报表上已存在的打印对象进行逐一匹配绑定,进而对绑定的打印对象进行控制,从而实现动态报表的目的。

How to Design Key Activities in an Oral English Class

Analyzing the current situation of oral teaching and factors against students’progress in oral English of vocational and technological colleges,the essay focuses on three strategies to design key oral English activities,aimed at the improvement of students’oral competence.