The electronic structure, vibrational and dielectric properties of MoS2 were studied by first-principles based on density functional theory (DFT). The band structure, density of states, the dielectric function spectrum and the infrared reflectivity spectrum were presented. The results indicate that MoS2 is a semiconductor with indirect band gap. The dielectric tensors are highly anisotropic. It is found that lattice vibration makes less contribution to the dielectric constant than that of electronic screening. Due to the existence of Infrared active modes over the range of 300 similar to 500 cm(-1), there is a strong interaction between the material and electromagnetic wave, impairing the wave-transparent properties of MoS2.

The method is proposed for noise reduction of chaotic time series technique based on singularity spectrum. On the one hand, singularity spectrum has a good performance in the noise reduction for chaotic time series. On the other hand, what determine the order of singularity spectrum have not proposing. If the order selected is too high, full reduction of noise is not achieved. If the order selected is too low, the completeness of signal suffers distortion. So the order selected is a very important in chaotic noise reduction technique based on singularity spectrum. A novel arithmetic based on singularity entropy is introduced in this paper. The increment of singularity Entropy is sensitive with change of the order of singularity spectrum. Finally, experimental results show that the method is quite effective for determining noise reduction order in the field of chaotic time series.

Structural, electronic and chemical bonding properties of the (001) surface of cubic SrHfO3 have been investigated with both SrO and HfO2 termination using the plane-wave ultrasoft pseudopotential technique based on the first-principles density-functional theory. The relaxed structures of two slabs have been analyzed, which shows the interplanar distance of two slabs has the same changed trend. The electronic band structures and density of states of two slabs have been discussed, showing the reduced band gaps by comparison with those of bulk system. The chemical bonding between Sr and O between the surface layer and subsurface layer as well as Hf and O has been increased. The surface energy, work function and stability have been calculated, which indicates SrO-terminated slab is more stable.

We calculated the structural parameters, elastic, mechanical, electronic and optical properties of 3R- and 2H-CuGaO2 using the first-principles density-functional theory. The results show that the structural parameters of two phases are in good agreement with previous theoretical and experimental data. Two phases are mechanically stable, behave in ductile manner and have indirect band gap. The analyses of electronic structures and charge densities of two phases show mainly covalent nature in Cu–O bonds and coexistence of both ionic and covalent nature in Ga–O bonds. The optical properties are obtained and discussed, including the complex dielectric function, refractive index, extinction coefficient, optical reflectivity, absorption coefficient, energy-loss spectrum and complex conductivity function, which provide useful information for the future applications of CuGaO2.

This article analysed the characteristics of Mindmap and WebQuest.Based on the characteristics of Internet,discussed the ways of combination with Mindmap and WebQuest.A suitable for JITT mode of teaching model is put forward—complement with ＂traditional teaching method＂ and ＂online WebQuest learning＂.It helps learners completed in merging of knowledge and internalization of ability,enhanced innovation ability.

随着各种慢性乙型肝炎治疗药物及方案的出现,以及人们对乙型肝炎自然史的进一步了解,意识到HBeAg发生血清转化是抗病毒免疫达到新平衡点的指征.因此,了解自然状态下,HBeAg阳性的乙肝病毒携带者年血清自然转换率,对于正确阐明慢性乙肝治疗疗效具有重要基线参考意义.

BACKGROUND:To assess the incidence and economic burden of rotavirus diarrhea and the potential cost-effectiveness of a rotavirus immunization program in rural Zhengding County in Hebei Province, China.METHODS:Population-based surveillance was conducted during the peak season for diarrhea among children who were <5 years of age in Zhengding County from 14 October 2004 through 19 January 2005. The cost of illness was measured from the perspectives of both patient and society. A decision-analytic model was applied to the cost-effectiveness analysis using real data derived from surveillance and from a cost-of-illness study.RESULTS:During the surveillance period, 500 episodes of diarrhea were registered. Of these 500 episodes, 125 (25%) occurred in patients who were positive for rotavirus. Of these 125 episodes, 63 (50%) occurred in patients who were hospitalized. The overall incidence rate of rotavirus infection was 61.4 cases per 1000 children per year during the 14-week epidemic season. For a Chinese cohort of 5000 newborns, a universal rotavirus immunization program would prevent 1764 cases of rotavirus diarrhea, averting 882 hospitalizations of patients <or=5 years of age. At 2004 prices, the net savings due to the immunization program would be US$14,112 from a societal perspective and US$34,751 from a patient perspective.CONCLUSION:Rotavirus was a leading cause of severe diarrhea among children <5 years of age and an economic burden for farmers in rural Zhengding County. Rotavirus vaccination should be considered as a potential cost-effective measure against rotavirus infection in China.

甲型病毒性肝炎(甲肝)疫苗的问世为预防和控制甲肝的流行提供了有效的预防措施.尤其是国产甲肝减毒活疫苗的诞生,因其价格低廉、有效,更适于在经济尚不发达的农村地区推广使用.甲肝减毒活疫苗免疫的持久性、是否需要加强免疫以及如何加强免疫,一直是人们非常关心的问题.本研究在甲肝减毒活疫苗1针法免疫的基础上,尝试了2针法加强免疫,并对免疫后2组的抗体持久性进行了观察比较,以期对加强甲肝减毒活疫苗的免疫效果提供科学依据.

Applications of multi-agent system in Web-based education have received much attention. In recent years, research on multi-agent collaborative learning platform becomes hot topics. In this paper, on the basis of analyzing the characteristics of Web-based collaborative learning platform and summarizing the author's teaching experience, a multi-agent collaborative learning platform model is designed. Its implementing magnesium is analyzed. In addition, a multi-agent collaborative learning platform of Computer Organization and Architecture with B/S Structure is implemented by using KQML wrapped with JSP and XML. Its application in teaching shows that it is helpful to enhance learning interest, learning effects and communicative and collaborative competences of students.

OBJECTIVE:To determine the "alpha"dominant mutation of hepatitis B virus (HBV) in community-based Zhengding. Analysis the role of the newborn hepatitis B vaccination on the mutation.METHODS:Based on the national surveillance of hepatitis B, 11,478 people's sera were collected and tested by SPRIA with kits. Collect people's sera with positive HBsAg and amplify the S gene. Sequencing and clastwaling them with the standard sequences.RESULTS:Overall, HBV DNA was successfully amplified and sequenced in 434 of 443 samples. 6.7% samples mutated in HBV "alpha" dominant region. The difference between the mutation ratio of the two loops of HBV "alpha" dominant between the people born before and after the year 1986 has no significance.CONCLUSION:There were HBV "alpha" dominant mutant virus in the local area with a low infection rate in the population born after the year 1986. It could not explain the newborn hepatitis B vaccination can induce the prevalence of the "alpha" dominant mutate HBV.

—Due to the multiple advantages of XML, many researchers are interested in multi-agent Web-learning system based on XML in recent years. In this paper, a multi-agent collaborative learning platform model based on XML is designed, in which agent structure is more reasonable and characteristics and advantages of collaborative learning can fully be presented. Its implementing magnesium is analyzed and a multi-agent collaborative learning system of Computer Organization and Architecture with B/S Structure is implemented by using Knowledge Query and Manipulation Language (KQML) wrapped with XML manipulated by JSP. Its application shows that it is helpful to enhance learning interest, learning effects and communicative and collaborative competences of students.

OBJECTIVE:To observe the immunological effects of three doses of H2 strain live attenuated hepatitis A vaccine 8 years after the administration and to compare with that of one dose of the vaccine.METHODS:In a country area, 110 children of 1 to 7 years old susceptible to HAV were screened and administered with one dose of the vaccine, as group B; Group A were 42 children from one of the villages and administered with 3 doses of the vaccine according to 0, 2, 6 month schedule. Blood samples were taken for the children 1, 2, 6, 7, 8, 12, 24, 36 and 96 months after the administrations respectively and detected for anti-HAV antibody.RESULTS:For group B, the sero conversion rate of anti-HAV and GMC reached peak at 92.2% and 126.2 mIU/ml respectively, and then, began to drop with time; For group A, after 2 dose of the vaccine, the sero-conversion rate reached 100%, and the GMC reached peak of 2 739 mIU/ml one month after the third dose at 7 months. So that, group A has a better short-term immunological effects than that of group B. During 36 through 96 months, the anti-HAV positive rate in group B was 75%-71% and 80-89 mIU/ml respectively, and comparatively in group A were 100% and 918.2-480.6 mIU/ml respectively. The differences between group A and B were significantly important.CONCLUSION:A 3-dose schedule administration of H2 strain live attenuated hepatitis A vaccine has better immunological effects than 1-dose schedule in 8years and further observations are needed.

Previous studies have shown that cost of illness (COI) measures are lower than the conceptually correct willingness-to-pay (WTP) measure of the economic benefits of disease prevention. We compare COI with stated preference estimates of WTP associated with shigellosis in a rural area of China. COI data were collected through face-to-face interviews at 7 and 14 days after culture-confirmed diagnosis. WTP to avoid an episode similar to the one the respondent just experienced was elicited using a sliding-scale payment card. In contrast to previous studies' findings, average COI estimates (2002 PPP adjusted US dollars 28.2) approximate an upper bound estimate of WTP, rather than a lower bound. One explanation for the similarity between COI and WTP is that preventive expenditures and disutility due to pain and suffering are low for shigellosis. WTP to avoid additional cases in children aged 0-5 years is higher than in adults. Also, average COI (2002 PPP adjusted US dollars 28.4) for children is similar to a lower bound estimate of WTP (2002 PPP adjusted US dollars 16.4) and lies within the WTP range. Because the monetary loss associated with another episode in children is small, caregivers' higher WTP may be attributable to the disutility of illness due to the children's pain and suffering. These findings suggest that for some diseases, COI may approximate more comprehensive measures of economic benefits.

Live, attenuated hepatitis A vaccines are used widely in China but there is uncertainty regarding the persistence of vaccine-induced anti-HAV antibodies after single dose and booster dose administrated at month 12. A large scale clinical trial to evaluate the live, attenuated hepatitis A vaccine was conducted in Hebei province between 1996 and 1999. Five years after the trials, children in single dose and booster dose groups were bled and followed. Seventy two percent (61/85) of children who received a single trial dose had detectable anti-HAV antibodies for 96 months (GMC at 96 months: 89.0mIU/mL). In the booster group 98% (48/49) children remained anti-HAV positive with GMC of 262.8mIU/mL at month 96. The reinjection with live attenuated HAV vaccine can elicit a booster effect. Results from single dose group seems not to support the need for booster doses of live attenuated hepatitis A vaccine in immunocompetent individuals regarding the persisting anti-HAV and anamnestic response of a single dose vaccine. Continued monitoring of anti-HAV antibodies is needed for a rational hepatitis A immunization strategy in China.

Objective To understand the status of HBV infection and the level of the anti-HBs after immunization.Methods The population of 8 villages of pilot town of Zhengding County,Hebei was chosen,10010 serum specimens were collected for detecting HBsAg and anti-HBs by SPRIA in 2005.The results were analyzed by Epi Info and SAS software.Results The average HBsAg positive rate of the population vaccinated was 5.32%(the adfusted rate 4.82%),reduced by 37.90%(the adjusted rate 40.90%),compared with 8.57%(the adjusted rate was 8.16%) before immunization.The average HBsAg positive rate of the population aged 1-19 years was 1.46%,and that of the children below 15 years was 0.49%.The average positive rate of effective anti-HBs was 46.86% of the vaccinated population,that of the population aged 1-19 years was 53.77%,which increased significantly comparing with 38.22% before immunization in 1983.Conclusion The HBsAg positive rate of the population aged 1-19 years old in 2005 whose immunization reached the levels of lower infective countries,and the HBV infective levels of the population older than 20 years in 2005 was similar with that of same age population in 1983.

Objective To investigate immune effect of homemade recombinant Hepatitis B vaccine to new born baby after inoculating 1-8 years. Methods Based on the investigation of short-term effect of inoculating to new born baby with recombinant Hepatitis B vaccine(CHO),the serum samples of all children born from 1997 to 1999,who live in 4 villages of 7 experimental villages,were collected.HBsAg,anti-HBc and anti-HBs were detected by ELISA.Results After 8 years inoculating,the average positive rate of antiHBs is 91.95%.The effective positive rate of anti-HBs is 75.74%.The geometry mean concentration(GMC) of S/N of anti-HBs is 30.14.The general tendency is that the GMC and positive of anti-HBs descend gradually with the prolongation of time.In this study,HBsAg and anti-HBc positive rates are 0.67%,1.39% respectively.No ascent was found.Conclusion Both the protection efficacy and persistence of anti-HBs of homemade recombinant Hepatitis B vaccine(CHO) are very well to new born baby after 1-8 years inoculating.

Objective To study the burden of shigellosis in Zhengding,Hebei province.Methods In 2002,a population and treatment center-based surveillance targeted to treate diarrhea was conducted in Zhengding.Stool sample was collected from each consented diarrhea cases for Shigetta.spp isolatiou.The incidence rates were calculated by age groups.To detect potential sequelae related to Shtgella infection,the confirmed shigellosis cases were followed-up in 90 days after presentation.Results In 2002,the incidence of diarrhea in catchment area was 133/1?000/year.The highest incidence rate(1?388/1?000/year)was found in infants;the incidence was 618/1?000/year in children under 5 years of age.Shigella.spp was isolated from 331 diarrhea patients.The incidence rate was 4.4/1?000/year.The highest incidence rate was found in children of 3 to 4 years of age.Followed with incidence in people elder than 60 years of age,which was 7/1000/yearo Feve-r and bloody stool were the most important clinical characteristics of shigellosis.No Shigella infection related sequelae or death were found during study period.Significant relationships were found between incidence of shigetlosis,average temperature and rainfall.Conclusion Compared with the noticeable infectious diseases report,tremendous disease burden of shigellosis was found in Zhengding.To control the epidemic of shigellosis,mass immunization targeted to children under 5 years old and people eider than 60 years old should be considered.

Rotavirus is the pathogen most commonly associated with severe gastroenteritis in young children in the People's Republic of China, yet there are few population-based data on the incidence of rotavirus infection. The present study investigated the burden of rotavirus diarrhea and rotavirus infections in rural China, according to age. Population-based surveillance was used to study the incidence of rotavirus infection among children < 5 years of age in 4 townships of Zhengding County, Hebei Province, China. The total population in the catchment area in 2002 was 75,630 individuals, including 2997 children aged < 5 years. Stool samples were obtained and were tested for rotavirus antigen by use of an enzyme-linked immunosorbent assay. During 2002, a total of 2010 cases of diarrhea were detected among children < 5 years of age. The incidence of treated cases of diarrhea was 671 cases/1000 children/year for children < 5 years of age, and it was highest for children < 12 months of age (1467 cases/1000 children/year). The estimated incidence of rotavirus infection was 151 cases/1000 children/year for children < 5 years of age. The highest incidence of rotavirus infection was among children aged 1 - 2 years (340 cases/1000 children/year). Widespread immunization of children against rotavirus before 6 months of age should be considered for the control of rotavirus diarrhea.