The Morphology of the Primary Dental Arch of Chinese Children in Shijiazhuang-City Part-I: Research concerning the size of the primary tooth crown, primary dental arch and the condition of primary occlusion

The purpose of this study was to investigate the size of the primary tooth crowns, primary dental arches, standard values and frequency distribution of primary occlusion in Chinese children. With the cooperation of a kindergarten in Shijiazhuang-city, China, the dental plasters from 55 children (36 boys and 19 girls, age range from 3-6 years old) with normal primary occlusion were collected. Because of different growth rates of the children, these children were divided into two groups, one comprising children less than 5 years old and the other of 5 years old or older. According to the method that the Japanese Society of Pediatric Dentistry reported, the data were statistically analyzed and compared to Japanese children. The results were summarized as follows: 1. Except lower primary lateral incisors, the values of the mesio-distal width of primary crowns of each tooth were significantly larger for boys than for girls in all tooth types. Also the Chinese children were inclined to show smaller mesio-distal tooth crown width than those of the Japanese children in all types of teeth. 2. Compared with the Japanese children, the Chinese children were inclined to show smaller primary dental arch length both in the maxilla and the mandible. But in the senior group, the Chinese girls were inclined to show smaller primary dental arch width than their Japanese female counterparts. On the contrary, the Chinese children tended to show larger dimensioned primary dental arch height than those of the Japanese children. 3. Though spaces between teeth (primate and growth spaces) were found in the Chinese children, the frequency was lower than that of the Japanese children. 4. The frequency of terminal plans in the Chinese children was 41.8% in the vertical type, 6.4% in the distal-step type and 51.8% in the mesial step type. 5. The primary canines occlusal relationship in the Chinese children was 63.1% in type I, 13.6% in type II and 23.7 in type III

新疆森林公园的分布及旅游开发初探

新疆森林公园的分布以山地为主,平原为辅,主要集中在天山北坡和阿尔泰山;树种等资源在山地主要有雪岭云杉,新疆落叶松,新疆冷杉等针叶林,平原则主要以胡杨、灰杨等荒漠湖岸林为主,并分布着多种新疆特色的灌木,新疆森林公园起步较晚,但数量稳步增长,并已根据不同层次的需求,进行旅游开发建设,发展势头良好。通过对新疆森林公园的数量、级别、面积及建设时间等基本情况进行分析,进一步对新疆森林公园的现状及功效分析,得出进一步更好的发展森林公园的必要性。最后,提出抓住森林公园“天然养吧”等资源优势,结合龙头景区,因地制宜开发建设,并在开展旅游活动中突出地方特色,不断完善森林公园管理规范,实现资源永续利用的发展建议

功率分流式混合动力系统的加速性能分析

为满足功率分流式混合动力汽车的加速性能设计要求，使用构型矩阵对双行星排构成的功率分流式混合动力系统进行穷举，并根据构型合理性及设计目标进行筛选。对于各种构型的双行星排功率分流系统，提出了其能够输出最大转矩的系统解法。利用求解结果对各种构型的系统进行百公里加速仿真，得出最优构型

Location Independent Coverage Control Algorithm for Wireless Sensor Networks

提出一个分布的、与节点位置无关的无线传感器网络覆盖控制算法(a Location Independent Coverage Control Algo-rithm for Wireless Sensor Networks,LICA).LICA采用基于节点分层成簇的思想,节点与邻居交换信息,并通过节点距离与覆盖模型找出覆盖节点.在保证覆盖性能的前提下,关闭覆盖节点的通信设备.仿真实验结果表明,LICA算法不仅可以提供高质量的覆盖性能,而且具有良好的节能性能.特别适合低成本、资源缺乏、工作在恶劣环境中的分布式无线传感器网络

混合动力系统效率研究及控制策略优化

为了提高功率分流式混合动力系统汽车的燃油经济性，建立了混合动力系统物理模型和系统控制模型，利用优化初值的粒子群算法对混合动力系统的效率进行优化，仿真得到效率最优时的功率分流控制策略，并将其移植到搭载了该系统的某公交车上，进行了实验验证。结果表明，优化初值的粒子群算法可以有效提高动力系统的综合系统效率，降低整车油耗

混联式混合动力轿车制动器辅助发动机起动控制

针对混联式混合动力轿车起动过程的顿挫等动力性问题，提出一种新型的利用制动器辅助发动机起动的方案，设计了制动器夹紧力矩控制、转矩协调等控制策略，并进行了仿真分析与试验验证。试验结果显示，发动机起动过程动力性改善明显。结果表明，利用制动器辅助发动机起动的方案合理，所设计的起动过程控制策略可行

Raman Study of Transformation Behaviors of Tungsten-containing Peroxo Species Affected by Different Precursors and Solution Acidities

[中文文摘]识别水溶液体系中含过渡金属W ,Mo的过氧物种结构是探索烯烃、醇及醛等与双氧水催化选择氧化反应机理的关键所在 ,本研究借助高灵敏度的共焦显微Raman光谱表征手段 ,考察了Na2 WO4,(NH4) 10 [H2 W12 O42 ]和H3 PW12 O40 三种含钨前驱体在不同pH值条件下与过量双氧水作用产生的主要过氧物种的结构特征 ,推测在酸性较强 (pH <2 3 )的条件下三者产生的主要过氧物种结构相同 ,可能是单核式的 [WO2 (O2 ) 2 (H2 O) ] 2 -,而二聚态或多聚态的过氧物种几乎不存在于体系中 ;此外 ,还首次建立了通过Raman光谱来半定量测定双氧水浓度的分析方法 ,并尝试用于双氧水催化分解的动力学研究中。[英文文摘]Tungsten and molybdenum compounds act as efficient catalysts for oxidations of olefins, alcohols or aldehydes by hydrogen peroxide. The nature of the peroxo species formed in solutions with different precursors including Na 2WO 4, (NH 4) 10[H 2W 12O 42] and H 3PW 12O 40 in the presence of excess H 2O 2 has been studied by Raman spectroscopy. Regardless of tungsten-containing precursors, mononuclear species of [WO 2(O 2) 2(H 2O)] 2- is likely principal peroxo species under the conditions with low pH (pH < 213) and excess H2O2 , and other dimeric or polymeric species are almost absent . Moreover , novel method for determining H2O2 concentrations by Raman spectroscopic analysis was established and applied in kinetics study of H2O2 catalytic dismutation to H2O and O2。福建省自然科学基金(No.E0110005)资助项目