信息技术在初中化学实验教学中的应用试析

化学是初中新开的一门课程,学生在之前并没有接触过。学习化学不仅要学习理论知识,还要学会做实验,这是基础。但有些学校考虑到学生的安全,可能就不会让学生在课上做实验,为了能让学生更好的理解实验,教师可以借助信息技术,例如多媒体设备等放映实验过程的视频,从中学习到实验的注意事项和具体步骤。

膜分离技术在生物化工中的应用试析

从我国近代史的发展来看,有着许多高科技技术的诞生。尤其是从二十世纪末以来,世界上的各个国家都对于膜分离技术非常重视,都普遍认为这是目前最有作用、前途最广的一项技术,已经成为了每个国家都重点研究的对象。与传统的分离技术做比较,这种膜分离技术能够更加的节省时间、节省能源以及提高工作的效率。而且这种技术在成本方面比传统的分离技术更低,设计也没有那么复杂烦琐,更加让工作人员方便操作,同时在以下六个方面也极为精通,比如吸附、吸收、浸泡、结晶以及萃取。其他方面也有很大的优势,更加为人民提供服务。

Mechanical behaviour analysis and support system field experiment of confined concrete arches

Soft rock control is a big challenge in underground engineering.As for this problem,a high-strength support technique of confined concrete(CC)arches is proposed and studied in this paper.Based on full-scale mechanical test system of arch,research is made on the failure mechanism and mechanical properties of CC arch.Then,a mechanical calculation model of circular section is established for the arches with arbitrary section and unequal rigidity;a calculation formula is deduced for the internal force of the arch;an analysis is made on the influence of different factors on the internal force of the arch;and a calculation formula is got for the bearing capacity of CC arch through the strength criterion of bearing capacity.With numerical calculation and laboratory experiment,the ultimate bearing capacity and internal force distribution is analyzed for CC arches.The research results show that:1)CC arch is 2.31 times higher in strength than the U-shaped steel arch and has better stability;2)The key damage position of the arch is the two sides;3)Theoretical analysis,numerical calculation and laboratory experiment have good consistency in the internal force distribution,bearing capacity,and deformation and failure modes of the arch.All of that verifies the correctness of the theoretical calculation.Based on the above results,a field experiment is carried out in Liangjia Mine.Compared with the U-shaped steel arch support,CC arch support is more effective in surrounding rock deformation control.The research results can provide a basis for the design of CC arch support in underground engineering.

Measurement Module for Young for Thermal Insulation Composite Polymeric

To analyze the feasibility of application of composite material as the insulating material, it is necessary to have knowledge of some of its mechanical properties. An insulating material may suffer from the most different efforts, but the major applications suggest mechanical bending and compression tests because the insulation can be applied on roofs of homes, liners similar to, in the form of plates. Thus, the product is continually flexed. When the material is used on a floor, it suffers constant compressions over its use. For tests performed in this study, we used the ASTM D695-96 for compression, an example of literature. Using such a standard test, specimens were produced for compression test, with specimens made of cylindrical shapes, respecting the condition that the height of the specimen corresponds to twice the diameter of the base. Polyurethane castor without charge vermiculite and mass loads of 10%, 15% and 20% matrix： four specimens for each type of material were produced. The composites were tested in a universal testing machine at a speed of 2 mm/s. The results are average values of four test samples, and initially show the behavior of castor oil polyurethane during the compression test, which is detailed in the stress versus strain curve. The achieved results are promising, and detailed in this paper.

Cost-benefit timing for applying slurry seal on actual roadway tests in China

Determining the optimal timing is the core of preventive maintenance. Highway agencies always face with the challenge of determining optimal timing for preventive maintenance, particularly in China where there are no condition indicators designed for determining adequate timing for applying preventive maintenance and little literature relating to the development of pavement performance. This work presented the indicators, including crack ratio （Rc）, rutting depth （DR）, international roughness index （IIR） and sideway force coefficient （CsF） to determine the adequate timing for preventive maintenance in China. The proper ranges of each indicator to apply to preventive maintenance were then recommended. They are 0.28%-1.4% for Rc, 10-15 mm for DR, 1.97-3.5 for lrR, 40--50 for CSF. Based on pavement condition survey data collected on the test roads in Hebei Province, China, on the application of slurry seal at different timings, the pavement performance was established and the adequate timings for applying slurry seal was studied. Based on benefit-cost analysis, it is suggested that the fourth year is the optimal timing for applying slurry seal based on the condition in China. A framework is established to determine the adequate timings of applying other preventive maintenance methods.

Experiment Study of Dynamic Compaction Applied in Collapsible Loess

The collapsibility of loess, which can be effectively eliminated by the dynamic compaction, does great harm to the safety of constructions. The effect of the dynamic compaction is evaluated through the contrast and analysis of the physical and mechanical properties of the collapsible loess before and after dynamic compacting. The compacting effect can be divided into three phases along the depth, and the most effective improved depth is from 3 to 8 m.

TEST ANALYSIS OF COLLEGE STUDENTS' CAPABILITY IN ENGLISH COMMUNICATION

While Colleague English Tests (CET) have promoted the college English teaching, they have also led to the extension of test-oriented education and hindered students' capability in communication. To examine the validity of CET Band Four, resumed tests were carried out in sampled students of Grade 2001 one year after they took CET-4 in December, 2002. The control class was examined with the original paper of CET-4 2002, while the treatment class was tested with the same paper in which the multiple-choice questions were all changed into the subjective ones. The test scores were processed by statistical analysis. The results showed that although there was no significant difference between the two classes in CET-4 scores, there was significant difference between them in their experimental test scores. The scores of the treatment class were significantly lower than that of the control class, which proves that CET cannot objectively reflect students' capability in communication, and thus its validity is low. To eliminate the negative backwash effect of CET, suggestions are put forward that CET be devised as a criterion-referenced test, frequency of the test be reduced, subjective questions be increased, and commercialization of the test be avoided.