化学课中怎样培养学生动手的能力

学生化学实验技能培养的尝试化学是一门以实验为基础的学科，通过课堂演示实验或学生实验。可以使学生获得生动的感性知识，从而更好地理解、巩固所学化学知识，形成化学概念，促进观察、分析和解决问题等各方面能力的提高，并可激发学生的。学习兴趣。

Application of Chemical Tracing Experiment Technique in Leakage Detection of Hydraulic Engineering

[Objective] The research aimed to study the application of chemical tracing experiment technique in leakage detection of hydraulic engineering.[Method] According to the current situation of Sanyuan Western Suburb Reservoir in Xianyang City of Shaanxi Province,three sections （L1,L2 and L3） were set.KI was selected as the chemical tracer to carry out the tracing and detection research.[Result] There was no obvious leakage phenomenon in L1,L2 and L3 sections.The impermeability of rock in some dam abutments was bad.[Conclusion] The leakage reason of Western Suburb Reservoir was that the impermeability of rock in some dam abutments couldn’t satisfy seepage requirement.After the reservoir was put into operation,the water level in front of dam rose,and the ground water level of dam abutment also rose.The penetration water pressure correspondingly increased,and the water content of bank slope at the downstream of dam increased.

Transmutations by Nanosecond Electromagnetic Impulses

Some experiments on radiation of hydrocarbons and the alloys including Bismuth and Lead by power nanosecond electromagnetic pulses are described. The list of the used equipment and technique of experiments are given. The result of these experiences is change of a chemical composition of the irradiated samples in comparison with the initial ones. Conversion of part of Bismuth to Lead is observed. The hypothesis of such changes is made.

Experimental Study on Local Mass Transfer of Structured Packing with the Method of Flow Visualization

A chromochemical reactive mass transfer technique has been employed to study local mass transfer characteristics of structured packing. This technology adopted by experiment is an Ammonia Adsorption Method （AAM） that yields the surface distribution of transferred mass by analyzing the color distribution on a filter paper with the results of the color chemical reaction. A digital image processing technology is applied for data visualiza-tion. The three-dimensional plot of the local mass transfer coefficients shows that there exist three peak values on different positions of a unit cell of structured packing. In order to improve mass transfer efficiency of the structured packing, one piece of baffle is added between packing sheets. As a result, the average mass transfer coefficient increases by （10 20）% and the pressure drop decreases by （15-55）%.

Labeling and experimental studies of infection imaging agent ^(99m)Tc-CPF

Objective： To discuss the biodistribution of ^99mTc-Ciprofloxacin （^99mTc-CPF） and its effectiveness of imaging in infection disease in mice. Methods： CPF was labeled with ^99mTc and its radiochemical purity and labeling rate were measured. Mice model of infection was established and the biodistribution of ^99m Tc-CPF in the model and whole-body scintigraphy were achieved. Results： ^99mTc-Ciprotech was stable within 6 hours at room temperature. The labeling rate of ^99mTc-CPF was over 90%. Most of radioactivity was cleared in liver and kidney, and the clearance from blood was rapid. Both biodistribution and imaging results showed a high uptake of ^99mTc-CPF in infection site. The infection tissue/normal tissue reached a peak as 4.30 at 4 h after injection. Condusion： ^99mTc-CPF is a sensitive radiopharmaceutical agent for scintigraphy of infection lesions, and it is easy to prepare.

Electrochemical behavior and electrowinning of palladium in nitric acid media

In this study,the electrochemical behavior of Pd(II)in nitric acid media was investigated using various electrochemical techniques.By analyzing the cyclic voltammogram of Pd(II)recorded at Pt electrode,a series of electrochemical reactions associated with palladium were recognized,indicating that Pd(II)undergoes a single step two-electrons irreversible process.Electroreduction reaction of Pd(II)and auto-catalytic reactions of nitrous acid are supposed to play a leading role in low and high concentrations of nitric acid,respectively.Stirring could facilitate the reduction of Pd(II)in relatively low nitric acid concentration(3 mol/L).The value of charge transfer coefficient was determined to be 0.18 for the measurements at 298 K.The diffusion coefficient of Pd(II)increased from 1.89×10 8cm2/s at 288 K to 4.23×10 8cm2/s at 318 K,and the activation energy was calculated to be 21.5 kJ/mol.In electrowinning experiments,SEM images of palladium obtained by electrolysis reveal the dendrite growth in all cases,which is uniform all over the entire surface of Pt electrode.The recovery ratios of Pd at different nitric acid concentrations are high,and the faradic efficiency of electrolysis decreases with increasing the nitric acid concentration.When stirring was introduced during electrolysis,the electrodeposition rate of Pd increased substantially.

Steric paper based ratio-type electrochemical biosensor with hollow-channel for sensitive detection of Zn2+

The construction of flexible platform possessing the functions of immobilizing, separating, rinsing, and high-throughput analysis plays a significant role in biological and clinical research. Herein, hollow- channel technique was integrated with lab-on-paper for the simultaneous determination of two different concentrations of Zn2＋ based on the origami principle, in which microfiuidic channels were first patterned on a cellulose paper using commercial solid-state wax printer. Hollow-channels were created by laser cutting method as the role of both injecting ending and reaction tank. After screen printing three elec- trodes system, the resulting planar paper sheets were then folded into steric structures and functional- ized by in-situ synthesized reduced graphene oxide. As a proof-of-concept, such lab-on-paper device was employed in the ratiometric electrochemical monitoring of zinc ion from the environment and HepG2 cells extract, by combining with co-catalysis of porous metal-organic frameworks and hemin/ G-quadruplex toward H202 in the linear range of 0.1-7,000 nmol/L. The results indicated that integrating hollow-channel with steric lab-on-paper offered a new methodological approach for the development of metal ions monitoring research. It is believed that it could be useful for various point-of-care related research fields, such as, on-site environmental monitoring, food safety, and disease diagnosis.