Typical tree slelction and random sampling were applied for systematic studies on individual variation of gutta-percha content in samaras of Eucommia ulmoides and the correlations between the characters of samara containing gutta-percha and several macroscopic properties.

A new method of determining pectin content in ramie by microwave-assisted extraction(MAE) is described,the optimum condition was studied in single factor test,and the pectin was determined qualitatively by FTIR spectroscopy.

The changes of degree of hardness,polygalacturonase(PG)actives and pectin content of new picked Mango(Da Tai Nong)which were after there adoptions by the different storages approach clones during the storage were studied.

Polygalacturonase(PG),pectinesterase(PE)activity and water-soluble pectin content of hawthorn fruit were determined,when the fruits were stored by refrigerated storage and gas storage.

This study was conducted for a full understanding of the growth characteristics of the bark of Eucommia ulmoides Oliv and of its gutta-percha content characteristics as well as the content variation, which as a result provides a theoretical basis for its new clones' selection and effective utilization.

To confirm the index for selecting clones with high yielding gutta-percha of Eucommia ulmoides,comprehensive analysis and comparison of gutta-percha contents were conducted among samara,bark and leaves,which were collected through typical samplings and random samplings.

Determination of rubber content of EPDM waterproofing membrane;

The following measures have been taken to reduce the rubber content in cord ply compound of tractor tire: a) use OESBR instead of SBR; b) increase the black level; c) use SAC aluminum silicate or SOS super fine active calcium carbonate partly instead of carbon black.