In the synthetic ammonia plant with the annual production of 3,000 tons of synthetic ammonia,the method of tannin extract in the industrial production experiment for the desulfurization of H₂S in the semi water gas was carried out.The result was fairly good. The principle of desulfurization in this method was in general similar to that of the improved method of ADA.The tannin extract possessed more hydroxyl and carboxyl groups.In alkaline medium it possessed rather strong oxygen-absorbing power.It was a good oxygen carrier in oxidation process. Under the following conditions:pH of the desulfurization liquid was 8.5—9.0;the total alkalinity was 0.7—0.8 N;sodium metavanadate was 2—2.5 g/liter;tannin was 0.6—1.0g/liter;regeneration temperature was 35—45℃;the amount of regenerated air was 450—550m³/hour,it was possible to reduce the amount of H₂S in semi water gas to less than 0.1g/m³.The efficieney of desulfurization reached 99%.The recovery of sulphur was 85—90%.

The forest land in the hilly area of the sounthern part of Fukien is rather dry and infertile.Such site was considered not suitable for plantation C.lanceolata,the local people used to use P.massoniana as an associated species to estabilish the mixed forest.In this way,the mean height growth of C.lanceolata in 13—18 year is 9.4—11.6m and growing stock is nearly 8.06—10.75m³. The better way to estabilish the mixed forest is mixture by single tree and plant at the same time.The plant hole must be bigger. In order to make the crowns of C.lanceolata above the canopy the measure of trimming,topping and thinning of pine may be taken.

From 1962 to 1964,we have studied the changes of soil moisture,the seasonal growth and transpiration of the trees planted in four young plantations at the Mount Miao-Feng near Peking.It is found that drought is a dominating factor affecting seasonal growth of diameter and course of transpiration.In the season with high air temperature and low soil moisture,from the beginning of June to the middle of July,tree growth is much retarded and intensity of transpiration is reduced greatly.Among the 4 species studied,Robinia pseudoacacia is more sensitive to drought than Platycladus orientalis and Quercus variabilis.Drought resistance of Pinus tabulaeformis is lower than the latter two species,but is higher than the former one.Based on this study,choise of species at the lower elevation in northern China is discussed.

One of the most important to be solved urgently in introducing olive tree to China,is to breed and select some new varieties which will adap't to the climatic characteristics of this country.In such work,to select individuals with best qualities,from olive plantations and from pollinated progenies based on scientific selective methods,is of significant importance.Therefore,the author did some work in selecting "plus" olive tree and suggested that,the number of leaves persistent on a branchlet,disease resistance,cold resistance,quantity of fruit produced per tree,oil content of fruit,and homogeneity of fruit maturity were eonsisdered to be the basis for "plus" tree selection in olive tree improvement.

This optical dendrometer with a telescope(2.4x)attached consists of two identicaleircular wedge-prisms,a pair of penta-prism and a circular hypsometer.It is small size,light weight and inexpensive.This instrument is capable of measuring upperdiamter of a stem,distance,height,etc.Although base rule(a variable base line)of the dendrometer is only 300 mm.the measurement of diameter may be widened to three meters and height lengthened to sixty meters by means of counter-rotating the pair of wedge-prism.The technical identification committee checked the accuracy and approved satisfactorily.

Korean pine is the most common and important timber tree cultivated in northeastern China in recent years.But it is considerably damaged by blister rust disease.The pathogenic fungus of the disease is identified as Cronartium sp.although the taxonomic diagnosis has not been fully resolved.The fungus alternates between Pinus koraiensis Sieb.et Zucc.as its aecial host and three Pedicularis species as its telial host under natural conditions in northeastern China.Under artificial inoculation conditions,the fungus also infected three Ribes species.The pycnia appeared in early September,aecia appeared in early June next year.From June to August the Uredia were found on the leaves of lousewort.In August a great amount of telia began to form.The rates of terminal shoot growths decreased in the diseased trees by 82—94%;the lengths of needles decreased by 30%;the pH of diseased barks decreased by 0.3 and the pH of diseased older barks decreased by 0.4.The experiments of chemical control demonstrated that the application of creosote and dyrene to blister rust could kill their aeciospores;creosote,dyrene,carbondaxol and thiram could kill the germ-tubes of aeciospores too.Tests carried out in the forest indicated that to smear creosote on the surfaces of pine stems appeared to be reasonably effective. Some herbicides (viz.reglone,gramoxone,pentachlorophenol natrium,2.4.D Na,2-methyl-4-chlorophenoxyacetic acid,atrazine and fenuron etc.)could considerably killthe louseworts.

The willow gall midge,Rhabdophaga sp.is the most injurious insects of the willow (Salix sp.)in Kiangsu Province.It causes considerable damage to the trunk of the willow annually.In order to hold this species in check,a study was carried out during 1977.The main results obtained from this study are summarized as follows. The willow gall midge as in generation a year in Kiangsu Province.It overwinters in the larvae stage on the willow trunk bark.The fullgrown larvae pupate near surface of galls in early March of the next year.The adults emerge in late March to late April and lay eggs in the emerge holes of the gall,at the base of adventitious buds and the crevices of the trunk bark.Each female lays about 150 egges.The larvae at first injure the bark and then bore into the trunk and last to add to building galls on the willow trunk. Preliminary experiments showed that the following control measures were effective: 1. In mide and late March to brush the gall of the trunk with Fuel oil and BHC mixture at a concentration of 10:1 was good to kill the pupae and fullgrown larvae. 2. In late April and late May to inject 40% omethoate or 40% Rogol emulsion into the hole,made with a chisel or to scratch and brush the trunk with the same emulsion,was good to kill the larvae in galls.

This report describes the process of the bandsaw teeth hardfacing with stellite,high chromium cast iron and high speed steel respectively.Through cutting of around 2,000m³ foreign and native hard wood production practice,it proves that the hardfacing of bandsaw teeth,for cutting,can prolong the service life of saw teeth about 3—4 times than that of conventional ones.

The absorbability and the linear expansion of 4 native broad-leaved timbers treated with 10 different solutions have been investigated.The size of specimens is 3×3×1cm.The specimens were oven-dried and placed in the solutions for 2 and 4 hours,and 1,2,4,7,12,20,30 and 40 days,and were then weighed.The results obtained are as follows: 1. The absorbability and the linear expansion of timbers are different in the different solutions within a species or in the different species within a solution. 2. The absorb rate and the linear expansion of timbers increase quickly in the first day of treatment and decrease with various degrees subsequently. 3. The linear expanisons of timbers on tangential direction are larger 1.1—3.1 times than that on radial direction. 4. Generally,the linear expansion of timbers in liquid of lower molecular weight ceased its function earlier than that of higher molecular weight ceased its function earlier than that of higher molecular weight. 5. The larger the dielectric constant the longer the linear expansion of timbers will be.

The hole erosion about the cylinder liner-cylinder body is different than the pure electrochemistry erossion.It comes from the high-frequency vibration knocked by piston to the cylinder liner.Such vibration enables to produce"bulb"there in and vanish afterwards successively in the cooling water.As a result of the"bulb"vanisned shock waves are formed and dashed against the cylinder liner—the cylinder surface,thus some parts of which are suffered,here the name of so-called hole erosion is given. Such problem can be effectively prevented or cured in some degree by taking certain measures such as narrowing the space between piston and cylinder wall probably,improving the support of the cylinder liner,enlarging the space of the water jacket around the cylinder body,reforming the cooling water system and adding NL emulsifier in it,etc.