Application of Multi-Exponential Inversion Method to NMR Measurements

A new multi-exponential inversion method for NMR relaxation signals is presented and tested, which is based on a solid iteration rebuild technique (SIRT). The T2 spectra inversed by the new method are compared with MAP-II results. The T1 and T2 inversion results with different pre-assigned relaxation times and different SNR show that 16 to 64 logarithm equal spaced time constants is better obviously than MAP-II. And in particular, it can ensure the relaxation time distribution when the SNR of the measured signal is very low. The new algorithm has been applied in rock core NMR analysis and NMR logging data process and interpretation.

Removal of aqueous phenol compound by vacuum membrane distillation

The effects of feed temperature and pH value on the removal of aqueous phenol wastewater by vacuum membrane distillation process are studied by experiments employing micro porous membranes of poly vinylidene fluoride (PVDF) and ploy tetrafluoro ethylene (PTFE) with nominal average pore sizes 0.22 mm and 0.20 mm, respectively. It is found that the optimal feed temperature for PVDF membrane is 50 ℃; and for PTFE membrane, 60 ℃. The pH value of the feed has little influence on the membrane fluxes and ion rejection ratios, while it influenced considerably on the selectivity. Increase of pH value of the feed is conducive to the increase of selectivity. In the same experimental conditions, PTFE membrane shows better separation performance than PVDF membrane does.

Regional characteristics of dust events in China

The regional characteristics of dust events in China has b een mainly studied by using the data of dust storm, wind-blown sand and floating dust from 338 observation stations through China from 1954 to 2000. The results of this study are as follows: (1) In China, there are two h igh frequent areas of dust events, one is located in the area of Min feng and Hotan in the South Xinjiang Basin, the other is situated in the area of Minqin and Jilantai in the Hexi Region. Furthermore, th e spatial distributions of the various types of dust events are diffe rent. The dust storms mainly occur in the arid and semiarid areas co vering the deserts and the areas undergoing desertification in northern China. Wind-blown sand and floating-dust not only occur in the areas where dust storms occur, but also extend to the neighboring areas. The range of wind-blown sand extends northeastward and southeastward, b ut floating-dust mainly extends southeastward to the low-latitude region such as the East China Plain and the area of the middle and lower reaches o f the Yangtze River. Compared with wind-blown sand, the floating-dust seldo m occurs in the high latitude areas such as North Xinjiang and North east China. (2) The affected areas of dust storms can be divided into seven sub-regions, that is, North Xinjiang Region, South Xinjiang Reg ion, Hexi Region, Qaidam Basin Region, Hetao Region, Northeastern China Region and Qinghai-Xizang (Tibet) Region. The area of the most freque nt occurrence of dust storms and floating-dust is in South Xinjiang Region, and of wind-blown sand in the Hexi Region. In general, the frequency of d ust events in all the seven regions shows a decreasing tendency from 19 54 to 2000, but there are certain differences between various dust events in d ifferent regions. The maximum interannual change and variance of dust events during this time happened in South Xinjiang Region and Hexi Re gion. The dust events generally occur most frequently in April in most pa rts of China. The spring occurred days of dust events occupied 60-70% of the whole year in Hetao Region and Northeastern China Region. However, in South Xinjiang Region and North Xinjiang Region, which was less affec ted by monsoon climate, dust events may occur at any time of the year, le ss than 50% of the events in this region occur during spring. In the remaining three regions 50-60% of the dust events occur in spring of a year.

THE IMPACT OF HUMAN ACTIVITIES ON GROUNDWATER RESOURCES IN THE SOUTH EDGE OF TARIM BASIN, XINJIANG

In the modern times, the population growth, development of industrial andagricultural production and the petroleum exploitation, brought about the unceasing expansion ofartificial oasis and abrupt increase of water demand. The artificial hydraulic irrigationengineering took the place of the natural river system, the reservoirs took the place of naturallakes, which in turn enhanced the space-time redistribution of surface water based on the naturalevolution, and so did groundwater: The groundwater recharge reduced 26. 2% in 46 years from 1950 to1995 in the southern piedmont flood plain of Tarim Basin due to mean yearly population increase rateof 27. 7 per thousand and associated with the water use rate increasing from 24. 6% to 58. 4%. Atthe same time the artificial water system seepage give primary play to groundwater recharge, whichis up to 57. 6% whilst that of the natural system reduce to 33.7%. As a result, groundwater leveldrop 3 - 5m widespread except some irrigation area and surroundings of plain reservoir. Spring waterdischarge also reduce about 37. 6% and discharge zone continuously move away to the north with thevalue of 0. 5 - 1. 2km in the past 40 years.

Study on new technique of rapidly following curtain filling

The present problem of mining of narrow and gentle dip vein was analyzed. A new technique of rapidly following curtain filling was put forward. The results show that the new technique is feasible, has the characteristic to make the whole curtain wall filter, makes relative density of the filling tailings slurry reach saturation of 78.0% 80.0% in 25 min, and keeps the roof of mined out space stable in 60 min. The new technique of the rapidly following curtain filling has solved the difficult problem of the filling body filtering slowly and promptly controlling underground pressure, which cannot be solved in traditional ways.

Progresses in geology and hazards analysis of Tianchi Volcano

A number of different lahars have been recognized from a systematic survey of a mapping project. The high setting temperature feature of the deposits indicates a relationship between the lahar and the Millennium eruption event of Tianchi Volcano. The lahars caused a dramatic disaster. Recognize of the huge avalanche scars and deposits around Tianchi Volcano imply another highly destructive hazard. Three types of different texture of the avalanche deposits have been recognized. There was often magma mixing processes during the Millennium eruption of Tianchi Volcano, indicating a mixing and co-eruption regime of the eruption.

A Nickel-Manganese-Modified Low Zinc Phosphate Solution for Cathode-Electrophoretic Painting of Steel Substrates

Phosphate coatings are partially dissolved in the cathodic area during the cathode-electrophoretic painting processes causing the result that the coatings adhesion, corrosion protection, alkaline resistance are decreased. Furthermore, the service life of the coated production will be shortened. The addition of Ni2+, Mn2+ to the phosphating bath to improve the corrosion stability, alkaline resistance, as well as the adhesion of coating layers is studied in the article. These heavy metals do not only catalyse the surface reactions but generate a more corrosion resistant surface. We perfected the trecation phosphate solution by reducing the sludge, accelerating the phosphating reactions, improving corrosion protection and alkaline resistance. More even and finer grain structures, excellent corrosion resistance were obtained compared to the traditional phosphating technique.

Cultivating High Efficient Bacteria of Degrading Pulping Wastewater by Ultraviolet Mutagenic Technology

Instead of pure bacteria, induction mutation of activated sludge by ultraviolet (Uv) was studied and used to treat pulping wastewater by continuous- flow. The result showed the mutagenic activated sludge had remarkable effect and application potential in pulping wastewater treatment. Comparing with common activated sludge, the mutagenic activated sludge was more suitable for lignose decomposition and had high decomposing efficiency.