A comparison of the3He melting curve,T c(P) curve,and the susceptibility of lanthanum-diluted cerium magnesium nitrate below 50 mK

The ac susceptibility of lanthanum-diluted cerium magnesium nitrate has been compared to the temperature scales as derived from the (P, T) relation determined by Halperin and that was measured recently by Greywall. It is found that the susceptibility does not obey a simple Curie-Weiss law over the temperature range between 1 and 50 mK. The results of these calibrations are also used to determine the temperatures for the second-order phase transitions into the superfluid phases of³He at several pressures. TheseT _c(P) values are compared to results of earlier experiments that used thermometry based on the susceptibility of platinum as well as other thermometry techniques.     

A simple handling technique for mammalian oocytes and embryos during preparation for transmission electron microscopy

Due to their small size, mammalian oocytes and embryos pose unique problems during preparation for transmission electron microscopy. This paper outlines a method which combines protein embedding with centrifugation to locate the specimens on the face of a Beem capsule mould. This method facilitates both the processing of oocytes with minimal loss and rapid location of the specimens within the block for simultaneous sectioning, staining and examination.     

Transport of K in PVC matrix membranes containing valinomycin

We report impedance measurements on PVC matrix membranes which contain KBPh₄ with varying proportions of valinomycin. In agreement with our earlier measurements the value of the bulk membrane resistance (R_b) is much larger in the presence of valinomycin, indicating that the mobility of K⁺ is greatly reduced by the valinomycin. R_b shows a linear variation with valinomycin/K⁺ ratio between 0 and 1, but it is invariant at higher valinomycin/K⁺ ratios. Thus there is no evidence for a special transport mechanism for K⁺ in these membranes.     

Drying cellulose triacetate in a dryer with a vibrational fluidized bed

Conclusions The process of drying cellulose triacetate in a vibrating bed has been studied.For final drying of cellulose triacetate before solution, it is recommended to use an industrial specimen of a unit with a vibrating bed having a capacity of 2700 kg/h.This assembly can be used to dry other fibre-forming disperse polymeric materials containing strongly bound moisture.Translated from Khimicheskie Volokna, No. 3, pp. 49–51, May–June, 1984.     

N.m.r. line shape-relaxation correlation analysis of bitumen and oil sands

The first results of the analysis of bitumen and oil sands using the recently developed n.m.r. spingrouping technique are presented. The n.m.r. relaxation experiments were carried out on bitumen, and on natural and dried oil sands samples. The results indicate that the spin-grouping can resolve and quantify several components of the samples studied. The bitumen and bitumen fraction of the oil sands are resolved according to their spin-spin relaxation times into three major groups: solid-like (rigid), solid-like (mobile) and semi-liquid. The water in the oil sands exists in two different environments. Tentatively one environment is assigned to be the bridges between the sand grains, while the other is assigned to be the clay surface. One can conclude that with spin grouping of complex mixtures the decomposition (in which components are resolved according to their dynamic state) is possible. The accuracy of such resolution is of the order of a few per cent.