This article shows out the situation of cold chain in sub-Saharan countries through an investigation carry out in 34 cold stores in Cameroon. The cold chain in sub-Saharan countries still remains uncertain. The stacki...This article shows out the situation of cold chain in sub-Saharan countries through an investigation carry out in 34 cold stores in Cameroon. The cold chain in sub-Saharan countries still remains uncertain. The stacking conditions are hardly respected and are especially limited on temperature control. The equipments of transportation of refrigerated foodstuff and the display cases made for the selling of perishable foodstuff are poorly used. And, many consumers do not have domestic refrigerators to store products. The main reasons for this situation are： poverty, unawareness, unqualified refrigeration technicians and finally an insufficient political policy. Nevertheless, some solutions could be outlined： sensitisation and training at different levels, an international support based on the training and the respect of cold chain norms, the promotion of traditional food conservation techniques （drying, smoking, salting） which are more accessible and appropriate to local feeding styles.展开更多
N-type and p-type 6H-SiC metal oxide semiconductor (MOS) capacitor samples are fabricated with a typical method,and the high frequency capacitor voltage (C-V) curves of these samples are measured at temperatures rangi...N-type and p-type 6H-SiC metal oxide semiconductor (MOS) capacitor samples are fabricated with a typical method,and the high frequency capacitor voltage (C-V) curves of these samples are measured at temperatures ranging from 293 to 533 K.There exists huge difference between the n-type and p-type samples.Flat-band voltage shift of the n-type sample becomes larger with temperature rising,but that of the p-type sample have very little change.This may be caused by the residual Al in the p-type oxide.Both types of the SiC samples follow the same rule of flat-band voltage changing with temperature.But their mechanisms are different as temperature is above 453 K.Of both types the p-type SiC is more suitable for high temperature applications.展开更多
文摘This article shows out the situation of cold chain in sub-Saharan countries through an investigation carry out in 34 cold stores in Cameroon. The cold chain in sub-Saharan countries still remains uncertain. The stacking conditions are hardly respected and are especially limited on temperature control. The equipments of transportation of refrigerated foodstuff and the display cases made for the selling of perishable foodstuff are poorly used. And, many consumers do not have domestic refrigerators to store products. The main reasons for this situation are： poverty, unawareness, unqualified refrigeration technicians and finally an insufficient political policy. Nevertheless, some solutions could be outlined： sensitisation and training at different levels, an international support based on the training and the respect of cold chain norms, the promotion of traditional food conservation techniques （drying, smoking, salting） which are more accessible and appropriate to local feeding styles.
文摘N-type and p-type 6H-SiC metal oxide semiconductor (MOS) capacitor samples are fabricated with a typical method,and the high frequency capacitor voltage (C-V) curves of these samples are measured at temperatures ranging from 293 to 533 K.There exists huge difference between the n-type and p-type samples.Flat-band voltage shift of the n-type sample becomes larger with temperature rising,but that of the p-type sample have very little change.This may be caused by the residual Al in the p-type oxide.Both types of the SiC samples follow the same rule of flat-band voltage changing with temperature.But their mechanisms are different as temperature is above 453 K.Of both types the p-type SiC is more suitable for high temperature applications.
