scholarly journals On non-local representations of the ageing algebra

2011 ◽  
Vol 847 (3) ◽  
pp. 612-627 ◽  
Author(s):  
Malte Henkel ◽  
Stoimen Stoimenov
Author(s):  
Samuel R. Bowman ◽  
Benjamin Lokshin

<p>Idiosyncratically transparent vowels—those that fail to either undergo or trigger harmony in a particular morpheme but do both elsewhere—have not been documented in any language, and have been claimed to be impossible as recently as Mahanta (2012). We present two affixes in Kazakh that contain idiosyncratic vowels, and present evidence from wordlist elicitations and phonetic studies with two native speakers from different regions. We discuss the implications of these findings for constraint-based theories of vowel harmony: we show that they cannot be readily analyzed in conventional strictly-local harmony system, and present analyses in two recent systems that allow for non-local representations. Both Rhodes's (2010) system for vowel harmony in Agreement by Correspondence and Kimper's (2011) Trigger Competition can be made to accommodate lexical specifications that force vowels in particular morphemes to act as transparent, and we show that implementing these lexical specifications in Trigger Competition forces us to make somewhat stronger predictions about the rarity of idiosyncratic transparency.  </p>


Author(s):  
Zhifeng Shao

Recently, low voltage (≤5kV) scanning electron microscopes have become popular because of their unprecedented advantages, such as minimized charging effects and smaller specimen damage, etc. Perhaps the most important advantage of LVSEM is that they may be able to provide ultrahigh resolution since the interaction volume decreases when electron energy is reduced. It is obvious that no matter how low the operating voltage is, the resolution is always poorer than the probe radius. To achieve 10Å resolution at 5kV (including non-local effects), we would require a probe radius of 5∽6 Å. At low voltages, we can no longer ignore the effects of chromatic aberration because of the increased ratio δV/V. The 3rd order spherical aberration is another major limiting factor. The optimized aperture should be calculated as


Author(s):  
Zhifeng Shao ◽  
A.V. Crewe

For scanning electron microscopes, it is plausible that by lowering the primary electron energy, one can decrease the volume of interaction and improve resolution. As shown by Crewe /1/, at V0 =5kV a 10Å resolution (including non-local effects) is possible. To achieve this, we would need a probe size about 5Å. However, at low voltages, the chromatic aberration becomes the major concern even for field emission sources. In this case, δV/V = 0.1 V/5kV = 2x10-5. As a rough estimate, it has been shown that /2/ the chromatic aberration δC should be less than ⅓ of δ0 the probe size determined by diffraction and spherical aberration in order to neglect its effect. But this did not take into account the distribution of electron energy. We will show that by using a wave optical treatment, the tolerance on the chromatic aberration is much larger than we expected.


1998 ◽  
Vol 08 (PR8) ◽  
pp. Pr8-309-Pr8-316 ◽  
Author(s):  
Y. Z. Povstenko
Keyword(s):  

Sign in / Sign up

Export Citation Format

Share Document