A Study of a-Si:H Absorption Edge Using Dunstan’s Model

تم استخدام نموذج الامتصاص البصري في أشباه الموصلات غير المتبلورة المنسوب   Dunstan لتحليل بعض بيانات للامتصاص البصري لـلسيليكون العشوائي المهدرج. يقدم هذا النموذج اضطرابًا في امتصاص حزمه-الى حزمه من خلال التوزيع الأسي الخطي لفجوة الطاقة الموضعيه، والذي يمكن أن يفسر كلا من منطقتيUrbach وTauc من حافه الامتصاص البصري. مقارنة بالنماذج الأخرى ذات الأسس المماثلة، مثل نموذجيO’LearyوGuerra، فهو أبسط في الشكل الرياضي وله معنى فيزيائي مباشر. نموذج دونستان نجح  في تفسير بيانات الامتصاص البصري ل Jackson et alو Maurer et al، تم استخراج معلمات فيزيائية مهمة خاصة فجوه الطاقه المتعلقه بأنتقالات حزمه-الى حزمه والتي هي فجوة الطاقة في حالة عدم وجود اللانتظام ، والتي يمكن تفسيرها على أنها فجوة التحركيه للماده.The optical absorption data of Hydrogenated Amorphous Silicon was analyzed using a Dunstan model of optical absorption in amorphous semiconductors. This model introduces disorder into the band-band absorption through a linear exponential distribution of local energy gaps, and it accounts for both the Urbach and Tauc regions of the optical absorption edge.Compared to other models of similar bases, such as the O’Leary and Guerra models, it is simpler to understand mathematically and has a physical meaning. The optical absorption data of Jackson et al and Maurer et al were successfully interpreted using Dunstan’s model. Useful physical parameters are extracted especially the band to the band energy gap , which is the energy gap in the absence of disorder, that can be interpreted as the mobility gap of the material

Functional magnetic resonance imaging shows oxytocin activates brain regions associated with mother-pup bonding during suckling

Oxytocin is released in the maternal brain during breastfeeding and may help strengthen the mother-infant relationship. Here, we used functional magnetic resonance imaging to determine whether oxytocin modulates brain activity in postpartum day 4-8 dams receiving suckling stimulation. During imaging sessions, dams were exposed to pup suckling before and after administration of an oxytocin receptor antagonist. Another group of dams received oxytocin alone. Changes in brain activation in response to suckling closely matched that elicited by oxytocin administration. The overlapping brain areas included the olfactory system, nucleus accumbens, insular cortex, prefrontal cortex, ventral tegmental area, cortical amygdala, and several cortical and hypothalamic nuclei. Blockade of oxytocin receptors largely attenuated activation in these regions. The data suggest that oxytocin may strengthen mother-infant bond formation partly by acting through brain areas involved in regulating olfactory discrimination, emotions, and reward

A Quantitative Approach to Estimate the Damage Inflicted by Traffic Pollution on Historic Buildings in Al-Salt City, Jordan

Traffic in the city of Al-Salt is not only putting pedestrians at risk and threatening the health of citizens, it is also damaging the town's historic buildings. Most stone buildings in the heritage-rich city are suffering adverse effects from vehicle-related pollution. This effect is highly visible soiling and discoloration from deposited carbon particles in the form of fine soot on most buildings. The level and progress of the damage depends on the geology of the stone and the proximity of the structure from traffic congestion. The accumulation of soot leads to the buildup of black sulfate (gypsum) skins on the limestone facade which causes the sound stone behind it to disintegrate. It is vital to the well-being of this historic treasure that the volume of the city traffic must be reduced and traffic flow improved. The main objective of this study is to qualitatively and quantitatively assess the damage caused to buildings of historical and cultural value by traffic pollution. Age of vehicles running on city’s streets and the rate of their emissions are quantified and analyzed. Several field investigations and laboratory tests were conducted to identify the chemical relations between pollutants and stone decay on these buildings. Keywords: Traffic pollution, tailpipe emission, vehicular emission, historic buildings, limeston

Generative RGB-D face completion for head-mounted display removal

Head-mounted displays (HMDs) are an essential display device for the observation of virtual reality (VR) environments. However, HMDs obstruct external capturing methods from recording the user's upper face. This severely impacts social VR applications, such as teleconferencing, which commonly rely on external RGB-D sensors to capture a volumetric representation of the user. In this paper, we introduce an HMD removal framework based on generative adversarial networks (GANs), capable of jointly filling in missing color and depth data in RGB-D face images. Our framework includes an RGB-based identity loss function for identity preservation and several components aimed at surface reproduction. Our results demonstrate that our framework is able to remove HMDs from synthetic RGB-D face images while preserving the subject's identity

Effect of Composition on Electrical and Optical Properties of Thin Films of Amorphous GaxSe100−x Nanorods

We report the electrical and optical studies of thin films of a-GaxSe100−x nanorods (x = 3, 6, 9 and 12). Thin films of a-GaxSe100−x nanorods have been synthesized thermal evaporation technique. DC electrical conductivity of deposited thin films of a-GaxSe100−x nanorods is measured as a function of temperature range from 298 to 383 K. An exponential increase in the dc conductivity is observed with the increase in temperature, suggesting thereby a semiconducting behavior. The estimated value of activation energy decreases on incorporation of dopant (Ga) content in the Se system. The calculated value of pre-exponential factor (σ0) is of the order of 101 Ω−1 cm−1, which suggests that the conduction takes place in the band tails of localized states. It is suggested that the conduction is due to thermally assisted tunneling of the carriers in the localized states near the band edges. On the basis of the optical absorption measurements, an indirect optical band gap is observed in this system, and the value of optical band gap decreases on increasing Ga concentration