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Intentionally fabricated autobiographical memoriesJustice, L.V., Morrison, Catriona M., Conway, M.A. 28 October 2016 (has links)
Yes / Participants generated both autobiographical memories (AMs) that they believed to be true and intentionally fabricated autobiographical memories (IFAMs). Memories were constructed while a concurrent memory load (random 8-digit sequence) was held in mind or while there was no concurrent load. Amount and accuracy of recall of the concurrent memory load was reliably poorer following generation of IFAMs than following generation of AMs. There was no reliable effect of load on memory generation times; however, IFAMs always took longer to construct than AMs. Finally, replicating previous findings, fewer IFAMs had a field perspective than AMs, IFAMs were less vivid than AMs, and IFAMs contained more motion words (indicative of increased cognitive load). Taken together, these findings show a pattern of systematic differences that mark out IFAMs, and they also show that IFAMs can be identified indirectly by lowered performance on concurrent tasks that increase cognitive load.
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Adult recollections of childhood memories: What details can be recalled?Wells, C.E., Morrison, Catriona M., Conway, M.A. 12 November 2013 (has links)
No / In a memory survey, adult respondents recalled, dated, and described two earliest positive and negative memories that they were highly confident were memories. They then answered a series of questions that focused on memory details such as clothing, duration, weather, and so on. Few differences were found between positive and negative memories, which on average had 4/5 details and dated to the age of 6/6.5 years. Memory for details about activity, location, and who was present was good; memory for all other details was poorer or at floor. Taken together, these findings indicate that (full) earliest memories may be considerably later than previously thought and that they rarely contain the sort of specific details targeted by professional investigators. The resulting normative profile of memory details reported here can be used to evaluate overly specific childhood autobiographical memories and to identify memory details with a low probability of recall.
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“It's the Somali thing that's key” : A qualitative study on the Somalian diaspora in Denmark and their humanitarian actions in SomaliaBlicher Ørtenblad, Frida January 2024 (has links)
This study investigates the Somalian diaspora in Denmark, contributing to existingliterature on diaspora humanitarianism with a Danish-Somalian perspective. It furtherenhances an understanding of how the diaspora navigates a Somalian social support systemand introduces an understudied theoretical framework combining hope, mobility anddiaspora. The aim of the study is to understand how and why the Somalian diaspora inDenmark engages in humanitarian work in Somalia. Through interviews and an analyticalframework of collective memories and hope, it explores the practices and culturalunderstandings within the Danish-Somalian diaspora, related to their humanitarian actionsin Somalia. The humanitarian actions are provided through (social) remittances distributedthrough informal systems of kinship and clan, with a focus of helping fellow Somalians.The findings indicate that a strong connection and sense of moral obligation to Somalia,along with hope for Somalia’s future and the possibility of a return, drive the diasporashumanitarian efforts.
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Organic Planar Heterojunction Phototransistor DevicesBai, Shaoling 15 July 2024 (has links)
Organic phototransistors (OPTs) can enable essential applications, such as nonvolatile memory, artificial synapses, and photosensors in next-generation optical communication and wearable electronics. Among these applications, nonvolatile OPT memories are particularly promising, as they can retain captured visual information for extended periods, making them valuable for data storage, image and video processing applications. The capability of storing multi-bit information, which provides a low-cost way to increase the memory density per unit cell area, is one of the most critical challenges of memory products. In this work, we explore different solution-processible electrets to obtain highly sensitive phototransistor memory devices. Different planar heterojunctions, including small molecule/small molecule and small molecule/polymer, are used to fabricate OPT memories. Additionally, we explore the feasibility of producing polymer/polymer planar heterojunctions through printing processes.
Firstly, OPT memories that can be programmed with white light and erased by applying a negative voltage are fabricated with a planar heterojunction of a nonconductive nanographene layer and a semiconducting layer of 2,9-didecyldinaphtho[2,3-b:2’,3’-f]thieno[3,2-b]thiophene (C10-DNTT). We systematically study the optical and memory characteristics of devices with an 8 nm nanographene (NG) layer. The photosensitivity of such devices can be as high as 3.4×105. The memory also shows quite good endurance and data-storing stability; an endurance of 100 write-read-erase-read (WRER) cycles and 1.5×105 s retention time are obtained. The thickness of the NG layer has a considerable influence on the performance of fabricated devices. The results suggest that devices with a thicker NG layer are more sensitive to weak light. In comparison, devices with a relatively thin NG layer are found to be promising for multi-bit photo memory devices.
Secondly, we fabricate OPT memories by replacing the nanographene layer with a commercially available semiconducting polymer, namely Poly(2,5-bis(2-octyldodecyl)-3,6-di(pyridin-2-yl)-pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione-alt-2,2’-bithiophene) (PDBPyBT). This polymer possesses a narrow bandgap and exhibits a broad range of light absorption, spanning from ultraviolet (UV) to red light wavelengths. As a result, the fabricated devices are capable of responding to a broad spectrum of light colors. The light response of these devices is investigated in terms of their reaction to different colors of light. Also, devices with varying thicknesses of the PDBPyBT layer are fabricated and studied. The results indicate that all of the fabricated devices demonstrate multi-bit programming properties, and the devices incorporating a thin, ribbon-structured PDBPyBT layer are particularly well-suited for applications as light dosimeters. Moreover, the results highlight that both the C10-DNTT and the PDBPyBT layer function as photo exciton generation and charge-trapping layers.
Last, we seek to fabricate cost-effective organic multilayer devices through a solution-processing approach, eliminating the need for orthogonal solvents. We observe a crosslinking effect in the thin films caused by thermal annealing without using any crosslinker. Remarkably, this effect is found to be universal for several commercial semiconducting polymers investigated in our study. Following annealing at 200 ºC or higher temperatures, the thin films exhibit enhanced stability against the original solvent. Various analytical techniques are employed to examine the thin films to gain insights into the microstructural changes. Our results suggest that the observed crosslinking effect is predominantly attributed to a physical transformation, whereby the films became more crystalline after annealing at relatively high temperatures. To further explore the feasibility of fabricating multilayer devices, we simulate the construction of multilayer devices by top-gate-bottom-contact (TGBC) devices using the same solvent for the polymer dielectric layer and the semiconducting layer. We also fabricated planar polymer/polymer heterojunction via this method. Encouragingly, this approach demonstrated that thermal annealing could work as a straightforward and promising method for producing cost-effective organic multilayer devices, e.g., fully solution-processed diodes, functional transistors, and solar cells.:Abstract iii
Contents vii
1 Introduction 1
1.1 Motivation 1
1.2 Organic semiconductor 2
1.2.1 Atom orbitals and molecular orbitals 2
1.2.2 Energy levels in solid 5
1.2.3 Fermi level 6
1.2.4 Band bending 7
1.2.5 From orbital to states 8
1.2.6 Organic semiconductor materials 9
1.2.7 Nanographene 10
1.2.8 Charge carrier transport in organic semiconductors 11
1.3 Organic field-effect transistors (OFET) 11
1.3.1 OFET architectures 12
1.3.2 OFET operation principle 12
1.3.3 OFET performance parameters 14
1.3.4 OFET memory 17
1.4 Optical electronics 20
1.4.1 Exciton pair generation. 20
1.4.2 Photoelectronic devices 21
1.4.3 Phototransistor devices 22
1.5 Phototransistor memories 23
1.5.1 Working mechanism of phototransistor memories 23
1.5.2 Phototransistor memory architecture 24
1.5.3 State-of-the-art organic phototransistor memory 25
1.6 Objective and outline 27
2 Materials and methods 29
2.1 Materials 29
2.2 Device fabrication 30
2.2.1 Substrate cleaning 30
2.2.2 Solution shearing 30
2.2.3 Thermal vapor deposition 31
2.3 Characterization 31
2.3.1 Thin film characterization 31
2.3.2 Current voltage characteristics 35
2.3.3 Capacitance 36
3 C10-DNTT/NG planar heterojunction phototransistor memories 37
3.1 Introduction 37
3.2 Thin films 39
3.2.1 Film and device fabrication 39
3.2.2 Characterization of thin films 39
3.3 Transfer characteristics under light 41
3.3.1 Writing process 41
3.3.2 Erasing process 48
3.3.3 C10-DNTT-only devices 51
3.4 Summary of working principle 52
3.5 Output characteristics and evaluation of the optical properties 52
3.6 Memory properties of NG-based OPT memory devices 55
3.7 Devices with different NG thicknesses 56
3.7.1 The impact of NG thickness 56
3.7.2 Devices fabricated from 0.05 mg ml-1 NG solution 60
3.8 Conclusion 64
4 C10-DNTT/PDBPyBT heterojunction phototransistor memories 67
4.1 Introduction 67
4.2 Device Architecture 68
4.3 Physical characterization of PDBPyBT and C10-DNTT thin films 69
4.4 Performance of devices with a thick PDBPyBT layer 72
4.4.1 Erasing and programming process 72
4.4.2 Response to different colors of light 78
4.5 Variation of PDBPyBT thickness 80
4.5.1 Transfer characteristics 80
4.5.2 Morphology of C10-DNTT 85
4.5.3 Output characteristics 86
4.5.4 Multi-level programming test 86
4.6 Comparison of the devices 92
4.7 Summary 93
5 Organic multilayer devices fabricated via thermal annealing 95
5.1 Introduction 95
5.2 Film Fabrication 97
5.3 Study on thin films 97
5.3.1 Thickness changes 97
5.3.2 Characterization of the thin films 99
5.3.3 Impact of re-annealing 107
5.3.4 Other semiconducting polymers 108
5.4 Discussion of the working mechanism 110
5.5 Impact of thermal annealing on devices’ performance 111
5.5.1 BGTC devices fabrication 111
5.5.2 TGBC devices fabrication 113
5.6 Planar heterojunction devices via solution processing 116
5.7 Conclusion 117
6 Conclusions and outlook 119
6.1 Conclusions 119
6.2 Outlook 120
Bibliography 123
List of Figures 143
List of Tables 155
List of abbreviations 157
Appendix A 159
Appendix B 165
B1.1 Introduction 165
B1.2 Devices with a 7 nm shear coated Al2O3 dielectric 166
B1.2.1 Normal-sized channel devices 166
B1.2.2 Ultra-wide channel devices 167
B1.3 Devices with a 30 nm ALD Al2O3 dielectric 169
B1.3.1 Normal-sized channel devices 169
B1.3.2 Ultra-wide channel devices 170
B1.4 Ferroelectric organic phototransistor devices 172
B1.4.1 Dielectric layer 172
B1.4.2 Devices with 10 nm HZO 173
B1.4.3 Devices with 30 nm HZO 175
Conclusion 176
Publications 177
Acknowledgment 179
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Memories on film: digital storytelling with people in residential dementia careCapstick, Andrea, Ludwin, Katherine January 2015 (has links)
No / Memories on film is the outcome of an 18-month study funded by the National Institute for Health Research’s School for Social Care Research. Based on the principles of Participatory Video (Milne et al 2012), the study used digital storytelling and co-production techniques to create short films with 10 participants in a Leeds dementia care facility. Choice of images and narrative content were decided by the participants, who were aged between 76 and 99 years, and had lived in Leeds for most if not all of their lives. Almost all of them decided to tell the story of their own early life and its defining events, and the participants’ own voices, both speaking and singing, feature on the soundtrack to their films. We made extensive use of local history websites, and archives such as Leodis, when putting the films together. We were particularly keen to find out whether the creation of digital stories with this group of people – who can experience isolation and marginalisation – would help to increase their social participation. As a result we are now interested, not only in discussing the film-making process and the study outcomes, but also in identifying opportunities to have the completed films hosted by other websites and community groups. The summative focus groups for the study identified a number of potential uses for the films, including inter-generational work with schools, staff development initiatives, and raising public awareness.
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Identitetsrelaterade positiva och negativa autobiografiska platsminnen / Self-related positive and negative autobiographical place memoriesConcha, Carolina, Heierson, Karin January 2018 (has links)
Syftet med studien var att undersöka självbiografiska positiva och negativa platsminnen relaterat till platsidentitet och de tio fenomenologiska dimensionerna. Autobiografiska minnen är minnen som refererar till viktiga livsperioder och utgör en del av vår identitet. Total 81 kvinnor och 28 män i åldern 39 – 76 år deltog i studien. Designen för analyserna av kvantitativa data var en mellanpersonsdesign, med en oberoende variabel Plats (positiv/negativ) och två beroende variabler platsidentitet (emotionell/kognitiv komponent) samt de tio fenomenologiska dimensioner i det självbiografiska minnet. Mätinstrumentet bestod av en enkät i tre delar som innehöll frågor baserat på tidigare forskning. Resultatet visade en effekt av Typ av Platsminne. Effekten var associerad med både den emotionella och kognitiva komponenten i platsidentiteten. Resultatet visade också en effekt av Typ av Plats på de tio fenomenologiska dimensionerna. Effekten var associerad med sex av dessa. Det kvalitativa resultatet visade att positiva platsminnen innehåller minnen från rurala miljöer medan negativa minnen i huvudsak var urbana miljöer. Resultatet visade även att en övervägande del av minnena i huvudsak innehöll barndomsminnen oavsett positiva eller negativa platsminnen. / The aim was to investigate positive and negative place-related autobiographical memories related to place-identity and phenomenological dimensions of the autobiographical memory. Autobiographical memories are memories that refer to important life periods, grounding our identity. 81 women and 28 men. Between-subject-design was used for quantitative data, with an independent variable of Place (positive / negative) and two dependent variables of Place-identity (emotional / cognitive component) as well as the ten phenomenological dimensions of the autobiographical memory. The measuring instrument consisted of a three-part questionnaire that contained questions based on previous research. Results showed an effect of Type of Place associated with both emotional and cognitive components of place identity. We also reported an effect of Type of Place on six of ten phenomenological dimensions. The qualitative results showed that positive memories contain memories from rural environments, while negative memories contain mainly urban environments. The results also showed that a majority of the memories contained mainly childhood associated memories, regardless of positive or negative place memories.
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Ferroelectric hafnium oxide for ferroelectric random-access memories and ferroelectric field-effect transistorsMikolajick, Thomas, Slesazeck, Stefan, Park, Min Hyuk, Schroeder, Uwe 17 October 2022 (has links)
Ferroelectrics are promising for nonvolatile memories. However, the difficulty of fabricating ferroelectric layers and integrating them into complementary metal oxide semiconductor (CMOS) devices has hindered rapid scaling. Hafnium oxide is a standard material available in CMOS processes. Ferroelectricity in Si-doped hafnia was first reported in 2011, and this has revived interest in using ferroelectric memories for various applications. Ferroelectric hafnia with matured atomic layer deposition techniques is compatible with three-dimensional capacitors and can solve the scaling limitations in 1-transistor-1-capacitor (1T-1C) ferroelectric random-access memories (FeRAMs). For ferroelectric field-effect-transistors (FeFETs), the low permittivity and high coercive field Ec of hafnia ferroelectrics are beneficial. The much higher Ec of ferroelectric hafnia, however, makes high endurance a challenge. This article summarizes the current status of ferroelectricity in hafnia and explains how major issues of 1T-1C FeRAMs and FeFETs can be solved using this material system.
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A Deep Study of Resistance Switching Phenomena in TaOₓ ReRAM Cells: System-Theoretic Dynamic Route Map Analysis and Experimental VerificationAscoli, Alon, Menzel, Stephan, Rana, Vikas, Kempen, Tim, Messaris, Ioannis, Demirkol, Ahmet Samil, Schulten, Michael, Siemon, Anne, Tetzlaff, Ronald 02 February 2024 (has links)
The multidisciplinary field of memristors calls for the necessity for theoreticallyinclined researchers and experimenters to join forces, merging complementary expertise and technical know-how, to develop and implement rigorous and systematic techniques to design variability-aware memristor-based circuits and systems. The availability of a predictive physics-based model for a memristor is a necessary requirement before commencing these investigations. An interesting dynamic phenomenon, occurring ubiquitously in non-volatile memristors, is fading memory. The latter may be defined as the appearance of a unique steady-state behavior, irrespective of the choice of the initial condition from an admissible range of values, for each stimulus from a certain family, for example, the DC or the purely-AC periodic input class. This paper first provides experimental evidence for the emergence of fading memory effects in the response of a TaOₓ redox-based random access memory cell to inputs from both of these classes. Leveraging the predictive capability of a physics-based device model, called JART VCM v1, a thorough system-theoretic analysis, revolving around the Dynamic Route Map graphic tool, is presented. This analysis allows to gain a better understanding of the mechanisms, underlying the emergence of history erase effects, and to identify the main factors, that modulate this nonlinear phenomenon, toward future potential applications.
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Sound Perception:Encapsulating Intangible Voice Memories in a Physical MementoMakhlouf, Mona Mahmoud 01 January 2017 (has links)
We live in a very busy world with a variety of sensory stimulation including the olfactory, visual, tactile, and auditory. The five senses are triggered by our surroundings and help us to form meaning about the world.ⅰ Based on where someone grows up, she or he is introduced to various sites and sounds, affecting how they interpret the world. Sounds relate meaning through the association between hearing, memory and an event. Hearing is one of the learning processes, in which individuals give, receive, and store information. We typically rely on our five senses, which contribute to the process of understanding, communicating, and comprehending information. Moving beyond visual perception requires systematic attention to individual learning modalities.ⅱ Sound is one of the developing areas in the field of perception that moves beyond vision to help people understand nature, objects, narratives and varieties of perception. In order to comprehend how people hear, it is important to understand the role of perception. Sound functions as a signal, but also varies according to the capacity to hear. An individual’s physical ability to hear, and their unique experiences with sound, differ from one person to the next, and can result in a range of emotions and reactions. Certain sounds, like the voice of a loved one, also have the power to trigger emotion and convey meaning due to the association between hearing, memory and specific events from one›s past In short, the three aspects of sound perception–signal, hearing, and emotional reaction–play an integral role in auditory perception and the subjectivity of sound. However, the value of sound is often taken for granted or viewed as secondary to visual perception. This thesis will explore the value of sound perception by investigating two of its primary aspects–hearing and emotional response–in application to memory. Through a series of experiential objects, that trigger the senses. The aim is to utilize design to memorialize precious sounds in order to raise awareness about the emotional value of sound to the human experience.
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TALK TO ME, I AM LISTENINGBen, Larbi Sami 09 December 2009 (has links)
An introductory conversation with a new person I just met usually goes like this: So, where is your accent from ? Are you American? Well, yes, .....but no. Not really. I do have American citizenship and I lived in the US for fifteen years but I grew up in France. Ok, so you’re French? Well, yes, but .....not totally. My mother is French but my father is Tunisian. Ok, so you’re Tunisian? Well, yes, but... not wholly. I don’t speak Arabic, so I don’t totally feel Tunisian. So what are you? American? French? Tunisian? With my work, I ask the same questions. What is this? What does it do? How do I, the maker, relate to it? How does the viewer, the other side of the conversation, relate to it and understand it? Can we understand each other if we do not speak the same language? Who am I and who are you anyway?
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