Multi-port Memory Design for Advanced Computer Architectures

In this thesis, we describe and evaluate novel memory designs for multi-port on-chip and off-chip use in advanced computer architectures. We focus on combining multi-porting and evaluating the performance over a range of design parameters. Multi-porting is essential for caches and shared-data systems, especially multi-core System-on-chips (SOC). It can significantly increase the memory access throughput. We evaluate FinFET voltage-mode multi-port SRAM cells using different metrics including leakage current, static noise margin and read/write performance. Simulation results show that single-ended multi-port FinFET SRAMs with isolated read ports offer improved read stability and flexibility over classical double-ended structures at the expense of write performance. By increasing the size of the access transistors, we show that the single-ended multi-port structures can achieve equivalent write performance to the classical double-ended multi-port structure for 9% area overhead. Moreover, compared with CMOS SRAM, FinFET SRAM has better stability and standby power. We also describe new methods for the design of FinFET current-mode multi-port SRAM cells. Current-mode SRAMs avoid the full-swing of the bitline, reducing dynamic power and access time. However, that comes at the cost of voltage drop, which compromises stability. The design proposed in this thesis utilizes the feature of Independent Gate (IG) mode FinFET, which can leverage threshold voltage by controlling the back gate voltage, to merge two transistors into one through high-Vt and low-Vt transistors. This design not only reduces the voltage drop, but it also reduces the area in multi-port current-mode SRAM design. For off-chip memory, we propose a novel two-port 1-read, 1-write (1R1W) phasechange memory (PCM) cell, which significantly reduces the probability of blocking at the bank levels. Different from the traditional PCM cell, the access transistors are at the top and connected to the bitline. We use Verilog-A to model the behavior of Ge2Sb2Te5 (GST: the storage component). We evaluate the performance of the two-port cell by transistor sizing and voltage pumping. Simulation results show that pMOS transistor is more practical than nMOS transistor as the access device when both area and power are considered. The estimated area overhead is 1.7�, compared to single-port PCM cell. In brief, the contribution we make in this thesis is that we propose and evaluate three different kinds of multi-port memories that are favorable for advanced computer architectures

Control and mitigation of microwave crosstalk effect with superconducting qubits

Improving gate performance is vital for scalable quantum computing. The universal quantum computing also requires the gate fidelity to reach a high level. For superconducting quantum processor, which operates in the microwave band, the single-qubit gates are usually realized with microwave driving. The crosstalk between microwave pulses is a non-negligible error source. In this article, we propose an error mitigation scheme to address this crosstalk issue for single-qubit gates. There are three steps in our method. First, by controlling the detuning between qubits, the microwave induced classical crosstalk error can be constrained within the computational subspace. Second, by applying the general decomposition procedure, arbitrary single-qubit gate can be decomposed as a sequence of $\sqrt{X}$ and virtual Z gates. Finally, by optimizing the parameters in virtual Z gates, the error constrained in the computational space can be corrected. Using our method, no additional compensation signals are needed, arbitrary single-qubit gate time will not be prolonged, and the circuit depth containing simultaneous single-qubit gates will also not increase. The simulation results show that, in specific regime of qubit-qubit detuning, the infidelities of simultaneous single-qubit gates can be as low as which without microwave crosstalk

Cloning and expression analysis of potassium channel gene NKT3 from Nicotiana tabacum

Potassium (K+) is the predominant inorganic ion of plant cells. K+ channels in higher plant cells play an important role in regulating the influx and efflux of K+ from cells, and activity of these channels might be involved in plant stress resistance. A completely new K+ channel gene of Nicotiana tabacum was obtained through homologous cloning strategy. The complete cDNA sequence was submitted to the National Center for Biotechnology Information (NCBI) GenBank, designated as NKT3 and the accession number is FJ230956. The phylogenetic analysis indicated that NKT3 is located at the branch of weak-inwardly rectifying K+ channels and might be a member of the Shaker family. The spatial and temporal expression of the gene was also investigated. NKT3 is expressed abundantly in the roots, while little in the leaves of N. tabacum. It might be involved in the process of K+ acquirement and release in tobacco roots.Keywords: Potassium channel gene, NKT3, RACE, Nicotiana tabacu

Design Economic Policies that do not Create Bumpy Recovery

This chapter studies how to make sure when the economic performance indicators approach some pre-determined target values due to the effect of adopted policies, the economy also develops reasonably well without experiencing much severe up and-down fluctuations. This problem of concern is resolved by addressing the corresponding problem of pole placement of the general control-theory model of the economic system. This chapter (1) discusses conditions under which the poles of a constant coefficient linear economic system can be arbitrarily placed, (2) provides a way to calculate the matrix of feedback gain that is useful in placing the poles by using the feedback control mechanism so that the resultant constant coefficient linear economic system possesses a good quality stability and fast response speed, and (3) investigates the problem of how to design state or output feedbacks (economic policies) so that the resultant closed-loop economic system will have the pre-determined poles. At the end, some open problems of great importance are posed for future research. This chapter relates the issue of economic policy making and the pole placement of the general control-theory model of the economic system. The results are expected to provide practically useful guidelines

Case report: Neglected subacute thyroiditis: a case following COVID-19 vaccination

We report a case of overlooked Subacute Thyroiditis (SAT) potentially induced by the administration of a COVID-19 vaccine. This case prompted a thorough review of the existing literature to elucidate possible mechanisms by which immune responses to the COVID-19 vaccine might precipitate thyroid damage. The primary objective is to enhance the clinical understanding and awareness of SAT among healthcare professionals. Subacute thyroiditis is a prevalent form of self-limiting thyroid disorder characterized by fever, neck pain or tenderness, and palpitations subsequent to viral infection. The development of numerous SARS-CoV-2 vaccines during the COVID-19 pandemic was intended to mitigate the spread of the virus. Nevertheless, there have been documented instances of adverse reactions arising from SARS-CoV-2 vaccines, such as the infrequent occurrence of subacute thyroiditis. While the majority of medical practitioners can discern classic subacute thyroiditis, not all cases exhibit typical characteristics, and not all systematic treatments yield positive responses. In this study, we present a rare case of subacute thyroiditis linked to the administration of the SARS-CoV-2 vaccine. A previously healthy middle-aged female developed fever and sore throat 72 h post-inoculation with the inactivated SARS-CoV-2 vaccine. Initially attributing these symptoms to a common cold, she self-administered ibuprofen, which normalized her body temperature but failed to alleviate persistent sore throat. Suspecting a laryngopharyngeal disorder, she sought treatment from an otolaryngologist. However, the pain persisted, accompanied by intermittent fever over several days. After an endocrinology consultation, despite the absence of typical neck pain, her examination revealed abnormal thyroid function, normal thyroid antibodies, heterogeneous echogenicity on thyroid ultrasonography, and elevated levels of Erythrocyte Sedimentation Rate (ESR) and C-Reactive Protein (CRP). These findings led to a consideration of the diagnosis of SAT. Initially, she was treated with non-steroidal anti-inflammatory drugs (NSAIDs) for her fever, which proved effective, but her neck pain remained uncontrolled. This suggested a poor response to NSAIDs. Consequently, steroid therapy was initiated, after which her symptoms of fever and neck pain rapidly resolved

Bean-dreg-derived carbon materials used as superior anode material for lithium-ion batteries

The structures of modified carbons from bean dregs were regulated via graphitization treatment and chemical activation. The microstructure and electrochemical performance were studied using X-ray diffraction, Raman spectrometer, SEM and TEM techniques. The electrochemical performance was investigated using electrochemical methods. After heat-treatment at 2800 °C, the obtained BDC-2800 possessed a high degree of graphitization and showed an outstanding cycling performance, delivering capacity decay from 423 to 396 mAh g at 0.1 C after 100 cycles. The chemical-treated carbons also demonstrated enhanced electrochemical performance, especially for the KOH-treated sample. The BDC-K displayed superior specific charge capacity of 801 mAh g at 0.1 C, and showed an impressive rate capability of 643 mAh g at 1 C. In addition, this sample delivered capacity retention of 94% after 500 cycles at 1 C. This good electrochemical performance was mainly due to its high surface area and abundant mesoporous structure

Freestanding MXene‐based macroforms for electrochemical energy storage applications

Freestanding MXene-based macroforms have gained significant attention as versatile components in electrochemical energy storage applications owing to their interconnected conductive network, strong mechanical strength, and customizable surface chemistries derived from MXene nanosheets. This comprehensive review article encompasses key aspects related to the synthesis of MXene nanosheets, strategies for structure design and surface medication, surface modification, and the diverse fabrication methods employed to create freestanding MXene-based macroform architectures. The review also delves into the recent advancements in utilizing freestanding MXene macroforms for electrochemical energy storage applications, offering a detailed discussion on the significant progress achieved thus far. Notably, the correlation between the macroform's structural attributes and its performance characteristics is thoroughly explored, shedding light on the critical factors influencing efficiency and durability. Despite the remarkable development, the review also highlights the existing challenges and presents future perspectives for freestanding MXene-based macroforms in the realms of high-performance energy storage devices. By addressing these challenges and leveraging emerging opportunities, the potential of freestanding MXene-based macroforms can be harnessed to enable groundbreaking advancements in the field of energy storage

Utilization and Associated Factors of Community Health Management Services in Hypertensive and Diabetic Patients

BackgroundHypertension and diabetes have been included in the list of China's essential public health services since 2009. During these years, the use and associated factors of community health management services in community-living hypertensive and diabetic patients are not very clear and need to be further studied.ObjectiveTo investigate the use and potential associated factors of community health management services in Shenzhen community-living hypertensive and diabetic residents.MethodsData stemmed from the results of Shenzhen Epidemiological Survey on Chronic Non-communicable Diseases and Risk Factors conducted between September and November 2018. The chi-square test and multinomial Logistic regression were used to examine the association of sex, age, place of hukou registration (Shenzhen or not) , marital status, monthly household income per capita, occupation type, years of living in Shenzhen, prevalence of medical insurance enrollment, and the level of medical institutions making a definite diagnosis with the use of community health management services.ResultsAltogether, 10 042 participants were finally enrolled, including 1 132 with self-reported hypertension, and 402 with self-reported diabetes. Among the hypertensive participants, 530 (46.82%) indicated that they received follow-up management of hypertension from the community health center. Specifically, 436 (82.31%) received blood pressure measurement by the doctor, and 399 (75.25%) received medication guidance from the doctor. Of the diabetic patients, 194 (48.26%) indicated that they received follow-up management of diabetes from the community health center. Specifically, 173 (89.37%) of the 193 cases (one case was excluded due to missed information) received blood glucose measurement by the doctor, and 154 (79.62%) received medication guidance from the doctor. The prevalence of hypertensive participants receiving guidance on smoking cessation or smoking less from the doctor was relatively low (lower than 40%) , and so was that of diabetic participants. The prevalence of hypertensive participants receiving guidance on drinking cessation or drinking less from the doctor was relatively low (lower than 40%) , and so was that of diabetic participants. Multinomial Logistic regression analysis revealed that sex, age, monthly household income per capita, years of living in Shenzhen, and prevalence of medical insurance enrollment were associated with the utilization of community health management services in hypertensive patients (P<0.05) . Age, occupational type, and monthly household income per capita were associated with the utilization of community health management services in diabetic patients (P<0.05) .ConclusionLess than half of the community-living hypertensive and diabetic participants used or were involved in community health management services. Being female, 18-44-year-old, low or moderate monthly household income per capita, and short years of living in Shenzhen were associated with lower rate of utilizing such services. Moreover, hypertensive cases without medical insurance, and diabetics engaging in a manual labor job were far less likely to utilize the services. In view of this, it is suggested to strengthen the publicity of essential public health services in the above-mentioned priority groups. Besides that, the awareness of doctors in community health centers should be strengthened to provide patients with guidance on developing healthy lifestyles, such as stopping smoking and drinking