Desired Circuit Research Articles

Advanced exact synthesis of Clifford+T circuits

Quantum systems provide a new way of conducting computations based on the so-called qubits. Due to the potential for significant speed-ups, this field received significant research attention in recent years. The Clifford+T library is a very promising and popular gate library for these kinds of computations. Unlike other libraries considered so far, it consists of only a small number of gates for all of which robust, fault-tolerant realizations are known for many technologies that seem to be promising for large-scale quantum computing. As a consequence, (logic) synthesis of Clifford+T quantum circuits became an important research problem. However, previous work in this area has several drawbacks: Corresponding approaches are either only applicable to very small quantum systems or lead to circuits that are far from being optimal. The latter is mainly caused by the fact that current synthesis realizes the desired circuit by a local, i.e., column-wise, consideration of the underlying unitary transformation matrix to be synthesized. In this paper, we analyze the conceptual drawbacks of this approach and propose to overcome them by taking a global view of the matrices and perform a separation of concerns regarding individual synthesis steps. We precisely describe a corresponding algorithm as well as its efficient implementation on top of decision diagrams. Experimental results confirm the resulting benefits and show improvements of up to several orders of magnitudes in costs compared to previous work.

Genetic circuit design automation for yeast.

Cells can be programmed to monitor and react to their environment using genetic circuits. Design automation software maps a desired circuit function to a DNA sequence, a process that requires units of gene regulation (gates) that are simple to connect and behave predictably. This poses a challenge for eukaryotes due to their complex mechanisms of transcription and translation. To this end, we have developed gates for yeast (Saccharomyces cerevisiae) that are connected using RNA polymerase flux as the signal carrier and are insulated from each other and host regulation. They are based on minimal constitutive promoters (~120 base pairs), for which rules are developed to insert operators for DNA-binding proteins. Using this approach, we constructed nine NOT/NOR gates with nearly identical response functions and 400-fold dynamic range. In circuits, they are transcriptionally insulated from each other by placing ribozymes downstream of terminators to block nuclear export of messenger RNAs resulting from RNA polymerase readthrough. Based on these gates, Cello 2.0 was used to build circuits with up to 11 regulatory proteins. A simple dynamic model predicts the circuit response over days. Genetic circuit design automation for eukaryotes simplifies the construction of regulatory networks as part of cellular engineering projects, whether it be to stage processes during bioproduction, serve as environmental sentinels or guide living therapeutics.

The therapeutic role of signifier opposition and fort-da in the treatment of a child diagnosed with autism spectrum disorder (ASD): a case report

From a lacanian perspective interventions in cases of autism should aim to introduce a symbolic absence that mobilizes the circuit of desire. The case of a 2-year-old boy (Q) diagnosed with autism spectrum disorder attending to lacanian treatment is presented. The fort-da paradigm (using a pair of signifiers to represent the presence-absence) was introduced to address problems with attachment, communicative intention, and symbolic game. After treatment Q learned how to use his own language and symbolic game to regulate and express anxiety and other emotions in the absence of his mother.

Neural Circuit Mechanism Underlying the Feeding Controlled by Insula-Central Amygdala Pathway.

SummaryThe Central nucleus of amygdala (CeA) contains distinct populations of neurons that play opposing roles in feeding. The circuit mechanism of how CeA neurons process information sent from their upstream inputs to regulate feeding is still unclear. Here we show that activation of the neural pathway projecting from insular cortex neurons to the CeA suppresses food intake. Surprisingly, we find that the inputs from insular cortex form excitatory connections with similar strength to all types of CeA neurons. To reconcile this puzzling result, and previous findings, we developed a conductance-based dynamical systems model for the CeA neuronal network. Computer simulations showed that both the intrinsic electrophysiological properties of individual CeA neurons and the overall synaptic organization of the CeA circuit play a functionally significant role in shaping CeA neural dynamics. We successfully identified a specific CeA circuit structure that reproduces the desired circuit output consistent with existing experimentally observed feeding behaviors.

A flexible remote laboratory with programmable device under test

Experimental practice in laboratory is a fundamental teaching issue in electrical and electronic measurement courses. Unfortunately, crowded classes, along with limited universities resources, do not allow to meet this need through actual laboratory sessions. In such a context, remote laboratories have proved to be an excellent solution.A significant added value, in a remote laboratory, is the possibility to modify the test circuit, in order to vary the type of experiment.The authors suggest, in the paper, to overcome t he considered limitations by integrating inside the remote laboratory suitable devices that can be remotely configured, i.e. a Field Programmable Analog Array (FPAA). FPAA is exploited for emulating the behavior of a large variety of analog circuits, thus making it possible for users, either students or technicians, to select the desired test circuit and carry out the experiment from home.

(Invited) Innovative Advances in Copper Electroplating for IC Substrate Manufacturing

Low cost electroplating of copper to create Fine Line Space (FLS) features and Blind Micro Via’s (BMV) is a key technology element of high density substrates for integrated circuit packaging. In this work, we demonstrate a capable deposition methodology to influence gap fill behavior inside microvia along with a uniform deposit in the fine line patterned regions for substrate packaging applications. Interconnect circuitry in IC substrate packages comprises of stacked microvia that varies in depth from 20µm to 100µm with an aspect ratio of 0.5 to 1.5 and fine line patterns defined by photolithography. Photolithography defined pattern regions incorporate a wide variety of feature sizes including large circular pad structures with diameter of 20µm - 200µm, fine traces with varying widths of 3µm - 30µm and additional planar regions to define a IC substrate package. Electrodeposition of copper is performed to establish the desired circuit. Electrodeposition of copper in IC substrate applications holds certain unique challenges in that they require a low cost manufacturing process that enables a void free gap fill gap fill inside the microvia along with uniform deposition of copper on exposed patterned regions. Deposition time scales to establish the desired metal thickness for such packages could range from several minutes to few hours. In this work, we show case an electrodeposition methodology that achieves void free gap fill inside the microvia and uniform plating in FLS (Fine Lines and Spaces) regions with significantly higher deposition rates than traditional approaches. In order to achieve this capability, systematic experimental and simulation studies were performed to show a strong correlation of the independent parameters that govern the electrodeposition process to the deposition kinetics and deposition uniformity in fine patterned regions and gap fill rate inside the microvia.

Pyeis: A Python-Based Electrochemical Impedance Spectroscopy Analyzer and Simulator

Electrochemical Impedance Spectroscopy can be a powerful analytical tool for the electrochemist as it can have the ability of separating kinetics, double-layers, adsorption, and mass-transport from a current/voltage response. This can often be a difficult task as the response depends on a large parameter space, such as: electrode configuration, porosity, pore size morphology, reference electrode, distance between working- and reference electrode, interfacial layers that depends on, among other, electrolyte composition, current collectors, potential, temperature, etc. Electrochemical processes can be described through circuit elements and a combination of these are referred to as equivalent circuit elements that model the cell or interface in question. Classically, kinetic contributions are referred to as charge-transfer resistances, double-layer as capacitors and their derivatives, and mass-transport have a wide range of terms. PyEIS is an open-source platform that is able to simulate, evaluate data quality, fit, and plot electrochemical impedance spectroscopy data. It is built in a modular layout to facilitate add-ons, modifications, and it is therefore possible with relative ease to add any desired equivalent circuit. It is based on an open-source packages4–6 and is written in Python, a modern high-level computing language commonly used by the scientific community. PyEIS will be available as a Python package and currently includes 27 equivalent circuits where some represent simple non-faradaic and faradaic systems, the impedance of macro disk- and microdisk electrodes with well-defined mass-transport regimes, as well as non-faradaic and faradaic porous electrodes with and without solid-state diffusion. PyEIS has the ability to simulate any equivalent circuit including the dependency on potential of the i) the charge-transfer resistance following Butler-Volmer or Marcus-Hush-Chidsey infinite or finite kinetic theories, ii) the mass-transport elements of the macro- and microdisk electrodes, and iii) the double-layer capacitance following the theories of Gouy-Chapman or Stern. This makes it possible to predict the impedance of any equivalent circuit following the potential dependency of the above-mentioned theories allowing the user to simulate and adjust experimental parameters to optimize experimental conditions. PyEIS also contains algorithms for the linear Kramers-Kronig validity analysis that investigate the experimental data quality for causality, linearity, stability, and finite. The algorithm uses a weighed complex non-linear least-squares fitting procedure with RC-elements following the work of Boukamp1, where resistances are fitted to experimental data with log spaced time constants. The relative residuals are illustrated as a function of the measured frequency and PyEIS contains an automatic optimization algorithm that ensures a correct number of -(RC)- elements are utilized such that data is neither over- or under-fitted2. PyEIS is able to fit experimental data through the weighed complex non-linear least squares fitting procedure using scipy’s lmfit package3 where the following statistical weighing options are available: unit, modulus, and proportional. The software is capable of batch fitting any number of spectra without any additional key strokes and the output is automatically plotted with a number of plotting options available. In additional, the parameters of the equivalent circuit model are saved and are easily accessed for post analysis. References B. A. Boukamp, J. Electrochem. Soc., 142, 1885–1894.M. Schönleber, D. Klotz, and E. Ivers-Tiffée, Electrochimica Acta, 131, 20–27 (2014).J. O. Oliphant, P. Peterson, and et al., 2001 http://www.scipy.org/.S. van der Walt, S. C. Colbert, and G. Varoquaux, Computing in Science & Engineering, 13, 22–30 (2011).F. Johansson, www.mpmath.org.J. D. Hunter, Computing in Science & Engineering, 9, 90–95 (2007).

The Dick Pic: Harassment, Curation, and Desire

The combined rise of digital photography and social media has expanded what might be considered photo worthy. Among the pouting selfies and food stuffs of the day exists the ubiquitous dick pic. The mainstream media generally focuses on dick pics of the unsolicited kind, which, negatively positioned, are commonly associated with heterosexual harassment. Considering the ubiquity of dick pics across apps and platforms, research on the topic nevertheless remains scarce. In this article, we examine the dick pic as an online communicative form, first considering how it manifests the ability to harass and then moving beyond this dominant framing to analysis of contexts where such images are collated, expected, and sought after. Through this analysis of dick pics as figures and actors of harassment, curation, and desire, we demonstrate the simultaneous tenacity and flexibility of their meanings in connection with the dynamics of consent and non-consent, intimacy and distance, and complex circuits of desire. We further address the role of platforms, apps, and app stores, via their community standards and terms of use, in shaping the nature, and presence, of dick pics, and discuss the affective and communicative functions that these affordances serve (or fail to serve). Our analysis of three key modes of engagement with dick pics demonstrates the ambiguity and multiple valences of the phenomenon addressed.

Chlorinated Polymers for Efficient Solar Cells with High Open Circuit Voltage: The Influence of Different Thiazole Numbers.

The chlorination strategy has gradually become a promising approach to improve the open circuit voltage (VOC ) in polymer solar cells. In this work, by using an efficient thiazole-induced strategy in a polymer backbone, three thieno[3,4-b]thiophene (TT)-based polymers-PBClTTz-0, PBClTTz-1, and PBClTTz-2-are designed and synthesized with a Cl-substituted benzodithiophene (BDT) moiety and a thiazole unit as a π spacer. As expected, all of the polymers show a desirable open circuit voltage (VOC ) of >0.94 V in the solar cells; specifically, the voltage can reach 1.01 V for polymer PBClTTz-2 with two thiazole moieties. In addition, due to the excellent surface morphology and weak recombination of the active layer, photovoltaic devices based on PBClTTz-1 with one thiazole unit exhibit the highest power conversion efficiency (PCE) of 8.42%, which is noticeably superior to the fluorinated analogue PBClTTz-0 (6.85%). This work reveals the influence of the thiazole unit in a quinoid polymer backbone and confirms that the Donor-Acceptor(π)-Quinoid strategy is a promising construction method in molecular design.

Analog circuit topology synthesis by means of evolutionary computation

Designing an analog electrical circuit requires substantial effort and time by a highly-skilled designer. Many tools have been devised to aid engineers in the design procedure, from simulators to parameter optimization tools, which largely assist in fine-tuning the parameter values of circuits with predetermined topologies. In this paper, we propose a new approach to circuit optimization that is capable of searching not only for the parameter but also the topological space. Starting from a high-level statement describing a desired circuit functionality, the proposed method can either improve a given circuit, or create a novel topology with given resources, based on the Darwinian theory of evolutionary selection. Our method uses a global parameter optimization method PSADE to speed up evolutionary convergence. We use the proposed algorithm (both single- and multi-objective) to successfully evolve passive, active, and BiCMOS circuits.

Probing Oxide-Nitride Selectivity As a Function of CeO2 Valence State Relevant to STI CMP

Electrical isolation within a desired circuit requires shallow trench isolation (STI) to separate active regions with tetraethyl orthosilicate (TEOS) filled trenches. STI chemical mechanical planarization (CMP) is used to facilitate bulk oxide removal by selectively targeting TEOS overburden with colloidal suspensions (slurries) containing ceria (CeO2) nanoparticles. A critical factor in maintaining high removal rates is the presence of CeO2 surface oxygen vacancies (Ovac); commonly associated with unoxidized Ce3+ particles which when filled, change the oxidation state to a less reactive Ce4+ form. The goal of this work is to utilize modified slurries at various Ce3+/Ce4+ ratios and determine the influence of oxidation state on oxide/nitride removal rates. Characterization of the CeO2 particles was determined through UV/Visible and fluorescence spectroscopy along with a novel UV/Visible spectroscopic flow cell technique. The modified slurries were then used to polish both TEOS and Si3N4 wafers to probe selectivity with respect to various mechanical parameters. Preliminary results show that greater concentrations of Ce3+ valence states, in slurries containing a novel reducing agent, result in higher oxide removal rates than the unmodified slurry. Future work will focus on characterization of the post polish effluent to determine the influence of polishing on certain particle properties, such as oxidation state, zeta potential, and size.

A Variable (n/m)X Switched Capacitor DC–DC Converter

High gain bidirectional dc–dc converter with high efficiency and high power density is a much desired circuit in any converter/inverter system. It is well known that switched capacitor circuits that are variants of the Dickson converter are suitable candidates for such a system. Modular design, absence of external magnetic components, and high efficiency are some of the features that make them suitable candidates. But, the inability to provide fractional and variable voltage gains at high efficiency during normal operation severely limits their application. It also leads to higher voltage stress in the overall system. The aim of this paper is twofold. First, a generalized modular switched capacitor converter, the “( n / m )X converter,” which is a variant of the original Dickson converter is introduced. Using this generalized configuration, the converter can be designed for a required fractional gain. Next, two different methods to enable dynamic variation in gain with high efficiency using the ( n / m )X converter are proposed. Detailed analysis, design steps, equivalent circuits, and experimental results for a 1 kW prototype of a variable (4/0.5)X boost converter validate the proposed theory. A peak measured efficiency of over 95% is achieved for the prototype. The design framework and analysis in this paper can be extended to a generic ( n / m )X converter.

Mathematical modeling of a vertical shaft impact crusher using the Whiten model

Vertical Shaft Impact (VSI) crushers have been used as interesting alternatives to cone crushers, particularly in the production of aggregates for the construction industry, not only due to their good energy efficiency but also to their ability to generate more isometric and tougher particles, which is highly desirable in cement mortars and concrete applications. Several mathematical models for the VSI crusher have been proposed in the last two decades or so. The Whiten crusher model, originally developed for cone crushers, has served as the basis of several approaches to model VSI crushers. In the present work, the Andersen/Awachie/Whiten model has been used as the basis for modeling a VSI crusher operating in an industrial plant in Brazil, processing quarry rock to product manufactured sand. Nineteen industrial experiments, covering a range of feed rates, rotor speeds, feed distributor types and feed size distributions, have been carried out. The approach demonstrated to be capable of providing satisfactory estimates of the VSI performance, being able to predict the product size distribution and the specific energy consumption with confidence over a wide range of operating conditions. Since it uses a model that is already available in commercial plant simulators, it may be used, with additional expressions, in simulating any desired circuit. Model parameters such as K3 and T10 were found to be particularly influenced by key operational variables such as feed rate and rotor frequency. The significant effect of feed rate on the performance of the VSI crusher studied has been discussed on the basis of simulations of the material flow pattern inside its feed distributing system, simulated using the discrete element method. According to these simulations, it has been inferred that change in the behavior of VSI from lower to higher feed rates may be related to the transition from material being fed predominantly to the rotor, to the increasing contribution of the cascading effect.

Reading Stein’s Genders: Transmasculine Signification in the 1910s and 1920s

Abstract Gertrude Stein’s 1933 The Autobiography of Alice B. Toklas and experimental writings from the 1910s and the 1920s are animated by a circuit of desire in which Toklas’s gaze establishes and...

Unifying Gate Synthesis and Magic State Distillation.

The leading paradigm for performing a computation on quantum memories can be encapsulated as distill-then-synthesize. Initially, one performs several rounds of distillation to create high-fidelity magic states that provide one good T gate, an essential quantum logic gate. Subsequently, gate synthesis intersperses many T gates with Clifford gates to realize a desired circuit. We introduce a unified framework that implements one round of distillation and multiquibit gate synthesis in a single step. Typically, our method uses the same number of T gates as conventional synthesis but with the added benefit of quadratic error suppression. Because of this, one less round of magic state distillation needs to be performed, leading to significant resource savings.

An Analytical Approach for the Design of Class-E Resonant DC–DC Converters

We present a new approach to design resonant dc–dc converters, that allows us to achieve both a more accurate implementation and a simpler architecture, by reducing the number of required passive components. The approach is applied to a class-E topology, and it is based on the analytic solution of the system of differential equations regulating the converter evolution. Our technique is also capable of taking into account the most important circuit nonidealities. This represents an important breakthrough with respect to the state of the art, where class-E circuit analysis is based on strong simplifying assumptions, and the final circuit design is achieved by means of numerical simulations after many time-consuming parametric sweeps. The developed methodology is dimensionless, and the achieved design curves can be denormalized to easily get the desired circuit design. Measurements on two different prototypes confirm an extremely high adherence to the developed mathematical approach.

The Design of Fifth-Order Butterworth Lowpass Log-Domain Filter for Bluetooth/Wi-Fi Receiver Using Signal Flow Graph Method

In this study, a fifth-order lowpass log-domain Butterworth filter, which is appropriate for Bluetooth/Wi-Fi receiver, is designed with signal flow graph approach. The filter is realized by using a unique translinear integrator circuit. Bluetooth and Wi-Fi modes are obtained without changing the circuit configuration. To change the mode of the filter, it is needed to change the cutoff frequency of the filter that can be electronically tuned by adjusting the external currents. Wi-Fi and Bluetooth receivers have 6[Formula: see text]MHz and 600[Formula: see text]kHz cutoff frequencies, respectively. Only BJTs and grounded capacitors were utilized to achieve the desired circuit. Lowpass log-domain Butterworth filter was simulated by using SPICE simulation program. A validated BJT and idealized BJT models are used to obtain simulation results confirming the theoretical analysis.

Multi-objective optimization framework to obtain model-based guidelines for tuning biological synthetic devices: an adaptive network case.

BackgroundModel based design plays a fundamental role in synthetic biology. Exploiting modularity, i.e. using biological parts and interconnecting them to build new and more complex biological circuits is one of the key issues. In this context, mathematical models have been used to generate predictions of the behavior of the designed device. Designers not only want the ability to predict the circuit behavior once all its components have been determined, but also to help on the design and selection of its biological parts, i.e. to provide guidelines for the experimental implementation. This is tantamount to obtaining proper values of the model parameters, for the circuit behavior results from the interplay between model structure and parameters tuning. However, determining crisp values for parameters of the involved parts is not a realistic approach. Uncertainty is ubiquitous to biology, and the characterization of biological parts is not exempt from it. Moreover, the desired dynamical behavior for the designed circuit usually results from a trade-off among several goals to be optimized.ResultsWe propose the use of a multi-objective optimization tuning framework to get a model-based set of guidelines for the selection of the kinetic parameters required to build a biological device with desired behavior. The design criteria are encoded in the formulation of the objectives and optimization problem itself. As a result, on the one hand the designer obtains qualitative regions/intervals of values of the circuit parameters giving rise to the predefined circuit behavior; on the other hand, he obtains useful information for its guidance in the implementation process. These parameters are chosen so that they can effectively be tuned at the wet-lab, i.e. they are effective biological tuning knobs. To show the proposed approach, the methodology is applied to the design of a well known biological circuit: a genetic incoherent feed-forward circuit showing adaptive behavior.ConclusionThe proposed multi-objective optimization design framework is able to provide effective guidelines to tune biological parameters so as to achieve a desired circuit behavior. Moreover, it is easy to analyze the impact of the context on the synthetic device to be designed. That is, one can analyze how the presence of a downstream load influences the performance of the designed circuit, and take it into account.Electronic supplementary materialThe online version of this article (doi:10.1186/s12918-016-0269-0) contains supplementary material, which is available to authorized users.

Tristram Shandy ’s Strange Loops of Reading

In response to recent efforts to contextualize Tristram Shandy in relation to the eighteenth-century novel, this essay considers Sterne’s book as a reflexive romance. Tristram Shandy is formed of Quixotic pleasures of reading, those transitive circuits of desire that are the founding joke of Cervantes’s neo-romance, and it provokes such laughable desires in turn. By laying bare this central mechanism of romance, the circulation of desire through stories of desire, Tristram Shandy offers an entry into a centrifugal literary history organized by futurity and the strange temporalities of readerly play, which I further explore in Raymond Federman’s adaptation of Sterne.

Enhancement of XeF2-assisted gallium ion beam etching of silicon layer and endpoint detection from backside in circuit editing

Within the semiconductor industry, backside circuit editing is the process of modifying individual nanometer-scale devices after they have been fabricated by conventional mass production techniques. The technique includes the removal of bulk silicon, to reach the devices, followed by the removal of small and precisely defined volumes of silicon and other materials. It also includes the ability to deposit precise patterns of conductors or insulators to modify the devices in question. Essential to the circuit edit processes are the focused ion beam (FIB) instruments, usually providing a gallium ion beam, to sputter away the volumes which need to be removed. When used in conjunction with specific “precursor” gases, the FIB instrument can deposit metals and insulators in arbitrary patterns to achieve the desired circuit repair or modification. Other gases, such as xenon difluoride (XeF2), can work in conjunction with the FIB to improve the effectiveness and the rate of material removal. Our experimental investigation found that the removal rate of backside silicon by a gallium FIB could be enhanced by 100 times when used in conjunction with the XeF2 gas. The XeF2 also reduced the redeposition of the removed silicon material, making the removal more effective. And importantly, the production of secondary electrons was found to offer a viable endpoint signal to indicate the transition to a new material.