3,307 research outputs found
Modelling delay and noise in arbitrarily coupled RC trees.
Full text linkClosed-form equations for second-order transfer functions of general arbitrarily coupled resistance-capacitance (RC) trees with multiple drivers are reported. The models allow precise delay and noise calculations for systems of coupled interconnects with guaranteed stability and represent the minimum complexity associated with this class of circuits. Their accuracy is extensively compared against other relevant models and is found to be better or comparable to more expensive models. All results are derived from a theoretical approach, and their physical basis is examined. The simplicity, accuracy, and generality of the models make them suitable for use in early signal integrity analyses of complex systems and incremental physical optimization
Minimal deletion regions in lung squamous cell carcinoma: Association with abnormality of the DNA double-strand break repair genes and their applications on gene identification and prognostic biomarkers
No full textA Compact 10-MHz RC Frequency Reference With a Versatile Temperature Compensation Scheme
No full textThis article presents the design and implementation of a compact CMOS RC frequency reference. It consists of a frequency-locked loop (FLL) that locks the period of a voltage-controlled oscillator (VCO) to the time an RC network takes to charge to a reference voltage. Conventionally, an RC time constant with a near-zero temperature coefficient (TC) is realized by using a trimmed network of resistors with different TCs. In this work, such a network is used to realize a temperature-dependent reference voltage whose TC cancels that of a single-resistor RC time constant. Compared with the conventional approach, which requires resistors with TCs of opposite polarity, the proposed approach can be implemented with resistors with TCs of similar polarity, and so it can be implemented in most CMOS processes. To compensate for RC spread, a trimmed capacitor is used to adjust the nominal frequency. Two prototype chips were made, one based on p- /n-polysilicon resistors and other based on silicided/p-diffusion resistors. Fabricated in a standard 180-nm CMOS technology, the polysilicon-based prototype has an active area of 0.01 mm2 and an absolute inaccuracy of ±2800 ppm from -45 °C to 125 °C with a fixed TC-trim and a one-point frequency trim. After one week of accelerated aging at 150 °C, however, significant drift (5000 ppm) was observed. The diffusion-based prototype exhibits greater inaccuracy (±14 400 ppm) but much less drift (600 ppm).Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic InstrumentationMicroelectronic
A CMOS Dual-RC frequency reference with ±250ppm inaccuracy from -45°C to 85°C
No full textTo comply with wired communication standards such as USB, SATA and PCI/PCI-E, systems-on-chip require frequency references with better than 300ppm accuracy. LC-based references achieve 100ppm accuracy [1], but suffer from high power consumption (∼20mW). Thermal diffusivity (TD) references require less power (∼2mW), at the expense of less accuracy (1000ppm) [2]. RC-based references offer the lowest power consumption, but their accuracy is typically limited to ∼0.1% [3]. In RC relaxation oscillators, comparator offset and delay are the major sources of inaccuracy [4,5]. References based on frequency-locked loops (FLLs) circumvent these by locking an oscillator's frequency to the time-constant of an RC filter, but their accuracy is then limited by the nonlinear temperature dependency of on-chip resistors [3,6].Session 3.3 Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic Instrumentation(OLD)Applied Quantum ArchitecturesMicroelectronic
Feasibility Study of Steel Fibers as a Substitute for Transverse Reinforcement in New RC Columns
No full text國內的建築物中，鋼筋混凝土結構(Reinforced Concrete, RC)佔了絕大多數，主要因為RC結構有下列優點：耐久性佳、易維護，與成本低。隨著時代的演進，高樓層建築是現今的趨勢。隨著樓層的提高，位於底層的柱需承受整體結構物荷重產生的高軸力，若用傳統的RC結構，勢必得放大低樓層柱的斷面。因此日本在1988年推出為期5年的New RC Project，以提高材料強度的方法，減少材料的用量，使得結構物輕量化。高強度材料的RC結構，不僅可以降低柱斷面的尺寸、減量材料的用量與成本，也提升建築物的使用空間。
然而高強度的材料的脆性行為是其隱憂，由於高強度混凝土開裂時，裂縫會直接通過粗骨材與砂漿，因此一旦到達極限強度，結構物會立即破壞，造成嚴重的損害。除此之外，台灣位處地震發生頻繁之地震帶，結構物必須具有一定的韌性，越高的韌性越能折減地震力。為了提高結構物韌性表現，在傳統RC結構中添加新材料便是方法之一。根據文獻顯示，鋼纖維能提高混凝土材料的韌性以及剪力抗性，減少橫向箍筋量的需求，降低鋼筋籠綁紮的繁瑣。而且纖維不僅能預防早期保護層剝落，抑制裂縫生長，並會在其他部份產生多重裂縫，避免瞬間破壞的發生。
本研究主要探討在雙曲率反覆側推行為下，高強度鋼纖維鋼筋混凝土柱的行為表現，並與高強度鋼筋混凝土柱進行比較。主要分為兩大主軸，其一為「高強度混凝土與高強度鋼纖維混凝土比較」，探討相同混凝土設計強度下，一般混凝土與鋼纖維混凝土的行為差異。其二為「以鋼纖維取代橫向箍筋之評估」，以放大箍筋間距的方式，探討鋼纖維與橫向箍筋的取代關係，間距最大到規範訂定剪力鋼筋間距最嚴苛的標準，也就是一半的斷面深度。另外針對鋼筋混凝土柱以及鋼纖維鋼筋混凝土柱之韌性指數進行回歸，提出預測公式。並且根據預測公式建立圍束效應與反覆側推行為之關係式，未來具備試體設計斷面，便可以此關係式判斷反覆側推實驗結果能否通過側力衰減至80%時，層間變位角達到3%之標準。There are several advantages of reinforced concrete. For example, reinforced concrete is durable. Also, the buildings built by reinforced concrete are easy to conserve and maintain the structure. Moreover, the cost is low to build the buildings with reinforced concrete. It is a trend that people start to build high-rise buildings. The higher the building is, the more axial load of the columns at the bottom sustain. If the high- rise buildings are built with the traditional RC structure, the lower floors’ dimension must be enlarged. Therefore, in 1988, New RC project was proposed in Japan. The purposes of the project were increasing the strength of the construction materials and reducing the amount of the materials. With high strength material, the size of columns’ dimension is decreased, also the available space of buildings is increased.
However, the brittleness is the disadvantage of the high strength materials. Once the maximum concrete strength is reached, the construction will immediately be destroyed. Besides, Taiwan is located in a seismic belt, so the toughness is required for most of the buildings. The higher the toughness, the more it can reduce the strength caused by the earthquake. In order to increase the toughness in a traditional construction, adding new materials is one of the methods. According to the references, the toughness and the shear resistance in concrete materials are increased by adding the steel fiber into concrete. Also, the amount of the transverse steel is reduced and the process of tying steel cage is simplified. Moreover, adding the steel fiber can not only prevent the early cover spalling, but also restrain the cracks’ development that may cause immediate destruction.
The performance of high-strength steel fiber reinforced concrete columns under the condition of double curvature cyclic loading test is investigated in this study. The study can be divided into two parts. The first part is using the same designed strength to compare the differences between the original concrete and steel fiber concrete. The second part is the feasibility of substitution of the steel fiber for transverse steel based on the method that enlarging the spacing between transverse steel. Furthermore, not only the regression between the toughness of RC columns and the toughness of steel fiber RC columns was proposed in the study, but also the prediction formula. In addition, the relationship between the confinement effect that built by the prediction formula and the cyclic loading test is proposed in the study.目錄
口試委員會審定書 #
誌謝 ii
中文摘要 iii
ABSTRACT iv
目錄 v
表目錄 ix
圖目錄 x
照片目錄 xiv
參數對照表 xv
第一章、緒論 1
1.1 動機與目的 1
1.2 研究範圍與內容 3
1.3 研究流程 4
第二章、文獻回顧 5
2.1 圍束設計規範介紹 5
2.1.1 美國混凝土協會 ACI 318-11[5] 5
2.1.2 加拿大規範 CSA A23.3-04[6] 6
2.1.3 NCREE建議公式[7] 8
2.1.4 美國混凝土協會 ACI 318-14[12] 9
2.2 剪力設計規範介紹 11
2.2.1 美國混凝土協會 ACI 318-11[5] 11
2.2.2 Sezen 剪力預測公式[13] 13
2.3 撓曲強度 15
2.4 鋼纖維混凝土力學性質 18
2.4.1 鋼纖維添加至混凝土的力學性質影響 18
2.4.2 韌性指數定義 24
2.5 端鉤型鋼纖維拉拔能量 26
2.5.1 端鉤型鋼纖維拉拔機制 26
2.5.2 端鉤型鋼纖維拉拔能量預測模型 27
2.5.3 等效握裹強度 34
2.6 鋼纖維混凝土韌性參數 35
2.7 鋼筋混凝土柱韌性參數 36
2.7.1 鋼筋混凝土柱的圍束效應 36
2.8 韌性比回歸公式 39
2.8.1 鋼纖維混凝土的韌性比回歸公式 39
2.8.2 鋼筋混凝土的韌性比回歸公式 40
2.8.3 鋼纖維鋼筋混凝土柱的韌性比回歸公式 42
2.9 破壞模式 44
2.10 資料庫蒐集 46
第三章、實驗計畫 47
3.1 試驗背景 47
3.2 試體設計 47
3.2.1 設計細節 48
3.2.2 試體編號 53
3.3 試驗材料與配比 54
3.3.1 試驗材料 54
3.3.2 試驗配比 56
3.4 試驗儀器與設備 57
3.4.1 測試系統 57
3.4.2 內部量測系統 63
3.4.3 外部量測系統 71
3.4.4 其他 73
3.5 試體製作 75
3.5.1 應變計黏貼 75
3.5.2 試體澆置 77
3.6 破壞模式預測 80
3.7 測試流程 86
3.7.1 實驗前置 86
3.7.2 實驗進行 89
3.8 韌性比回歸公式 90
3.8.1 高強度鋼筋混凝土柱 90
3.8.2 高強度鋼纖維鋼筋混凝土柱 94
3.9 韌性比與反覆側推實驗修正公式 98
第四章、試驗結果 100
4.1 材料試驗 100
4.1.1 高強度鋼筋 100
4.1.2 高強度鋼纖維混凝土 107
4.2 反覆側推實驗 110
4.2.1 重要參數點 110
4.2.2 位移與遲滯迴圈 112
4.2.3 裂縫發展 122
4.2.4 鋼筋降伏時間 126
4.2.5 曲率量測 127
4.2.6 剪力位移量測 130
第五章、結果與討論 133
5.1 韌性比回歸公式驗證 133
5.1.1 高強度鋼筋混凝土柱 133
5.1.2 高強度鋼纖維鋼筋混凝土柱 134
5.2 韌性比與反覆側推實驗修正公式驗證 135
5.3 反覆側推實驗結果比較 136
5.3.1 位移與遲滯迴圈比較 136
5.3.2 消能機制與勁度衰減比較 146
5.3.3 鋼筋混凝土柱韌性比預測值與反覆側推實驗目標性能點比較 155
第六章、結論與建議 156
6.1 結論 156
6.2 建議 157
參考文獻 159
附錄A應變計分析 163
附錄B反覆側推實驗照片 210
附錄C混凝土材料檢驗報告 219
附錄D試體設計圖說 230
附錄E反覆側推實驗資料庫(橫箍柱) 23
Experimental and theoretical investigation of crack width calculation methods for RC ties
No full textThis paper theoretically and experimentally investigates the semi-empirical formulas recommended by Eurocode 2 (EC2), fib Model Code 2010 (MC2010), and Eurocode 2 with the German National Annex (DIN) for calculating crack widths in reinforced concrete. It is shown that the formulas can be derived from the principles for the idealized behavior of RC ties. However, instead of explicitly solving the resulting differential equations, the use of simplifications leads to inconsistent formulas. An experimental study was carried out involving the testing of eight RC ties to discover the modeling uncertainty of the formulas. It was found that EC2 substantially overestimated the crack widths for the RC ties. MC2010 and DIN seemed to predict the crack widths better, but gave rather a large number of nonconservative crack width predictions. These experimental results, combined with the theoretical study, suggest that a more consistent calculation model should be formulated by explicitly solving the resulting differential equation.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Applied Mechanic
RC SMOOTHING OF SPECTRA
No full textAuthor Institution: Department of Physics, Michigan State University East LansingBy convoluting an exponential function with calculated spectra consisting of single and multiple sets of lines of various widths and line shapes, we have determined the effects that time constant (RC) has on recorded spectra. For equivalent experiments, in which the scanning rates d/dt are equal, we have concluded that the optimum value of RC is essentially independent of whether the spectrum is to be digitized or not, and independent of the sampling rate if digitization is used. A trade-off among the desirable and undesirable effects of RC leads us to recommend a value of RC about one-tenth of the full width at half height of the sharpest individual lines in the observed spectrum. This research was supported by a grant from the National Science Foundation
Nonlinear analysis to investigate effect of connection type on behavior of steel plate shear wall in RC frame
No full textIn the reinforced concrete (RC) structures with steel plate shear walls (SPSWs) as a lateral resisting system, to obtain maximum capacity of SPSW, implementing proper connections play an important role to transfer force from wall to the frame. In this paper, four connection types are proposed and numerically investigated to transfer the tension field forces between SPSW and RC frame (RCF). Three types of connections are applicable for rehabilitating of existing RC structures and one type can be used for new construction. The behavior of connections has been evaluated using non-linear finite element analysis (NLFEA). Results of the specimens with different types of connections demonstrated that the use of SPSW in RCF with appropriate connections could provide excellent ductility as well as high load carrying capacity and initial stiffness by distributing the yielding zone in SPSW along the wall height
AgnostiqHQ/covalent: v0.234.1-rc.0
No full text<h2>[0.234.1-rc.0] - 2024-05-10</h2>
<h3>Authors</h3>
<ul>
<li>Andrew S. Rosen <a href="mailto:[email protected]">[email protected]</a></li>
<li>Sankalp Sanand <a href="mailto:[email protected]">[email protected]</a></li>
<li>Co-authored-by: Alejandro Esquivel <a href="mailto:[email protected]">[email protected]</a></li>
<li>Casey Jao <a href="mailto:[email protected]">[email protected]</a></li>
<li>Co-authored-by: Santosh kumar <a href="mailto:[email protected]">[email protected]</a></li>
</ul>
<h3>Fixed</h3>
<ul>
<li>Sublattice electron function strings are now parsed correctly</li>
<li>The keys of dictionary inputs to electrons no longer need be strings.</li>
<li>Fixed inaccuracies in task packing exposed by no longer uploading null attributes upon dispatch.</li>
</ul>
<h3>Operations</h3>
<ul>
<li>Fixed nightly workflow's calling of other workflows.</li>
<li>Fixed input values for other workflows in <code>nightly-tests</code> workflow.</li>
</ul>
<h3>Operations</h3>
<ul>
<li>Removing author email from changelog action</li>
<li>Fixed nightly worfkflow's calling of other workflows.</li>
</ul>
A CMOS Dual- RC Frequency Reference With ±200-ppm Inaccuracy From -45 °C to 85 °C
No full textThis paper presents a 7-MHz CMOS RC frequency reference. It consists of a frequency-locked loop in which the output frequency of a digitally controlled oscillator (DCO) is locked to the combined phase shifts of two independent RC (Wien bridge) filters, each employing resistors with complementary temperature coefficients. The filters are driven by the DCO's output frequency and the resulting phase shifts are digitized by high-resolution phase-to-digital converters. Their outputs are then combined in the digital domain to realize a temperature-independent frequency error signal. This digitally assisted temperature compensation scheme achieves an inaccuracy of ±200 ppm from -45 °C to 85 °C after a two-point trim. The frequency reference draws 430 μA from a 1.8-V supply, while achieving a supply sensitivity of 0.18%/V and a 330-ppb Allan deviation floor in 3 s of measurement time.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic InstrumentationMicroelectronics(OLD)Applied Quantum Architecture
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