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The formation and dynamics of a single drop of liquid under the influence of gravity can be experienced as everyday phenomena, and have been the subject of scientific investigations since at least the work of Leonardo da Vinci in the early 1500s and Mariotte in the 1680s. Experiences with liquid drops in everyday life are captured by poets and artists as well as scientists, whose theoretical and experimental investigations develop fundamental understanding of drops with size 107 m. This paper presents observations of the formation of a single liquid drop of molten steel following bursting of a liquid film formed by illuminating a steel plate by a high energy laser. The hole morphology is analyzed with a proposed kinematic model of hole expansion for the very early stages in the bursting of the hole. Estimates of the hole eccentricity, area, perimeter, and circularity obtained from the model are presented and discussed. Experimental measurements show that a single drop of liquid steel detaches from the end of a neck that then cools to room temperature. Measurements also show that the liquid drop oscillates while falling under gravity. No satellite drops are observed.

This paper proposes a new approach to stabilize the spin of a suspended litter during air ambulance rescue hoist operations. Complex forces generated by the helicopter’s downwash may cause a patient suspended in a rescue litter to spin violently. In severe cases, the spin destabilizes the suspended load, risks injury to the patient, and jeopardizes the safety of the aircrew. The presented design employs an anti-torque device to arrest the spin that is safer and faster than a tagline and is without the tactical constraints of the tagline. The device follows tailored control laws to accelerate a flywheel attached to the litter, thereby generating sufficient angular momentum to counteract the spin and stabilize the suspended litter. An inertial measurement unit (IMU) measures the position, angular velocity, and angular acceleration of the litter and delivers this information to a microcontroller. The research and prototype design were developed under the support of the U.S. Army 160th Special Operations Aviation Regiment (SOAR).

This paper presents a compound lens experiment design suitable for upper-division undergraduate laboratory courses in which teams of students constructed and measured the properties of Galilean beam expanders. Skill in developing Galilean beam expanders is useful for undergraduates who will build a magneto-optical trap in a follow-on course. This laboratory experiment was performed by third-year undergraduate students in our applied optics course and provided students with the opportunity to gain knowledge about lasers, lenses, and alignment of optical components prior to their laboratory work building a magneto-optical trap.

This research proposes an interdisciplinary collaboration to improve hoist stabilization for medical evacuation and successful rescues. This paper would include the collaborative efforts from a diverse range of fields to include Systems Engineering, Mechanical Engineering, Physics, and the Special Collections & Archives Division of the United States Military Academy Library. The research objective of this effort is to create an algorithm which could limit the displacement angle of a suspended individual below a helicopter. This would be accomplished by changing the relative length of the cable at different points within the swing of the slung mass. This could all be done while reeling in the hoisted individual to the helicopter by changing the rate at which the hoist is lessening its cable. Elements of the mathematical principles that this research is built on are illustrated through Edgar Allen Poe’s application of the pendulum in his short story “The Pit and the Pendulum”. Poe was an individual who attended, but did not graduate from, USMA; however, his education at the Military Academy and his subsequent writings are the birthplace of this research endeavor. It is a multi-semester goal, and this paper will present an initial proof of concept.

A control strategy for stabilization of single-point sling loads and hoists is proposed. Nonlinear oscillations of an elastically suspended mass are described by a suitable nonlinear dynamic model that incorporates delayed position feedback for active stabilization of both sling loads and hoist. Helicopter maneuvers are described by assigned trajectories of the mass suspension point to model oscillations of the payload. For the sling load case, stability analysis is performed to estimate optimal control gains. For the hoist case, a genetic algorithm is adopted to estimate optimal control parameters. The controlled system is simulated via time integration of the nonlinear equations of motion.

This paper presents a generalized theoretical analysis of Tsui's phase measurement approach for the situation in which there are N simultaneous signals, where one of the signals is strong and N - 1 signals are weak. Signal amplitudes are normalized to the amplitude of the strongest signal. This approach provides the capability to extract values of the signal parameters. The capability for up to N = 4 simultaneous signals is desired in the design goal for electronic warfare receivers.

This paper presents applications of a generalized theoretical analysis of Tsui's phase measurement approach to detection of N - 1 ultraweak signals. A closed-form analytical expression is obtained for one application. A detection approach is presented for real-time estimation of the slope and curvature of sampled data of the instantaneous frequency. This approach provides the capability for early simultaneous signal detection and extraction of signal parameters. The capability for N = 4 simultaneous signals is desired for electronic warfare (EW) receivers.

Initiatives to designate and recognize important events in engineering and technology history, such as the IEEE Milestones program, are just part of one set of ways to help preserve and promote that history. Another approach is to collect oral history interviews with those involved in such events. At the same time, there is a growing global recognition that women-over one-half of Earth's population-have been underrepresented in engineering. Both Milestones and oral histories offer an opportunity to preserve and promote the accomplishments of women as part of the efforts to recruit more women into engineering This paper chronicles an ongoing project, begun five years ago by Prof. Mary Lanzerotti when she was at the Air Force Institute of Technology, to have women in the earliest stages of technical careers conduct and process oral history interviews of living female leaders in science, technology, and mathematics. The IEEE History Center has been a partner of the project since the beginning, and hosts the finished oral history transcripts; the Center for the History of Physics at the American Institute of Physics has since joined as a partner as well. To date, interviewees have been based in the U.S. and in Taiwan, but further international expansion is envisioned. This program is unique because it simultaneously fills a number of important functions. It preserves the memories of these important leaders, and enhances the IEEE's oral history collection. It creates a record for students of role models in the careers they are considering. It enables the participating students to have one-on-one conversations with this role model, and opens up the possibility for mentorship. Finally, the oral histories are structured so that the responses of the interviewees contribute to research on how women choose STEM careers and what barriers they face in pursuing those careers. This paper will present the background of the project and the results to date, and will discuss the impact at the present and the potential for future impact and scaling up the project.

This paper extends a methodology for microelectronics verification to the situation in which signal switches are applied to library circuits containing INV, NAND2, NOR2, NAND3, and NOR3 gates. Monte Carlo methods are used to sample the frequency distributions of the topological genus of library circuits including a 4-bit adder.

The beauty, kinematics, and dynamics of thin liquid soap films under the influence of gravity have inspired experimental and theoretical investigations by scientists at least since the research of Plateau and Lord Rayleigh in the mid1800s. The wide-ranging interest in thin films may also be attributed in part to readily available, inexpensive ingredients as well as to the enjoyable nature of the interactive activity itself. While the creation of the films produces relatively long-lived persistent films, the violent destruction of the films follows a rupture that may occur spontaneously and can also be initiated by external forces. This paper presents thick liquid films of molten steel and discusses the fundamental nature of the behavior of vertical thick films under the influence of gravity. This paper presents observations of stable thick liquid films of molten steel with thicknesses of 1.5 mm, 1.8 mm, and 1.9 mm. We observe spontaneous bursting of vertical thick films in the presence of gravity, without any other external forces, with an initial horizontal speed of 0.68 m/s–0.9 m/s and a vertical acceleration of ∼(6 ± 1)g, with sudden hole enlargement, like soap film popping. Experimental measurements of the preburst films, following cooling to room temperature, show the presence of a three-dimensional dimple and bulge and fairly agree well with theoretical predictions of Surface Evolver, due to a liquid surface tension that is strong enough to resist the force of gravity.The beauty, kinematics, and dynamics of thin liquid soap films under the influence of gravity have inspired experimental and theoretical investigations by scientists at least since the research of Plateau and Lord Rayleigh in the mid1800s. The wide-ranging interest in thin films may also be attributed in part to readily available, inexpensive ingredients as well as to the enjoyable nature of the interactive activity itself. While the creation of the films produces relatively long-lived persistent films, the violent destruction of the films follows a rupture that may occur spontaneously and can also be initiated by external forces. This paper presents thick liquid films of molten steel and discusses the fundamental nature of the behavior of vertical thick films under the influence of gravity. This paper presents observations of stable thick liquid films of molten steel with thicknesses of 1.5 mm, 1.8 mm, and 1.9 mm. We observe spontaneous bursting of vertical thick films in the presence of gravity, without...

This paper quantifies error in the estimation of signal parameter values in a multi-tier weak radio signal detection process with N simultaneous signals having continuous phase. Estimates of the zero crossings are obtained from sampled data values of the instantaneous frequency of the combined signal. The instantaneous frequency is sampled with different sample periods, and values of the error in the signal parameter estimates are obtained for each case. As an example, for instantaneous frequency data with N = 2, a strong signal of 850MHz, and sample period of 1/(200π) microseconds, the frequency of a weak signal can be estimated (i) to within a few Hz for f 2 = 855 MHz; (ii) to within a few tenths Hz for f 2 = 852 MHz; and (iii) to within a few hundredths Hz for f 2 = 851 MHz. This approach provides a method to quantify the capability of this method for identification of zero crossings and extraction of signal parameters. This work has applications for electronic warfare receivers for detection and characterization of weak signals with unknown parameters. Next steps are to incorporate noise into the models.

This paper describes components and outcomes of an interdisciplinary undergraduate research program intended to motivate female students to graduate with STEM degrees. This year, the program graduated the first student, who is the first STEM graduate in her family. The program is intended to inspire underrepresented undergraduate students to graduate with STEM bachelor's degrees by providing participating students with unique mentorship from distinguished leaders in STEM fields while the students simultaneously pursue technical research. The mentorship is provided to the students when they identify and interview leaders whose careers align with the desired career fields of the students. The interviews are conducted in collaboration with the IEEE History Center and American Institute of Physics. Research results produced by the students are presented at national conferences and published in conference proceedings. Transcripts of the interviews are published in perpetuity on the IEEE Engineering Technology and History Wiki. The project will continue within the STEM environment.

A detailed cause-and-effect stochastic model is developed to relate the type, size, location, and frequency of observed defects to the final yield in IC manufacturing. The model is estimated on real data sets with a large portion of unclassified defects and un inspected layers, and in presence of clustering of defects. Results of this analysis are used for evaluating kill ratios and effects of different factors, identifying the most dangerous cases and the most probable causes of failures, forecasting the yield, and designing optimal yield-enhancement strategies.

This paper presents topological constraints of gate-level circuits obtained through standard cell recognition applied to gate-level commercial microelectronics verification. A suite of topological constraints, including the gate vertex count, net vertex count, terminal count, blocks, circuit genus, Euler characteristic, and number of faces are extracted from gate-level circuits obtained through standard cell recognition. Topological constraints are computed for two full adder cells at fourth level of abstraction and for two full adder cells at the third level of abstraction. Two mathematical frameworks are also introduced to describe physically distinct situations in hardware that are represented in a schematic as functionally equivalent. The first method uses the concept of a braid word, and the second method uses the concept of a crossing vertex. Schematic braid words corresponding to each of two full adder cell schematics at fourth level of abstraction and for two full adder cell schematics at the third level of abstraction are derived. Chip braid words corresponding to the set of unique physical designs that could potentially be realized in chip hardware from a schematic are obtained and discussed. Potential capabilities of these approaches for gate-level circuits are discussed.

This paper presents a generalization of Tsui's phase measurement approach to detection of N − 1 weak signals to situations in which the weak signals have a phase that is continuous at any point in time. Examples are provided for the situation in which N = 2 and for four cases in which φ2 takes on each of the values {0, Π/2, Π, −Π/2}. This approach provides the capability for accurate identification of zero crossings and extraction of signal parameters. The capability for N ≤ 4 simultaneous signals is desired for electronic warfare (EW) receivers.

This paper describes an interdisciplinary undergraduate research program in STEM fields intended to motivate female students to graduate with STEM degrees. The goal of the dual-role approach is to provide unique mentorship from distinguished technical leaders to female students while the students simultaneously pursue STEM research as a team. The students receive mentorship from distinguished female leaders in STEM fields through conducting an Oral History Project in collaboration with the IEEE History Center. Research results produced by the students are presented at national conferences and published in national conference proceedings, and oral history transcripts of the distinguished leaders are published on the IEEE Global History Network.

Research on Rent's rule in electrical engineering, the applied sciences, and technology has been based on the publication of a 1971 interpretation of Rent's memoranda by B. S. Landman and R. L. Russo. Because of the wide impact of Rent's work and requests from researchers, we present his original memoranda in this paper. We review the impact of Rent's work and present the memoranda in the context of IBM computer hardware development since the 1950s. Furthermore, because computer hardware components have changed significantly since the memoranda were written in 1960, a new interpretation is needed for today's ultra-large-scale integrated circuitry. On the basis of our analysis of the memoranda, one of the authors' personal knowledge of the 1401 and 1410 computers, and our experience in the design of high-performance circuitry for microprocessor chips, we have derived an historically equivalent interpretation of Rent's memoranda that is suitable for today's computer components. We describe an application of our historically equivalent interpretation to the problem of assessing on-chip interconnection requirements of control logic circuitry in the IBM POWER4TM microprocessor.

Computer hardware components have changed significantly since the 1960s, 1970s, 1980s, and even since the early 1990s. Work concerning Rent's memos prior to the present paper has been based on a 1971 interpretation of two unpublished memoranda written in 1960 by E. F. Rent while working at IBM, even though today's computer components are significantly different from those in 1960 and 1971. However, because of the significant changes in the design and implementation of computer hardware components since 1960 and 1971, a new interpretation of Rent's memos is needed for today's components. We have obtained copies of Rent's two memos. In these memos, Rent describes the method that he used to obtain an empirical relationship between properties of the computer hardware components of the IBM 1401 and the IBM 1410 computers. We have studied these memos carefully in order to understand Rent's original intent. Based on our careful reading of these two memos, the personal knowledge of one of us with the 1401 and 1410 computers, and our experience designing ultralarge-scale integrated (ULSI) circuits for high-performance microprocessors, we have derived an historically equivalent interpretation of Rent's memos suitable for today's computer components. The purpose of this paper is to present a new interpretation of the memos and to present an application to wirelength distributions of real ULSI circuitry. In this paper, we will: 1) describe the contents of the memos and Rent's method; 2) provide an historically-equivalent interpretation of Rent's memos for today's computer components; and 3) apply this new interpretation to real ULSI control logic circuitry in the 1.3-GHz IBM POWER4 microprocessor. In this paper, we will show that this new interpretation of the two memos provides improved wirelength distribution models with better qualitative agreement with measurements and more accurate estimates of wirelength distributions and wirelength requirements for real ULSI designs compared with prior methods.

Ultralarge-scale integrated (ULSI) chip design data is needed for an assessment of existing on-chip wirelength distribution models. Data extracted from modern chips such as high-performance microprocessors provide information about actual wire length requirements in ULSI chip designs. These requirements are compared with wirelength estimates obtained by evaluating existing models as functions of Rent's parameters that are extracted from the designs. This brief assesses the extent to which existing models estimate wirelength requirements in 100 ASIC-like control logic designs in the 1.3-GHz POWER4 microprocessor. For each design, physical design characteristics and wirelength requirements are measured and compared with model estimates. Lack of agreement between the data and models is observed for most designs, and possible reasons for the lack of agreement are discussed.

This paper reviews the results of a generalized theoretical analysis of Tsui's phase measurement approach for detection of extremely weak radio signals to the situation in which there are N simultaneous signals, where one signal is strong, and N − 1 signals are weak. Applications to a multi-tier detection process for N = 2, N = 3, and N = 4 simultaneous signals are described. Signal parameters are extracted for the case of N = 2. This work has applications for electronic warfare receivers for detection and characterization of weak signals with unknown parameters.

The DARPA TRUST program was established to address the need to verify integrated circuits (ICs). This paper explores methodologies to resolve conflicts among IC designs in prior applications of commercial software to verify designs ranging in size from 1 to 283,359 cells. Preliminary results show the capability of commercial software tools to generate test cases for evaluation.

This paper presents a method of characterizing single-walled carbon nanotube (SWCNT) ink and discusses preliminary research results of our characterization efforts. First, the process of ink jet printing SWCNT ink onto organic and inorganic substrates is discussed. Next, the tests for measuring sheet resistance, conductance, thickness, roll-off, and S-parameters of the ink are described. Future research directions will be discussed, including the additional characterization of SWCNT ink

We present the results of a comprehensive investigation of the quantum-noise properties of a continuous-wave phase-conjugate mirror (PCM) formed using backward-four-wave mixing in potassium vapor. We characterize the quantum-noise properties of the PCM as functions of the vapor density, pump detuning from resonance, and relative frequency detuning of the signal beam from the probe beam. We compare the noise measurements of the PCM with the predicted noise of an ideal quantum-noise-limited PCM and determine the value of the minimum signal that can be used to perform phase conjugation with unity signal-to-noise ratio. For the range of vapor densities studied, we find that the PCM operates nearest the quantum-noise limit and that the value of the minimum signal is lowest under conditions in which the reflectivity is maximized. These results demonstrate that it is possible to perform phase conjugation with signals as weak as 14 fW with near-unity reflectivity. Our measurements are in qualitative agreement with the predictions of a quantum theory of phase conjugation via nearly degenerate four-wave mixing in a two-level system.

A quantum theory of nearly degenerate backward four-wave mixing in a two-level atomic system is developed. The theory is used to calculate the quantum noise produced by a phase-conjugate mirror based on this system. The results indicate that in the case of pure radiative broadening the ideal quantum-noise limit is reached for relatively small pump-wave strengths and for relatively large probe-pump and pump-resonance detunings, so that the phase-conjugate reflectivity is far from its maximum value. Conversely, in the collisionally broadened case, operation closest to the quantum-noise limit occurs near the point of maximum reflectivity.

We demonstrate phase conjugation and aberration correction of femtowatt signals using nearly degenerate four-wave mixing in an atomic vapor. Our theoretical and experimental results are in qualitative agreement and show that the conditions under which the minimum signal can be phase conjugated are similar to the conditions under which the phase-conjugate mirror can be operated near its quantum-noise limit.

The phase contrast imaging of surface steps in reflection electron microscopy is analysed. It is shown that the typical images are seriously affected by incoherence effects and that this arises, not from the strong inelastic scattering which is often present, but from the effective angular spread in the illumination which is frequently determined by the width of the Bragg reflection.

A 1-{mu}sec pulsed proton beam is being used to study H{sup +} thermalization and reemission from solid target surfaces in ultrahigh vacuum in order to help clarify analogous experiments using muon beams. Using a solid Ar target, vapor deposited on an {approx}6-K Cu substrate, the reemission probability {ital Y} is 6{times}10{sup {minus}4} at a proton implantation energy {ital E}{sub H}{sup +}=1.4 keV and falls with increasing energy to 3{times}10{sup {minus}4} at {ital E}{sub H}{sup +}=5 keV and 2{times}10{sup {minus}4} at {ital E}{sub H}{sup +}=15 keV. Ne exhibits a 25% larger yield, while the yield for Kr is a factor of 4 lower. The reemitted protons are slow, with kinetic energies of order 1 eV. The reemitted proton yield {ital Y} decreases with an {approx}100-m time constant, presumably due to deposition of neutral contaminants associated with the incoming beam, and thus ruling out the possibility that the slow protons originate from surface contaminants. For Ar, the observed variation of {ital Y} with {ital E}{sub H}{sup +} is interpreted with the help of a Monte Carlo calculation of the stopping and backscattering of the incident protons.

This paper presents models and a methodology to evaluate tradeoffs between technology and design to obtain the highest frequency in ULSI design projects and quantifies the performance improvement that can be expected. With respect to the standard chip design process, it is well known in the academic community that circuits and chips are required to satisfy specific constraints, most notably the requirement that all signals must have zero slack when the transistors and wires are manufactured at some pre-specified technology node. To amortize the cost of the design process, which is time-consuming and complex, there is a need to migrate the designs to future technology nodes with minimal redesign. However, this problem and the associated implications of design migration are less well known, and at present there are no existing models to help designers evaluate whether migrated designs will operate successfully in a future technology or whether migrated designs will fail and thus cause chip failure. Thus, there is a need for research to evaluate the impact of design changes on chip performance. This paper presents a methodology to evaluate and quantify the performance impact of design changes, where we express the impact on performance as an effective change in dielectic constant in the wire environment. In this study, as in a previous study[1], performance estimates obtained from the model are compared with values obtained for interconnections in 18 ASIC-like control logic designs in the Instruction Fetch Unit (IFU) of the 1.3GHz POWER4 microprocessor.

Power reduction techniques are a critical issue in the design of today's ULSI chips. This paper is concerned with methods to characterize the capacitive load on the POWER4 on-chip global clock distribution [1], which is a large contributor to the overall chip power dissipation. A characterization of the capacitive load is needed because the contributions of the on-chip devices and interconnections are typically overestimated and are not well understood for high performance microprocessors. One problem that results from the lack of this information is excessively high power dissipation in the chip global clock distribution; the global clock distribution is over-designed and stronger than necessary to drive the actual (lower) chip load. Information about the capacitive load is difficult to obtain because the data volume is large, and extracting the interconnect data is a complex task. Sophisticated computer software is needed to extract the circuit and physical design data for hundreds of devices and wire segments within the chip design schedule.This paper presents the first comprehensive characterization of the clock load for ASIC-like control logic designs in the 1.3GHz POWER4 microprocessor core [1], [2]. This characterization was achieved with the use of sophisticated software written for this study to accomplish the task of extracting the data from these designs. Analysis of the data shows that the wire contribution to the chip capacitive load is significant and can increase the capacitive load of a design by 30% on average and by as much as 130% for some designs. The results also suggest that the wire load contribution on each metal layer can be reduced if an alternate interconnect design style is selected. Two alternate design styles are presented and show that a capacitive load reduction of 8.4% to 20% is expected for each design. Extended to the entire chip, the results show that the load reduction for the core is expected to be as high as 10%. These values are large enough that one alternate design style has been implemented in the design methodology of future chips.

This paper presents a comprehensive assessment of interconnect requirements in ULSI control logic circuitry and quantifies the agreement observed (1) between estimates and measurements of average wire-length in individual designs in real chips, and (2) between wire-length distributions provided by the models and wire-length distributions obtained from measurements. In this study, actual interconnect data is measured in ASIC-like control logic designs in the six functional units of the 1.3GHz POWER4. This paper compares interconnect measurements with estimates for control logic in individual designs, in functional units, and in the entire POWER4 core. The results presented in this paper show that the estimates are typically lower than the actual wire-length measurements. The results also show that the estimates of the total wire-length for all of the control logic in the POWER4 agree to within 31% of the total measured wire-length.

We report on a high‐reflectivity (up to 670%) wide‐bandwidth (up to 230 MHz) phase‐conjugate mirror formed using backward‐four‐wave mixing with continuous‐wave pump beams in a 2‐mm potassium vapor cell. The reflectivities and bandwidths are significantly larger than have been measured previously, and the bandwidth is ten times greater than is predicted theoretically. The reflectivity‐bandwidth product is more than an order of magnitude improvement over those previously achieved with other continuous‐wave phase‐conjugate systems.

Because of the wide impact of Mr. E. F. Rent's work in engineering, the applied sciences, and technology, the original memos of Mr. Rent and historically equivalent (HE) applications to today's complex integrated circuitry were published in the IBM Journal of Research and Development in 2005. It has been shown that evaluating existing wirelength distribution models with this HE interpretation of Rent's memos provides improved qualitative agreement with measurements and more accurate estimates of on-chip wirelength requirements for application-specific integrated circuit designs in the POWER4™ microprocessor core. Because of the increasing impact of Rent's work, including research on integration density for future computers and expansion to the fields of post-CMOS devices and bioengineering, this paper presents a review of these contributions and a new mathematical framework that explains the HE interpretation of Rent's memos. This framework provides topological constraints for today's ultralarge-scale integrated circuits, as well as a model that predicts this HE interpretation. The model arises from the underlying topology of the circuitry and interconnectivity of the circuit components. Using this model, predictions of the HE Rent parameters are obtained and show agreement to within -5% to +12% of the experimental values obtained from published data for the POWER4 microprocessor circuit designs.

This Summer 2014 issue marks the third issue of the sixth year of IEEE Solid-State Circuits Magazine. In this issue, we are pleased to feature Prof. Rinaldo Castello. We thank Prof. Andrea Baschirotto for serving as guest editor for this issue. We also present a feature article, "Rinaldo Castello: Trying to Balance Industry and Academia with Family Life: A Pattern of Life's Gifts and Trials That Combine Themselves to Make a Beautiful Picture, by Rinaldo Castello. We also present 10 expert articles on this topic.

Studies of the growth of crystals of energetic materials under conditions of high acceleration in an ultracentrifuge are reported. When a saturated solution is accelerated in an ultracentrifuge, the solute molecules move individually through the solvent molecules to form a crystal at the outer edge of the tube if the solute is more dense than the solvent. Since there is no evaporation or temperature variation, convection currents caused by simultaneous movement of solvent and solute are minimized and crystal defects are potentially minimized. Crystal growth is controlled by the g-level of the acceleration. We present results of TNT, RDX, and TNAZ grown at high g from various solutions. Crystals grown at high g were free of solution inclusions and gas bubbles.

This Spring 2013 issue marks the second issue of the fifth year of the IEEE Solid-State Circuits Magazine. In this issue, we are pleased to feature Dr. Gabor Temes. This special issue is titled "Gabor Temes: Creativity in Analog Circuits." We are honored to have the opportunity to present the achievements in this special issue in honor of Dr. Temes, who is professor of electrical and computer engineering at Oregon State University (Gabor.Temes@oregonstate.edu). We thank Dr. Kenneth Martin for serving as guest editor for this issue. In this issue, we present Prof. Temes' feature article, "Fifty-Five Fun-Filled Years in Circuit Design" and eight expert articles written in honor of Prof. Temes.

Height profiles spaced 0.008 μm apart across the fracture surface of TNT melt-cast in polycarbonate sleeves have been obtained with an atomic force microscope (AFM). Spatial power spectra (wavelengths of 0.016 μm to 4.0 μm) have been calculated using both a prolate spheroidal data window and a Kaiser window in the horizontal space domain prior to using a fast Fourier transform algorithm. Results based on topographical profiles across the surface include the following. The power spectral density of the individual fracture surface profiles is found to decrease with increasing spatial frequency over the dimensional region examined, ≈ 1.0 μm−1 to ≈ 10.0 μm−1. The spectral amplitudes are found to have a frequency dependence proportional to f s. The determined values of s in the dimensional region 1–10 μm−1 scatter in the range -1 < s < -4. Those values of s outside the range -3 < s < -2 indicate non-fractal fracture. There is significant structure in the spectra even for those with slopes within the range of a fractal dependence. Both observations are consistent with the appearance of numerous peaks in the spectra that indicate that a substantial amount of the fracture occurs at grain boundaries in the form of large clusters of TNT. Such a fracture process is deterministic.

Studies of the growth of TNAZ (1,3,3-trinitroazetidine) crystals of energetic materials under conditions of high acceleration in an ultracentrifuge are reported. When a saturated solution is accelerated in an ultracentrifuge, the solute molecules move individually through the solvent molecules to form a crystal at the outer edge of the tube if the solute is more dense than the solvent. Since there is no evaporation or temperature variation, convection currents caused by simultaneous movement of solvent and solute are minimized and crystal defects are potentially minimized. Crystal growth is controlled by the g-level of the acceleration. In addition, solution inclusions and bubbles migrate out of the saturated solution as a result of the pressure gradient induced by the g-force. We present results for TNAZ grown at high g from various solutions.