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According to researchers from the Singapore University of Technology and Design (SUTD), a recently discovered family of two-dimensional (2D) semiconductors could pave the way for high-performance and energy-efficient electronics. Their findings, published in npj 2D Materials and Applications, may lead to the fabrication of semiconductor devices applicable in mainstream electronics and optoelectronics—and even potentially replace silicon-based device technology altogether.

In the quest of miniaturizing electronic devices, one well-known trend is Moore’s law, which describes how the number of components in the integrated circuits of computers doubles every two years. This trend is possible thanks to the ever-decreasing size of transistors, some of which are so small that millions of them can be crammed onto a chip the size of a fingernail. But as this trend continues, engineers are starting to grapple with the inherent material limitations of silicon-based device technology.

“Due to the quantum tunneling effect, shrinking a silicon-based transistor too small will lead to highly uncontrollable device behaviors,” said SUTD Assistant Professor Ang Yee Sin, who led the study. “People are now looking for new materials beyond the ‘silicon era’, and 2D semiconductors are a promising candidate.”

The short curing time and consequently quick healing process is advantageous for these self-healing structures with embedded healing agent reservoirs compared to many other previously reported self-healing materials. For instance, self-healing materials with microvascular networks reported by Toohey et al.¹⁸ needed to be kept at room temperature for a period of 12 hours in order to become healed. Self-healing materials with interpenetrating microvascular networks reported by Hansen et al.³² had to go under cyclic bending (50 cycles at 100 μ m displacement) to enhance the mixing of the healing agents at the location of the crack, and after that required to be subjected to 48 hours of curing at 30 °C.

Various mechanical tests were conducted to investigate the healing capability of the structures. For each test, three identical samples with an overall dimension of 5 × 10 × 77 mm (H × W × L) were printed using a top-down SLA-based 3D printer. A notch with equal width and depth of 200 µm was incorporated in the middle of the CAD (computer aided design) model of two out of three specimens (Fig. 1a). This notch enhances the repeatability of the experiments and encourages the initiation of a straight crack under flexural (3-point bending) tests³². When a crack forms, propagates, and reaches the reservoir, the resin wicks into the crack planes as a result of capillary forces and closes the crack when it becomes cured under exposure to UV light. These forces are not high enough to drain out and deplete the large amount of healing agent in the reservoirs. The agent’s relatively high viscosity, approximately 850‑1000 cps at 25 °C, further aids in limiting its flow out of the damaged area. After healing, the specimen is tested again, and a new crack is formed under a new critical load and the aforementioned process is repeated. The small amount of leaked healing agent in the self-healing samples becomes cured relatively quickly under the UV radiation with a wavelength of 405 nm. A UV-light source was employed to cure the leaked-healing agent for 3 min. at 50 °C. To compare the effectiveness of the capillary forces for filling the crack, the notch of the second sample was manually filled before the tests. The last unnotched specimen (virgin) remained unfilled and was tested to provide a reference. It is worth noting that for simplicity’s sake, the structures were placed into a UV oven for curing; however, other types of UV sources can initiate and complete the healing process. In the case of a difficult to access part, on-site repair can be easily implemented using a remote UV source. Additionally, unloading the structure is not necessary to the healing process. A damaged structure is able to cure under loading as the healing mechanism is not affected.

The samples underwent tensile tests following the ASTM D638 standard and their force-displacement curves were recorded at a constant crosshead speed of 13 mm min⁻¹. Figure 2 shows the force-displacement curves for each specimen type. There was a difference of 22% between the tensile fracture load of the virgin specimen without a notch and the sample that was manually repaired. By comparing the fracture force of the healed sample before and after healing (182 N for Capillary – Cycle 1 and 199 N for Capillary – Cycle 2), it can be seen that the fracture force increases by around 17 N after the sample was repaired. There is a significant difference between the fracture force of the manually repaired sample and the sample after healing (Capillary – Cycle 2). This indicates that the self-healing process is effective and is reviving the original mechanical performance of the structure.

Critical flaws discovered in an Azure app that Microsoft secretly installed on Linux virtual machines.

Is there something special about consciousness? Can our inner subjective experience—the sight of purple, smell of cheese, sound of Bach—ever be explained in purely physical terms? Even in principle? Most scientists see consciousness as a science problem to solve. Some philosophers claim that consciousness can never be explained in terms of current science.

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“With a single packet, an attacker can become root on a remote machine by simply removing the authentication header.” ‘ Unfortunately, Microsoft can’t fix it for you. Users affected by these vulnerabilities must manually update the OMI agent to the patched versions.

Microsoft on Tuesday addressed a quartet of security flaws as part of its Patch Tuesday updates that could be abused by adversaries to target Azure cloud customers and elevate privileges as well as allow for remote takeover of vulnerable systems.

The list of flaws, collectively called OMIGOD by researchers from Wiz, affect a little-known software agent called Open Management Infrastructure that’s automatically deployed in many Azure services

Continue reading “Critical Flaws Discovered in Azure App That Microsoft Secretly Installed on Linux VMs” »

Every piece of data that travels over the internet — from paragraphs in an email to 3D graphics in a virtual reality environment — can be altered by the noise it encounters along the way, such as electromagnetic interference from a microwave or Bluetooth device. The data are coded so that when they arrive at their destination, a decoding algorithm can undo the negative effects of that noise and retrieve the original data.

Since the 1950s, most error-correcting codes and decoding algorithms have been designed together. Each code had a structure that corresponded with a particular, highly complex decoding algorithm, which often required the use of dedicated hardware.

Researchers at MIT.

The crystals neatly sidestep some of physics’ most iron-clad laws.

Time-resolved photon counting plays an indispensable role in precision metrology in both classical and quantum regimes. Therein, time-correlated single-photon counting (TCSPC) [1] has been the key enabling technology for applications such as fluorescence lifetime microscopy [2], time-gated Raman spectroscopy [3], photon counting time-of-flight (ToF) 3D imaging [4], light-in-flight imaging [5], and computational diffuse optical tomography [6]. For all these applications, one of the most important figures of merit is the single-photon timing resolution (SPTR, also referred to as photon counting timing jitter). The TCSPC SPTR is limited by the available single-photon detectors. For example, photomultiplier tubes typically provide an SPTR larger than 100 ps [7]. Meanwhile, superconducting nanowire single-photon detectors have superior SPTR in the sub-10-ps range [8, 9]. However, cryogenic cooling significantly increases the system complexity. Single-photon avalanche diodes (SPADs) operate at moderate temperature, which makes them a popular choice for various applications mentioned above. Nevertheless, their SPTR is still limited to tens-of-picoseconds level [10]. On the other hand, orders-of-magnitude enhancement on SPTR is required for many challenging applications such as the study of ultrafast fluorescent decay dynamics [11,12].

In this Letter, we demonstrate a time-magnified TCSPC (TM-TCSPC) that achieves an ultrashort SPTR of 550 fs using an off-the-shelf single-photon detector. The key component is a quantum temporal magnifier using a low-noise high-efficiency fiber parametric time lens [13,14] based on four-wave mixing Bragg scattering (FWM-BS) [15 – 17]. A temporal magnification of 130 with a 97% photon conversion efficiency has been achieved while maintaining the quantum coherence of the signal under test (SUT). Detection sensitivity of -{95}\;rm{dBm}$ (0.03 photons per pulse), limited by the spontaneous Raman scattering noise, is possible and allows efficient processing and characterization of quantum-level SUT. The TM-TCSPC can resolve ultrashort pulses with a 130-fs pulse width difference at a 22-fs accuracy. When applied to photon counting ToF 3D imaging, the TM-TCSPC greatly suppresses the range walk error (RWE) that limits all photon counting ToF 3D imaging systems by 99.2% (130 times) and thus provides high depth measurement accuracy and precision of 26 µm and 3 µm, respectively. The TM-TCSPC is a promising solution for photon counting at the femtosecond regime that will benefit various research fields such as fluorescence lifetime microscopy, time-gated Raman spectroscopy, light-in-flight imaging, and computational diffuse optical tomography.

Researchers describe how electrons move through two-dimensional layered graphene 0 findings that could lead to advances in the design of future quantum computing platforms.

New research published in Physical Review Letters describes how electrons move through two different configurations of bilayer graphene, the atomically-thin form of carbon. This study, the result of a collaboration between Brookhaven National Laboratory, the University of Pennsylvania, the University of New Hampshire, Stony Brook University, and Columbia University 0 provides insights that researchers could use to design more powerful and secure quantum computing platforms in the future.

“Today’s computer chips are based on our knowledge of how electrons move in semiconductors, specifically silicon,” says first and co-corresponding author Zhongwei Dai, a postdoc at Brookhaven. “But the physical properties of silicon are reaching a physical limit in terms of how small transistors can be made and how many can fit on a chip. If we can understand how electrons move at the small scale of a few nanometers in the reduced dimensions of 2-D materials, we may be able to unlock another way to utilize electrons for quantum information science.”