The pseudo-single-crystal method: a third approach to crystal structure determination

A novel method that enables single-crystal diffraction data to be obtained from a powder sample is presented

Identification of state registers of FSM through full scan by data analytics

Finite-state machine (FSM) is widely used as control unit in most digital designs. Many intellectual property protection and obfuscation techniques leverage on the exponential number of possible states and state transitions of large FSM to secure a physical design with the reason that it is challenging to retrieve the FSM design from its downstream design or physical implementation without knowledge of the design. In this paper, we postulate that this assumption may not be sustainable with big data analytics. We demonstrate by applying a data mining technique to analyze sufficiently large amount of data collected from a full scan design to identify its FSM state registers. An impact metric is introduced to discriminate FSM state registers from other registers. A decision tree algorithm is constructed from the scan data for the regression analysis of the dependency of other registers on a chosen register to deduce its impact. The registers with the greater impact are more likely to be the FSM state registers. The proposed scheme is applied on several complex designs from OpenCores. The experiment results show the feasibility of our scheme in correctly identifying most FSM state registers with a high hit rate for a large majority of the designs.Ministry of Education (MOE)Accepted versionThis work was supported in part by the National Natural Science Foundation of China under Grant 61672182, the Guangdong Natural Science Foundation under Grant 2016A030313662, and in part by the Singapore Ministry of Education Tier 1 Grant MOE2018-T1-001-131 (RG87/18)

Effect of sol aging time on the anti-reflective properties of silica coatings templated with phosphoric acid

Silica anti-reflective coatings have been prepared by a sol–gel dip-coating process using the sol containing phosphoric acid as a pore-forming template. The effect of the aging time of the sol on the anti-reflective properties has been investigated. The surface topography of the silica AR coatings has been characterized. With increasing sol aging time, more over-sized pores larger than 100 nm are formed in the silica coatings. These could act as scattering centers, scattering visible light and thereby lowering transmittance. The optimal aging time was identified as 1 day, and the corresponding silica coatings showed a maximum transmittance of 99.2%, representing an 8% increase compared to the bare glass substrate. Keywords: Thin films, Anti-reflective coatings, Aging, Dip-coating, Sol–gel preparatio

Efficient Active Oxygen Free Radical Generated in Tumor Cell by Loading-(HCONH2)·H2O2 Delivery Nanosystem with Soft-X-ray Radiotherapy

Tumor hypoxia is known to result in radiotherapy resistance and traditional radiotherapy using super-hard X-ray irradiation can cause considerable damage to normal tissue. Therefore, formamide peroxide (FPO) with high reactive oxygen content was employed to enhance the oxygen concentration in tumor cells and increase the radio-sensitivity of low-energy soft-X-ray. To improve stability of FPO, FPO is encapsulated into polyacrylic acid (PAA)-coated hollow mesoporous silica nanoparticles (FPO@HMSNs-PAA). On account of the pH-responsiveness of PAA, FPO@HMSNs-PAA will release more FPO in simulated acidic tumor microenvironment (pH 6.50) and subcellular endosomes (pH 5.0) than in simulated normal tissue media (pH 7.40). When exposed to soft-X-ray irradiation, the released FPO decomposes into oxygen and the generated oxygen further formed many reactive oxygen species (ROS), leading to significant tumor cell death. The ROS-mediated cytotoxicity of FPO@HMSNs-PAA was confirmed by ROS-induced green fluorescence in tumor cells. The presented FPO delivery system with soft-X-ray irradiation paves a way for developing the next opportunities of radiotherapy toward efficient tumor prognosis

Enhanced Electrochemical Performance of Li_1.27Cr_0.2Mn_0.53O₂ Layered Cathode Materials via a Nanomilling-Assisted Solid-state Process

Li1.27Cr0.2Mn0.53O2 layered cathodic materials were prepared by a nanomilling-assisted solid-state process. Whole-pattern refinement of X-ray diffraction (XRD) data revealed that the samples are solid solutions with layered α-NaFeO2 structure. SEM observation of the prepared powder displayed a mesoporous nature composed of tiny primary particles in nanoscale. X-ray photoelectron spectroscopy (XPS) studies on the cycled electrodes confirmed that triple-electron-process of the Cr3+/Cr6+ redox pair, not the two-electron-process of Mn redox pair, dominants the electrochemical process within the cathode material. Capacity test for the sample revealed an initial discharge capacity of 195.2 mAh·g−1 at 0.1 C, with capacity retention of 95.1% after 100 cycles. EIS investigation suggested that the high Li ion diffusion coefficient (3.89 × 10−10·cm2·s−1), caused by the mesoporous nature of the cathode powder, could be regarded as the important factor for the excellent performance of the Li1.27Cr0.2Mn0.53O2 layered material. The results demonstrated that the cathode material prepared by our approach is a good candidate for lithium-ion batteries

Identification of FSM state registers by analytics of scan-dump data

Big data analytics have gained tremendous successes in mining valuable information in various fields. However, its potential to solve complex problems in hardware security has not been adequately tapped. This paper presents a non-invasive approach to identify the state registers of a finite state machine (FSM) in an integrated chip. The state registers of the FSM are mined from the scan-dump data by exploiting the strongly connected property and chronologically correlated state codes of the FSM. The sequence of data scanned out of each scan register is partitioned into non-overlapping strings of high weighted frequencies by a string-matching algorithm. A coherency between a pair of registers is defined and computed based on the partitioned strings. The dimension of the coherency matrix is first reduced by pruning some registers of low influence by a regression analysis. The registers are then clustered to minimize the within-cluster variances based on their coherency values. The proposed scheme is applied to some IP cores from OpenCores. The experimental results show that our scheme can correctly identify the FSM state registers in most designs with high hit rate.Submitted/Accepted versionThis work was supported in part by the National Natural Science Foundation of China under Grant 62174045, in part by the Guangdong Basic and Applied Basic Research Foundation under Grant 2021A1515011862, and in part by the Shenzhen Fundamental Science Research Foundation under Project JCYJ20190806143203510 and Project GXWD20201230155427003-20200824112646001

Promotive effect of multi-walled carbon nanotubes on Co3O4 nanosheets and their application in lithium-ion battery

Co3O4/MWCNTs composites have been synthesized by a simple hydrothermal method using a surfactant (CTAB) and a precipitation agent (urea). The samples were characterized by XRD, SEM and BET methods. The electrochemical properties of the samples as anode materials for lithium batteries were studied by EIS and Galvanostatic measurements. The Co3O4/MWCNTs composites displayed higher capacity and better cycle performance in comparison with the Co3O4 nanosheets. The remarkable improvement of electrochemical performance within the hybrid composites is probably related to the addition of MWCNTs that possesses improved properties such as excellent electric conductivity and large surface area, which helps to alleviate the effect of volume change, shorten the distance of lithium ion diffusion, facilitate the transmission of electron and keep the structure stable

The comparison: photoluminescence and afterglow behavior in CaSnO3:Dy3+ and Ca2SnO4:Dy3+ phosphors

This paper reports the comparison of photoluminescence and afterglow behavior of Dy3+ in CaSnO3 and Ca2SnO4 phosphors. The samples containing CaSnO3 and Ca2SnO4 were prepared via solid-state reaction. The properties have been characterized and analyzed by utilizing X-ray diffraction (XRD), photoluminescence spectroscope (PLS), X-ray photoelectron spectroscopy (XPS), afterglow spectroscopy (AS) and thermal luminescence spectroscope (TLS). The emission spectra revealed that CaSnO3:Dy3+ and Ca2SnO4:Dy3+ phosphors showed different photoluminescence. The Ca2SnO4:Dy3+ phosphor showed a typical F-4(9/2) to H-6(j) energy transition of Dy3+ ions, with three significant emissions centering around 482, 572 and 670 nm. However, the CaSnO3:Dy3+ phosphor revealed a broad T-1 -> S-0 transitions of Sn2+ ions. The XPS demonstrate the existence of Sn2+ ions in CaSnO3 phosphor caused by the doping of Dy3+ ions. Both the CaSnO3:Dy3+ and Ca2SnO4:Dy3+ phosphors showed a typical triple-exponential afterglow when the UV source switched off. Thermal simulated luminescence study indicated that the persistent afterglow of CaSnO3:Dy3+ and Ca2SnO4:Dy3+ phosphors was generated by the suitable electron or hole traps which were resulted from the doping the calcium stannate host with rare-earth ions (Dy3+)

Effect of Microstructure on the Thermal Conductivity of Plasma Sprayed Y2O3 Stabilized Zirconia (8% YSZ)

In this paper, the effect of microstructure on the thermal conductivity of plasma-sprayed Y2O3 stabilized ZrO2 (YSZ) thermal barrier coatings (TBCs) is investigated. Nine freestanding samples deposited on aluminum alloys are studied. Cross-section morphology such as pores, cracks, m-phase content, grain boundary density of the coated samples are examined by scanning electron microscopy (SEM) and electron back-scattered diffraction (EBSD). Multiple linear regressions are used to develop quantitative models that describe the relationship between the particle parameters, m-phase content and features of the microstructure such as porosity, crack-porosity, and the length density of small and big angle-cracks. Moreover, the relationship between the microstructure and thermal conductivity is investigated. Results reveal that the thermal conductivity of the coating is mainly determined by the microstructure and grain boundary density at room temperature (25 °C), and by the length density of big-angle-crack, monoclinic phase content and grain boundary density at high temperature (1200 °C)