Experimental Study on the Reliability of Scaling Down Techniques Used in Direct Shear Tests to Determine the Shear Strength of Rockfill and Waste Rocks

The determination of shear strength parameters for coarse granular materials such as rockfill and waste rocks is challenging due to their oversized particles and the minimum required ratio of 10 between the specimen width (W) and the maximum particle size (dmax) of tested samples for direct shear tests. To overcome this problem, a common practice is to prepare test samples by excluding the oversized particles. This method is called the scalping scaling down technique. Making further modifications on scalped samples to achieve a specific particle size distribution curve (PSDC) leads to other scaling down techniques. Until now, the parallel scaling down technique has been the most popular and most commonly applied, generally because it produces a PSDC parallel and similar to that of field material. Recently, a critical literature review performed by the authors revealed that the methodology used by previous researchers to validate or invalidate the scaling down techniques in estimating the shear strength of field materials is inappropriate. The validity of scaling down techniques remains unknown. In addition, the minimum required W/dmax ratio of 10, stipulated in ASTM D3080/D3080M-11 for direct shear tests, is not large enough to eliminate the specimen size effect (SSE). The authors’ recent experimental study showed that a minimum W/dmax ratio of 60 is necessary to avoid any SSE in direct shear tests. In this study, a series of direct shear tests were performed on samples with different dmax values, prepared by applying scalping and parallel scaling down techniques. All tested specimens had a W/dmax ratio equal to or larger than 60. The test results of the scaled down samples with dmax values smaller than those of field samples were used to establish a predictive equation between the effective internal friction angle (hereafter named “friction angle”) and dmax, which was then used to predict the friction angles of the field samples. Comparisons between the measured and predicted friction angles of field samples demonstrated that the equations based on scalping scaling down technique correctly predicted the friction angles of field samples, whereas the equations based on parallel scaling down technique failed to correctly predict the friction angles of field samples. The scalping down technique has been validated, whereas the parallel scaling down technique has been invalidated by the experimental results presented in this study.

Scavenger with Protonated Phosphite Ions for Incredible Nanoscale ZrO2-Abrasive Dispersant Stability Enhancement and Related Tungsten-Film Surface Chemical–Mechanical Planarization

For scaling-down advanced nanoscale semiconductor devices, tungsten (W)-film surface chemical mechanical planarization (CMP) has rapidly evolved to increase the W-film surface polishing rate via Fenton-reaction acceleration and enhance nanoscale-abrasive (i.e., ZrO2) dispersant stability in the CMP slurry by adding a scavenger to suppress the Fenton reaction. To enhance the ZrO2 abrasive dispersant stability, a scavenger with protonate-phosphite ions was designed to suppress the time-dependent Fenton reaction. The ZrO2 abrasive dispersant stability (i.e., lower H2O2 decomposition rate and longer H2O2 pot lifetime) linearly and significantly increased with scavenger concentration. However, the corrosion magnitude on the W-film surface during CMP increased significantly with scavenger concentration. By adding a scavenger to the CMP slurry, the radical amount reduction via Fenton-reaction suppression in the CMP slurry and the corrosion enhancement on the W-film surface during CMP performed that the W-film surface polishing rate decreased linearly and notably with increasing scavenger concentration via a chemical-dominant CMP mechanism. Otherwise, the SiO2-film surface polishing rate peaked at a specific scavenger concentration via a chemical and mechanical-dominant CMP mechanism. The addition of a corrosion inhibitor with a protonate-amine functional group to the W-film surface CMP slurry completely suppressed the corrosion generation on the W-film surface during CMP without a decrease in the W- and SiO2-film surface polishing rate.

A Strategy to Mitigate Single Event Upset in 14 nm CMOS Bulk FinFET Technology

3D TCAD simulations demonstrated that reducing the distance between the well boundary and NMOS or PMOS can mitigate the cross section of Single Event Upset (SEU) in 14 nm CMOS bulk FinFET technology. The competition of charge collection between well boundary and sensitive nodes, the enhanced restore currents and the change of bipolar effect are responsible for the decrease of SEU cross section. Different from Dual-interlock cells (DICE) design, under the presence of enough taps to ensure the rapid recovery of well potential, this approach is more effective under heavy ion irradiation of higher LET. Besides, the feasibility of this method and its effectiveness with feature size scaling down are discussed.

Shearing Characteristics of Cu-Cu Joints Fabricated by Two-Step Process Using Highly -Oriented Nanotwinned Cu

Cu-Cu bonding has the potential to break through the extreme boundary of scaling down chips’ I/Os into the sub-micrometer scale. In this study, we investigated the effect of 2-step bonding on the shear strength and electrical resistance of Cu-Cu microbumps using highly <111>-oriented nanotwinned Cu (nt-Cu). Alignment and bonding were achieved at 10 s in the first step, and a post-annealing process was further conducted to enhance its bonding strength. Results show that bonding strength was enhanced by 2–3 times after a post-annealing step. We found 50% of ductile fractures among 4548 post-annealed microbumps in one chip, while the rate was less than 20% for the as-bonded counterparts. During the post-annealing, interfacial grain growth and recrystallization occurred, and the bonding interface was eliminated. Ductile fracture in the form of zig-zag grain boundary was found at the original bonding interface, thus resulting in an increase in bonding strength of the microbumps.

CAN GOVERNMENT FUNDING REVIVE ZOMBIE ENTERPRISES? EVIDENCE FROM LISTED CHINESE MANUFACTURING ENTERPRISES

This study tests how different types of government funding affect the recovery of zombie enterprises in the manufacturing sector of China. The results show that funding for production and innovation can revive zombie enterprises in expanding industries, while funding for interest cannot. Furthermore, funding for production and innovation can share costs, increase investment in selling or innovation, and promote the scaling down of businesses through external governance effects, helping zombie enterprises to recover. Finally, none of the funding types can revive zombie enterprises in contracting industries; these can recover only through access to larger overseas markets.

Continuous-Flow Synthesis of Perovskite Particles for Optical Application

Conventional chemical synthesis methods for nanomaterials fabrication do not always provide precise reproducible synthesis with controllable physicochemical parameters. A better control over the resultant properties of nanomaterials can be achieved by scaling down the synthesis approach to the microlevel. This can be realized by means of microfluidics. In this work, a microfluidic approach is applied for the controllable synthesis of perovskite particles with defined cubic morphology. The structural characterization of perovskite particles is performed using scanning electron microscopy and X-ray diffraction. All the synthesized particles demonstrate photoluminescence.

Performance And Reliability Improvement In Intercalated MLGNR Interconnects Using Optimized Aspect Ratio

In this work, aspect ratio of various intercalation doped MLGNR interconnects are optimized using a numerical approach toachieve improved performance and reliability. A numerical optimization method is presented to estimate optimized aspect ratio considering combined effects of performance, noise and reliability metrics for any arbitrary nano interconnect system. This approach is cost effective and will be extremely useful to industry for selection of aspect ratio of interconnects as it is a non-SPICE method and reduces fabrication iterations for achieving desired performance and reliability. Our numerical method suggests that by minimizing the figure of merit (i.e. Noise Delay Power Product (NPDP) / Breakdown Power PBD ratio), aspect ratio of FeCl3 doped MLGNR interconnect is optimized at 0.987, 0.61 and 0.579 for local, intermediate and global level, respectively at 7 nm node. Comparing the optimized performance metrics in this work with the estimated metrics at prescribed aspect ratio by IRDS roadmap, delay, noise delay product (NDP), power delay product (PDP), PDP/PBD ratio and figure of meritare improved by (∼2% and ∼25%), (∼44% and ∼50%), (∼9% and ∼48%), (∼6% and ∼48%) and (∼49% and ∼68%) for 10 µm and 1 mm long FeCl3 doped MLGNR interconnect, respectively at 7 nm node. Increase in contact resistance leads to significant decrease in performance and increase in optimized aspect ratio of local FeCl3 doped MLGNR interconnect. Scaling down from 10 nm to 7 nm node results in increase of optimized aspect ratio in all levels of interconnects. Even though theperformance of MLGNR degrades with scaling down but when compared to copper, the performance improves with technology scaling. Finally, this study provides circuit designers a detailed guideline for selecting an optimized aspect ratio for achieving better performance, power efficiency and reliability in doped MLGNR interconnects.

Spectral matching RotD100 target spectra: Effect on records characteristics and seismic response

This article investigates three different approaches to generate seismic input compatible with RotD100 design spectra: (1) separately matching each horizontal component to the target spectrum, (2) separately matching and then scaling-down the records to improve the match and (3) directly pursuing the match of RotD100 by simultaneously modifying both horizontal components. We examine the strong motion characteristics of the resulting records individually and their variability as suites of input records. The records generated, along with a set of amplitude-scaled records, are used as input for bi-directional non-linear response history analyses of idealized single column reinforced concrete bridge piers with different geometric and reinforcement characteristics. It is shown that the records generated pursuing a direct match of the target spectrum attain the closest match, retain better the strong motion characteristics of the seed records and their horizontal components exhibit a spectral variability comparable to suites of amplitude-scaled records. Regarding the effect on seismic response, the suites constructed separately matching each component consistently imposed larger peak inelastic and total energy demands than all other suites. Directly pursuing the match of RotD100 generated responses close but consistently below the expected from amplitude-scaled suites. The best results were obtained using the direct match methodology but using as target 110% the RotD100 spectrum as required in ASCE 7-16.

A Bidirectional Switch in the Shank3 Phosphorylation State Biases Synapses toward Up or Down Scaling

Homeostatic synaptic plasticity requires widespread remodeling of synaptic signaling and scaffolding networks, but the role of posttranslational modifications in this process has not been systematically studied. Using deepscale, quantitative analysis of the phosphoproteome in mouse neocortical neurons, we found wide-spread and temporally complex changes during synaptic scaling up and down. We observed 424 bidirectionally modulated phosphosites that were strongly enriched for synapse-associated proteins, including S1539 in the ASD-associated synaptic scaffold protein Shank3. Using a parallel proteomic analysis performed on Shank3 isolated from rat neocortical neurons by immunoaffinity, we identified two sites that were hypo-phosphorylated during scaling up and hyper-phosphorylated during scaling down: one (rat S1615) that corresponded to S1539 in mouse, and a second highly conserved site, rat S1586. The phosphorylation status of these sites modified the synaptic localization of Shank3 during scaling protocols, and dephosphorylation of these sites via PP2A activity was essential for the maintenance of synaptic scaling up. Finally, phosphomimetic mutations at these sites prevented scaling up but not down, while phosphodeficient mutations prevented scaling down but not up. Thus, an activity-dependent switch between hypo- and hyperphosphorylation at S1586/ S1615 of Shank3 enables scaling up or down, respectively. Collectively our data show that activity-dependent phosphoproteome dynamics are important for the functional reconfiguration of synaptic scaffolds, and can bias synapses toward upward or downward homeostatic plasticity.