Computation-in-memory (CIM) is a promising candidate to improve the energy efficiency of multiply-and-accumulate (MAC) operations of artificial intelligence (AI) chips. This work presents an static ...random access memory (SRAM) CIM unit-macro using: 1) compact-rule compatible twin-8T (T8T) cells for weighted CIM MAC operations to reduce area overhead and vulnerability to process variation; 2) an even-odd dual-channel (EODC) input mapping scheme to extend input bandwidth; 3) a two's complement weight mapping (C2WM) scheme to enable MAC operations using positive and negative weights within a cell array in order to reduce area overhead and computational latency; and 4) a configurable global-local reference voltage generation (CGLRVG) scheme for kernels of various sizes and bit precision. A 64 × 60 b T8T unit-macro with 1-, 2-, 4-b inputs, 1-, 2-, 5-b weights, and up to 7-b MAC-value (MACV) outputs was fabricated as a test chip using a foundry 55-nm process. The proposed SRAM-CIM unit-macro achieved access times of 5 ns and energy efficiency of 37.5-45.36 TOPS/W under 5-b MACV output.
Abstract
Most chemical vapor deposition methods for transition metal dichalcogenides use an extremely small amount of precursor to render large single-crystal flakes, which usually causes low ...coverage of the materials on the substrate. In this study, a self-capping vapor-liquid-solid reaction is proposed to fabricate large-grain, continuous MoS
2
films. An intermediate liquid phase-Na
2
Mo
2
O
7
is formed through a eutectic reaction of MoO
3
and NaF, followed by being sulfurized into MoS
2
. The as-formed MoS
2
seeds function as a capping layer that reduces the nucleation density and promotes lateral growth. By tuning the driving force of the reaction, large mono/bilayer (1.1 mm/200 μm) flakes or full-coverage films (with a record-high average grain size of 450 μm) can be grown on centimeter-scale substrates. The field-effect transistors fabricated from the full-coverage films show high mobility (33 and 49 cm
2
V
−1
s
−1
for the mono and bilayer regions) and on/off ratio (1 ~ 5 × 10
8
) across a 1.5 cm × 1.5 cm region.
Lead halide perovskites exhibit extraordinary optoelectronic performances and are being considered as a promising medium for high‐quality photonic devices such as single‐mode lasers. However, for ...perovskite‐based single‐mode lasers to become practical, fabrication and integration on a chip via the standard top‐down lithography process are strongly desired. The chief bottleneck to achieving lithography of perovskites lies in their reactivity to chemicals used for lithography as illustrated by issues of instability, surface roughness, and internal defects with the fabricated structures. The realization of lithographic perovskite single‐mode lasers in large areas remains a challenge. In this work, a self‐healing lithographic patterning technique using perovskite CsPbBr3 nanocrystals is demonstrated to realize high‐quality and high‐crystallinity single‐mode laser arrays. The self‐healing process is compatible with the standard lithography process and greatly improves the quality of lithographic laser cavities. A single‐mode microdisk laser array is demonstrated with a low threshold of 3.8 µJ cm−2. Moreover, the control of the lasing wavelength is made possible over a range of up to 6.4 nm by precise fabrication of the laser cavities. This work presents a general and promising strategy for standard top‐down lithography fabrication of high‐quality perovskite devices and enables research on large‐area perovskite‐based integrated optoelectronic circuits.
Large‐area single‐mode laser arrays are achieved through a self‐healing lithographic patterning technique by using CsPbBr3 nanocrystals. The self‐healing process is compatible with the standard lithography and enables the fabrication of high‐quality perovskite cavities with a significantly improved lasing performance. The fabricated single‐mode laser is realized with a low threshold of 3.8 µJ cm−2 and wavelength controllability up to 6.4 nm.
This work presents a novel photo‐electrochemical architecture based on the 3D pyramid‐like graphene/p‐Si Schottky junctions. Overcoming the conventional transfer technique by which only planar ...graphene/Si Schottky junctions are currently available, this work demonstrates the 3D pyramid‐like graphene/p‐Si Schottky junction photocathode, which greatly enhances light harvesting efficiency and exhibits promising photo‐electrochemical performance for hydrogen generation. The formation of 3D pyramid‐like graphene/p‐Si Schottky junctions exhibits enhanced electrochemical activity and promotes charge separation efficiency compared with the bare pyramid Si surface without graphene. The inherent chemical inertness of graphene significantly improves the operational stability of 3D graphene/p‐Si Schottky junction photo‐electrochemical cells. The 3D pyramid‐like graphene/p‐Si Schottky junction photocathode delivers an onset potential of 0.41 V and a saturated photocurrent density of −32.5 mA cm−2 at 0 V (vs RHE) with excellent stability comparable to values reported for textured or nanostructured p‐Si photocathodes coated with ultrathin oxide layers by the conventional atomic layer deposition technique. These results suggest that the formation of graphene/Si Schottky junctions with a 3D architecture is a promising approach to improve the performance and durability of Si‐based photo‐electrochemical systems for water splitting or solar‐to‐fuel conversion.
This work demonstrates a novel 3D pyramid‐like graphene/p‐Si Schottky junction photocathode for H2 production based on the unique advantages of excellent carrier transport, high transparency, and superior corrosion protection of graphene. The formation of graphene/Si Schottky junctions with 3D architecture is a promising approach to improve the performance and durability of Si‐based photo‐electrochemical systems for water splitting or solar‐to‐fuel conversion.
Aims
This study aimed at evaluating the effect of family factors on the occurrence of Internet addiction and determining whether Internet addiction could make any difference in the family function.
...Methods
A total of 2293 adolescents in grade 7 participated in the study. We assessed their Internet addiction, family function, and family factors with a 1‐year follow up.
Results
In the prospective investigation, inter‐parental conflict predicted the incidence of Internet addiction 1 year later in forward regression analysis, followed by not living with mother and allowance to use Internet more than 2 h per day by parents or caregiver. The inter‐parental conflict and allowance to use Internet more than 2 h per day also predicted the incidence in girls. Not cared for by parents and family APGAR score predicted the incidence of Internet addiction among boys. The prospective investigation demonstrated that the incidence group had more decreased scores on family APGAR than did the non‐addiction group in the 1‐year follow‐up. This effect was significant only among girls.
Conclusions
Inter‐parental conflict and inadequate regulation of unessential Internet use predicted risk of Internet addiction, particularly among adolescent girls. Family intervention to prevent inter‐parental conflict and promote family function and Internet regulation were necessary to prevent Internet addiction. Among adolescents with Internet addiction, it is necessary to pay attention to deterioration of family function, particularly among girls.
Convolutional neural network (CNN) offers significant accuracy in image detection. To implement image detection using CNN in the Internet of Things (IoT) devices, a streaming hardware accelerator is ...proposed. The proposed accelerator optimizes the energy efficiency by avoiding unnecessary data movement. With unique filter decomposition technique, the accelerator can support arbitrary convolution window size. In addition, max-pooling function can be computed in parallel with convolution by using separate pooling unit, thus achieving throughput improvement. A prototype accelerator was implemented in TSMC 65-nm technology with a core size of 5 mm 2 . The accelerator can support major CNNs and achieve 152GOPS peak throughput and 434GOPS/W energy efficiency at 350 mW, making it a promising hardware accelerator for intelligent IoT devices.
Recently, interest in aluminium ion batteries with aluminium anodes, graphite cathodes and ionic liquid electrolytes has increased; however, much remains to be done to increase the cathode capacity ...and to understand details of the anion-graphite intercalation mechanism. Here, an aluminium ion battery cell made using pristine natural graphite flakes achieves a specific capacity of ∼110 mAh g
with Coulombic efficiency ∼98%, at a current density of 99 mA g
(0.9 C) with clear discharge voltage plateaus (2.25-2.0 V and 1.9-1.5 V). The cell has a capacity of 60 mAh g
at 6 C, over 6,000 cycles with Coulombic efficiency ∼ 99%. Raman spectroscopy shows two different intercalation processes involving chloroaluminate anions at the two discharging plateaus, while C-Cl bonding on the surface, or edges of natural graphite, is found using X-ray absorption spectroscopy. Finally, theoretical calculations are employed to investigate the intercalation behaviour of choloraluminate anions in the graphite electrode.
Lithium–sulfur batteries are appealing as high‐energy storage systems and hold great application prospects in wearable and portable electronics. However, severe shuttle effects, low sulfur ...conductivity, and especially poor electrode mechanical flexibility restrict sulfur utilization and loading for practical applications. Herein, high‐flux, flexible, electrospun fibrous membranes are developed, which succeed in integrating three functional units (cathode, interlayer, and separator) into an efficient composite. This structure helps to eliminate negative interface effects, and effectively drives synergistic boosts to polysulfide confinement, electron transfer, and lithium‐ion diffusion. It delivers a high initial capacity of 1501 mA h g−1 and a discharge capacity of 933 mA h g−1 after 400 cycles, with slow capacity attenuation (0.069% per cycle). Even under high sulfur loading (13.2 mg cm−2, electrolyte/sulfur ratio = 6 mL g−1) or in an alternative folded state, this three‐in‐one membrane still exhibits high areal capacity (11.4 mA h cm−2) and exceptional application performance (powering an array of over 30 light‐emitting diodes (LEDs)), highlighting its huge potential in high‐energy flexible devices.
Integrated “three‐in‐one” electrospun fibrous membranes are developed for flexible and high‐loading lithium–sulfur batteries. This structure can eliminate negative interface effects and effectively drives synergistic boosts to polysulfide confinement, electron transfer and Li+ diffusion. As a result, excellent battery performance is achieved even under the high sulfur loading of 13.2 mg cm−2 and an alternative folded state.
Previous SRAM-based computing-in-memory (SRAM-CIM) macros suffer small read margins for high-precision operations, large cell array area overhead, and limited compatibility with many input and weight ...configurations. This work presents a 1-to-8-bit configurable SRAM CIM unit-macro using: 1) a hybrid structure combining 6T-SRAM based in-memory binary product-sum (PS) operations with digital near-memory-computing multibit PS accumulation to increase read accuracy and reduce area overhead; 2) column-based place-value-grouped weight mapping and a serial-bit input (SBIN) mapping scheme to facilitate reconfiguration and increase array efficiency under various input and weight configurations; 3) a self-reference multilevel reader (SRMLR) to reduce read-out energy and achieve a sensing margin 2<inline-formula> <tex-math notation="LaTeX">\times </tex-math></inline-formula> that of the mid-point reference scheme; and 4) an input-aware bitline voltage compensation scheme to ensure successful read operations across various input-weight patterns. A 4-Kb configurable 6T-SRAM CIM unit-macro was fabricated using a 55-nm CMOS process with foundry 6T-SRAM cells. The resulting macro achieved access times of 3.5 ns per cycle (pipeline) and energy efficiency of 0.6-40.2 TOPS/W under binary to 8-b input/8-b weight precision.
Aims: This study aimed to (i) evaluate the association between Internet addiction and harmful alcohol use, and (ii) evaluate the associated personality characteristics of Internet addiction as well ...as harmful alcohol use.
Methods: A total of 2453 college students were invited to complete the Chen Internet Addiction Scale, Behavior Inhibition System and Behavior Approach System Scale(BIS/BAS scale), and the Alcohol Use Disorders Identification Test from May 2005 to May 2006.
Results: The results demonstrated Internet addiction was associated with harmful alcohol use among college students. College students with Internet addiction had higher scores on the BIS and BAS fun‐seeking subscales. However, college students with harmful alcohol use had higher scores on the BAS drive and fun‐seeking subscales, and lower scores on the BIS subscale.
Conclusions: Internet addiction is associated with harmful alcohol use. Furthermore, fun seeking was the shared characteristic of these two problem behaviors and might contribute to the association. However, further studies are necessary to evaluate the underlying mechanisms accounting for the association between Internet addiction and harmful alcohol use.
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