Nano-microcrystals revealed on Tang dynasty gilded bronze using advanced TEM-SEM and synchrotron methods.

Over the years, numerous gold and silver artifacts have been excavated from the tombs of the Tang dynasty, which give evidence of the sophisticated metalworking techniques at that time. Few of the artifacts were thoroughly studied and their manufacturing processes were barely known. The present investigation concerns a metal headgear from a newly excavated tomb of a female in Xi'an of the Tang dynasty (618-907 A.D.), using advanced techniques in a complementary way, especially performing a detailed analysis of the corrosion products and alloying processes. The combined state-of-the-art methods and instrumentation used for the corrosion study included spectroscopy, diffraction, electron microscopy, synchrotron and their versions for specific measurements and sample preparation. The investigated headgear metal consists of a copper-based core, which is gilded by a thin gold layer, consisting of an Au-Hg alloy with a thin layer of about 400 nm. The technique used for shaping and hammered embellishments led to the creation of nanosized grains on the side that would eventually be the interior of the headgear. It was gilded using the mercury-amalgamation process, and the liquid diffusion caused the development of intermetallic compounds. This is the first recorded instance of these nano-scale and eutectic phases being observed on objects from an archaeological context. The crystallographic analysis offered valuable insights into the formation of needle-like malachite crystals growing on a layer of cuprite found on the surface of the corroded piece. The results highlight that the artisans utilized advanced methods in the creation of funerary items during the Tang dynasty.

Design of a Bistable Artificial Venus Flytrap Actuated by Low Pressure with Larger Capture Range and Faster Responsiveness.

The rapid closure of the Venus flytrap (Dionaea muscipula) can be completed within 0.1-0.5 s due to the bistability of hyperbolic leaves and the curvature change of midrib. Inspired by its bistable behavior, this paper presents a novel bioinspired pneumatic artificial Venus flytrap (AVFT), which can achieve a larger capture range and faster closure action at low working pressure and low energy consumption. Soft fiber-reinforced bending actuators are inflated to move artificial leaves and artificial midrib fabricated from bistable antisymmetric laminated carbon fiber-reinforced prepreg (CFRP) structures, and then the AVFT is rapidly closed. A two-parameter theoretical model is used to prove the bistability of the selected antisymmetric laminated CFRP structure, and analyze the factors affecting the curvature in the second stable state. Two physical quantities, critical trigger force and tip force, are introduced to associate the artificial leaf/midrib with the soft actuator. A dimension optimization framework for soft actuators is developed to reduce their working pressures. The results show that the closure range of the AVFT is extended to 180°, and the snap time is shortened to 52 ms by introducing the artificial midrib. The potential application of the AVFT for grasping objects is also shown. This research can provide a new paradigm for the study of biomimetic structures.

Building Ohmic Contact Interfaces toward Ultrastable Zn Metal Anodes.

Zn metal holds grand promise as the anodes of aqueous batteries for grid-scale energy storage. However, the rampant zinc dendrite growth and severe surface side reactions significantly impede the commercial implementation. Herein, a universal Zn-metal oxide Ohmic contact interface model is demonstrated for effectively improving Zn plating/stripping reversibility. The high work function difference between Zn and metal oxides enables the building of an interfacial anti-blocking layer for dendrite-free Zn deposition. Moreover, the metal oxide layer can function as a physical barrier to suppress the pernicious side reactions. Consequently, the proof-of-concept CeO2 -modified Zn anode delivers ultrastable durability of over 1300 h at 0.5-5 mA cm-2 and improved Coulombic efficiency, the feasibility of which is also evidenced in MoS2 //Zn full cells. This study enriches the fundamental comprehension of Ohmic contact interfaces on the Zn deposition, which may shed light on the development of other metal battery anodes.

Technological characterization of gold jewellery from the Sogdian tomb of Shi Jun (d. 579 CE) in Xi'an, Shaanxi Province.

Northern dynasties (386-581 CE) of China witnessed extensive cultural contacts with the outside world. Several gold objects of this period indicate multiple culture influences. However, very few of them were testified by metallurgic analysis. The gold jewellery including a finger ring and an earring with exotic features were uncovered from the joint elite Sogdian tomb of Shi Jun and his wife of the Northern Zhou dynasty (557-581 CE) in Xi'an. The current study applied multiple non-destructive analyses to investigate the decorative techniques and materials of the two objects. The results showed that both ornaments were made of refined gold. Autogenous welding and brazing were employed for joining the granules of the earring, indicating different technical choices. More interestingly, niello made of silver sulfide was identified as an innovative technology to decorate the finger ring, presenting the earliest evidence of niello inlay in ancient China. It is noteworthy that powders of silver and sulfur were applied separately, deferring from the traditional method of silver sulfide being synthesised prior to being used. These findings help us gain insights into understanding the technical features of early Medieval gold jewellery, as well as the goldsmith's methods and intentions.

Mechanistic investigation of silver vanadate as superior cathode for high rate and durable zinc-ion batteries.

Rechargeable aqueous Zn-ion batteries have shown considerable potential for stationary grid-scale energy storage systems owing to their characteristics of low cost and non-pollution. Nevertheless, the development of high-performance cathode materials is still a formidable challenge. In this work, for the first time, we report a superior silver vanadate (ß-AgVO3) cathode for Zn-ion batteries, and demonstrate the fundamental Zn2+ storage mechanism in detail. In sharp contrast to the previously-reported layered vandium-based materials, the ß-AgVO3 cathode experiences an initial phase transition to form a layered Zn3V2O7(OH)2·2H2O through a displacement/reduction reaction of Zn2+/Ag+ in the first discharge process. The in situ generated Ag0 along with the residual Ag+ and structural water within the framework afford high electronic/ionic conductivity, thus enabling enhanced Zn2+ intercalation/deintercalation kinetics in the layered phase. As a consequence, the cathode can deliver remarkable rate performance (103 mAh g-1 at 5000 mA g-1) and long-term cycling stability (95 mAh g-1 after 1000 cycles at 2000 mA g-1). The present study offers a totally new insight into the exploration of non-layered-structured vandium-based cathodes for high performance Zn-ion batteries.

Study on River Snail Shells Unearthed from Laoniupo Shang Dynasty Site.

The samples of river snail shell pieces, unearthed from Laoniupo Shang dynasty site, were observed and characterized by SEM, Raman and IR to obtain the information about their chemical component and crystal structure. The uneven surface of the cuticle was covered with nanoparticles, which formed rough surface of the shells. The surface of pearl layer was combined with nano-sized flakes and kept smooth on the whole. The insection of shell was composed of three layers: the cuticle (100-120 µm in thickness), the prismatic layer (-130-140 µm in thickness), and the thickest pearl layer (280-300 µm in thickness). All layers had the component of calcium carbonate with aragonite structure and they were different in nanostructures because of different biomineralization processes.

[Transurethral enucleation plus pneumo-cystostomy rotary cut for large benign prostatic hyperplasia].

OBJECTIVE: To investigate the feasibility, effectiveness and practicability of transurethral enucleation plus pneumocystostomy rotary cut (TUE + PCRC) for large benign prostatic hyperplasia (BPH). METHODS: We performed TUE + PCRC for 26 BPH patients aged 62 - 85 years with the prostate volume of 80 - 165 ml. We conducted transurethral enucleation of the hyperplastic prostate glands and pushed them into the bladder, followed by bladder puncture for pneumo-cystostomy rotary cut. RESULTS: All the surgical procedures were successfully accomplished, with the mean surgical time of 41 (32 - 54) minutes and intraoperative blood loss < 60 ml in all the cases. Twenty-three of the patients were followed up for 2 - 8 months, which revealed no stricture of the urethra or any other severe complications. Compared with the preoperative baseline, significant improvement was achieved in the IPSS (6.5 +/- 2.2 vs 26.2 +/- 2.4), QOL (1.4 +/- 0.9 vs 4.6 +/- 1.2) and Qmax ([5.8 +/- 1.0 ] vs [19.6 +/- 2.8] ml/s) of the patients after surgery (P < 0.01). CONCLUSION: TUE + PCRC, with its advantages of short operation time and less severe complications, is a safe and effective approach to the management of large BPH.

[X-ray guided internal urethroplasty with PlasmaKinetic electrodes for urethratresia].

OBJECTIVE: To evaluate endourethral surgery for urethratresia under the X-ray guide. METHODS: We performed transurethral urethroplasty for 11 patients with urethratresia using the PlasmaKinetic electrodes under the guidance of C arm xanthippe. RESULTS: In the 11 cases, operations were all successful, 9 achieved smooth urination and 2 needed regular urethral dilation. CONCLUSION: X-ray guided internal urethroplasty with PlasmaKinetic electrodes is a simple and efficient treatment for urethratresia.