Animal Safety Test of Bacillus thuringiensis BT Protein

[Objectives]To determine the biological safety of BT protein from Bacillus thuringiensis(Bt)fermentation broth to mammals at high doses.[Methods]Healthy mice were randomly divided into 4 groups with 10 mice in each group.The experimental groups were fed with Bt fermentation supernatant at 0.2,0.6 and 1.0 mL/kg,respectively,once a day for 7 consecutive days.The blank control group was fed normally without intragastric administration.[Results]There was no significant difference in blood routine and blood biochemical analysis between the experimental group and the control group.After intragastric administration,the mice were dissected,and no obvious pathological changes were found;the heart,liver,spleen,lung and kidney were taken to make tissue sections,and no pathological changes were found by microscopic observation.[Conclusions]Mice can tolerate high doses of BT protein from B.thuringiensis fermentation broth.

An insight on the mechanism of efficient leaching of vanadium from vanadium shale induced by microwave-generated hot spots

Microwave heating can rapidly and uniformly raise the temperature and accelerate the reaction rate.In this paper,microwave heating was used to improve the acid leaching,and the mechanism was investigated via microscopic morphology analysis and numerical simulation by COMSOL Multiphysics software.The effects of the microwave power,leaching temperature,CaF_(2) dosage,H_(2)SO_(4) concentration,and leaching time on the vanadium recovery were investigated.A vanadium recovery of 80.66%is obtained at a microwave power of 550 W,leaching temperature of 95℃,CaF_(2) dosage of 5wt%,H_(2)SO_(4) concentration of 20vol%,and leaching time of 2.5 h.Compared with conventional leaching technology,the vanadium recovery increases by 6.18%,and the leaching time shortens by 79.17%.More obvious pulverization of shale particles and delamination of mica minerals happen in the microwave-assisted leaching process.Numerical simulation results show that the temperature of vanadium shales increases with an increase in electric field(E-field).The distributions of E-field and temperature among vanadium shale particles are relatively uniform,except for the higher content at the contact position of the particles.The analysis results of scaleup experiments and leaching experiments indicate high-temperature hot spots in the process of microwave-assisted leaching,and the local high temperature destroys the mineral structure and accelerates the reaction rate.

Supercapacitive properties of MnNiS_(x)@Ti_(3)C_(2)T_(x) MXene positive electrode assisted by functionalized ionic liquid

MnNiS_(x)@Ti_(3)C_(2)T_(x)as the positive electrode of supercapacitor was successfully prepared by hydrothermal method with the assistance of amino-functionalized ionic liquids.The micromorphological structures of MnNiS_(x)@Ti_(3)C_(2)T_(x)were analyzed using X-ray diffraction,scanning electron microscope,X-ray photoelectron spectroscopy,transmission electron microscope,and energy dispersive spectrometer to reveal the synergistic effect between MnNiSxand Ti_(3)C_(2)T_(x)MXene.MnNiS——x grew into a three-dimensional coral-like structure on the surface and between layers of Ti_(3)C_(2)T_(x)nanosheets.This structure alleviated the collapse and stacking of Ti_(3)C_(2)T_(x),increased the specific surface area of Ti_(3)C_(2)T_(x),and promoted the charges transfer on the surface of Ti_(3)C_(2)T_(x).The electrochemical performances of MnNiS_(x)@Ti_(3)C_(2)T_(x)positive electrode,such as cyclic voltammetry,galvanostatic charge/discharge,and electrochemical impedance spectroscopy,were investigated.The synergistic effect between MnNiSxand Ti_(3)C_(2)T_(x)MXene improved the specific capacitance and the capacitance retention of the MnNiS_(x)@Ti_(3)C_(2)T_(x)electrode.An asymmetric solid-state supercapacitor(ASC)assembled using MnNiS_(x)@Ti_(3)C_(2)T_(x)as cathode material had the power density of 816.34 W·kg^(-1),and the energy density of 35.11 Wh·kg^(-1).The capacitance retention of ASC reached 98% after 5000 cycles at a current density of 5 A·g^(-1).

不同转移部位的非小细胞肺癌患者的生存时间比较

背景与目的肺癌是全球范围内发病率和死亡率最高的恶性肿瘤,导致其高病死率的主要原因是局部复发和远处转移,而转移部位对患者的预后有一定预测作用,本研究旨在比较不同远处转移部位的非小细胞肺癌(non-small cell lung cancer, NSCLC)患者的生存时间。方法从美国监测、流行病学和最终结果(Surveillance, Epidemiology, and End Result, SEER)数据库中提取出2010年-2014年间确诊的NSCLC患者共117,542例,回顾性分析其远处转移部位与生存时间的关系。结果在确诊的117,542例NSCLC患者中,42,071例(35.8%)患者病史中发生不同程度的远处转移,其中单器官转移26,932例,多器官转移15,139例,分别占转移患者总数的64.0%和36.0%。病史中无转移的患者的中位生存时间是21个月;而在病史中有转移患者中,中位生存时间分别是7个月(肺)、6个月(脑)、5个月(骨)、4个月(肝)、3个月(多器官转移),差异显著(P<0.001,肝转移与多器官转移除外P=0.650);且绝大多数NSCLC患者(88.4%)最终死于肺癌。结论 NSCLC患者远处转移提示预后差,在单器官转移患者中,肺转移预后最佳,肝转移预后最差;多器官转移患者预后差于单器官转移。

Toward Intelligent Machine Tool

With the development of modern information technology-and particularly of the new generation of artificial intelligence(AI)technology-new opportunities are available for the development of the intelligent machine tool(IMT).Based on the three classical paradigms of intelligent manufacturing as defined by the Chinese Academy of Engineering,the concept,characteristics,and systemic structure of the IMT are presented in this paper.Three stages of machine tool evolution-from the manually operated machine tool(MOMT)to the IMT-are discussed,including the numerical control machine tool(NCMT),the smart machine tool(SMT),and the IMT.Furthermore,the four intelligent control principles of the IMT-namely,autonomous sensing and connection,autonomous learning and modeling,autonomous optimization and decision-making,and autonomous control and execution-are presented in detail.This paper then points out that the essential characteristic of the IMT is to acquire and accumulate knowledge through learning,and presents original key enabling technologies,including the instruction-domain-based analytical approach,theoretical and big-data-based hybrid modeling technology,and the double-code control method.Based on this research,an intelligent numerical control(INC)system and industrial prototypes of IMTs are developed.Three intelligent practices are conducted,demonstrating that the integration of the new generation of AI technology with advanced manufacturing technology is a feasible and convenient way to advance machine tools toward the IMT.

Isomerization of n-pentane catalyzed by amide-AlCl3-based ionic liquid analogs with various additives

The isomerization of n-pentane to generate high-quality blending components for clean gasoline was catalyzed by several amide-AlCl3-based ionic liquid(IL) analogs with various amides as donor molecules. The catalytic performance of these IL analogs was evaluated in a magnetic agitated autoclave operated in batch mode.IL analog based n-methylacetamide(NMA)-AlCl3 with the amide/AlCl3 molar ratio of 0.65 showed excellent performance toward n-pentane isomerization because 0.65 NMA-1.0 AlCl3 had a low viscosity and bidentate coordination structure. The influences of reaction time, reaction temperature, and stirring speed on the catalytic performance were also investigated. Optimal reaction conditions comprised the reaction time of 1 h, the reaction temperature of 40 °C, and the stirring speed of 1500 r·min-1. Under optimal condition, the n-C5 conversion,research octane number(RON) increment, total liquids yield, and isoparaffin yield in isomerized oil were56.80%, 13.51, 89.90 wt%, and 44.32 wt%, respectively. A new mathematical model was constructed to predict the relationships among RON increment, RON increment/n-C5 conversion ratio, and n-C5 conversion. The new model indicated that an appropriate conversion per pass of n-C5 did not exceed 50%–55%. Various cycloparaffin additives were used to improve the catalytic performance of 0.65 NMA-1.0 AlCl3. The n-C5 conversion increased from 56.80% to 67.32%. The RON increment, total liquids yield, and isoparaffin yield reached 17.83, 97.36 wt%,and 63.74 wt%, respectively.

Analysis of long term catalytic performance for isobutane alkylation catalyzed by NMA–AlCl3 based ionic liquid analog

Isobutane alkylation with 2-butene to produce high-quality gasoline was catalyzed by Nmethylacetamide(NMA)-AlCl3 based ionic liquid(IL) analog with a NMA/AlCl3 molar ratio of 0.75 and CuCl modification,which was marked as CuCl-modified 0.75 NMA-1.0 AlCl3.The long-term experiment was carried out in the autoclave operated in continuous mode to investigate the distribution of alkylate under different experimental nodes.The result indicated that the long-term alkylation was divided into three stages:rising,stable,and descending regions.C8 selectivity and molar ratio of trimethylpentanes(TMPs) to dimethylhexanes(DMHs) reached the highest level in the stable region,and research octane number(RON) of alkylate was as high as 97.Anionic Al species([AlbCl7]^-,[A1 CuC15]^-) and cationic Al species([AlCl2 L]^+) from IL analog as two active Lewis acidic species played a catalytic role in the long-term alkylation,whereas the neutral Al species did not participate into the alkylation.Moreover,the structure of CuCl-modified 0.75 NMA-1.0 AlCl3 was destroyed after the deactivation,and CuCl was enriched in the CD2 Cl2-insoluble substance,resulting in a decreasing TMP/DMH ratio.The catalytic lifetime of IL analog was similar with CuCl-modified 0.55 Et3 NHCl-1.0 AlCl3 IL,but IL analog had a lower cost.

Corrosion inhibiting performance and mechanism of protic ionic liquids as green brass inhibitors in nitric acid

Four protic ionic liquids(ILs)were synthesized via a one-step method by using benzotriazole(BTA)and benzimidazole as cations,and benzenesulfonic acid and 2-naphthalenesulfonic acid(NSA)as anions.These ILs were used as green corrosion inhibitors for brass specimens in a nitric acid solution.The structure of the protic ILs was characterized by 1H-NMR,13C-NMR,and FT-IR spectroscopy.The effects of the IL structure,IL concentration,acid concentration,and corrosion time on the surface morphology of brass specimens and the inhibition efficiency(η%)of ILs were investigated by the weight loss method combined with SEM and EDS spectroscopy.Polarization curves and impedance spectroscopy were used to analyze the electrochemical corrosion inhibition mechanism of ILs.Results showed that IL synthesis was a proton transfer process,and the proton of the–SO3H group on NSA was deprived by BTA.IL[BTA][NSA],which had a high charge density and large conjugateπband,was the most effective inhibitor for brass corrosion.Theη%of[BTA][NSA]decreased with the increase in acid concentration and corrosion time,which showed an increment with the increase in[BTA][NSA]concentration.The higher theη%of[BTA][NSA]is,the smoother the surface of the brass specimens is,and the smaller the undistributed area of Cu element will be.Corrosion inhibiting mechanism from electrochemical analysis indicated that the addition of[BTA][NSA]increased the polarization resistance of the brass electrode significantly and suppressed both anodic and cathodic reactions.

Physicochemical properties of amide–AlCl_3 based ionic liquid analogues and their mixtures with copper salt

The physicochemical properties of three different amide–AlCl_3 based ionic liquid(IL) analogues and their mixtures with copper salt, such as conductivity, viscosity, density and isobutane solubility were determined over a wide range of temperatures.The effects of amide structure, amide/AlCl_3 molar ratio and CuCl modification on these physicochemical properties were investigated.Results showed that the conductivity of amide–AlCl_3 based IL analogues was much lower than that of traditional Et_3NHCl–AlCl_3 IL with same ligand/AlCl_3 molar ratio due to incomplete splitting of AlCl_3, whereas the density and viscosity of amide–AlCl_3 based IL analogues were slightly higher.The viscosity of amide–AlCl_3 based IL analogues was closely related to the amide structure,and followed the order of DMA–AlCl_3>AA–AlCl_3>NMA–AlCl_3 with same amide/AlCl_3 molar ratio.Meanwhile,the density of amide–AlCl_3 based IL analogues ranked in the following order: AA–AlCl_3>NMA–AlCl_3>DMA–AlCl_3.Increasing the amide/AlCl_3 molar ratio decreased the conductivity and density, while increased the viscosity.The solubility experiment indicated that the isobutane solubility in NMA–AlCl_3 was highest than that in two other IL analogues.Under the modification of CuCl, the conductivity, viscosity and density of these IL analogues increased, whereas the isobutane solubility decreased.These results provide the foundation for the development of a suitable IL analogue catalyst for isobutane alkylation.

Early Ordovician-Middle Silurian Subduction-Closure of the Proto-Tethys Ocean:Evidence from the Qiaerlong Pluton at the Northwestern Margin of the West Kunlun Orogenic Belt,NW China

Early Paleozoic magmatism in the West Kunlun Orogenic Belt(WKOB)preserves important information about the tectonic evolution of the Proto-Tethys Ocean.This paper reports whole-rock compositions,zircon and apatite U-Pb dating,and zircon Hf isotopes for the Qiaerlong Pluton(QEL)at the northwestern margin of WKOB,with the aim of elucidating the petrogenesis of the pluton and shedding insights into the subduction-collision process of this oceanic slab.The QEL is mainly composed of Ordovician quartz monzodiorite(479±3 Ma),quartz monzonite(467–472 Ma),and syenogranite(463±4 Ma),and is intruded by Middle Silurian peraluminous granite(429±20 Ma)and diabase(421±4 Ma).Zirconε_(Hf)(t)values reveal that quartz monzodiorites(+2.1 to+9.9)and quartz monzonites(+0.6 to+6.8)were derived from a mixed source of juvenile crust and older lower crust,and syenogranites(−5.6 to+4.5)and peraluminous granites(−2.9 to+2.0)were generated from a mixed source of lower crust and upper crust;diabases had zirconε_(Hf)(t)values ranging from−0.3 to+4.1,and contained 463±5 Ma captured zircon and 1048±39 Ma inherited zircon,indicating they originated from enriched lithospheric mantle and were contaminated by crustal materials.The Ordovician granitoids are enriched in LILEs and light rare-earth elements,and depleted in HFSEs with negative Nb,Ta,P,and Ti anomalies,suggesting that they formed in a subduction environment.Middle Silurian peraluminous granites have the characteristics of leucogranites with high SiO_(2)contents(74.92 wt.%–75.88 wt.%)and distinctly negative Eu anomalies(δEu=0.03–0.14),indicating that they belong to highly fractionated granite and were formed in a post-collision extension setting.Comparative analysis of these results with other Early Paleozoic magmas reveals that the Proto-Tethys ocean closed before the Middle Silurian and its southward subduction resulted in the formation of QEL.

Efficient cutting path planning for a non-spherical tool based on an iso-scallop height distance field

Iso-scallop height machining means,when machining a freeform surface,the scallop height between any two neighboring tool paths on the surface will be a constant(i.e.,the given threshold),which is preferable among various freeform surface machining strategies due to its high machining efficiency as well as better machine tool’s dynamics.However,all the existing iso-scallop height path planning methods pertain to only the ball-end or flat-end types of tools.In recent years,the non-spherical cutting tool has become more and more popular,especially for five-axis machining of complex freeform surfaces,majorly owing to its non-constant curvature which can be utilized to adaptively fit the tool to the surface to both avoid the local gouging and enlarge the cutting width.However,there have been no reported works on iso-scallop height five-axis tool path generation for a non-spherical tool,and,in this paper,we present one.Specifically,we first define and construct two fields on the surface to be machined-the collision-free tool orientation field(vector)and the iso-scallop height distance field(scalar).The iso-lines of the scalar field and their associated tool orientation field vectors then naturally serve as potential iso-scallop height five-axis tool paths,and we present a propagation-based algorithm to construct the desired tool path from the iso-lines.The computer simulation and physical cutting experiments confirm that everywhere on the surface,except maybe near the saddle curves of the scalar filed,the scallop height is exactly the given thresh-old.By adding the saddle curves as extra tool paths,the final machined surface then is assured of the required scallop height requirement.

High synchronization absolute distance measurement using a heterodyne and superheterodyne combined interferometer

We propose an absolute distance measurement method that employs heterodyne and superheterodyne combined interferometers to achieve synchronous detection and demodulation of multiwavelengths.Coarse and fine synthetic wavelengths are generated by a dual-longitudinal-mode He-Ne laser and four acoustic optical frequency shifters.Further,to improve phase synchronization measurement for multiwavelengths,we analyze the demodulation characteristics of coarse and fine measurement signals and adopt a demodulation method suitable for both signals.Experimental results demonstrate that the proposed method can achieve high-precision synchronous demodulation of multiwavelengths,and standard deviation is 1.7×10^(-5)m in a range of 2 m.

Design of a high frequency accuracy heterodyne laser source working in a wide temperature range

To ensure the frequency accuracy of a heterodyne laser source in the ambient temperature range of-20℃ to 40℃, a duallongitudinal-mode thermally stabilized He–Ne laser based on non-equilibrium power locking was designed. The ambient adaptive preheating temperature setting scheme ensured the laser could operate normally in the range of-20℃ to40℃. The non-equilibrium power-locked frequency stabilization scheme compensated for the frequency drift caused by different stabilization temperatures. The experimental results indicated that the frequency accuracy of the laser designed in this study could reach 5.2 × 10^(-9)in the range of-20℃ to 40℃.

High-speed PGC demodulation model and method with subnanometer displacement resolution in a fiber-optic micro-probe laser interferometer

As the key of embedded displacement measurement,a fiber-optic micro-probe laser interferometer(FMI)is of great interest in developing high-end equipment as well as precision metrology.However,conventional phasegenerated carrier(PGC)approaches are for low-speed scenes and local error analysis,usually neglecting the global precision analysis and dynamic effect of system parameters under high-speed measurement,thus hindering their broad applications.We present a high-speed PGC demodulation model and method to achieve subnanometer displacement measurement precision in FMI.This model includes a global equivalent resolution analysis and revelation of the demodulation error mechanism.Utilizing this model,the failure issues regarding the PGC demodulation method under high speed and large range are addressed.Furthermore,an ultra-precision PGC demodulation algorithm based on the combination of static and dynamic delay adaptive regulation is proposed to enable high-speed and large-range displacement measurement.In this paper,the proposed model and algorithm are validated through simulation and experimental tests.The results demonstrate a displacement resolution of 0.1 nm with a standard deviation of less than 0.5 nm when measuring at a high velocity of 1.5 m/s—nearly a tenfold increase of the latest study.

Enhanced electrochemical performance of CoNiS_(x)@Ti_(3)C_(2)T_(x)electrode material through in-situ doping of cobalt element

The composite electrode of CoNiS_(x)and Ti_(3)C_(2)T_(x)MXene was successfully prepared using a onestep hydrothermal method under the in-situ doping of the cobalt element.The effects of in-situ doping of the cobalt element on the micromorphology and electrochemical performance of the electrodes were investigated.After insitu doping of the cobalt element,NiS with a needle-like structure was converted into a CoNiS_(x)with petal-like structure.The petal-like CoNiS_(x)with a rough surface was very dense and evenly wrapped on the surface and interlamination of Ti_(3)C_(2)T_(x),which helped increase the specific surface area and pore volume of the electrode.Under the identical test conditions,CoNiS_(x)@Ti_(3)C_(2)T_(x)had a higher specific capacitance and capacitance retention than NiS@Ti_(3)C_(2)T_(x).This result indicated that the in-situ doping of the cobalt element promoted the electrochemical performance of the electrode.The energy density of the CoNiS_(x)@Ti_(3)C_(2)T_(x)/nickel foam(NF)//activated carbon(AC)/NF asymmetric supercapacitor device was 59.20 Wh·kg^(–1)at a power density of 826.73 W·kg^(–1),which was much higher than that of NiS@Ti_(3)C_(2)T_(x)/NF//AC/NF.Three CoNiS_(x)@Ti_(3)C_(2)T_(x)/NF//AC/NF in series were able to illuminate the light emitting diode lamp for about 10 min,which was higher than the 5 min of three NiS@Ti_(3)C_(2)T_(x)/NF//AC/NF in series under the same condition.The CoNiS_(x)@Ti_(3)C_(2)T_(x)/NF//AC/NF with high energy density had better application potential in energy storage than the NiS@Ti_(3)C_(2)T_(x)/NF//AC/NF.

Real-time suppression of random phase drift for laser ranging with high-frequency intermode beats

Laser ranging with frequency comb intermode beats[IMBs]has been suffering from random phase drifts[RPDs]for two decades.In this study,we reveal the influence of signal transmission path on the RPDs and propose a real-time suppression method using two IMBs of similar frequencies from different combs.As the two IMBs obtain similar RPDs during their transmission through same signal paths,the RPD of the original probing signal IMB is suppressed by deducting the RPD of the newly added local IMB in real time.In our experiments,a real-time suppression of RPDs is achieved using IMBs of 1001 and 1000 MHz.For the sampling time of 100 s,the effect of 19-fold suppression has been achieved.The proposed method provides a new solution for the long-standing phase drift problem in laser ranging with comb IMBs.

Large-range displacement measurement in narrow space scenarios:fiber microprobe sensor with subnanometer accuracy

The embedded ultra-precision displacement measurement is of great interest in developing high-end equipment as well as precision metrology.However,conventional interferometers only focus on measurement accuracy neglecting the sensor volume and requirement of embedded measurement,thus hindering their broad applications.Here we present a new sensing method for realizing large-range displacement measurement in narrow space scenarios based on the combination of a fiber microprobe interference-sensing model and precision phase-generated carrier.This is achieved by microprobe tilted-axis Gaussian optical field diffraction and high-order carrier demodulation to realize large-range displacement sensing.It is uncovered that the microprobe element misalignment and phase demodulation means play pivotal roles in the interference signal and the accuracy of large-range displacement sensing.The analysis shows that the proposed interference-sensing method can effectively reduce the nonlinearities.Experimental results illustrate that the measurement range extends from 0 to 700 mm.Furthermore,the maximum nonlinear error is reduced from tens of nanometers to 0.82 nm over the full range,allowing subnanometer accuracy for embedded measurements in the hundreds of millimeters range.

高端精密装备精度测量基础理论与方法

完整而精确的测量信息获取是装备设计优化、制造过程调控和服役状态保持的基础,是实现重大装备“上水平”“高性能”的内在要素。本文分析了我国高端精密装备精度测量基础理论发展所面临的重大需求挑战,总结了当前高端精密装备制造精度测量理论、方法与技术领域的主要进展,凝炼了该领域未来5~10年的重大关键科学问题,探讨了前沿研究方向和科学基金资助战略。

Optimal interface surface determination for multi-axis freeform surface machining with both roughing and finishing

In the current practice of multi-axis machining of freeform surfaces, the interface surface between the roughing and finishing process is simply an offset surface of the nominal surface. While there have already been attempts at minimizing the machining time by considering the kinematic capacities of the machine tool and/or the physical constraints such as the cutting force, they all target independently at either the finishing or the roughing process alone and are based on the simple premise of an offset interface surface. Conceivably, since the total machining time should count that of both roughing and finishing process and both of them crucially depend on the interface surface, it is natural to ask if, under the same kinematic capacities and the same physical constraints, there is a nontrivial interface surface whose corresponding total machining time will be the minimum among all the possible（infinite） choices of interface surfaces, and this is the motivation behind the work of this paper. Specifically, with respect to the specific type of iso-planar milling for both roughing and finishing, we present a practical algorithm for determining such an optimal interface surface for an arbitrary freeform surface. While the algorithm is proposed for iso-planar milling, it can be easily adapted to other types of milling strategy such as contour milling. Both computer simulation and physical cutting experiments of the proposed method have convincingly demonstrated its advantages over the traditional simple offset method.

Unsupervised Plot-Scale LAI Phenotyping via UAV-Based Imaging, Modelling, and Machine Learning

High-throughput phenotyping has become the frontier to accelerate breeding through linking genetics to crop growth estimation,which requires accurate estimation of leaf area index(LAI).This study developed a hybrid method to train the random forest regression(RFR)models with synthetic datasets generated by a radiative transfer model to estimate LAI from UAV-based multispectral images.