西欧兔“碳循”世界

随着国家“双碳”战略的推进,作为“主角”的二氧化碳(CO_(2))逐渐被人们所关注。然而,大众对CO_(2)循环及碳减排等缺乏系统、深入的理解。本实验开发了一套碳循环实验,包含CO_(2)的性质、产生、转化及捕集,通过光合作用和化学吸收等分别模拟自然界与工业固碳减排过程,实现碳减排、碳中和。通过指示剂变色、喷泉及沉淀等多种形式展示CO_(2)的变化过程。实验原料多取自生活,操作简单;互动方案丰富,趣味性高,生动科普碳循环的化学原理,普及“双碳”知识,让低碳节能理念深入人心。

“双碳”相关实验开发——蛋壳源CaO的制备、表征及其碳捕集性能

碳捕集技术是实现“双碳”目标的重要途径。高温工业源CO_(2)的捕集更宜使用钙基吸收剂。本文立足“双碳”背景,将碳捕集前沿技术融入仪器分析实验课程,开发了蛋壳源CaO的制备、表征及其碳捕集性能的设计性综合实验。选择高钙废弃物鸡蛋壳为原料,采用醋酸处理得到醋酸钙,再经高温煅烧制备了具有较好碳捕集性能的CaO;利用EDTA配位滴定、扫描电子显微镜、X射线衍射、红外光谱、拉曼光谱和热重分析等多种分析手段,测试了CaO的纯度、形貌、结构及其对CO_(2)的捕集性能。本实验采用项目式教学方式,引导学生自行设计实验方案并进行实践和总结,不仅锻炼了学生综合运用专业知识解决实际问题的能力,而且培养了学生的科研素养和团队合作精神。

Efficient and stable PtFe alloy catalyst for electrocatalytic methanol oxidation with high resistance to CO

Direct methanol fuel cells(DMFC) are widely considered to be an ideal green energy conversion device but their widespread applications are limited by the high price of the Pt-based catalysts and the instability in terms of surface CO toxicity in long-term operation.Herein,the PtFe alloy nanoparticles(NPs) with small particle size(~4.12 nm) supported on carbon black catalysts with different Pt/Fe atomic ratios(Pt_(1)Fe_(2)/C,Pt_(3)Fe_(4)/C,Pt_(1)Fe_(1)/C,and Pt_(2)Fe_(1)/C) are successfully prepared for enhanced anti-CO poisoning during methanol oxidation reaction(MOR).The optimal atomic ratio of Pt/Fe for the MOR is 1:2,and the mass activity of Pt_(1)Fe_(2)/C(5.40 A mg_(Pt)^(-1)) is 13.5 times higher than that of conventional commercial Pt/C(Pt/C-JM)(0.40 A mg_(Pt)^(-1)).The introduction of Fe into the Pt lattice forms the PtFe alloy phase,and the electron density of Pt is reduced after forming the PtFe alloy.In-situ Fourier transform infrared results indicate that the addition of oxyphilic metal Fe has reduced the adsorption of reactant molecules on Pt during the MOR.The doping of Fe atoms helps to desorb toxic intermediates and regenerate Pt active sites,promoting the cleavage of C-O bonds with good selectivity of CO_(2)(58.1%).Moreover,the Pt_(1)Fe_(2)/C catalyst exhibits higher CO tolerance,methanol electrooxidation activity,and long-term stability than other Pt_(x)Fe_(y)/C catalysts.

基于智能手机及机器学习技术对食品中多种抗生素的识别

基于铬黑T与铕离子构建了比色和荧光双通道探针(EBT/Eu^(3+)),利用智能手机颜色识别和荧光测试获得四种四环素加入EBT/Eu^(3+)后颜色和荧光信号的变化,结合机器学习中模式识别方法,成功实现了蜂蜜中四种四环素的识别。本实验将探针制备、智能手机颜色获取、荧光测试、机器学习、多种抗生素识别等多个知识点进行创新融合,综合性强。

磁性纳米Fe_(3)O_(4)制备及在酵母RNA提取分析中的应用

磁珠法提取核酸是新冠病毒核酸检测的关键一环。基于此,以安全无毒的酵母RNA为对象,开发了一个涉及多学科化学知识交叉的综合实验,包括Fe_(3)O_(4)纳米磁珠制备与表征、RNA提取方法建立与机制探究、实际样品应用等。本实验既能锻炼学生综合运用化学知识和实验手段解决实际问题的能力,又能引导学生关注公共事件,培养其社会责任感。

Low-cost and efficient visible-light-driven CaMg(CO_3)_2@Ag_2CO_3 microspheres fabricated via an ion exchange route

CaMg(CO3)2microspheres were prepared and used as hard templates to fabricate a series of CaMg(CO3)2@Ag2CO3composite microspheres via a fast and low‐cost ion exchange process.The effects of ion exchange time and temperature on the physicochemical properties and photocatalytic activities of the composite microspheres were studied through photocatalytic degradation of Acid Orange II under xenon lamp irradiation.The obtained samples were analyzed by X‐ray diffraction,scanning electron microscopy,Fourier transform infrared spectroscopy,UV‐vis diffuse reflectance spectroscopy,N2physical adsorption,and photocurrent tests.The CaMg(CO3)2@Ag2CO3sample with the highest activity was obtained with an ion exchange time of4h and temperature of40°C.The degradation rate of Acid Orange II by this sample reached83.3%after15min of light irradiation,and the sample also performed well in phenol degradation.The CaMg(CO3)2@Ag2CO3produced under these ion exchange conditions showed a well‐ordered hierarchical morphology with small particle sizes,which was beneficial to light absorption and the transfer of photoelectrons(e-)and holes(h+)to the catalyst surface.Moreover,the separation of photogenerated carriers over the composites was greatly improved relative to bare CaMg(CO3)2.Despite the very low content of Ag2CO3(2.56%),excellent photocatalytic performance was obtained over the CaMg(CO3)2@Ag2CO3microspheres.

Evolution of Surface Sensible Heat over the Tibetan Plateau Under the Recent Global Warming Hiatus

Based on regular surface meteorological observations and NCEP/DOE reanalysis data, this study investigates the evolution of surface sensible heat（SH） over the central and eastern Tibetan Plateau（CE-TP） under the recent global warming hiatus. The results reveal that the SH over the CE-TP presents a recovery since the slowdown of the global warming. The restored surface wind speed together with increased difference in ground-air temperature contribute to the recovery in SH.During the global warming hiatus, the persistent weakening wind speed is alleviated due to the variation of the meridional temperature gradient. Meanwhile, the ground surface temperature and the difference in ground-air temperature show a significant increasing trend in that period caused by the increased total cloud amount, especially at night. At nighttime, the increased total cloud cover reduces the surface effective radiation via a strengthening of atmospheric counter radiation and subsequently brings about a clear upward trend in ground surface temperature and the difference in ground-air temperature.Cloud–radiation feedback plays a significant role in the evolution of the surface temperature and even SH during the global warming hiatus. Consequently, besides the surface wind speed, the difference in ground-air temperature becomes another significant factor for the variation in SH since the slowdown of global warming, particularly at night.

Micropropagation of Pinus densiflora and the evaluation of nematode resistance of regenerated microshoots in vitro

To accelerate the breeding and selection of Pinus densiflora Siebold and Zucc. resistance to pine wilt disease, a micropropagation system was established and nematode resistance evaluated in vitro. Cotyledon-hypocotyl explants from 28-day-old seedlings were first cultured on Gresshoff and Doy medium supplemented with 4.0 mg L^(-1) 6-benzyladenine and 0.2 mg L^(-1) a-naphthaleneacetic acid(NAA) to stimulate the formation of buds. Induced buds were subsequently subcultured on Gupta and Durzan medium supplemented with 0.1%(w/v)activated charcoal for elongation. Stem sections derived from shoots were used as explants for the further multiplication. Roots were formed from shoots transferred to woody plant medium containing 0.2 mg L^(-1) NAA for4 weeks. The nematode resistance test showed that symptoms in micropropagated shoots after infection with pine wood nematode(PWN) were similar to those in plants infected in the field. The wilting rate varied from 20 to100% among different clones 18 days after inoculation.The most susceptible clone was Clone 6-4 with a 100%wilting rate, while Clone 8-4 showed a relatively high resistance with a 20% wilting rate. The number of nematodes recovered from Clone 8-4 shoots was significantly lower(P = 0.05) than from Clones 5-10 and 16-4. This work contributes to the breeding of PWN resistance in P.densiflora.

Correlation Analysis of Energy Consumption of Agricultural Rotorcraft

With the rapid development of unmanned aerial vehicle technology,unmanned aerial vehicles(UAVs)have been widely used in the field of agricultural plant protection.Compared with fuel-driven UAVs,electrically driven rotorcrafts have many advantages such as lower cost,simpler operation,good maneuverability and cleaner power,which them popular in the plant protection.However,electrical rotorcrafts still face battery problems in actual operation,which limits its working time and application.Aiming at this issue,this paper studied the influence of rotorcraft flight parameters on energy consumption through series of carefully designed flight experiments.First of all,the linear motion experiments have been designed that the rotorcraft was made to perform speed tests and acceleration test with the speed varied from 2∼9 m/s.Secondly,the turning maneuver experiments are carried out under the different circular routes,a rotorcraft was made to conduct successive steering maneuvers at a certain speed of 2 m/s.With the collected tests data,the relation of the energy consumption and the flight dynamic parameter are analyzed through correlation analysis,and the test results of different pairs of experiments have been compared.The research results of this paper would encourage the agricultural rotorcraft to make less maneuvers during operation,which can also provide practical experience and data support for subsequent optimization of flight parameters and reduction of energy consumption.

Binocular Vision Positioning Method for Safety Monitoring of Solitary Elderly

In nowadays society,the safety of the elderly population is becoming a pressing concern,especially for those who live alone.There might be daily risks such as accidental falling or treatment attack on them.Aiming at these problems,indoor positioning could be a critical way to monitor their states.With the rapidly development of the imaging techniques,wearable and portable cameras are very popular,which could be set on human individual.And in view of the advantages of the visual positioning,the authors propose a binocular visual positioning algorithm to real-timely locate the elderly indoor.In this paper,the imaging model has been established with the corrected image data from the binocular camera;then feature extraction has been completed to provide reference to adjacent image matching based on the binary robust independent elementary feature(BRIEF)descriptor,finally the camera movement and the states of the elderly have been estimated to distinguish their falling risk.In the experiments,the real-sense D435i sensors were adopted as the binocular cameras to obtain indoor images,and three experimental scenarios have been carried out to test the proposed method.The results show that the proposed algorithm can effectively locate the elderly indoor and improve the real-time monitoring capability.

Stability Analysis of Transfer Alignment Filter Based on theμTheory

The performance of the transfer alignment has great impact on inertial navigation systems.As the transfer alignment is generally implemented using a filter to compensate the errors,its accuracy,rapidity and anti-disturbance capability are key properties to evaluate the filtering process.In terms of the superiority in dealing with the noise,H∞filtering has been used to improve the anti-disturbance capability of the transfer alignment.However,there is still a need to incorporate system uncertainty due to various dynamic conditions.Based on the structural value theory,a robustness stability analysis method has been proposed for the transfer alignment to evaluate the impact of uncertainty on the navigation system.The mathematical derivation has been elaborated in this paper,and the simulation has been carried out to verify the effectiveness of the algorithm.

Effect of Temperature and Metal Ions on Degradation of Oxytetracycline in Different Matrices

Composting is widely applied in animal manure treatment and reclamation. The degradation of organic pollutants during the composting treatment is attributed to two parallel processes: one is the bioprocess induced by the used microorganisms, and the other is the chemical process. In order to clarify the relative contribution of the chemical process to the compositing, in this paper, oxytetracycline (OTC) was chosen to study the degradation of tetracyclines (TCs) in water and chicken manure. It was observed that the degradation of OTC in water was much faster than that in chicken mature. At 40°C, 95% of OTC in water could be removed in two days, while it took about one month in mature. By increasing the temperature to 50°C, 60°C and 70°C, the required degradation time (with the degradation efficiency more than 95%) was shortened to 22, 13 and 9 days, respectively. This difference was caused by desorption hysteresis and irreversible fixation due to the formation of complexes of OTC with co-existed metal ions in the matrix. It was found that the coexisted Ca2+, Zn2+ and Ni2+ ions decreased the degradation of OTC, whereas Cu2+ ions promoted the degradation of OTC.

Evaluation of somatic embryo production during embryogenic tissue proliferation stage using morphology,maternal genotype,proliferation rate and tissue age of Pinus thunbergii Parl

To determine the optimal embryogenic capacity(somatic embryo production)of the selected elite nematode-resistant genotypes of Pinus thunbergii,variables such as embryogenic tissue(ET)morphology,maternal genotype,proliferation rate and tissue age were analyzed.ET morphology and histological evaluation of the proliferation stage showed a decrease in filamentous clump and protuberant surfaces and a decline in the acetocarmine-staining area,which indicates a decrease in somatic embryo production(SEP).Variations in cell physiology during the prolifera-tion stage showed that SEP was positively correlated with soluble sugars and proteins,but negatively correlated with starch,peroxidase,and superoxidase.In addition,SEP was significantly(p<0.001)affected by maternal genotype,tis-sue age and proliferation rate.Moreover,SEP was positively correlated with proliferation rate(r=0.98,p<0.001),but negatively correlated with tissue age(r=−0.95,p<0.001).In general,the results suggest that SEP could be assessed in ET proliferation stages by the apparent cell morphology,histology,proliferation rate and tissue age,which provides novel insights for evaluating the ET maturation capacity(number of somatic embryos)during the proliferation stage of P.thunbergii somatic embryogenesis.

In operando study of orthorhombic V_(2)O_(5) as positive electrode materials for K-ion batteries

Herein, the electrochemical performance and the mechanism of potassium insertion/deinsertion in orthorhombic V_(2)O_(5) nanoparticles are studied. The V2O5 electrode displays an initial potassiation/depotassiation capacity of 200 mAh g^(−1)/217 mAh g^(−1) in the voltage range 1.5–4.0 V vs. K^(+)/K at C/12 rate, suggesting fast kinetics for potassium insertion/deinsertion. However, the capacity quickly fades during cycling, reaching 54 mAh g^(−1) at the 31st cycle. Afterwards, the capacity slowly increases up to 80 mAh g^(−1) at the 200th cycle. The storage mechanism upon K ions insertion into V2O5 is elucidated. In operando synchrotron diffraction reveals that V_(2)O_(5) first undergoes a solid solution to form K_(0.6)V_(2)O_(5) phase and then, upon further K ions insertion, it reveals coexistence of a solid solution and a two-phase reaction. During K ions deinsertion, the coexistence of solid solution and the two-phase reaction is identified together with an irreversible process. In operando XAS confirms the reduction/oxidation of vanadium during the K insertion/extraction with some irreversible contributions. This is consistent with the results obtained from synchrotron diffraction, ex situ Raman, X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). Moreover, ex situ XPS confirms the “cathode electrolyte interphase” (CEI) formation on the electrode and the decomposition of CEI film during cycling.

A Novel Design of Mechanical Switch for the High Overload Environment

The internal structure of the inertial measurement unit(IMU)in active state is easily damaged in the high overload environment.So that the IMU is usually required to be powered within the disappearance of the high overload.In this paper,a mechanical switch is designed to enable the IMU based on the analysis of the impact of high overload on the power-supply circuit.In which,parameters of mechanical switch are determined through theoretical calculation and data analysis.The innovation of the proposed structure lies in that the mechanical switch is triggered through the high overload process and could provide a delay signal for the circuit.After all,the proposed switch is tested through mechanical simulation,impact test and practical test.The experimental results show that the designed mechanical switch can effectively and reliably provide the delay for the circuit and guarantee operation of the IMU under high overload.

Design of Automatic Batch Calibration and Correction System for IMU

Thanks to its light weight,low power consumption,and low price,the inertial measurement units(IMUs)have been widely used in civil and military applications such as autopilot,robotics,and tactical weapons.The calibration is an essential procedure before the IMU is put in use,which is generally used to estimate the error parameters such as the bias,installation error,scale factor of the IMU.Currently,the manual one-by-one calibration is still the mostly used manner,which is low in efficiency,time-consuming,and easy to introduce mis-operation.Aiming at this issue,this paper designs an automatic batch calibration method for a set of IMUs.The designed automatic calibration master controller can control the turntable and the data acquisition system at the same time.Each data acquisition front-end can complete data acquisition of eight IMUs one time.And various scenarios of experimental tests have been carried out to validate the proposed design,such as the multi-position tests,the rate tests and swaying tests.The results illustrate the reliability of each function module and the feasibility automatic batch calibration.Compared with the traditional calibration method,the proposed design can reduce errors caused by the manual calibration and greatly improve the efficiency of IMU calibration.

The Identification of the Wind Parameters Based on the Interactive Multi-Models

The wind as a natural phenomenon would cause the derivation of the pesticide drops during the operation of agricultural unmanned aerial vehicles(UAV).In particular,the changeable wind makes it difficult for the precision agriculture.For accurate spraying of pesticide,it is necessary to estimate the real-time wind parameters to provide the correction reference for the UAV path.Most estimation algorithms are model based,and as such,serious errors can arise when the models fail to properly fit the physical wind motions.To address this problem,a robust estimation model is proposed in this paper.Considering the diversity of the wind,three elemental time-related Markov models with carefully designed parameterαare adopted in the interacting multiple model(IMM)algorithm,to accomplish the estimation of the wind parameters.Furthermore,the estimation accuracy is dependent as well on the filtering technique.In that regard,the sparse grid quadrature Kalman filter(SGQKF)is employed to comprise the computation load and high filtering accuracy.Finally,the proposed algorithm is ran using simulation tests which results demonstrate its effectiveness and superiority in tracking the wind change.

Molecular cloning and structural analysis of human norepinephrine transporter gene(NETHG)

A cDNA molecule encoding a major part of the hu-man Norepinephrine transporter(hNET) was synthesized by means of Polymerase Chain Reaction(PCR) technique and used as a probe for selecting the human genomic NET gene. A positive clone harbouring the whole gene was ob-tained from a human lymphocyte genomic library through utilizing the "genomic walking" technique. The clone, des-ignated as phNET, harbours a DNA fragment of about 59 kb in length inserted into BamH Ⅰ site in cosmid pWE15.The genomic clone contains 14 exons encoding all amino acid residues in the protein. A single exon encodes a dis-tinct transmembrane domaill, except for transmembrane domain 10 and 11, which are encoded by part of two ex-ons respectively, and exon 12, which encodes part of do-main 11 and all of domain 12. These results imply that there is a close relationship between exon splicing of a gene and structural domains of the protein, as is the case for the human γ-aminobutyric acid transporter(hGAT) and a number of other membrane proteins.

LaBr_(3)(Ce)-CsI(Tl)紧凑式叠层反康伽马探测器研制

本工作研制了一套由圆柱形LaBr_(3)(Ce)主晶体和井形CsI(Tl)次晶体组成的叠层伽马探测器,该探测器主要用于鉴别来自LaBr_(3)(Ce)主晶体的康普顿散射光子并进行反符合测量。两种不同的晶体耦合到同一个光电倍增管上。入射辐射沉积在每一层探测器的能量,可以通过PMT给出的信号脉冲形状差异进行识别。利用Geant4模拟结果,验证了脉冲形状甄别性能和康普顿散射抑制效果。利用^(60)Co伽马源对探测器进行了实验测试,测试结果表明,该探测器本底抑制系数为2.33(1),达到了康普顿本底抑制两倍以上的预期目标。

A Multi-Objective Scheduling and Routing Problem for Home Health Care Services via Brain Storm Optimization

At present,home health care(HHC)has been accepted as an effective method for handling the healthcare problems of the elderly.The HHC scheduling and routing problem(HHCSRP)attracts wide concentration from academia and industrial communities.This work proposes an HHCSRP considering several care centers,where a group of customers(i.e.,patients and the elderly)require being assigned to care centers.Then,various kinds of services are provided by caregivers for customers in different regions.By considering the skill matching,customers’appointment time,and caregivers’workload balancing,this article formulates an optimization model with multiple objectives to achieve minimal service cost and minimal delay cost.To handle it,we then introduce a brain storm optimization method with particular multi-objective search mechanisms(MOBSO)via combining with the features of the investigated HHCSRP.Moreover,we perform experiments to test the effectiveness of the designed method.Via comparing the MOBSO with two excellent optimizers,the results confirm that the developed method has significant superiority in addressing the considered HHCSRP.