Enhancing Learners’Performance in Grade 7 Mathematics Through 50-30-20 Exercise

Assessment exercises constitute a crucial component of the teaching and learning process,serving the purpose of gauging the degree to which learning objectives have been accomplished.This study aims to assess the mathematics performance of Grade 7 learners using the 50-30-20 exercise.Specifically,this study seeks to determine the learners’pre-test and post-test mean scores,identify significant differences between the pre-test and post-test results,evaluate learners’exercises,and propose enhanced exercises.The research employs a quasi-experimental design,with 40 Grade 7 learners in the school year 2023-2024 as participants,selected through purposive non-random sampling.Statistical data analysis involves the use of mean,standard deviation,paired t-test,and Cohen’s D effect size.Ethical considerations were paramount,as evidenced by a letter of authorization from the school head outlining the strict adherence to voluntary participation,informed parental consent,anonymity,confidentiality,risk mitigation,results-sharing protocols,and the commitment to keeping research data confidential.The data yielded a remarkable outcome:the experimental group exhibited improvement in both the pre-test and post-test.This result substantiates the initial objective of the study,showcasing a noteworthy and favorable performance among the participants.Consequently,it suggests that a majority of the participants strongly agree that the 50-30-20 exercises contribute to enhancing their understanding and problem-solving skills,as well as their ability to grasp mathematical concepts and improve their overall performance in mathematics.Therefore,the 50-30-20 exercises not only facilitated students in understanding mathematics lessons but were also aligned with the Department of Education’s development plan.

Fabrication and Performances of 1-3-2 Piezoelectric Ceramic/Polymer Composite

A novel 1-3-2 piezoelectric composite has been developed,which consists of piezoelectric ceramic plate and 1-3 piezoelectric composite.The composite was fabricated by dicing PZT ceramic along mutual perpendicular two directions and then filling epoxy into grooves.The piezoelectric and electromechanical properties of the novel composite were determined. The results show a coefficient d_ (33) of 405pC/N,a vibration displacement of 113.5pm,an acoustic impendence of 13.3 Mraly, a bandwidth of 12kHz and a thickness electromechanical coupling coefficient of 0.56.

Ce&F multifunctional modification improves the electrochemical performance of LiCoO_(2)at 4.60 V

Lithium cobalt oxide(LiCoO_(2))is proverbially employed as cathode materials of lithium-ion batteries attributed to the high theoretical capacity,and currently,it is developing towards higher cut-off voltages in the pursuit of higher energy density.However,it suffers from serious structural degradation and surface side reactions,in particular,at the voltage above 4.60 V,leading to rapid decay of the battery life.Taking into account the desirable oxygen buffering property and the fast ion mobility characteristic of cerium oxide fluoride,in this work,we prepared Ce&F co-modified LiCoO_(2)by using the precursors of Ce(NO_(3))_(3)·6H_(2)O and NH_(4)F,and evaluated the electrochemical performance under voltages exceeding 4.60 V.The results indicated that the modified samples have multiphase heterostructure of surface CeO_(2-x)and unique Ce-O-F solid solution phase.At 3.0–4.60 V and 25℃,the preferred sample LCO-0.5Ce-0.3F has a high initial discharge specific capacity of 221.9 mA h g^(-1)at 0.1 C,with the retention of 80.3%and 89.6%after 300 cycles at 1 and 5 C,comparing with the pristine LCO(56.4%and 22.6%).And at 3.0–4.65 V,its retention is 64.0%after 300 cycles at 1 C,versus 8.5%of the pristine LCO.Through structural characterizations and DFT calculations,it suggests that Ce^(4+)&F^(-)co-doping suppresses the H3 to H1/3 irreversible phase transition,stabilizes the lattice structure,and reduces the redox activity of the lattice oxygen by modulating the Co 3d–O 2p energy band,consequently improving the electrochemical performance of LiCoO_(2)at high voltages.

Long-term and combined effects of N-[2-(nitrooxy)ethyl]-3-pyridinecarboxamide and fumaric acid on methane production,rumen fermentation, and lactation performance in dairy goats

Background:In recent years,nitrooxy compounds have been identified as promising inhibitors of methanogenesis in ruminants.However,when animals receive a nitrooxy compound,a high portion of the spared hydrogen is eructated as gas,which partly offsets the energy savings of CH4mitigation.The objective of the present study was to evaluate the long-term and combined effects of supplementation with N-[2-(nitrooxy)ethyl]-3-pyridinecarboxamide(NPD),a methanogenesis inhibitor,and fumaric acid(FUM),a hydrogen sink,on enteric CH4production,rumen fermentation,bacterial populations,apparent nutrient digestibility,and lactation performance of dairy goats.Results:Twenty-four primiparous dairy goats were used in a randomized complete block design with a 2×2factorial arrangement of treatments:supplementation without or with FUM(32 g/d)or NPD(0.5 g/d).All samples were collected every 3 weeks during a 12-week feeding experiment.Both FUM and NPD supplementation persistently inhibited CH4yield(L/kg DMI,by 18.8%and 18.1%,respectively)without negative influence on DMI or apparent nutrient digestibility.When supplemented in combination,no additive CH4suppression was observed.FUM showed greater responses in increasing the molar proportion of propionate when supplemented with NPD than supplemented alone(by 10.2%vs.4.4%).The rumen microbiota structure in the animals receiving FUM was different from that of the other animals,particularly changed the structure of phylum Firmicutes.Daily milk production and serum total antioxidant capacity were improved by NPD,but the contents of milk fat and protein were decreased,probably due to the bioactivity of absorbed NPD on body metabolism.Conclusions:Supplementing NPD and FUM in combination is a promising way to persistently inhibit CH4emissions with a higher rumen propionate proportion.However,the side effects of this nitrooxy compound on animals and its residues in animal products need further evaluation before it can be used as an animal feed additive.

CATALYTIC PERFORMANCE OF ETHYLENE HYDROFORMYLATION OVER[H_XRu_3(CO)_9(CCO)]^(2-X)/SiO_2-Al_2O_3,SiO_2 AND MgO(X=0-2)CATALYSTS

The various surface species[H_XRu_3(CO)_9(CCO)]^(2-X)(X=0-2)prepared from impregnation of[PPN]_2[Ru_3(CO)_9(CCO)]on SiO_2-Al_2O_3,SiO_2 and MgO show quite different activities and selectivities for oxygenates and ethane in ethylene hydroformylation.

A multidimensional examination of performances of HSR (High-Speed Rail) systems

This paper deals with a multidimensional examination of the infrastructural, technical/technological, operational, economic, social, and environmental performances of high-speed rail （HSR） systems, including their overview, analysis of some real-life cases, and limited （analytical） modeling. The infrastructural performances reflect design and geometrical characteristics of the HSR lines and stations. The technical/technological performances relate to the characteristics of rolling stock, i.e., high-speed trains, and supportive facilities and equipment, i.e., the power supply, signaling, and traffic control and management system（s）. The operational performances include the capacity and productivity of HSR lines and rolling stock, and quality of services. The economic per- formances refer to the HSR systems＇ costs, revenues, and their relationship. The social performances relate to the impacts of HSR systems on the society such as congestion, noise, and safety, and their externalities, and the effects in terms of contribution to the local and global/country social- economic development. Finally, the environmental performances of the HSR systems reflect their energy consumption and related emissions of green house gases, land use, and corresponding externalities.

Microstructural Characteristics and Wear Performance of Plasma Sprayed Al_2O_3-13 wt. % TiO_2 Coating on the Surface of Extrusion Wheel

The conventional Al2O3-13 wt. % TiO2 composite ceramic coatings are fabricated by plasma spraying on the surface of extrusion wheel. The microstrueture, morphology and phase compositions of the substrate and coat- ing are investigated by using X-ray diffractometry （XRD） , scanning electron microsopy （SEM） and energy dis- persive spectroscopy （EDS）. Moreover, the microhardness of the substrate and the coating are investigated using Vickers mierohardness tester, the friction and wear behaviors of the substrate and the coating are investigated by using a block-on-ring tribometer under dry sliding conditions with the load of 245 N. The results show that both γ-Al2O3 and α-Al2O3 phases are observed in the as-sprayed coatings, the mian phase is γ-Al2O3. There are white particulates Al2O3 on its surface. The Al2O3-13 wt. % TiO2 coating possesses higher mierohardness which is about 1018HV and 1.6 times that of the substrate. The wear performance of coating is better than that of the substrate. In a practical application, the life of the extrusion wheel which is plasma sprayed Al2O3-13 wt. % TiO2 coating on the surface is 1.2 times that of the conventional extrusion wheel, and the life is about 330 h.

Preparation and performance of fluorescent polyacrylamide microspheres as a profile control and tracer agent

Polyacrylamide microspheres have been suc- cessfully used to reduce water production in reservoirs, but it is impossible to distinguish polyacrylamide microspheres from polyacrylamide that is used to enhance oil recovery and is already present in production fluids. In order to detect polyacrylamide microspheres in the reservoir pro- duced fluid, fluorescent polyacrylamide microspheres P（AM-BA-AMCO）, which fluoresce under ultraviolet irradiation, were synthesized via an inverse suspension polymerization. In order to keep the particle size distribu- tion in a narrow range, the synthesis conditions of the polymerization were studied, including the stirring speed and the concentrations of initiator, NaaCO3, and dispersant. The bonding characteristics of microspheres were deter- mined by Fourier transform infrared spectroscopy. The surface morphology of these microspheres was observed under ultraviolet irradiation with an inverse fluorescence microscope. A laboratory evaluation test showed that the fluorescent polymer microspheres had good water swelling capability, thus they had the ability to plug and migrate in a sand pack. The plugging rate was 99.8 % and the residual resistance coefficient was 800 after microsphere treatment in the sand pack. Furthermore, the fluorescent microspheres and their fragments were accurately detected under ultra- violet irradiation in the produced fluid, even though theyhad experienced extrusion and deformation in the sand pack.

Robust Optimization of Performance Scheduling Problem under Accepting Strategy

In this paper, the problem of program performance scheduling with accepting strategy is studied. Considering the uncertainty of actual situation, the duration of a program is expressed as a bounded interval. Firstly, we decide which programs are accepted. Secondly, the risk preference coefficient of the decision maker is introduced. Thirdly, the min-max robust optimization model of the uncertain program show scheduling is built to minimize the performance cost and determine the sequence of these programs. Based on the above model, an effective algorithm for the original problem is proposed. The computational experiment shows that the performance’s cost (revenue) will increase (decrease) with decision maker’s risk aversion.

基于超高效液相色谱-质谱分析的代谢组学在小檗碱治疗多囊卵巢综合征研究中的应用

多囊卵巢综合征(polycystic ovary syndrome,PCOS)是妇女最常见的内分泌和代谢紊乱性疾病,合理的药物治疗非常重要。本研究中,超重/肥胖的多囊卵巢综合征患者经过小檗碱治疗3个月,采集治疗前后的血样进行分析,利用超高效液相色谱-质谱联用技术(UHPLC-MS)对治疗前后血清中的内源性物质进行了相对含量测定。正交信号校正的偏最小二乘模式识别分析结果显示治疗前后有明显的区分。多变量分析结合非参数检验找出的与小檗碱治疗相关的差异代谢物均与脂类代谢有关。临床生化数据结合代谢组学数据显示,小檗碱治疗超重/肥胖型的多囊卵巢综合征患者可以增加机体胰岛素敏感性、改善脂类代谢。上述研究结果表明代谢组学是研究中药治疗疾病效果的有效工具之一。

液相色谱-串联质谱法测定水环境中的十氯酮

建立了分析测定水环境中十氯酮的液相色谱-串联质谱法。水样经液液萃取、净化后，采用 Eclipse plus C18柱（100 mm×2.1 mm，3.5μm）分离，乙腈和水为流动相进行梯度洗脱，在电喷雾负离子多反应监测模式下进行检测，同位素内标法定量。结果表明：采用液相色谱-质谱联用技术，证实了十氯酮在甲醇中以半缩醛的形式存在，而在丙酮/乙腈中以偕二醇的形式存在。由于十氯酮极性较强，在净化时难以洗脱，并且不耐酸，所以不能与其他有机氯农药一起分析。十氯酮在5～100μg / L 范围有良好的线性关系，相关系数 r2=0.999，检出限及定量限分别为0.70 ng / L 和2.8 ng / L；在5、40和100 ng / L 3个浓度添加水平的平均回收率为95.1％～98.9％，相对标准偏差为3.85％～4.72％。本方法具有良好的灵敏度、回收率和重现性，适用于水环境中十氯酮的测定。

超高效液相色谱-三重四极杆串联质谱法测定柑橘中4种苯甲酰脲类农药残留

建立了柑橘中虱螨脲、灭幼脲、氟啶脲和除虫脲4种苯甲酰脲类农药同时检测的超高效液相色谱-三重四级杆串联质谱（ UPLC-MS/MS）分析方法。样品采用QuEChERS前处理技术，超高效液相色谱-串联质谱电喷雾负离子模式检测测定。结果表明：在0.01~0.2μg/mL范围内，4种供试农药的质量浓度与其相应的峰面积间呈良好的线性关系，相关系数（ r ）均大于0.994。在0.01、0.05和0.1 mg/kg 3个添加水平下，4种农药的平均回收率为92％~105％，相对标准偏差（RSD）为0.4％~3.3％（n＝5）。4种农药在柑橘中的定量限（LOQ）均为0.01 mg/kg。该方法准确、灵敏、简单，适用于同时测定柑橘中4种苯甲酰脲类农药的残留量。

超高效液相色谱-串联质谱双内标法同时测定复方杏香兔耳风胶囊中的10种有效成分

建立了同时测定复方杏香兔耳风胶囊中原儿茶酸、原儿茶醛、绿原酸、野黄芩苷、异绿原酸 C、黄芩苷、木犀草素、芹菜素、白术内酯 III 和白术内酯 I 等10种有效成分含量的超高效液相色谱-串联质谱（ UPLC-MS / MS）双内标分析方法。以咖啡酸和淫羊藿苷为内标（IS），在 ZORBAX RRHD Eclipse Plus C 18色谱柱上，以甲醇和含0.3％甲酸的水为流动相进行梯度洗脱分离，流速为0.3 mL / min。在电喷雾电离（ESI）正、负离子切换模式下，采用多重反应监测模式进行检测。结果表明，原儿茶酸、原儿茶醛、绿原酸、野黄芩苷、异绿原酸 C、黄芩苷、木犀草素、芹菜素、白术内酯 III、白术内酯 I 的线性范围分别为0.00300～24.0 mg / L、0.0170～2.00 mg / L、0.0150～30.0 mg / L、0.00400～30.0 mg / L、0.0105～24.0 mg / L、0.00300～30.0 mg / L、0.00300～5.00 mg / L、0.00600～5.00 mg / L、0.00150～4.00 mg / L、0.000600～0.900 mg / L；检出限分别为1.0、11、5.0、1.5、3.5、1.0、1.0、2.0、0.50、0.20μg / L。10种成分的加样回收率为92.5％～106％，相对标准偏差均不大于3.2％。该方法快速简便、灵敏度高、重复性好，已成功用于实际样品的分析。

高效液相色谱-串联质谱法测定水产品中甲氧苄啶的残留

建立水产品中甲氧苄啶药物残留量测定的高效液相色谱-串联质谱方法。样品选择乙腈提取，用正己烷脱脂，固相萃取柱净化，采用LC-MS/MS选择反应监测（SRM）正离子模式测定进行定性、定量分析。结果表明：甲氧苄啶药物的检出限（LOD）为0.5μg/kg，定量限（LOQ）为1.0μg/kg，检测结果的相对标准偏差为1.78%-5.08%，加标回收率达到77.1%-93.5%。该方法具有比较高的重现性和选择性，在水产品中甲氧苄啶的残留测定中具有很好的应用前景。

Boosting CO_(2) electroreduction performance over fullerene-modified MOF-545-Co promoted by π –π interaction

Metal-organic frameworks(MOFs) have showed high promise in CO_(2)-electroreduction, yet their generally insufficient conductivity or low electron-transfer efficiency have largely restricted the wide-spread applications. Herein, fullerene molecules(i.e., C60and C70) have been successfully introduced into the pore-channels of a Co-porphyrin based MOF through a facile strategy. Thus-obtained hybrid materials present higher electron-transfer ability, enhanced CO_(2)adsorption-enthalpy and CO_(2)electroreduction activity. Notably, the charge transfer resistance(Rct) of C60@MOF-545-Co is almost 5 times lower of than that of MOF-545-Co, as well as 1.5 times increased for the CO_(2)adsorption enthalpy. As expect, the FECO of C60@MOF-545-Co(97.0%) is largely higher than MOF-545-Co(70.2%), C60@MOF-545(19.4%), C60(11.5%)and physical mixture(70.3%) and presented as one of the best CO_(2)electroreduction catalysts reported in H-cell system. The facile strategy would give rise to new insight into the exploration of powerful MOFbased hybrid materials in high-efficiency CO_(2)electroreduction.

凝胶渗透色谱-高效液相色谱-线性离子阱质谱法测定膳食样品中的氨基甲酸酯类农药残留

建立了高效液相色谱-线性离子阱质谱（ HPLC-LIT-MS）测定膳食样品中氨基甲酸酯类农药的检测方法。样品中加入同位素内标，用正己烷饱和的乙腈超声提取，凝胶渗透色谱净化。以乙腈和含5 mmol/L 甲酸铵和0.1％（v/v）甲酸的水溶液为流动相，目标化合物经 CAPCELL PAK CR（100 mm＆#215;2.1 mm，5μm；SCX-C18（1：4））色谱柱分离，梯度洗脱，流速0.2 mL/min。采用电喷雾电离，选择反应监测（ SRM）正离子模式三级离子监测。内标法定量。膳食类样品中氨基甲酸酯农药的平均加标回收率在60.4％~114％之间；相对标准偏差在3.46％~16.2％范围内；检出限（ LODs）在0.001~0.010 mg/kg之间。应用所建立的方法对2007年第四次中国总膳食研究项目的9类膳食样品基质中的氨基甲酸酯类农药进行了检测，在少量样品中检出了涕灭威和克百威。

液相色谱-四极杆飞行时间质谱法筛查猪肉中5类26种药物残留

建立了同时筛查测定猪肉组织中氟喹诺酮类、磺胺类、有机磷类、β-激动剂类、四环素类5类26种药物残留的液相色谱-四极杆飞行时间质谱分析方法.试样采用QuEChERS前处理方法,样品经酸化乙腈-甲醇（1％乙酸,10％甲醇）提取.提取液以C18分散剂和正己烷净化,氮吹浓缩、定容后过滤膜上机检测.液相色谱以甲醇-水（0.1％甲酸）作为流动相梯度洗脱,C18色谱柱分离;高分辨质谱采用正离子模式检测,以二级质谱特征离子定性,以分子离子精确质量数提取色谱峰面积定量.结果表明26种药物的定量下限为0.4～10μg/kg;加标回收率为56.7％～106.2％,相对标准偏差（RSD）为7.7％～15.8％.方法操作简单、快速、高效,可作为猪肉中26种药物残留的快速筛查检测方法.

超高效液相色谱-串联质谱测定营养强化食品中维生素B_(12)的含量

采用固相萃取（solid phase extraction, SPE）柱对样品中维生素B12进行浓缩与净化,提出了一种可灵敏测定营养强化食品中维生素B12含量的超高效液相色谱-串联质谱（ultra high performance liquid chromatography-tandem mass spectrometry, UPLC-MS/MS）方法,并通过实验考察了不同固相萃取柱对维生素B12含量测定结果的影响.实验结果表明,采用HLB（hydrophile-lipophile balance number）固相萃取柱进行富集与净化,维生素B12在0.5～100.0μg/L浓度范围内与其响应值呈良好的线性关系,检出限为1.0μg/kg,说明该方法具有分析速度快、灵敏度高、重复性好的优点,适用于对营养强化食品中维生素B12含量的测定.

Extending and analysis of X-Code

X-Code is one of the most important redundant array of independent disk （RAID）-6 codes which are capable of tolerating double disk failures. However, the code length of X-Code is restricted to be a prime number, and such code length restriction of X-Code limits its usage in the real storage systems. Moreover, as a vertical RAID-6 code, X-Code can not be extended easily to an arbitrary code length like horizontal RAID-6 codes. In this paper, a novel and efficient code shortening algorithm for X-Code is proposed to extend X-Code to an arbitrary length. It can be further proved that the code shortening algorithm maintains the maximum-distance-separable （MDS） property of X-Code, and namely, the shortened X-Code is still MDS code with the optimal space efficiency. In the context of the shortening algorithm for X-Code, an in-depth performance analysis on X-Code at consecutive code lengths is conducted, and the impacts of the code shortening algorithm on the performance of X-Code in various performance metrics are revealed.

Studies on 3-Amino-4-(1H-tetrazol-5-yl)-furazan:Crystal Structure, Thermal Behavior and Energetic Performance

The structure of 4-amino-3-(5-tetrazolate)-fiirazan(HAFT) was characterized by single crystal X-ray diffraction. The thermal decomposition process of HAFT was investigated by MS-FTIR-DSC-TG coupling technique. The result shows that the exothermic process occurs from 278.7-350℃, with a peak temperature of 324.7℃. The thennal decomposition gaseous products of HAFT are NO2, CO2, HCN, CO, NH3 and H2O. The detonation velocity and detonation pressure of HAFT were calculated by the nitrogen equivalent equation. The detonation velocity of HAFT is 7727.46 m/s, which is higher than that of TNT(7178 m/s). The detonation pressure of HAFT(25.27 GPa) is satisfactory. The sensitivity tests reveal HAFT possesses excellent insensitivities to impact and friction.