Considering participators' risk bias,which is measured by the method of value at risk,the risk constraints in a two-echelon supply chain coordination under buy-back contract is equal to giving the order of an uppe...Considering participators' risk bias,which is measured by the method of value at risk,the risk constraints in a two-echelon supply chain coordination under buy-back contract is equal to giving the order of an upper bound.With a risk-averse dominant enterprise(M)and a risk-neutral non-dominant one(R),the coordination which optimizes the supply chain under the risk constraints is achieved by a penalty mechanism L to reduce R's order.With risk-neutral M and risk-averse R,M can motivate R to increase his order by providing a risk subsidy K,and two cases are discussed.If the risk constraints of R cannot satisfy M's participation constraint to offer K,M will prefer to accept R's order to obtain a sub-optimization solution of the supply chain.Or else,with M's K,R's optimal order just coordinates the supply chain,which is equal to the case without risk bias,and in this situation R's risk bias only affects the profit distribution between the participators.展开更多
Horizontal air-cooled low-pressure hot-wall CVD (LP-HWCVD) system is developed to get highly qualitical 4H-SiC epilayers.Homoepitaxial growth of 4H-SiC on off-oriented Si-face (0001) 4H-SiC substrates is performed at ...Horizontal air-cooled low-pressure hot-wall CVD (LP-HWCVD) system is developed to get highly qualitical 4H-SiC epilayers.Homoepitaxial growth of 4H-SiC on off-oriented Si-face (0001) 4H-SiC substrates is performed at 1500℃ with a pressure of 1.3×103Pa by using the step-controlled epitaxy.The growth rate is controlled to be about 1.0μm/h.The surface morphologies and structural and optical properties of 4H-SiC epilayers are characterized with Nomarski optical microscope,atomic force microscopy (AFM),X-ray diffraction,Raman scattering,and low temperature photoluminescence (LTPL).N-type 4H-SiC epilayers are obtained by in-situ doping of NH 3 with the flow rate ranging from 0.1 to 3sccm.SiC p-n junctions are obtained on these epitaxial layers and their electrical and optical characteristics are presented.The obtained p-n junction diodes can be operated at the temperature up to 400℃,which provides a potential for high-temperature applications.展开更多
Here we report iron(Fe) isotopic data of three pure Fe solution standards(IRMM-014, GSB Fe, and NIST3126a) and five widely used geological reference materials(RMs) from the United States Geological Survey and Geologic...Here we report iron(Fe) isotopic data of three pure Fe solution standards(IRMM-014, GSB Fe, and NIST3126a) and five widely used geological reference materials(RMs) from the United States Geological Survey and Geological Survey of Japan obtained on a Neptune Plus multi-collector–inductively coupled plasma–mass spectrometer(MC-ICP-MS) in our laboratory over the past 3 years. The instrumental mass bias was corrected by three independent methods: sample-standard bracketing(SSB),Ni doping + SSB, and ^(57)Fe–^(58)Fe double spike + SSB.Measurements reveal that both the Ni doping and double spike methods helped calibrate short-term fluctuations in mass bias. Collectively, almost all measurements of RMs yielded δ^(56)Fe within ± 0.05 of recommended values,provided that each sample was measured four times on MC-ICP-MS. For the first time, new recommended values for NIST SRM3126a are reported(δ^(56)Fe = 0.363 ± 0.006,2SE, 95% CI; and δ^(57)Fe = 0.534 ± 0.010, 2SE).展开更多
This paper proposes a simple method to enlarge the estimation range of conventional carrier frequency offset (CFO) estimation methods based on correlations among the identical parts of the preamble. A novel preamble i...This paper proposes a simple method to enlarge the estimation range of conventional carrier frequency offset (CFO) estimation methods based on correlations among the identical parts of the preamble. A novel preamble is designed, which is composed of one regular OFDM training block with even numbers of identical parts and one irregular OFDM training block with odd numbers of identical parts. The initial estimates obtained over the two training blocks are next exploited to jointly estimate the CFO. By elaborately selecting the numbers of identical parts for the two training blocks, the proposed CFO estimator can estimate frequency offset over tens of the subcarrier spacing. Simulation results showed that the proposed CFO estimator satisfies the estimate range requirement for the practical OFDM systems, while achieving a very good estimate performance.展开更多
The nomaal moveout correction is important to long-offset observations, especially deep layers. For isotropic media, the conventional two-term approximation of the normal moveout function assumes a small offset-to-dep...The nomaal moveout correction is important to long-offset observations, especially deep layers. For isotropic media, the conventional two-term approximation of the normal moveout function assumes a small offset-to-depth ratio and thus fails at large offset-to-depth ratios. We approximate the long-offset moveout using the Pade approximation. This method is superior to typical methods and flattens the seismic gathers over a wide range of offsets in multilayered media. For a four-layer model, traditional methods show traveltime errors of about 5 ms for offset-to-depth ratio of 2 and greater than 10 ms for offset-to-depth ratio of 3; in contrast, the maximum traveltime error for the [3, 3]-order Pade approximation is no more than 5 ms at offset-to-depth ratio of 3. For the Cooper Basin model, the maximum oft'set-to-depth ratio for the [3, 3]-order Pade approximation is typically double of those in typical methods. The [7, 7]-order Pade approximation performs better than the [3.3]-order Pade armroximation.展开更多
In response to the downlink synchronization requirements of the user equipment(UE)or third-party radio equipment in fifth-generation(5G)mobile communication systems,a synchronization algorithm of primary synchroni-zat...In response to the downlink synchronization requirements of the user equipment(UE)or third-party radio equipment in fifth-generation(5G)mobile communication systems,a synchronization algorithm of primary synchroni-zation signal(PSS)was designed and developed in the 5G system based on block cross-correlation.According to the new characteristics of the 5G synchronization channel and broadcast channel,starting from the traditional downlink synchronization algorithm of long-term evolution(LTE),the detection performance of the algorithm under a low signal-to-noise ratio(SNR)is improved by introducing an incoherent accumulation,and the new scheme of joint coarse frequency offset estimation is used to improve the frequency offset estimation performance.Finally,the performance of the proposed synchronization algorithm is verified by conducting a simulation on a 5G downlink simulation platform based on MATLAB software.Simulation results show that the improved downlink synchronization algorithm has stable performance in the tapped delay line-C(TDL-C)and additive white Gaussian noise(AWGN)channels with large frequency deviation and low SNR.展开更多
In order to research the danger caused by the rockburst, the electromagnetic emission (EME) in the coal rock was monitored and analyzed. The higher the stress in the coal is, the stronger the deformation and the fai...In order to research the danger caused by the rockburst, the electromagnetic emission (EME) in the coal rock was monitored and analyzed. The higher the stress in the coal is, the stronger the deformation and the failure are, and also the signal of the EME will be. The EME is increased by a relatively large margin before the slight shock and rockburst break out at spot. Therefore, some methods to monitor and forecast the danger of rockburst were proposed, including the critical point and devia- tion values, which was by non-contract method. In the end, the observation of EME in Xingfu was used to analyze and forecast the danger level by the rockburst. Then, the measures were proposed to prevent and cure the rockburst.展开更多
A new preamble structure is designed for wireless LAN based on MIMO OFDM systems, which can be used for both synchronization and channel estimation. Modulatable orthogonal polyphase sequence is utilized in training sy...A new preamble structure is designed for wireless LAN based on MIMO OFDM systems, which can be used for both synchronization and channel estimation. Modulatable orthogonal polyphase sequence is utilized in training symbol design regarding its correlation properties. The time synchronization and channel estimation are achieved by measuring the correlation between the received training sequence and the locally generated training sequence. Repeated training symbols are used to get carrier frequency offset (CFO) estimation. It is shown from the analysis that the accuracy of frequency synchronization is close to the Cramer-Rao lower bound. The training sequences are optimal for channel estimation based on the minimum mean square error (MMSE).展开更多
The paper design a double eccentric mass driven spherical robot, the ball is also subject to eccentric force and inertia force that generate by internal drive units in movement. Due to the unique spherical shell, the ...The paper design a double eccentric mass driven spherical robot, the ball is also subject to eccentric force and inertia force that generate by internal drive units in movement. Due to the unique spherical shell, the robot in the dynamic state transition process, Friction cannot offset the robot motion state change due to internal driving motion error of small units. In order to make linear movement of the spherical robot that can smooth start, stop and speed control, the paper design a method for linear motion driven spherical robot with double eccentric mass control. The improved driving eccentric mass of robot total mass ratio is larger, that can provide the eccentric torque and inertia moment more, the robot has higher motion velocity.展开更多
In this paper, we consider Variational Iteration Method (VIM) and q-Homotopy Analysis Method (q-HAM) to sotve me partial differential equation resulted from Fingero Imbibition phenomena in double phase flow throug...In this paper, we consider Variational Iteration Method (VIM) and q-Homotopy Analysis Method (q-HAM) to sotve me partial differential equation resulted from Fingero Imbibition phenomena in double phase flow through porous media. We further compare the results obtained here with the solution obtained in [ 12] using Adomian Decomposition Method. Numerical results are obtained, using Mathematica 9, to show the effectiveness of these methods to our choice of problem especially for suitable values ofh and n.展开更多
Collaborative f iltering, as one of the most popular techniques, plays an important role in recommendation systems. However,when the user-item rating matrix is sparse,its performance will be degenerate. Recently,domai...Collaborative f iltering, as one of the most popular techniques, plays an important role in recommendation systems. However,when the user-item rating matrix is sparse,its performance will be degenerate. Recently,domain-specific recommendation approaches have been developed to address this problem.The basic idea is to partition the users and items into overlapping domains, and then perform recommendation in each domain independently. Here, a domain means a group of users having similar preference to a group of products. However, these domain-specific methods consisting of two sequential steps ignore the mutual benefi t of domain segmentation and recommendation. Hence, a unified framework is presented to simultaneously realize recommendation and make use of the domain information underlying the rating matrix in this paper. Based on matrix factorization,the proposed model learns both user preferences of multiple domains and preference selection vectors to select relevant features for each group of products. Besides, local context information is utilized from the user-item rating matrix to enhance the new framework.Experimental results on two widely used datasets, e.g., Ciao and Epinions, demonstrate the effectiveness of our proposed model.展开更多
It is difficult for normal moveout(NMO)correction of shallow long offset of vertical transversely isotropic medium,as seismic event after conventional NMO correction experienced strong stretching and distortion due to...It is difficult for normal moveout(NMO)correction of shallow long offset of vertical transversely isotropic medium,as seismic event after conventional NMO correction experienced strong stretching and distortion due to interleaving of signal.Even using higher order non-hyperbolic NMO correction,it still cannot get the right results.This paper aims to improve the accuracy of NMO correction.Based on the analysis of conventional NMO correction method and previous optimization move-out equation,we use longitudinal optimization method to correct seismic event.The results of the theoretical model and the real data show that our method can completely remove NMO stretching and greatly improve correction accuracy.展开更多
From the viewpoints of population,resources,environment and economic-social development,we establish the models of accounting for resource and environmental costs and coordinated(or relative coordinated) development...From the viewpoints of population,resources,environment and economic-social development,we establish the models of accounting for resource and environmental costs and coordinated(or relative coordinated) development degrees between economic growth and resources and the environment using the evaluation method of ecosystem service value.Synergistic effects between regional economic growth and resources and the environment in the Yangtze River Economic Zone was analyzed and driving forces were analyzed by regression of partial least squares.We found that from 1983 to 2012,resource and environmental costs in the Yangtze River Economic Zone(including seven provinces and two municipalities) increased from 4736.55 trillion CNY to 15 359.45 trillion CNY and corresponding weights dropped from 31.1% to 19.7% compared to the national level.The degree of coordinated development rose from 0.295 to 1.506,higher than the national average.In the years 1983,1993 and 2003,the main factor that drove the coordinated development of regional economic growth,resources and the environment was low level resource and environmental costs.With continuous increases in primary and tertiary industrial added values after 2012,the advantage of the Yangtze River Economic Zone has weakened.In the future,provinces should improve the rules and regulations on planning and implementing main functional areas,promote adjustment of industrial structure,restore ecology,improve resource utilization efficiency and reduce environmental loss costs to enhance quality of economic development and promote the coordinated development of regional economic growth and resources and the environment.展开更多
In this study we characterized and investigated the specific phenomenon of "companion drops" in the drop-ondemand(DOD) ink jetting process.A series of simulations based on a piezoelectric DOD printhead syste...In this study we characterized and investigated the specific phenomenon of "companion drops" in the drop-ondemand(DOD) ink jetting process.A series of simulations based on a piezoelectric DOD printhead system is presented,adapting the volume-of-fluid(VOF) interface-capturing method to track the boundary evolution and model the interfacial physics.The results illustrate the causality between the generation of companion drops and droplet deviation behavior,as well as their close correlations with ink jetting straightness and printing accuracy.The characteristics of companion drops are summarized and compared with those of satellite drops.Also,a theoretical mechanism for the generation of companion drops is presented,and their effects and behaviors are analyzed and discussed.Finally,the effects of critical factors on the generation of companion drops are investigated and characterized based on variations in the printable pressure range.Recommendations are given for the suppression of companion drops and for the improvement of printing accuracy.展开更多
基金The National Natural Science Foundation of China(No.70671025)the National Key Technology R&D Program of China during the 11th Five-Year Plan Period(No.2006BAH02A06)
文摘Considering participators' risk bias,which is measured by the method of value at risk,the risk constraints in a two-echelon supply chain coordination under buy-back contract is equal to giving the order of an upper bound.With a risk-averse dominant enterprise(M)and a risk-neutral non-dominant one(R),the coordination which optimizes the supply chain under the risk constraints is achieved by a penalty mechanism L to reduce R's order.With risk-neutral M and risk-averse R,M can motivate R to increase his order by providing a risk subsidy K,and two cases are discussed.If the risk constraints of R cannot satisfy M's participation constraint to offer K,M will prefer to accept R's order to obtain a sub-optimization solution of the supply chain.Or else,with M's K,R's optimal order just coordinates the supply chain,which is equal to the case without risk bias,and in this situation R's risk bias only affects the profit distribution between the participators.
文摘Horizontal air-cooled low-pressure hot-wall CVD (LP-HWCVD) system is developed to get highly qualitical 4H-SiC epilayers.Homoepitaxial growth of 4H-SiC on off-oriented Si-face (0001) 4H-SiC substrates is performed at 1500℃ with a pressure of 1.3×103Pa by using the step-controlled epitaxy.The growth rate is controlled to be about 1.0μm/h.The surface morphologies and structural and optical properties of 4H-SiC epilayers are characterized with Nomarski optical microscope,atomic force microscopy (AFM),X-ray diffraction,Raman scattering,and low temperature photoluminescence (LTPL).N-type 4H-SiC epilayers are obtained by in-situ doping of NH 3 with the flow rate ranging from 0.1 to 3sccm.SiC p-n junctions are obtained on these epitaxial layers and their electrical and optical characteristics are presented.The obtained p-n junction diodes can be operated at the temperature up to 400℃,which provides a potential for high-temperature applications.
基金supported by the National Natural Science Foundation of China(41473016)the State Key Laboratory of Geological Processes and Mineral Resources
文摘Here we report iron(Fe) isotopic data of three pure Fe solution standards(IRMM-014, GSB Fe, and NIST3126a) and five widely used geological reference materials(RMs) from the United States Geological Survey and Geological Survey of Japan obtained on a Neptune Plus multi-collector–inductively coupled plasma–mass spectrometer(MC-ICP-MS) in our laboratory over the past 3 years. The instrumental mass bias was corrected by three independent methods: sample-standard bracketing(SSB),Ni doping + SSB, and ^(57)Fe–^(58)Fe double spike + SSB.Measurements reveal that both the Ni doping and double spike methods helped calibrate short-term fluctuations in mass bias. Collectively, almost all measurements of RMs yielded δ^(56)Fe within ± 0.05 of recommended values,provided that each sample was measured four times on MC-ICP-MS. For the first time, new recommended values for NIST SRM3126a are reported(δ^(56)Fe = 0.363 ± 0.006,2SE, 95% CI; and δ^(57)Fe = 0.534 ± 0.010, 2SE).
基金Project supported by the Hi-Tech Research and Development Pro-gram (863) of China (No. 2003AA12331007) and the National NaturalScience Foundation of China (No. 60572157)
文摘This paper proposes a simple method to enlarge the estimation range of conventional carrier frequency offset (CFO) estimation methods based on correlations among the identical parts of the preamble. A novel preamble is designed, which is composed of one regular OFDM training block with even numbers of identical parts and one irregular OFDM training block with odd numbers of identical parts. The initial estimates obtained over the two training blocks are next exploited to jointly estimate the CFO. By elaborately selecting the numbers of identical parts for the two training blocks, the proposed CFO estimator can estimate frequency offset over tens of the subcarrier spacing. Simulation results showed that the proposed CFO estimator satisfies the estimate range requirement for the practical OFDM systems, while achieving a very good estimate performance.
基金supported by the National Natural Science Foundation of China(Nos.41130418 and 41374061)the National Major Project of China(No.2011ZX05008-006)and the Youth Innovation Promotion Association CAS(No.2012054)
文摘The nomaal moveout correction is important to long-offset observations, especially deep layers. For isotropic media, the conventional two-term approximation of the normal moveout function assumes a small offset-to-depth ratio and thus fails at large offset-to-depth ratios. We approximate the long-offset moveout using the Pade approximation. This method is superior to typical methods and flattens the seismic gathers over a wide range of offsets in multilayered media. For a four-layer model, traditional methods show traveltime errors of about 5 ms for offset-to-depth ratio of 2 and greater than 10 ms for offset-to-depth ratio of 3; in contrast, the maximum traveltime error for the [3, 3]-order Pade approximation is no more than 5 ms at offset-to-depth ratio of 3. For the Cooper Basin model, the maximum oft'set-to-depth ratio for the [3, 3]-order Pade approximation is typically double of those in typical methods. The [7, 7]-order Pade approximation performs better than the [3.3]-order Pade armroximation.
基金The Social Development Projects of Jiangsu Science and Technology Department(No.BE2018704).
文摘In response to the downlink synchronization requirements of the user equipment(UE)or third-party radio equipment in fifth-generation(5G)mobile communication systems,a synchronization algorithm of primary synchroni-zation signal(PSS)was designed and developed in the 5G system based on block cross-correlation.According to the new characteristics of the 5G synchronization channel and broadcast channel,starting from the traditional downlink synchronization algorithm of long-term evolution(LTE),the detection performance of the algorithm under a low signal-to-noise ratio(SNR)is improved by introducing an incoherent accumulation,and the new scheme of joint coarse frequency offset estimation is used to improve the frequency offset estimation performance.Finally,the performance of the proposed synchronization algorithm is verified by conducting a simulation on a 5G downlink simulation platform based on MATLAB software.Simulation results show that the improved downlink synchronization algorithm has stable performance in the tapped delay line-C(TDL-C)and additive white Gaussian noise(AWGN)channels with large frequency deviation and low SNR.
文摘In order to research the danger caused by the rockburst, the electromagnetic emission (EME) in the coal rock was monitored and analyzed. The higher the stress in the coal is, the stronger the deformation and the failure are, and also the signal of the EME will be. The EME is increased by a relatively large margin before the slight shock and rockburst break out at spot. Therefore, some methods to monitor and forecast the danger of rockburst were proposed, including the critical point and devia- tion values, which was by non-contract method. In the end, the observation of EME in Xingfu was used to analyze and forecast the danger level by the rockburst. Then, the measures were proposed to prevent and cure the rockburst.
文摘A new preamble structure is designed for wireless LAN based on MIMO OFDM systems, which can be used for both synchronization and channel estimation. Modulatable orthogonal polyphase sequence is utilized in training symbol design regarding its correlation properties. The time synchronization and channel estimation are achieved by measuring the correlation between the received training sequence and the locally generated training sequence. Repeated training symbols are used to get carrier frequency offset (CFO) estimation. It is shown from the analysis that the accuracy of frequency synchronization is close to the Cramer-Rao lower bound. The training sequences are optimal for channel estimation based on the minimum mean square error (MMSE).
文摘The paper design a double eccentric mass driven spherical robot, the ball is also subject to eccentric force and inertia force that generate by internal drive units in movement. Due to the unique spherical shell, the robot in the dynamic state transition process, Friction cannot offset the robot motion state change due to internal driving motion error of small units. In order to make linear movement of the spherical robot that can smooth start, stop and speed control, the paper design a method for linear motion driven spherical robot with double eccentric mass control. The improved driving eccentric mass of robot total mass ratio is larger, that can provide the eccentric torque and inertia moment more, the robot has higher motion velocity.
文摘In this paper, we consider Variational Iteration Method (VIM) and q-Homotopy Analysis Method (q-HAM) to sotve me partial differential equation resulted from Fingero Imbibition phenomena in double phase flow through porous media. We further compare the results obtained here with the solution obtained in [ 12] using Adomian Decomposition Method. Numerical results are obtained, using Mathematica 9, to show the effectiveness of these methods to our choice of problem especially for suitable values ofh and n.
基金supported in part by the Humanity&Social Science general project of Ministry of Education under Grants No.14YJAZH046National Science Foundation of China under Grants No.61402304the Beijing Educational Committee Science and Technology Development Planned under Grants No.KM201610028015
文摘Collaborative f iltering, as one of the most popular techniques, plays an important role in recommendation systems. However,when the user-item rating matrix is sparse,its performance will be degenerate. Recently,domain-specific recommendation approaches have been developed to address this problem.The basic idea is to partition the users and items into overlapping domains, and then perform recommendation in each domain independently. Here, a domain means a group of users having similar preference to a group of products. However, these domain-specific methods consisting of two sequential steps ignore the mutual benefi t of domain segmentation and recommendation. Hence, a unified framework is presented to simultaneously realize recommendation and make use of the domain information underlying the rating matrix in this paper. Based on matrix factorization,the proposed model learns both user preferences of multiple domains and preference selection vectors to select relevant features for each group of products. Besides, local context information is utilized from the user-item rating matrix to enhance the new framework.Experimental results on two widely used datasets, e.g., Ciao and Epinions, demonstrate the effectiveness of our proposed model.
文摘It is difficult for normal moveout(NMO)correction of shallow long offset of vertical transversely isotropic medium,as seismic event after conventional NMO correction experienced strong stretching and distortion due to interleaving of signal.Even using higher order non-hyperbolic NMO correction,it still cannot get the right results.This paper aims to improve the accuracy of NMO correction.Based on the analysis of conventional NMO correction method and previous optimization move-out equation,we use longitudinal optimization method to correct seismic event.The results of the theoretical model and the real data show that our method can completely remove NMO stretching and greatly improve correction accuracy.
基金Project of Humanities and Social Sciences of Ministry of Education in China(No.14YJAZH112)Social Sciences Planning Project of Liaoning(No.L13BJL019)
文摘From the viewpoints of population,resources,environment and economic-social development,we establish the models of accounting for resource and environmental costs and coordinated(or relative coordinated) development degrees between economic growth and resources and the environment using the evaluation method of ecosystem service value.Synergistic effects between regional economic growth and resources and the environment in the Yangtze River Economic Zone was analyzed and driving forces were analyzed by regression of partial least squares.We found that from 1983 to 2012,resource and environmental costs in the Yangtze River Economic Zone(including seven provinces and two municipalities) increased from 4736.55 trillion CNY to 15 359.45 trillion CNY and corresponding weights dropped from 31.1% to 19.7% compared to the national level.The degree of coordinated development rose from 0.295 to 1.506,higher than the national average.In the years 1983,1993 and 2003,the main factor that drove the coordinated development of regional economic growth,resources and the environment was low level resource and environmental costs.With continuous increases in primary and tertiary industrial added values after 2012,the advantage of the Yangtze River Economic Zone has weakened.In the future,provinces should improve the rules and regulations on planning and implementing main functional areas,promote adjustment of industrial structure,restore ecology,improve resource utilization efficiency and reduce environmental loss costs to enhance quality of economic development and promote the coordinated development of regional economic growth and resources and the environment.
基金Project supported by the National Key Technology R&D Program(No. 2011BAD01B03)the Key Project of Science and Technology Program of Zhejiang Province (No. 2009C11099)the Zhejiang Provincial Natural Science Foundation (No. Y1110230)
文摘In this study we characterized and investigated the specific phenomenon of "companion drops" in the drop-ondemand(DOD) ink jetting process.A series of simulations based on a piezoelectric DOD printhead system is presented,adapting the volume-of-fluid(VOF) interface-capturing method to track the boundary evolution and model the interfacial physics.The results illustrate the causality between the generation of companion drops and droplet deviation behavior,as well as their close correlations with ink jetting straightness and printing accuracy.The characteristics of companion drops are summarized and compared with those of satellite drops.Also,a theoretical mechanism for the generation of companion drops is presented,and their effects and behaviors are analyzed and discussed.Finally,the effects of critical factors on the generation of companion drops are investigated and characterized based on variations in the printable pressure range.Recommendations are given for the suppression of companion drops and for the improvement of printing accuracy.